ANALYZE BUSINESS MODELS FOR IMPLEMENTATION AND OPERATION OF A STATEWIDE GNSS RTN FHWA/MT-22-004/9922-807 Final Report prepared for THE STATE OF MONTANA DEPARTMENT OF TRANSPORTATION in cooperation with THE U.S. DEPARTMENT OF TRANSPORTATION FEDERAL HIGHWAY ADMINISTRATION October 2022 prepared by Ahmed Al-Kaisy Sajid Raza Rafael Teixeira Benjamin Meyer Montana State University Bozeman, MT R E S E A R C H P R O G R A M S You are free to copy, distribute, display, and perform the work; make derivative works; make commercial use of the work under the condition that you give the original author and sponsor credit. For any reuse or distribution, you must make clear to others the license terms of this work. Any of these conditions can be waived if you get permission from the sponsor. Your fair use and other rights are in no way affected by the above. Analyze Business Models for Implementation and Operation of a Statewide GNSS-RTN Final Report Prepared by Ahmed Al-Kaisy, Ph.D., PE – Professor & Program Manager Rafael Teixeira, EIT – Graduate Research Assistant Sajid Raza – Graduate Research Assistant Benjamin Meyer – Research Assistant of the Western Transportation Institute College of Engineering Montana State University Bozeman, MT 59717-4250 Prepared for the MONTANA DEPARTMENT OF TRANSPORTATION in cooperation with the U.S. DEPARTMENT OF TRANSPORTATION FEDERAL HIGHWAY ADMINISTRATION October 2022 TECHNICAL REPORT DOCUMENTATION PAGE 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA/MT-22-004/9922-807 4. Title and Subtitle 5. Report Date Analyze Business Models for Implementation and Operation of a Statewide GNSS- October 2022 RTN 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Ahmed Al-Kaisy, ORCID: 0000-0003-1198-0975 Rafael Teixeira, ORCID: 0000-0003-4314-0962 Sajid Raza, ORCID: 0000-0002-8223-1085 Benjamin Meyer, ORCID: 0000-0002-9447-0817 9. Performing Organization Name and Address 10. Work Unit No. Western Transportation Institute College of Engineering 11. Contract or Grant No. Montana State University MDT Contract # 9922-807 Bozeman, MT 59717-4250 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Research Programs Final Report (December 2020 – October Montana Department of Transportation (SPR) 2022) 2701 Prospect Avenue 14. Sponsoring Agency Code PO Box 201001 5401 15. Supplementary Notes Conducted in cooperation with the U.S. Department of Transportation, Federal Highway Administration. This report can be found at https://www.mdt.mt.gov/research/projects/planning/gnss.aspx DOI: https://doi.org/10.21949/1518323 Recommended Citation: Al-Kaisy, A., Teixeira, R., Raza, S., & Meyer, B. (2022). Analyze Business Models for Implementation and Operation of a Statewide GNSS-RTN (FHWA/MT-22-004/9922-807). Helena, MT: Montana Department of Transportation. https://doi.org/10.21949/1518323 16. Abstract The Global Navigation Satellite System (GNSS), commonly known as the global positioning system, has become one of the fastest- growing emerging technologies delivering location services to various sectors. The applications of geospatial data span every sphere of modern-day science and industry where geographical positioning matters. The list includes navigation, agriculture, surveying, construction, transportation, forestry, mining, and many others. The accuracy and precision of geospatial data using the GNSS Real- Time Network (RTN) technology enable advanced applications in many fields where geospatial data is used; and open the doors for new applications such as the emerging autonomous systems in transportation, mining, and agriculture. This research project is intended to provide information that would help the state’s efforts in the planning and implementation of the Montana GNSS-RTN system. Four major tasks were completed for this project, namely; state-of-the-art review, state-of-the-practice assessment, characterizing Montana existing GNSS-RTN infrastructure, and identifying and cataloging viable business models for statewide GNSS-RTN systems. 17. Key Words 18. Distribution Statement Geospatial data, Location data, Real time network, Global navigation No restrictions. This document is available through the satellite system, Global positioning system, GNSS-RTN, GPS, National Technical Information Service, Springfield, VA Reference stations, CORS, Location coordinates, Corrections. 22161. 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 140 pages ii DISCLAIMER STATEMENT This document is disseminated under the sponsorship of the Montana Department of Transportation (MDT) and the United States Department of Transportation (USDOT) in the interest of information exchange. The State of Montana and the United States assume no liability for the use or misuse of its contents. The contents of this document reflect the views of the authors, who are solely responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the views or official policies of MDT or the USDOT. The State of Montana and the United States do not endorse products of manufacturers. This document does not constitute a standard, specification, policy or regulation. ALTERNATIVE FORMAT STATEMENT Alternative accessible formats of this document will be provided on request. Persons who need an alternative format should contact the Office of Civil Rights, Department of Transportation, 2701 Prospect Avenue, PO Box 201001, Helena, MT 59620. Telephone 406-444-5416 or Montana Relay Service at 711. iii TABLE OF CONTENTS LIST OF FIGURES .................................................................................................................. vi LIST OF TABLES ................................................................................................................... vii ACRONYMS AND ABRECIATIONS ................................................................................... viii EXECUTIVE SUMMARY .........................................................................................................1 1. INTRODUCTION ...............................................................................................................3 2. LITERATURE REVIEW ....................................................................................................4 2.1 TECHNOLOGY ...........................................................................................................5 2.2 RECENT ADVANCEMENTS IN POSITION DATA CORRECTIONS .......................9 2.3 APPLICATIONS ........................................................................................................ 10 2.3.1 Transportation ...................................................................................................... 11 2.3.2 Agriculture ........................................................................................................... 12 2.3.3 Construction ........................................................................................................ 13 2.3.4 Surveying ............................................................................................................ 14 2.4 GNSS-RTN BUSINESS MODELS ............................................................................. 15 2.5 SYSTEM DESIGN ..................................................................................................... 22 2.6 SUMMARY................................................................................................................ 26 3. STATE-OF-THE-PRACTICE ASSESSMENT ................................................................. 27 3.1 GNSS-RTN OWNERS/OPERATORS SURVEY ........................................................ 27 3.1.1 Survey Results ..................................................................................................... 28 3.1.2 SUMMARY OF RTN OWNERS/OPERATORS SURVEY.................................. 45 3.2 VENDORS/MANUFACTURERS INTERVIEWS ......................................................... 47 3.2.1 TopCon ................................................................................................................ 47 3.2.2 Leica .................................................................................................................... 52 4. EXISTING INFRASTRUCTURE ..................................................................................... 58 4.1 MONTANA CORS INFRASTRUCTURE .................................................................. 58 4.1.1 Montana CORSs by Network ............................................................................... 59 4.1.2 Montana CORSs by Ownership ........................................................................... 60 4.1.3 Montana CORSs by Sampling Rate ...................................................................... 61 4.1.4 Montana CORSs by Communication Type ........................................................... 63 4.2 SUMMARY................................................................................................................ 65 5. IDENTIFY AND CATALOG VIABLE BUSINESS MODELS FOR STATEWIDE GNSS- RTN .......................................................................................................................................... 66 iv 5.1 EXISTING GNSS-RTN BUSINESS MODELS .......................................................... 66 5.1.1 Business Model 1 ................................................................................................. 66 5.1.2 Business Model 2 ................................................................................................. 67 5.1.3 Business Model 3 ................................................................................................. 68 5.1.4 Business Model 4 ................................................................................................. 68 5.1.5 Business Model 5 ................................................................................................. 69 5.1.6 Business Model 6 ................................................................................................. 70 5.1.7 Business Model 7 ................................................................................................. 71 5.1.8 Business Model 8 ................................................................................................. 71 5.2 BUSINESS MODELS: CONCEPTUAL ELEMENTS ................................................ 72 5.2.1 Infrastructure Ownership...................................................................................... 72 5.2.2 Costs .................................................................................................................... 74 5.2.3 User Access Charges ............................................................................................ 75 5.3 GNSS-RTN SYSTEMS: POSSIBLE BUSINESS MODELS ....................................... 76 5.4 HIGH-LEVEL ASSESSMENT OF THE GNSS-RTN BUSINESS MODELS ............. 78 5.5 SUMMARY................................................................................................................ 80 6. CONCLUSIONS AND RECOMMENDATIONS ............................................................. 82 REFERENCES ......................................................................................................................... 86 APPENDIX A: GNSS-RTN Survey Questionnaire ................................................................... 93 APPENDIX B: GNSS-RTN Survey Raw Data ........................................................................ 100 APPENDIX C: Vendors/Companies Interview Questions ........................................................ 112 APPENDIX D: Montana CORSs Geospatial Location and Mounting Type .............................. 121 APPENDIX E: Montana CORS Networks ............................................................................... 124 v LIST OF FIGURES Figure 1. Data Flow in RTN and Configuration of a VRN (image courtesy of Trimble) ..............7 Figure 2. GNSS CORS Network Management Model ............................................................... 17 Figure 3. Schematic Diagram of the Master Control Station ...................................................... 25 Figure 4. U.S. Survey Respondents Map (Map Source: mapchart.net) ....................................... 28 Figure 5. Ownership of RTN (a) Central Facility; (b) CORSs in the Networks .......................... 29 Figure 6. Companies Providing Hardware for CORSs in the U.S. .............................................. 30 Figure 7. Number of CORSs in Each State ................................................................................ 31 Figure 8. GNSS-RTN Coverage in the State .............................................................................. 32 Figure 9. Percent RTN Systems based on CORSs Spacing ........................................................ 33 Figure 10. Accuracy of Statewide GNSS-RTN System .............................................................. 33 Figure 11. Methods Used for Communication between CORSs and Central Facility ................. 34 Figure 12. Products of GNSS-RTN Available to Users .............................................................. 35 Figure 13. Number of Users of Statewide GNSS-RTN System .................................................. 37 Figure 14. Entity Responsible for Various Costs of RTN System .............................................. 39 Figure 15. Revenues of RTN System from User Fees/Charges .................................................. 41 Figure 16. Sources of Funds for RTN Systems .......................................................................... 42 Figure 17. Staff Assigned to RTN System for Daily Operations (In terms of FTE) .................... 43 Figure 18. Incorporation of Existing CORSs in Statewide RTN Systems ................................... 44 Figure 19. Incentives to Owners of Private CORSs ................................................................... 45 Figure 20. Coverage of TopNET Live in North America (Courtesy of TopCon) ........................ 49 Figure 21. Plan of CORSs in Montana ....................................................................................... 51 Figure 22. SmartNet Network Coverage in the U.S. (Courtesy of Smartnetna.com) ................... 54 Figure 23. CORSs in the State of Montana ................................................................................ 59 Figure 24. Montana CORSs with Known Sampling Rate ........................................................... 61 Figure 25. Type of Communication for Stations with Known Information in the MTSRN ......... 65 vi LIST OF TABLES Table 1. Differences of Various Correction Methods ...................................................................8 Table 2. Identified Tasks for RTN Development and Operations ............................................... 19 Table 3. Schedule of CORS-TR Service Fees ............................................................................ 21 Table 4. Rules/Charges for Accessing GNSS-RTN System ....................................................... 38 Table 5. CORSs by Network Affiliation .................................................................................... 62 Table 6. Montana CORSs with Respective Sampling Rate ........................................................ 64 Table 7. Possible GNSS-RTN Business Models ........................................................................ 77 Table 8. Assessment of Possible Business Models Using the Star Scoring Scheme .................... 80 vii ACRONYMS AND ABRECIATIONS Caltrans – California Department of Transportation CMR – Compact Measurement Record CORS – Continuously Operating Reference Station CPC – Central Processing Center DOP – Dilution of Precision DOT – Department of Transportation FA – Free Access GAGE – Geodetic Facility for the Advancement of Geoscience GPS – Global Positioning System GNSS – Global Navigation Satellite System IGS – International GNSS Service MAC – Master Auxiliary Concept MnCORS – Minnesota Continuously Operating Reference Station Network MTSRN – Montana State Reference Network NAVD 88 – North American Vertical Datum of 1988 NAVSTAR – Navigation Satellite Timing & Ranging NCN – NOAA CORS Network NGS – National Geodetic Survey NMEA – National Marine Electronics Association NOAA – National Oceanic and Atmospheric Administration NSRS – National Spatial Reference System viii OPUS – Online Positioning User Service NAD 83 – North American Datum of 1983 NTRIP – Networked Transport of RTCM via Internet Protocol ORGN – Oregon Real-Time GPS Network PPP – Precise Point Positioning RINEX – Receiver Independent Exchange Format RTK – Real-Time Kinematic RTN – Real-Time Network SPU – Seattle Public Utilities SSI – Signal Strength Indicator UC – User Charges UNAVCO – University NAVSTAR Consortium VRN – Virtual Reference Network WSRN – Washington State Reference Network ix EXECUTIVE SUMMARY The Global Navigation Satellite System (GNSS), commonly known as the global positioning system (GPS), has become one of the fastest-growing emerging technologies delivering location services to various sectors. The applications of geospatial data span every sphere of modern-day science and industry where geographical positioning matters. The list includes navigation, agriculture, surveying, construction, transportation, forestry, mining, and many others. The GNSS Real-Time Network (RTN) is a satellite-based positioning system using a network of ground receivers (also called base stations, reference stations, or continuously operating reference stations (CORSs)) to improve the accuracy of corrections in positioning data. The network of reference stations extenuates the atmospheric and satellite orbit biases and improves the accuracy and precision of geospatial positioning through real-time corrections sent from a central processing center to a rover. The utilization of ground sensors enables systems to have a range of 1 to 5 centimeters accuracy in positioning data. Although statewide GNSS-RTN systems have not been around for long, the benefits of this new technology have been proven in the states where it was implemented. Recognizing the significant role and potential benefits this technology brings to the state economy and citizens, the state of Montana is interested in establishing a statewide GNSS-RTN system where accurate and reliable location data is made available throughout the state. To that end, this research project is intended to provide information that would help the state’s efforts in the planning and implementation of the Montana GNSS-RTN system. Specifically, multiple tasks were successfully completed to gather the required information on all aspects of the GNSS-RTN system design, implementation, and operations. A literature review was carried out first where information on GNSS-RTN technology, system design, applications and business models were reviewed and summarized. This task used research articles, government publications, research reports, agency websites, and industry magazine articles to collect and compile information. The following task in the project aimed at screening the state of practice to collect information on the GNSS-RTN practices across the country. An online survey was designed and distributed to the owners/operators of the statewide GNSS-RTN systems in the country. Thirty states, represented 1 by thirty-eight respondents, contributed by submitting the survey. Further, a phone interview was conducted targeting major vendors/manufacturers that provide GNSS-RTN products and services in the US. The survey and interviews collected valuable information on the current state of practice regarding statewide GNSS-RTN systems including network ownership, system attributes and technologies, associated costs, and business models. The next task involved the assessment of all existing GNSS-RTN infrastructure in Montana and identifying aspects such as CORS ownership, sampling rate, current network, station coordinates, and mounting type. This task used data from governmental databases as well as data provided by the Montana Department of Transportation (MDT). It was found that a total of sixty-nine stations were then installed in Montana, with fifty-seven out of the total being publicly owned. The final task aimed at cataloging business models that are used in the current GNSS-RTN practice for providing geospatial location data nationally and internationally. The task provided an overview and identified the advantages and disadvantages of each business model using information collected in the previous project tasks. The information gathered was then used to discuss the conceptual elements of any business model and to provide a high-level assessment of all models identified in this task. This report discusses in detail the work performed on all project tasks and culminates with a summary of findings and recommendations. 2 1. INTRODUCTION The Global Navigation Satellite System, commonly known as the global positioning system, has become one of the fastest-growing emerging technologies delivering location services to various sectors. The applications of geospatial data span every sphere of modern-day science and industry where geographical positioning matters. The list includes navigation, agriculture, surveying, construction, transportation, forestry, mining, and many others. The accuracy and precision of geospatial data using the GNSS-RTN technology enable advanced applications in many fields where geospatial data is used; and open the doors for new applications such as the emerging autonomous systems in transportation, mining, and agriculture. The satellite-based position system, GNSS-RTN, consists of a network of continuously operating reference stations that communicate in real time with a Central Processing Center (CPC). The network receives satellite locational signals that are sent to the CPC where coordinates are corrected and sent to the end user in different formats. Over the years, many public and private entities in Montana established limited networks or individual CORSs seeking access to more accurate geospatial data. Realizing the significant role and potential benefits this technology brings to the state economy and citizens, the state of Montana is interested in establishing a statewide GNSS-RTN system where accurate and reliable location data is made available throughout the state. This research project is intended to provide information that would help the state’s efforts in the planning and implementation of the Montana GNSS-RTN system. Four major tasks were completed for this project. These tasks are: The chapters are: 1. Literature Review, 2. State-of-the-Practice Assessment, 3. Characterize Montana Existing GNSS-RTN Infrastructure, and 4. Identify and Catalog Viable Business Models for Statewide GNSS-RTN The final report consists of six chapters, one chapter for each of the four project tasks listed above, one chapter for the introduction, and another chapter for the major conclusions and recommendations. 3 2. LITERATURE REVIEW With the emergence of the Global Positioning System (GPS) Real-Time Kinematic (RTK) technology in the early 1990s, the use of GPS-RTK has become vital in various applications which require highly accurate positioning in real-time. However, the performance and accuracy of the traditional GPS-RTK are limited due to the distance between a reference station (also called base station or CORS), and a roving receiver (user device). The accuracy and reliability of the measurements degrade with the increase in baseline length (i.e., base-to-rover distance) due to distance-dependent errors such as ionospheric refraction, tropospheric refraction, and to some level, orbit errors. To achieve reliable and accurate results, specifically centimeter-level accuracy in positioning, from the GPS-RTK technique, it is required that the roving receiver (rover) is located within the restricted range (typically in the order of 10 km) of the reference station (1). To overcome the limitation of the baseline length of the traditional GPS-RTK technique and due to advancements in GNSS technology, GNSS Real-Time Network (RTN) concepts were introduced in the mid-1990s (2). GNSS-RTN is a satellite-based positioning system using a network of ground receivers (also called base stations, reference stations, or CORS). The network of reference stations extenuates and alleviates the spatially correlated atmospheric and satellite orbit biases (3) and improves the precision of geospatial positioning through real-time corrections sent from a central processing center to a rover. GNSS-RTN has been increasingly used in the U.S. and around the world for many benefits and applications where high-precision geospatial location data is needed. A GNSS-RTN benefits multiple public and private entities that utilize GPS survey and GIS mapping services. Geographic information system (GIS) mapping, survey-grade applications, precision agriculture, emergency management, construction engineering projects, infrastructure asset management, environmental studies, municipal infrastructure, and navigation are only some of the important applications of the GNSS-RTN system. As the accuracy and precision of positioning data continue to enhance with developments in technology and such data or services become more accessible to the users, more applications can utilize the positioning data that these methods and systems can produce. Geographical data are not only used in measuring ground distances and mapping topography (4), but they have become vital in various fields such as safety and sustainability with uses including structural health monitoring, natural disaster management and prevention (5), and precise localization and accurate navigation of autonomous vehicles (6). 4 These innovative and diverse applications drive the technological advancement towards precise and accurate measurements that the RTN system would produce. This chapter presents the results of the literature review project task which aims at screening the state of knowledge regarding the GNSS-RTN technology nationally and internationally. This chapter discusses various aspects regarding GNSS-RTN systems such as technology, technological improvements, applications, business models for implementation and operations, and system design. Those aspects are discussed in the following sections of this chapter. 2.1 TECHNOLOGY With the evolution of technology and advancement in satellite systems, the use of GNSS-RTN technology for the correction of positioning data has developed into commercially viable systems available today. The advent of GNSS-RTN made it possible to achieve highly accurate positioning over a distance of 70-100 km (7) (reference station spacing should generally not exceed 70-100 km) from the base station. Continuously operating reference stations (CORS) were long used as a source of differential GPS (DGPS) and RTK corrections, mainly for surveying and mapping applications. New applications for these reference stations have recently emerged; Utah’s TurnGPS and the North Carolina Geodetic Survey have considered CORS as a source for weather monitoring, while Japan and Washington have used CORS to study plate tectonics and provide early warning of earthquakes (8). Schrock acknowledged that, although the RTN technology was reasonably new, it had already had a significant impact on many fields and showed a tremendous increase in popularity. In the U.S., there were 18 systems at the beginning of 2005 and 40 in 2006 (9). RTN is a satellite-based positioning system that uses ground sensors such as CORS to improve the precision of corrections. One of the most significant issues with satellite-based positioning systems is calibration. Without ground sensors, signal ambiguities can sometimes deny satellite-based positioning systems a precise measurement. Ground sensors provide more reference stations to the system, allowing the system to overcome the ambiguities and generate corrections in real-time for any location and provide higher precision. The utilization of ground sensors will enable systems to have a range of 5 1 to 5 centimeters in accuracy, compared to a range of 1 to 10 meters when sensors are not utilized (9). The US Department of the Interior Bureau of Reclamation provided an overview of how data flows in an RTN (10). Data starts flowing when the rover connects to a virtual reference network (VRN) and sends a National Marine Electronics Association (NMEA) GGA string to a centralized server. The string has information about the location of the rover and the accuracy of the data being sent. The server uses nearby reference stations to compute corrections to send back to the rover. Finally, the rover receives the corrections and uses them in real-time as shown in Figure 1. The benefits and limitations of an RTN system were also discussed. Benefits included eliminating the need to establish a base station, integrity self-checking by the RTN, and a common reference coordinate system. Limitations included the high cost to establish and maintain such a system and accuracy being limited by the quality of the cellular phone connection (10). Rydlund and Densmore discussed the use of Global Navigation Satellite Systems (GNSS) technology by the U.S. Geological Survey in applications such as monitoring natural hazards, ensuring geospatial control for climate and land-use change, and gathering information necessary for investigative studies on water, the environment, energy, and ecosystems (11). The GNSS technology essentially provides three-dimensional positioning as a function of the North American Datum of 1983 ellipsoid. A GNSS survey is approachable in two different ways: post-processed positioning for static observations or real-time corrections. Field equipment can consist of one or multiple receivers that create a network. In the post-processed approach, the data is processed through the Online Positioning User Service (OPUS) – a universally accepted utility maintained by the National Geodetic Survey (NGS). The real-time approach can be described as a roving receiver augmented by a single-base station receiver, or a single-base real-time (RT) survey. The real-time network (RTN) method is more efficient: CORSs are used instead of a single-base receiver (11). 6 Figure 1. Data Flow in RTN and Configuration of a VRN (image courtesy of Trimble) Henning discussed reasons to use network RTK (N-RTK) (12). Reasons included not needing reconnaissance and recovery of passive control, no time lost setting up and breaking down a base station, reduced labor cost, regional inter-GIS compatibility, continual accuracy and integrity monitoring, and no distance correlated error. A description of NGS’s role in supporting network RTK is also presented, such as providing real-time uncorrected data streams (a process for officially recognizing RTNs as being compliant with the National Spatial Reference System (NSRS) within 2 centimeters horizontal and 4 centimeters vertical) and assessing site conditions for current or potential station sites to ensure optimal performance (12). In a recent article, Luccio provided an overview of the recent developments in the GNSS positioning systems (8). In search for a centimeter-level positioning, the automotive industry, smart consumer devices, and other forms of automation were behind the recent boom in correction services. Two established methods are analyzed: RTK and precise point positioning (PPP). In 7 RTK, a receiver obtains correction data from a single base station or a reference network. In PPP, the data is accessible worldwide, but initialization can take up to 30 minutes. Some PPP correction services only provide corrections for satellite clock and orbit errors, which lowers the accuracy in measurements. A third hybrid method is presented: combining PPP’s global access with the accuracy and quick initialization times of near-RTK. A network of reference stations, located within 150 kilometers of each other, collect data and calculate both satellite and atmospheric corrections. Results from the analysis of these methods are shown in Table 1 provided by GPS World magazine (8). Table 1. Differences of Various Correction Methods Note: Adapted from GPS World Magazine, (8) Richter provided a brief introduction to the development of PPP (13). Compared to RTK and RTN, PPP allows for accurate geolocations from remote regions, dismissing the need for established reference stations and networks. This is different from RTK where users need to manage their own reference stations and stay within the radio range of control points. RTN, on the other hand, eliminates the need for individual reference stations and allows for larger coverage, but users are still limited to the extent of the network. PPP allows for much larger coverage with precision to the centimeter level, but the time to access the data is not favorable (13). 8 2.2 RECENT ADVANCEMENTS IN POSITION DATA CORRECTIONS Since the 1990s, positioning technology has vastly improved. Whether that be with new constellations, new methods, or better hardware, GNSS and RTN improvements mean that the technology can provide positions more accurately than they were 25 years ago. New constellations increase the number of available satellites at any given time (38), new methods can account for error correction to yield more reliable results, and better hardware can increase accessibility to the system by decreasing the cost of entry. Karaim discussed the most serious sources of errors affecting GNSS signals (14). These errors differ in many ways and are grouped based on their similarities. Clock errors are related to differences between the receiver and satellite clocks while signal propagation errors are related to the shift between the satellite and the receiver’s location caused by the rotation of the earth. Examples of signal propagation errors include the Sagnac effect (errors caused by the earth’s rotation during signal propagation time between the satellite and the receiver), ionospheric errors (errors caused by the propagation time delay when the signal passes through the ionosphere), tropospheric errors (errors caused by the signal passing through the dry gases and water vapor of the troposphere), and multipath errors (errors caused when the signal reaches the receiver’s antenna via more than one path). System errors are the result of the nature of the system: examples include satellite orbital errors and receiver noise. Errors that are imposed by the service provider are called intentional error sources. These include selective availability, signal jamming, and signal spoofing. While not a source of error, the dilution of precision (DOP) factor (a factor related to the geometry of visible satellites) can affect the accuracy of the final results (14). Allahyari et al. evaluated the accuracy of shorter-duration RTN observations by analyzing data collection from two National Geodetic Survey (NGS) surveys in South Carolina and Oregon. The study explored the horizontal and vertical accuracy of real-time observations as a function of observation duration, examined the influence of the inclusion of Globalnaya Navigazionnaya Sputnikovaya Sistema (GLONASS) observables, compared results from real-time kinematic (RTK) positioning using a single-base station versus a network of base stations, and assessed the effect of baseline length on accuracy (15). An observational study was conducted in thirty-eight passive marks using RTN over a varying observation time range of 5 – 15s. The study found the range 180 – 300s to be the optimal real-time observation duration. The data from the network of 9 stations showed to be more accurate and precise. The inclusion of GLONASS observables was beneficial in obtaining more fixed solutions at longer baseline lengths (15). De Angelis et al. considered the issue of acquiring high-accuracy locations in urban scenarios and proposed the use of GNSS and mobile cellular networks to overcome the issue (16). The study suggests the combination of the time-difference-of-arrival (TDOA) technique measurements gathered from the cellular network with GNSS measurements. The data is integrated with the extended Kalman filter algorithm. Real measurements were used to simulate the results. The study showed an increase in location accuracy when the number of visible satellites is not adequate (16). NGS discussed efforts to build a tool – dubbed the “RTN Alignment Service” (RAS) – to provide checks to RTN users on how well the RTN is aligned to the National Spatial Reference System (NSRS) (17). Previously, RTN operators reported coordinates within the NSRS datums NAD 83 or NAVD 88. However, there was no way offered by NGS to check if any biases existed between the NSRS and RTN-based data. Such a system would work in two parts: the first part would align RTN base stations to the NSRS, while the second part would align the rover to the NSRS. The second part requires further study, and thus such a system is still under development (17). Jackson et al. evaluated the use of low-cost GNSS receivers within an RTN to investigate claims of centimeter-level accuracy (18). The study was done to predict future demand on the Minnesota Continuously Operating Reference Station (MnCORS) RTN. Five low-cost receivers ($540 or lower) were tested in rural, suburban, and urban environments using static and dynamic applications. The study found that the receivers could perform well in static applications in rural areas depending on equipment expectations, but the receivers performed below expectations in the other environments and the dynamic applications. Multifrequency receivers were recommended for future study in dynamic applications as they have better continuity and availability for fixed- integer solutions (18). 2.3 APPLICATIONS Besides the primary application of RTN to enable accurate positioning relative to the National Spatial Reference System (NSRS), RTN has played a pivotal role in advancing multidisciplinary investigations including in earth sciences and atmospheric sciences. The scope of applications of 10 RTN is multifaceted and growing with time. The GNSS technology and RTN are increasingly being utilized for a wide range of applications such as transportation, agriculture, construction, and surveying, by providing users with instant and highly accurate position information over distances of several tens of kilometers. According to a report on the CORS network in Vermont by NOAA/NGS (19), the VECTOR (Vermont Enhanced CORS and Transmission Of Real-time corrections) network of Vermont is used by land surveyors, engineering firms, GIS professionals, foresters, state and non-state agencies such as the agency of Natural resources and department of agriculture, University of Vermont, Maine, and New Hampshire, Lyndon and Johnson State Colleges, army corps of engineers, National weather service and other federal and international agencies, etc. In addition, several COR stations along the western border of Vermont stream data to the New York Department of Transportation (NY DOT) which includes it in the New York CORS network NYSNET. The data of VECTOR is also streamed to a private RTN with correction and made available to users in Vermont for a subscription. Other vendors have also shown interest to acquire and include real-time VT data in their networks (19). In the following sections, a brief description is provided for some of the applications in major fields where RTN data is used. 2.3.1 Transportation The application of RTN in transportation is perhaps one of the most obvious of all the major applications of GNSS-RTN. It can assist in accurate positioning of land transportation and provide accurate information to sea and aerial transportation for navigation. Specht et al. investigated the use of GNSS data to reproduce the trajectory of a railway geometric layout (20). The study used different methods of measurements in a comparative analysis. Measurements were made using tachometry, mobile satellite measurements, and satellite measurements using a measurement trolley (continuous RTK). An algorithm was used to enable the assessment of the compliance of satellite measurements with tachometer measurements. The continuous RTK method presented a mean value of residuals at a 5mm level. The GNSS measurements were found to be an efficient alternative to tachometer measurements (20). Liu et al. investigated problems with multisensory system integration implemented in land-vehicle 11 navigation (LVN) and studied the use of new smoothing algorithms to integrate systems and improve the accuracy of LVN (21). The Kalman Filter (KF) is frequently used in LVN multisensory configuration as a base for the integration of the Inertial Navigation System and Global Positioning System (INS/GPS). The study presented a method to solve issues with GPS signal loss in urban centers and - when INS is used in a stand-alone mode - inertial navigation errors are amplified with rapid-time. This method involves the use of secondary smoothing algorithms such as the Rauch-Tung-Striebel (RTS) smoother as part of a two-filter smoothing (TFS) algorithm. The performance of the RTS smoother compared and the TFS algorithm was validated using two different LVN INS/GPS datasets (21). Toledo-Moreo et al. investigated challenges for navigation systems such as lane-level positioning and map matching (22). For more beneficial results, the study strives for a navigation system in which lane-level positioning is achievable and its quality can be monitored with integrity parameters. Measurements from a GNSS receiver, an odometer, and a gyroscope are combined in the proposed system. Data from enhanced digital maps, capable of storing road information, is also used. The feasibility of the proposed system was provided through a set of experiments that took place in France and Germany which showed good results in terms of positioning, map matching, and integrity (22). Maaref et al. investigated the use of LiDAR data combined with pseudoranges drawn from unknown cellular towers to overcome GNSS-challenged environments (23). The study considered a vehicle-mounted LiDAR sensor that enters an environment where GNSS signals are of no use. An extended Kalman filter is used to fuse the pseudoranges produced by the receiver equipped in the vehicle to cellular towers, aid the LiDAR odometry, and estimate the vehicle’s 3-D position. The errors are corrected simultaneously through the difference between the positions of the cellular towers and the vehicle. Simulated and experimental results found a 68% reduction in the 2-D root- mean-square error over solely LiDAR odometry (23). 2.3.2 Agriculture Giannaros et al. introduced the assimilation of GNSS zenith tropospheric delay (ZTD), derived from more than 48 stations of the Hellenic GNSS network, into the operational numerical weather 12 predictions (NWPs) of the National Observatory of Athens, Greece (24). The study used the Weather Research and Forecasting (WRF) model to collect data over the dry and wet season of 2018; seven high-impact precipitation events occurred over that period. The use of ZTD along with the WRF model showed a positive impact. The results were more accurate especially during heavy rainfall events and improved the simulation of precipitation in the dry season (24). Due to the lack of a precipitable water vapor (PWV) dataset, Zhao et al. focused on generating an hourly PWV dataset for China using GNSS observations from the Crustal Movement Observations Networks of China (25). The study combined zenith total delay parameters (estimated by GAMIT/GLOBK software and validated with an average root-mean-square error of 4-5 millimeters), the zenith hydrostatic delay, and a weighted average temperature of atmospheric water vapor (calculated at the GNSS stations using the improved global pressure and temperature 2 wet (IGPT2w) model with an average root-mean-square error of 3.32 K). Between 2011 and 2017, the average root-mean-square error values of the generated PWV dataset were found to be less than 3 millimeters in China, which was validated using the corresponding AERONET and radiosonde data at specific stations (25). Yan et al. investigated the feasibility of the usage of the Signal Strength Indicator (SSI) recorded using data from GNSS receivers to estimate soil moisture (26). The study compared the in-situ soil moisture and an estimated SSI phase. A relationship was determined and used to estimate 36 days of soil moisture data. A correlation coefficient of approximately 0.7 between the SSI phase and the in-situ soil moisture was found, and a root-mean-square estimation error of soil moisture lower than 9.9%. The results showed that the use of SSI data is feasible for estimating soil moisture (26). 2.3.3 Construction Burak and Lysko studied the use of RTN technology to provide additional control over marking works and to develop practical recommendations to measure the axes of main buildings (27). Theoretical and experimental studies were performed to ensure accuracy. The studies measured the axes from two basis lines taken by the GNSS receiver in a way that coincides with the x- and y-axes of the object’s general plan. The investigation was made on the inherent basis, 10 kilometers from the permanent station, to minimize sporadic errors. The study found that the required 13 accuracy is provided when the main axes of construction netting coincide with the fixing baseline with a dual-frequency GNSS receiver (27). Another study by Burak and Lysko investigated the accuracy of measuring relatively short distances for performing survey, planning, and engineering geodesy work with dual-frequency GNSS receivers by performing seven experiments at varying locations (28). The investigation took place in the city of Ivano-Frankivsk, Ukraine, and was made on the inherent basis to minimize sporadic errors. The hypothesis claims the general dispersion of two normally distributed groups that receive an optimum quantity of necessary measurements when building lines are less than 200 meters to be equal. The results showed a range of accuracy depending on the location of network points and defined the designation of building vectors to be more accurate with GNSS receivers under different conditions of observations (28). Chang et al. (29) laid out a plan for the implementation of intelligent compaction (IC). IC is a technology that uses vibratory rollers outfitted with RTK receivers, measurement systems, and feedback systems to compact aggregates more uniformly. In hot mix asphalt (HMA), nonuniform compaction can result in a shorter pavement life or premature pavement failure. IC technology can identify and correct for substandard patches of pavement, resulting in a long-lasting and more consistent pavement. RTK is required for IC technology and is recommended to have a fixed position that equates to a precision of 1-3 centimeters. An RTN can send corrections to a rover for use with IC (29). 2.3.4 Surveying Krzyzek used RTN measurements, along with other methods, to determine the cartesian coordinates of buildings (30). During tests, the alternative of using RTN surveys to determine the location of a building was presented to surveying contractors. The HMM algorithm was used to harmonize various surveying methods used in the study. The study resulted in the determination of X, Y coordinates at the level of 0.03 meters, with the building corner’s mean location errors at the 0.02-meter level (30). Continuously operating reference stations (CORS) have long been used as a source of differential GPS (DGPS) and RTK corrections, mainly for surveying and mapping applications. New 14 applications for these reference stations have recently emerged; Utah’s TurnGPS and the North Carolina Geodetic Survey have considered CORS as a source for weather monitoring, while Japan and Washington have used CORS to study plate tectonics and provide early warning of earthquakes (8). U.S. Geological Survey used GNSS technology in various applications such as monitoring natural hazards, ensuring geospatial control for climate and land-use change, and gathering information necessary for investigative studies on water, the environment, energy, and ecosystems (11). Gabara and Sawicki investigated the accuracy of an unmanned aerial vehicle (UAV) for photogrammetry using an RTN (31). Eight hundred and fifty-one photos were used to generate a digital site model using a bundle block adjustment (BBA). The coordinates of control points noted during the flight were compared to coordinates generated from the BBA and error was calculated based on the differences between these coordinates and US and Polish technical accuracy requirements. Planimetric (XY) coordinates fell within the accepted 0.10-meter root mean squared (RMS), while vertical (Z) coordinates fell within the accepted 0.05-meter RMS (31). Yu et al. compared the use of N-RTK to the use of RTK and an accelerometer for monitoring dynamic displacement in bridges (32). An experiment was conducted at a local bridge where three sensors were set up: an RTK receiver, N-RTK receiver, and accelerometer. The results showed that N-RTK is a valid alternative to RTK; N-RTK was able to provide millimeter-level accuracy and successfully identify the frequency of the bridge. Additionally, in general, N-RTK had a lower standard deviation and a higher correlation coefficient with the accelerometer than RTK did. Furthermore, it was observed that the N-RTK measurements generally had less noise. The authors noted that the use of N-RTK was also beneficial in reducing the cost of monitoring by 80 percent while still providing a high level of robustness and reliability (32). 2.4 GNSS-RTN BUSINESS MODELS An RTN can be an excellent investment, but its success largely depends on the business plan to ensure implementation and sustainable system operation while meeting the needs of all users and stakeholders. In the following section, best practices for different aspects of a business plan are summarized. Overviews of existing business or operations plans of existing RTN are also 15 highlighted. Goodliss et al. performed a cost-benefit analysis on high-accuracy location (HALO) services (33). The analysis was performed by placing dollar values on various levels of injuries and predicting how many injuries could be prevented with the implementation of different technologies requiring HALO services such as curve speed warning, forward collision warning, and intersection collision warning. Certain mobility benefits were estimated as well. It was estimated that between $160 billion and $320 billion in benefits could come from HALO services over a horizon time of 22 years, with over 90 percent of those being safety benefits. These benefits were compared against the cost of infrastructure for an N-RTK system. By interviewing N-RTK operators, the authors were able to estimate a 22-year horizon cost per base station ranging between $220 thousand and $615 thousand ($570 thousand to $1.6 million with annual contingency costs included). Costs such as hardware, software, maintenance, and rent were included. If such a system were to cover the entire U.S., system implementation would cost between $1.6 billion and $4.4 billion (33). Hale et al. examined the development of a management model for CORS networks within Australia (34). A successful model will ensure national consistency among other CORS networks, consider professions beyond surveying, and remove legal barriers to using these networks for cadastral surveys. A potential model is shown in Figure 2. The data service providers and value- added resellers would buy the raw data at wholesale rates and sell the data to users. Value is added either through providing access to many different networks under one roof or by building other services to be used with the data. Such a system would require a nationally consistent coordinate system. This model would also help navigate legal barriers by supporting legal certification of the National Measurement Act and providing guidance to cadastral surveyors on best practices. Additional benefits include streamlining agreements with site hosts and GNSS suppliers, managing human connections (which ensures system continuity), and accounting for IT systems (34). 16 Figure 2. GNSS CORS Network Management Model Note: Adapted from “Validating a model for CORS network management”, (34) Rizos and Van Cranenbroeck considered a business model for an RTK provider that broadcasts full corrected coordinates to the user, not just corrections (35). The authors suggest that some providers do not charge for services because they cannot guarantee reliable coordinates. If providers can broadcast coordinates computed within the required reference frame, they can guarantee accurate results and justify charging a fee for services. If providers simply broadcast corrections and leave it to the user to compute the coordinates, they cannot justify a fee because the accuracy of the coordinates cannot be guaranteed by the provider. For this to work, the network needs not only geodesy specialists but also IT specialists. The added value could also be provided by a separate entity using raw data licensed for use by the provider. However, such a service requires bi-directional communications between the rover and central server (35). Martin undertook a review of six existing statewide RTN systems in areas including ownership, funding, system operations and maintenance, and system design (36). In most cases, the RTN was owned by the state department of transportation (DOT) with station ownership varying between the public and private sectors. Software is typically owned by the state while hardware ownership 17 varies between private entities and the state. Most stations are located on public land. Most operating costs are funded from the state, and while return on investment was not formally investigated in most states, Florida did calculate $964,360 in annual savings for its DOT. Most networks do not charge for access. System operations typically come from either the DOT or a separate state IT department, and generally required between 1.3 to 2 full-time equivalent (FTE) employees. Responsibility for station maintenance is typically that of the station owner, which varies between network partners and the state. Station construction standards are typically consistent with those set forth by NGS, although there is some variance. All networks surveyed are aligned with the NSRS and typically bring stations from other states into the network. For access to corrections, each network requires an internet connection as a basic requirement. Stations are connected to the network via either wired or wireless connection. No network engaged in a public-private partnership. Recommendations from states included seeking federal grants, partnering with local agencies that may have needed infrastructure, involving stakeholders in network implementation, and keeping the network separate from public sector IT. One network unique in terms of its ownership and system operations is the Washington State Reference Network (WSRN) (36). Washington State Reference Network (WSRN) outlined its ownership and operations structure on its website (37). The WSRN is a cooperative of about 80 different partners spanning the public and private sectors. The network is owned by the cooperative; joining the cooperative requires contributing a station to the network. Access to static files is free, while access to real-time corrections requires being either a partner or a subscriber, which requires an annual fee to help cover operations costs. Seattle Public Utilities hosts the central processing center for the network, provides stations to the network, and serves as a point of contact for WSRN matters. Central Washington University is also an important partner in providing infrastructure, expertise, and the backup central processing center (37). Weber et al. outlined a business plan for a potential geo-positioning cooperative between Idaho and Montana (38). Organizational structures, service priorities, and administrative needs, among other topics, were discussed. A mission of providing high-quality GNSS data to as broad of a user base as possible was established. An initial, informal partnership structure was proposed to be followed by a permanent structure that is legally and administratively simple and contains a 18 dedicated management office. The most important service priority was determined to be the operation of a multi-state control point database, followed by RTN set-up and operations and assisting the user community in using the system. Administratively, it was determined that manager, administrative support, and technical personnel roles would need to be filled, with potential options ranging from using host organization resources to student interns to volunteers. Tasks for RTN development and operations were also established; Table 2 below shows all the steps identified. Furthermore, preliminary budgets were also generated; over five fiscal years, $1,146,500 was estimated to be needed for the cooperative. Risk management tactics were also discussed; detailed work plans, effective project monitoring, competent personnel, being ready for delays, and formal commitments were identified as ways of reducing risk (38). Table 2. Identified Tasks for RTN Development and Operations Note: Adapted from “Business Plan for Development of Regional Geopositioning Cooperative for Idaho and Montana”, (38) Ojigi discussed an implementation plan for a GNSS-CORS system in Nigeria to provide RTK corrections services (39). A central data processing facility is proposed in the capital with regional and backup servers in six other cities. Three reference stations are proposed for each of the 36 19 states and capital territory to provide a total of 111 stations. The estimated cost for this system was ₦740 billion (equivalent to $3.70 billion in 2015 dollars). Furthermore, two possibilities for revenue were investigated: charging a fee for access to the system or treating the system as a utility and providing access for free. Charging a fee for access to the system would require client-server-based corrections in order to provide value to the product. The value comes from the provider controlling the results, whereas simply delivering corrections to the user provides no added value to the services because hardware and software errors may be present in the results. The provider can also free the users from having to learn complicated techniques or software (39). Jenssen et al. presented an overview of CORSnet-NSW, an RTN owned by the Government of New South Wales in Australia (40). At the time of writing, 75% of the state was within the maximum range of a base station. CORSnet-NSW also engages in data-sharing agreements with neighboring states to provide adequate coverage. The Government owns the equipment and conducts all the maintenance and operations. Three FTE staff work on the network within the surveying unit while other staff within the surveying unit provide 1.5 FTE for surveying, research, and management. Raw data is sold to three companies, while CORSnet-NSW subscriptions are sold through 16 authorized providers. Raw data is also made available to various positioning efforts including the Asia-Pacific Reference Frame (40). Bakici et al. (41) reviewed the business plan for the Turkish National Permanent GNSS Network – Active (CORS-TR). The CORS-TR system consists of 146 stations spread around Turkey and Northern Cyprus. The system is jointly operated by the General Directorate of Land Registry and Cadastre (GDLRC) and General Command Mapping (GCM); the terms of their partnership are outlined in a formal agreement and an executive board was established to make technical and administrative decisions. The executive board holds the power to determine access fees; principles of access for educational institutions; principles of maintaining and marketing the system; and plans for investment, research, and development. System setup costs $6.6 million, while operating costs can vary. Operating costs are covered by service fees; Table 3 shows a schedule of these fees. In 2016, revenue totaled $1.5 million, while operating costs totaled $270,000. Most users (63.96% of the 8455 total users as of February 2017) are from the private sector (41). 20 Table 3. Schedule of CORS-TR Service Fees TYPE OF SERVICE DATA TYPE FEES EXPLANATION Registration Fee - $42.00 One-Off RTK Fees Web-RTK $28.00 Monthly RTK Fees Web-RTK $210.00 Annual RTK Fees Web-DGPS $14.00 Monthly RTK Fees Web-DGPS $105.00 Annual Static Data RINEX 1 sec. $0.14 Station/Hour Static Data RINEX 30 sec. Free Station/Day Note: Adapted from “Business Model of CORS-TR (TUSAGA-AKTIF)”, (41) The North Carolina Geodetic Survey (NCGS) gave an overview of the economic benefits of the North Carolina Continuously Operating Reference Stations (NC CORS) network compared to its costs (42). Using data on industry spending patterns from IMPLAN in 2015, NCGS estimated that the system provided $360 million in annual economic benefits to North Carolina. This is compared to the annual operating cost of $625,000 per year. Furthermore, using data from the North Carolina Office of State Budget and Management, NCGS estimated the system to generate $3.5 million in state taxes annually, making the system self-sustaining in a sense. Access to the real-time network requires $500 for the first two ports followed by $250 for each additional port (42). Laaksonen (43) undertook a design of a business model for the FinnRef system operated by the National Land Survey of Finland (NLS). At the time of the study, there were two companies operating positioning services in Finland. The study considered the effects of NLS allowing the public to access data from its CORS facilities. The study concluded that allowing access to the data for a fee and access to an NLS-operated positioning service for free would provide the greatest value by making the barrier of entry for other positioning services lower while increasing competition in that sector. The proliferation of new positioning services would serve to drive down the costs of such services, thereby benefiting the consumer (43). 21 2.5 SYSTEM DESIGN The RTN system design is just as important as the business plan. The system design will ultimately dictate system establishment and operating costs, operating principles, and quality of service provided. While the best way to design the system is to get potential stakeholders involved early in the process, there are common practices that can be referenced. This section provides an overview of these practices as well as summaries of designs of existing networks. Henning et al. (44) detailed guidelines for the design of a GNSS real-time network (RTN). Topics covered included station construction and system planning and design. Stations should be constructed with an uninterruptible power supply and with physical disturbances such as high winds in mind. When mounted on buildings, antenna placement should be prioritized over receiver placement. Ground mounts are generally more expensive but more flexible with location. When designing the system, it is important to identify goals by involving stakeholders in the design process. With spacing, general guidelines call for 50 - 70-kilometer baselines, although this can change based on cost or usage. Some stations should be submitted for acceptance into the national CORS program; this ensures that the system is consistent with the NSRS. If using existing infrastructure, priorities of the station owner should be identified to make sure they line up with the goals and priorities of the network. Stations should be designed with multiple forms of communication to provide redundancy. When designing the central processing center (CPC), it is important to get IT involved as they will ultimately set policies regarding security and system access. It is also important to establish a mirror CPC to ensure service and to possibly offset load from the main CPC. The integrity of the RTN needs to be monitored to ensure proper precision and accuracy of corrections (44). Denys et al. (45) examined certain aspects of an N-RTK system that must be considered during system design. One critical aspect is communications services; available methods include wired and wireless connections. Wired connections are typically used to connect stations to the central server and are preferred over wireless connections. Wireless connections, such as through mobile networks, are typically used to connect users to stations. However, cell coverage may be limited or nonexistent in certain areas, and increased latency can lead to decreased solution accuracy. Stations should be placed between 50 and 70 kilometers away from each other. The network should be aiming for a precision much greater than that required by the user to reduce error propagation. 22 Furthermore, current day coordinates should be used rather than a set reference frame to account for regional motion differences. The goal is to provide corrections or a spatial model in near-real- time with biases modeled (45). Schrock (46) went over best practices for real-time GNSS networks. Communications from the station to the central processing center (CPC) should have low latency (less than 2-second latency), the bandwidth to handle multiple data streams, the ability to handle remote operation and maintenance, and the ability to receive static observations after outages. Communication methods should be contracted under guaranteed service agreements. The number of stations communicating via satellite should be limited due to latency issues. The CPC should consist of quality hardware and software capable of accepting station observations, processing observations in real-time and statically, tracking system health and accuracy, and administering accounts for system access. Access to the network from rovers should be provided through Standard for Networked Transport of RTCM via Internet Protocol (NTRIP) casters which can serve hundreds of users at a time while maintaining system security. RTNs should, at a minimum, be able to provide corrections via the Virtual Reference Station (VRS) method in either RTCM Version 3 or CMR+ formats, single-base corrections, network integrity monitoring, NTRIP casters and account management for system access, ionospheric condition monitoring, tropospheric condition monitoring, field results monitoring, static-post files for postprocessing, a static file request system, and a web portal. The network should provide corrections based on the official national or global reference frame but have the capability to provide corrections in other reference frames. Receivers should be specifically designed for CORS use and antennas should be labeled as geodetic-grade (46). Janssen (47) compared two different N-RTK methods and their required bandwidths. In the VRS concept, the rover sends its position to the server, which treats the coordinates as a virtual base station. The server then calculates corrections and sends them to the rover. The baseline between the rover and the virtual base station is short, so the rover can use the corrections and apply single- base RTK algorithms to obtain a position. This method has the advantage of requiring less bandwidth because the server models atmospheric effects but has the downsides of requiring two- way communication and issues with legal traceability (47). There is also the Master Auxiliary Concept (MAC) - as Leica Geosystems (2005) explains, a reference station acts as a master station that sends its corrections and coordinates to the rover, while auxiliary stations transmit corrections 23 and coordinate differences based on the master station (48). From there, the rover can perform calculations to get a final position. The MAC allows for one-way communication and legal traceability but has the downside of offloading calculations to the rover. Janssen went on to measure the bandwidth required of each concept. While the MAC required more bandwidth, common radios can support the bandwidth requirements. Janssen concludes by recommending the MAC from the perspective of a CORS operator since the user is supplied with raw data and surveys can be legally traced back to a physical reference station (48). Prescott et al. (49) outlined an operations plan for a network of GPS reference stations to study earthquake hazards. The stations were designed to operate continuously and with high precision. As part of the operations plan, guidelines for site selection and station construction were drafted. Sites should have an adequate view of the sky; be secure from theft or vandalism; be on firm, natural ground; and have sufficient power and communications equipment available nearby. An adequate view of the sky is one where there are no obstructions above 45-degree elevation, nothing above the expected antenna location that is within 3 meters of the expected antenna location, no power lines within 100 meters, and away from flat, reflective surfaces that may serve as sources of multipath. Five years of tree growth should be accounted for when considering unacceptable obstructions. At each site, the contractor was to install a metal box with 2 110-volt AC outlets and a plug for radio link and metal conduit containing power, phone, and cable from the antenna to the receiver (49). Lapine and Wellslager (50) discussed part of the process that went into designing the real-time network for the South Carolina Geodetic Survey (SCGS). GNSS receivers can receive data from both GPS and GLONASS satellites. Station spacing was desired to be 70 kilometers to provide centimeter-level accuracy on a 24-hour basis even if other stations in the network were offline. Antenna mounts are generally built to NGS standards. Additionally, mounts near the coast were designed to withstand category 3 hurricanes. Sites for stations were based on Internet access, building construction materials, and backup power access. For these reasons, most stations ended up on South Carolina Department of Transportation property. Where building construction materials were not to NGS standards, special steel towers were constructed to mount the stations to (50). Yildirim et al. (51) discussed the planning and infrastructure for the TUSAGA-Aktif (CORS-TR) 24 network. An initial prototype system covering an area of 300 x 150 kilometers was set up to test different techniques, hardware, and software. From the test, system planners determined that optimal station locations would be in city centers, on stable ground, easily accessible, close to the energy and communications sources, and less than 100 kilometers apart from each other. Stations mounted on roofs were set on galvanized steel, while stations mounted on the ground were set on concrete pillars. The master control station carries out functions such as computing reference station coordinates, modeling errors, storing data, and providing Web services. See Figure 3 for a schematic setup of the master control station. The system can broadcast corrections using either the VRS, MAC, or Flächen-Korrektur Parameter (FKP) methods. Reference stations are connected to the control stations via a duplex ADSL connection along with a GPRS/EDGE connection. Each reference station sends about 700 bytes of data per second to the control stations (51). Figure 3. Schematic Diagram of the Master Control Station Note: Adapted from “The Turkish CORS Network (TUSAGA-Aktif)”, (51) Wisconsin Department of Transportation (WisDOT) provided an overview of the design and technology of the Wisconsin Continuously Operating Reference Stations (WISCORS) Network 25 (52). A hundred stations are set approximately 50 kilometers apart from each other. Most stations are capable of utilizing the GPS, GLONASS, and Galileo constellations. Along with providing real-time corrections, station data is collected, stored, and made available via a web server for post- processing. Access to the webserver is password-protected, but users can register through the webserver. Each station consists of a mounting system (concrete pillar or building mount), GNSS receiver and antenna, coaxial cable, lightning suppressor, plastic conduit to carry the coaxial cable from the antenna to the lightning suppressor, enclosure for equipment, and backup battery (52). 2.6 SUMMARY This chapter presented the results from the literature review project task. The review offered a brief overview of the technology behind a GNSS-RTN and how users may utilize the system. While the main focus of the review was examining methods for implementing a business plan; other aspects of the systems in relation to technology, applications, and system design were also considered in this review. The review is divided into five parts: technology, recent advancements in GNSS data corrections, applications, GNSS-RTN business plans, and system design. Technology, advancement in GNSS data correction, and applications are briefly discussed to provide familiarity with the system and its potential uses. GNSS-RTN business plans are summarized, and best practices and guidelines are presented. Finally, system design considerations are reviewed by examining characteristics of existing systems and reviewing available guidance. 26 3. STATE-OF-THE-PRACTICE ASSESSMENT A state-of-practice screening has been conducted as part of the project “Analyze Business Models for Implementation and Operation of a Statewide GNSS-RTN.” This screening involved a practice survey that was sent to all statewide GNSS-RTN system owners/operators as well as interviews with major GNSS-RTN vendors/manufacturers. First, the online survey was conducted targeting owners/operators of the GNSS-RTN systems in the United States to evaluate various aspects of the statewide RTN system, RTN ownership and business model, system attributes including CORS types and spacing, the precision of location data, etc. Second, the vendors/manufacturers which provide products and services for developing, operating, and maintaining statewide GNSS-RTN systems were interviewed to gain more precise information about the costs and technologies involved in system development and gather more information about the different ways these vendors provide services to different GNSS-RTN system operators. This chapter is organized into two parts. The first part discusses the methodology, results, and findings from the online survey which aimed to examine the state of practice concerning establishing, operating, managing, and maintaining the statewide GNSS-RTN systems in different states. The second part of the chapter discusses the information gathered from the interviews with major technology vendors/manufacturers. A summary of the findings is presented at the end of the chapter. 3.1 GNSS-RTN OWNERS/OPERATORS SURVEY To better understand the current practice in establishing and operating the GNSS-RTN systems at the national level, a questionnaire survey was developed and sent to the GNSS-RTN system owners/ operators at different states across the U.S. The survey consisted of 23 questions divided into two sections: i) System general information, and ii) System operation. The questionnaire survey was created and administered using Qualtrics survey software. Thirty-eight respondents submitted the survey representing 30 states (4 states with two responses and 4 states with no GNSS-RTN system). The duplicate responses were removed and the response from the manager of GNSS-RTN was considered. Only five responses were incomplete, however, they provided answers for the majority of survey questions, thus included in the analysis. Out of the 30 respondents from the 30 different states, as shown in Figure 4, twenty-seven responses were from public agencies and only three responses were from private entities. The following section of this 27 chapter discusses the results of the questionnaire. A copy of the questionnaire is provided in APPENDIX A. Figure 4. U.S. Survey Respondents Map (Map Source: mapchart.net) 3.1.1 Survey Results This section discusses the results of the questionnaire survey and is divided into two sections, one for the system general information and one for system operations and services. 3.1.1.1 GNSS-RTN System General Information The results presented in this section summarize the information gathered from all 30 responses from the thirty different States. It is imperative to know about the ownership of the GNSS-RTN system and its components. When asked about the ownership of the RTN central facility and the CORSs, 80% of respondents 28 mentioned the central facility is owned by the public agencies in the corresponding states. Regarding the ownership of CORSs in respective states, 40% of respondents indicated that the CORSs are owned by both public and private entities, while around 57% of respondents indicated that the CORSs are owned solely by the public agency. Most of the state Departments of Transportation (DOT) own the central facility and operate the statewide RTN system. They also own most but not all of the CORSs within their respective networks. The results for system ownership are shown in Figure 5a and 5b. (a) (b) Figure 5. Ownership of RTN (a) Central Facility; (b) CORSs in the Networks 29 To obtain information on the vendors/suppliers of the GNSS-RTN products and services acquired for RTN systems in different states, questions were asked about the companies which supplied hardware for CORSs, hardware for the central processing facility, and the software for the RTN system. The complete response options were: Trimble, Leica, NavCon, TopCon, and Others (where respondents can write in text). It was allowed to select multiple options if more than one company has provided products or services to the statewide RTN system. Based on the responses from RTN operators, the top three companies that provided hardware for CORSs in the U.S. are Trimble, Leica, and TopCon as shown in Figure 6. The same three companies were the major suppliers of software and hardware for the central facility of the GNSS-RTN systems. Few DOTs are using their data servers to host the central facility data processing and storage. It is essential to know about the current practices of both the coverage area of the RTN system in each state and the inter-CORS spacing which is an important determinant of the accuracy of the spatial data. When asked “Total number of CORSs that are part of statewide GNSS-RTN system (including CORSs owned by entities other than the GNSS-RTN system owner/operator), respondents reported numbers which varied between 10 stations in Connecticut and 240 stations in Texas. Figure 6. Companies Providing Hardware for CORSs in the U.S. 30 These results, shown in Figure 7, clearly show that larger states have a higher number of CORSs in their systems which is anticipated. Moreover, the survey question “Your GNSS-RTN system provides coverage in the whole State or part of the State?” yielded results of ‘whole State coverage’ in approximately 86% of responses, and ‘part of the State coverage’ in 14% of responses as illustrated in Figure 8. Figure 7. Number of CORSs in Each State 31 Figure 8. GNSS-RTN Coverage in the State One of the important factors influencing the economic feasibility and the accuracy of the statewide GNSS-RTN system is the spacing between the CORSs. The lower the spacing between CORSs, the higher the accuracy of the spatial data and the higher the cost of the GNSS-RTN system. The current owners/operators of GNSS-RTN systems were asked about the average spacing between CORSs in their respective RTN systems, and the results of their responses are summarized in Figure 9. The results show that approximately 90% of statewide GNSS-RTN systems in the U.S use CORSs with a spacing of less than 70 km. The GNSS-RTN system owners/operators were asked about the accuracy of the statewide RTN systems, and the results are summarized in Figure 10. Four options were provided which are accuracy of 2-4 cm; 4-6 cm; 6-8 cm; and more than 8 cm. Twenty-seven out of 30 respondents indicated that their statewide RTN system provides an accuracy of 2-4 cm. Two respondents reported accuracy of 4-6 cm, and one respondent skipped this question. This high percentage of responses (90%) for high accuracy in location data (i.e., 2-4 cm) is consistent with the fact that the majority of the statewide GNSS-RTN systems have CORS spacing lower than 70 km as discussed earlier. 32 Figure 9. Percent RTN Systems based on CORSs Spacing Figure 10. Accuracy of Statewide GNSS-RTN System 33 3.1.1.2 System Operations and Services As CORSs need to communicate with the central processing facility for data correction, different communication means or methods can be used to connect the CORSs with the central facility. When asked about the “Communication methods currently in place to connect CORSs to central facility/server,” the respondents were provided with the following response options: mobile cellular network, internet-based communication, radio signal-based, and Others (where respondents can write in text). Based on the responses of the operators/owners of current statewide GNSS-RTN systems in the U.S., most of the networks use the internet or both internet and mobile cellular network for communication between CORSs and the central processing facility. Few states also use radio signals for communication as shown in Figure 11. Figure 11. Methods Used for Communication between CORSs and Central Facility To gather information on products/services provided by the statewide RTN systems to the users, the survey question “Does your GNSS-RTN system provide the following products to users [check all that apply]:” was asked with options of corrected coordinates (Real-time), network corrections (Real-time), post-processed data (Static), and Others (where respondents can write in text). The 34 results of the responses to this question are summarized in Figure 12. The results indicate that approximately 66% of the statewide RTN systems provide corrected coordinates (Real-time), network corrections (Real-time), and post-processed data (Static), whereas approximately 17% of the statewide RTN systems provide only network corrections (Real-time), and post-processed data (Static). Moreover, some statewide RTN systems also provide the following products (responses as Other): - Virtual Rinex - User statistics - Real-time & Historical Tracking of rovers for clients - Online post-processing solutions - Observation streams for science and industry Figure 12. Products of GNSS-RTN Available to Users To obtain information about the users who benefit from the statewide RTN, a question was asked to “Provide the average number of users of your GNSS-RTN system:” separately as total system users; annual subscriptions; less-than-a-year subscriptions; and others. Responses are summarized in APPENDIX B. which shows that Colorado state’s RTN system had the highest number of total 35 users, an average of 10,000 total users. The number of users of statewide RTN in Ohio, Florida, Michigan, and Minnesota varied in a range from approximately 5,000 to 7,700. A few states reported equal numbers of total users and annual subscriptions as shown in Figure 13, indicating that they only offer annual subscriptions to access the network. The statewide GNSS-RTN system provides highly accurate location services to public and private users. To know about the rules and charges of accessing the RTN system, respondents were asked: “Users of your GNSS-RTN access the system [check all that apply]” with the following options: free of cost; annual subscription fee; less-than-a-year subscriptions fee; charges based on access duration; charges based on data-size download; and others (where respondents can write in text). The current statewide RTNs differ in their access rules, however, most of the state DOTs offer free access to the networks. Approximately 60% of statewide GNSS-RTN systems’ access is entirely free of cost for both public and private users. Table 4 summarizes the details of charges/rules for accessing the GNSS-RTN systems in responding states. In California, direct access is only available to Municipalities. Public departments can access data from state-owned stations via the partner California Real-Time Network (CRTN). Colorado DOT offers free access to the public departments and private users pay an annual subscription fee through private vendors. Similarly, the RTN system in Pennsylvania is only accessible for DOT and private users can access private RTN based on the subscription fee. The Utah Reference Network GPS (TURN GPS) requires annual subscriptions to access TURN GPS for location services. The respondents from Washington state reported that users access the network based on annual subscriptions, however, the majority of the users are cooperative partners in the statewide network. As the RTN system is comprised of CORSs and central facility, the CORSs can be managed and maintained by the owner of the central facility or CORSs, or both, while the central facility of the GNSS-RTN system can be managed and maintained by the owner of the statewide GNSS-RTN system or partner with any other entities. To identify the current practices regarding the party responsible for maintenance, IT services, etc., the following question was asked: “Who is responsible for the cost of: user and IT support; communication between central facility and CORSs; maintenance of the central facility; and maintenance of CORSs.” The options provided were: central facility owner, CORSs owner, and others (where respondents can write in text). The results of the responses to these questions are summarized in Figure 14. 36 Figure 13. Number of Users of Statewide GNSS-RTN System 37 Table 4. Rules/Charges for Accessing GNSS-RTN System Charges to Access RTN Response Percent Frequency Annual subscription fee 1 3.6 Annual subscription fee, Less-than-a-year subscriptions fee, 1 3.6 Charges based on access duration Annual subscription fee, Less-than-a-year subscriptions fee 1 3.6 Annual subscription fee, Other, please specify: 2 7.1 Free of cost 17 60.7 Free of cost, Annual subscription fee 1 3.6 Free of cost, Annual subscription fee, Less-than-a-year 1 3.6 subscriptions fee Free of cost, Annual subscription fee, Less-than-a-year subscriptions fee, Charges based on access duration, Other, please 1 3.6 specify: Free of cost, Annual subscription fee, Other, please specify: 1 3.6 Other, please specify: 2 7.1 For user and IT support service costs, the owners of central facilities are responsible for approximately 64% of all the statewide RTN systems. In a few states such as California, Massachusetts, Texas, and Vermont, the state DOTs are operating statewide RTN system with private partners (who own some CORSs), hence, CORSs owners are also sharing the responsibility of the cost of user and IT support services. The central facility and CORSs are connected and communicate primarily via the internet or cellular network or both. These services cost a fair share of the operation costs. In most of the responding states, central facility owners are responsible for the cost of communication services between the central facility and CORSs, however, approximately 22% of respondents reported that CORSs’ owners also share the responsibility of the cost of communication with central facility owners. In a few states including Utah and West Virginia, only CORS owners are responsible for the cost of communication between central facility and CORSs. The GNSS-RTN system needs regular maintenance of the central facility and CORSs. The results of the survey indicate that approximately 85% of central facility owners are responsible for the maintenance costs of the central facility. In Texas, both the central facility’s owner and CORSs’ 38 owners share the responsibility of the cost of maintenance of the central facility. Whereas in Vermont, the central facility owner and the state agency of Digital Services are responsible for the maintenance of the central facility. Furthermore, the maintenance of CORSs is also a responsibility of central facility owners in most of the states (53.6% of total responses). However, CORS owners are also responsible in several states (28.6% of total responses) such as Colorado, Maine, Massachusetts, West Virginia, and Mississippi. In five states including California, Oregon, Texas, Vermont, and Washington, the central facility owners and CORSs’ owners are responsible for the maintenance costs of their own CORSs. Figure 14. Entity Responsible for Various Costs of RTN System To better understand the business model for RTN systems included in this survey, the respondents were asked about the revenues of the RTN system from any users’ fees or subscription charges. A more meaningful way to know about the revenues of the system is to ask in terms of the total system operation costs covered by users' fees. When asked “How much revenues are collected from user fees/charges in terms of total system operation costs,” the respondents provided 39 information that is quite surprising as presented in Figure 15. Most of the state agencies (17 out 26 respondents) reported revenues generated from users’ fees of “0% of total system operation cost” which indicates that these states provide access to the RTN system free of charge for all users. Two states, Tennessee, and Mississippi earn “1% to 20% of total operation cost” of the RTN system from users’ fees. The RTN system in Arizona, Illinois, and Georgia are privately owned networks (AZGPS, AZ; Kara Co. Inc, IL; eGPS Solution Inc, GA) and reported that users’ subscription charges make “60% to 80% of total operation cost”, “80% to 99% of total operation cost”, and “total cost of system operation”, respectively. Furthermore, the revenues obtained from the user fees in the states of Louisiana, Utah, and Washington cover the total cost of RTN system operation. Significant resources are required for establishing, operating, and maintaining the GNSS-RTN system. To get information on funding sources of current statewide GNSS-RTN systems in the United States, questions were asked to specify the funding sources for the establishment of the GNSS-RTN system, its operations, and maintenance, with options provided: Federal funds, State funds, Users/subscription fee, and Others (where respondents can write in text). Many of the GNSS-RTN systems in responding states were established using state funds (11 out of 27 responses), however, 8 RTN systems also received federal funds along with state funds as shown in Figure 16. Only two statewide RTN systems were built on federal funds. Tennessee state RTN system was established using state funds and users’ fees. The Washington state RTN was funded by an initial investment of Seattle Public Utilities, partners’ contributions, and users’ subscription fees. “Other” funding source reported by a respondent (owner of private network) from Georgia is “private business ownership for profit”. 40 Figure 15. Revenues of RTN System from User Fees/Charges Regarding funding sources for the operation of the GNSS-RTN system, somewhat similar responses were received. The operating costs of approximately 50% of statewide RTNs were entirely funded by the respective states. Furthermore, 5 out 27 RTN systems (approximately 20%) also received federal funds along with state funds for regular operations. Only the Tennessee state’s RTN system operating cost was funded by the state funds and users’ subscription fees. The operations of statewide RTN systems in Illinois (a private network), Louisiana, Utah, and Arizona (a private network) were fully funded by users’ charges. The respondent from Washington state reported that the operating cost of the RTN system is mainly funded by users’ fees, however, some partners contribute for software upgrades and other miscellaneous costs. These findings are summarized in Figure 16. 41 Figure 16. Sources of Funds for RTN Systems The GNSS-RTN system requires regular maintenance of CORSs and the central facility. When asked about the funding sources for maintenance purposes, the respondents provided somewhat similar responses as those for the funding source of operation costs. The results are shown in Figure 16. Most of the statewide GNSS-RTN systems are managed and operated in-house by state agencies. This requires assigning resources and staff to oversee the daily operations of the RTN system. It is essential to know the resources and staff (in terms of full-time equivalent - FTE) required for the in-house GNSS-RTN system operation. Therefore, operators of the current statewide RTN systems in various states were asked about the number of FTE staff assigned to the daily operations of the RTN system. The responses indicated that the number of FTE staff assigned for operating the RTN system varied between 0.75 FTE and 5 FTE, however, 34% of responses indicated 1 FTE, 21% reported 2 FTE, and 25% reported 3 FTE. A summary of the responses to this question is illustrated in Figure 17. 42 Figure 17. Staff Assigned to RTN System for Daily Operations (In terms of FTE) Before establishing a larger statewide GNSS-RTN system, some states have a number of existing CORSs owned by different entities such as private consultants, research institutes, municipalities etc. To reduce the initial cost of developing a statewide GNSS-RTN system, it is logical to consider the incorporation of existing CORSs. To gather information on the integration and inclusion of existing CORSs in the statewide GNSS-RTN system surveyed, the respondents were asked if they included existing CORSs in establishing their statewide GNSS-RTN systems. The responses are summarized in Figure 18, illustrating that 14 out of 25 (56%) states have incorporated existing CORSs, 8 out 25 (32%) have not incorporated existing CORSs, 2 respondents (8%) reported that there were no existing CORSs in their states, and one respondent selected ‘Other’ option and reported ‘adjacent states and municipal’. 43 Figure 18. Incorporation of Existing CORSs in Statewide RTN Systems To gather further information on the inclusion of CORSs and incentives provided to the owners of those already existing (private) CORSs, the operators/owners of the 15 statewide GNSS-RTNs that incorporated the existing CORSs were asked if they had been providing any incentives to the owners of the CORSs. Most of the respondents (73%) reported that they did not provide any incentives to the owners of existing CORSs as presented in Figure 19. Some states reported providing incentives to the owners of private CORSs in various forms such as unlimited access to data, access to value-added services, one free subscription per CORS, educational opportunities for schools that host CORSs, and reduced subscription charges. 44 Figure 19. Incentives to Owners of Private CORSs 3.1.2 SUMMARY OF RTN OWNERS/OPERATORS SURVEY A state of practice survey was conducted to learn about the current practices of operating and managing the GNSS-RTN systems and providing accurate location services in different states around the U.S. The survey was sent to the public and private GNSS-RTN owners/operators throughout the 50 States. Thirty-eight respondents submitted the survey representing 30 states (four states with duplicate responses and another four with no RTN system). This chapter presented and discussed the results of the survey of which the major findings are summarized below. ­ Most of the statewide GNSS-RTN systems surveyed are owned by the state Departments of Transportation (DOTs). The DOTs also own most of the CORSs within their respective network. ­ Based on the responses from GNSS-RTN operators, the top three companies that provide GNSS-RTN hardware and services in the U.S. are Trimble, Leica, and TopCon. ­ Most of the statewide GNSS-RTN systems provide coverage throughout the whole state. ­ Approximately 90% of statewide GNSS-RTN systems in the U.S. are based on CORSs 45 with an average spacing of less than 70 km. ­ The accuracy of position data offered by 90% of statewide GNSS-RTN systems is 2-4 cm. ­ Most of the statewide GNSS-RTN systems use either the internet or both internet and mobile cellular network for communication between CORSs and the central processing facility. ­ The statewide GNSS-RTN systems often provide corrected coordinates (Real- time), network corrections (Real-time), post-processed data (Static), and occasionally they may provide virtual Rinex. ­ Approximately 60% of statewide GNSS-RTN systems offer entirely free access to both public and private users. However, several statewide GNSS-RTN systems charge annual subscription fees. ­ The owners of central facilities are responsible for user and IT support service costs in approximately 64% of all the statewide GNSS-RTN systems. In addition, the central facility owners are responsible for the cost of communication services between the central facility and CORSs and for the cost of maintenance of the central facility in most of the GNSS-RTN systems surveyed. ­ Most of the state agencies (17 out 26 respondents) reported that they do not generate revenues from users’ fees. ­ The funding sources for the establishment of most of the statewide GNSS-RTN systems are either only state funds or some federal funds along with state funds. However, the funding sources for the daily operation of GNSS-RTN systems are state funds and users’ fees. ­ To manage and operate an in-house statewide GNSS-RTN system, 1 to 3 FTE staff are required. ­ Approximately 50% of the statewide GNSS-RTN systems did incorporate the already existing CORSs in their networks. Some states provide incentives to the owners of private CORSs in various forms such as unlimited access to data, access to value-added 46 services, one free subscription per CORS, educational opportunities for schools that host CORSs, and reduced subscription charges. 3.2 VENDORS/MANUFACTURERS INTERVIEWS After screening current practices of the statewide GNSS-RTN system, the researchers conducted in-depth interviews with representatives of major GNSS-RTN manufacturers and suppliers to obtain more precise information about the costs, technologies, and services provided by these companies. Based on the survey responses of operators/owners of current statewide GNSS-RTN systems, the top three manufacturers and suppliers were selected including Trimble, Leica, and TopCon. The researchers contacted more than six (06) officials at Trimble office including Trimble Public Relation (PR), and Trimble Sales and Support office via email and phone several times but did not receive any response. The researchers were able to arrange interviews with representatives from the other two manufacturers TopCon and Leica. The interview questions and topics were shared with TopCon Sale’s executive and Leica's Executive officer before the interviews which were conducted via web conferencing. The following subsections discuss in detail the responses of the company representatives to the interview questions. It should be noted that the cost information provided by the representatives during the interviews is only tentative and may be different from the actual cost solicited through a bidding process. The complete set of interview questions is available in APPENDIX C. 3.2.1 TopCon 3.2.1.1 Products and Services The researchers began the survey by asking the TopCon representative about the various product and services along with the costs and other attributes. When asked about the hardware kit for CORSs, hardware for a central facility, and software for the central facility, the respondent reported that the TopCon offers two types of antennas and two types of receivers for CORSs. The cost of a complete kit of hardware for a CORS is approximately $8,500. The central facility hardware consists of data servers and computers for the processing and storage 47 of data. The respondent reported that the central facility can be established using in-house servers or a hosted environment. The cost differential is based on different factors such as short- term and long-term hosting and in-house vs. hosted environment. For in-house central facility establishment, the reported approximate initial cost of servers ranges from $25,000 to $35,000. When asked about the cost of software for central facility servers and processing, the respondent reported that the cost of RTN software depends on the features and functionalities you wish to provide to the customers. For in-house private network establishment, the approximate cost of TopNET PLUS Server software is $54,000 plus $3,200 per CORS in the network (reported by the representative from TopCon). This software has additional charges of $6,000 per year for the annual maintenance of the software. Before establishing the statewide RTN system, the system is designed by professionals based on standards and the required attributes and functionalities such as ubiquity, reliability, and accuracy of location services. System design includes the number of CORSs required to achieve specific accuracy, number of servers, and processing power/CPU required for maximum efficiency. The representative was asked if the company offers design services for the RTN system, the respondent reported different options. TopCon does not offer stand-alone design consulting services, however, it offers online subscription services for the design and positioning of CORSs within the complete network. In addition, TopCon offers training and consulting services for the GNSS-RTN systems solely built by the company. The approximate cost for training client’s employees and setting up software is in the order of $2500 per day on-site for a minimum of 3 days or $250/h for remote services. When asked about building and/or establishing the components of the RTN system including CORSs and central processing facility, the respondent reported that TopCon provides building RTN components as part of building a complete statewide RTN system, in conjunction with hardware/software procurement, and/or in conjunction with system operation contract as well. To gain further information about the network operation services of statewide RTN, a question was asked “Does your company operate GNSS-RTN systems?” with options: operates as stand- alone service, or only for systems designed and built by your company. The respondent mentioned that TopCon does not operate statewide publicly owned networks, however, it operates TopNET Live which is a private network of Topcon. Figure 20 shows the coverage of TopNET Live North 48 America. TopNET Live Global has over 5000 reference stations in the Americas, Europe, Asia, China, and Russia. Topcon incorporates privately owned (third party) CORSs in TopNET Live and provides free subscriptions to the private owners of CORSs. TopNET Live has globally 250 private partners. Moreover, the respondent reported that the subscription fee for the entire west coast is $1300 per year. Figure 20. Coverage of TopNET Live in North America (Courtesy of TopCon) Apart from this information, TopCon has designed a plan of CORSs for the state of Montana as shown in Figure 21. Based on the TopCon estimate, 120 CORSs would be needed for full coverage in the state of Montana. In this figure, CORSs are spaced no more than 70 km which is the required spacing between CORSs for higher accuracy (2-4 cm). The radius of each coverage circle around each CORS is 35 km. Blue CORSs (25 stations) are existing CORSs that are part of the TopNET live, whereas the green CORSs (95 stations) are proposed new stations for the statewide GNSS- RTN system. The representative from TopCon communicated that if the state of Montana wants to be a part of TopNET live, the following incentives would be offered to the state agency (owner of CORSs): i. TopCon will be responsible for hosting Montana CORS and providing real- time location services, which means the state does not need: 49 a. To pay for the software of the central facility. b. In-house server development and expenses. c. To spend on maintenance of the central facility. ii. TopCon would offer two full-time free subscriptions per CORS. iii. The state agency would be able to purchase annual subscriptions for entire west coast coverage at a discounted rate and sell it to private customers. It is reported that the already existing CORSs can be incorporated into the larger statewide network. The respondent was asked about the subscription charges to access the network. He reported a $1,300 per year subscription charge that would offer full access to the entire west coast data including the state of Montana. An in-house GNSS-RTN system requires regular maintenance of the central facility and CORSs. TopCon provides maintenance services to the RTN system designed and built by TopCon. It offers depot repair services for CORSs. Besides, the respondent reported that warranty and extended warranties are also available for the hardware of CORSs. For maintenance of the central facility, an annual maintenance contract is required which costs $6,000 per year (primarily software upgrades). 50 Figure 21. Plan of CORSs in Montana 3.2.1.2 Current and Past Clients To gather information on TopCon's expertise and their market share of the GNSS-RTN industry, the representative of TopCon was asked about current clients of the company. The respondent reported that Topcon has several ongoing business relationships with key network clients such as the Geographical Survey Institute (GSI), an affiliate of the Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) in Japan. Topcon will provide a total of 450 receivers for the GPS Earth Observation Network System (GEONET) operated by the GSI. Topcon will also provide GPS observation/control software as well as a database management system exclusively designed for the GEONET. Since GEONET is an ever-changing and expanding network, Topcon is pleased to be a part of this important relationship. Further, TopCon was also selected to supply GNSS receivers for the Crustal Movement Observation Network of China (CMONOC). TopCon supplied 132 campaign-mode (portable) GNSS COR receivers and GNSS choke ring antennas for CMONOC. The CMONOC project was established by the China Earthquake Administration (CEA) of the People’s Republic of China, to 51 monitor crustal deformation and to predict earthquakes using GNSS technology. Moreover, in the United States, Topcon has been the GNSS-RTN provider for the Tennessee Department of Transportation (TDOT) for over ten years. TDOT owns and maintains a dense network of Reference Stations to provide statewide RTK coverage for highway projects carried out by TDOT staff and its consulting engineering and survey firms. 3.2.2 Leica The researchers had an online interview with the representative of Leica, a major GNSS-RTN services and hardware provider in the United States. The questionnaire was shared well in advance with the interviewee. 3.2.2.1 Products and Services The researchers started the interview with questions about the central facility, CORSs, and establishing of the GNSS-RTN system. The respondent reported that Leica offers four types of antennas and two types of receivers for CORSs. The cost of the receiver ranges from approximately $15,500 to $ 18,000, and the cost of the antenna ranges from approximately $1400 to $10,500 (depending on features and functionalities). The representative of Leica was asked if they provide GNSS-RTN system design services, he stated that Leica is an open platform and can offer an in- depth design of GNSS-RTN system as a stand-alone service, in conjunction with hardware or software procurement, and also for GNSS-RTN systems solely built by Leica. According to the respondent, the design of the network is part of the business partnership for developing the network. Leica does not charge for the design service as the establishment of the RTN system is a partnership and requires a team effort to include Information Technology (IT), management, and manufacturer. The respondent stated that very few manufacturers have the skill set and staff to facilitate network design from start to finish, including planning, implementation, management, and monitoring the network. He mentioned that Leica can provide the network adjustment to the National Spatial Reference Frame as well, however, it has a per-site fee. When asked about building and/or establishing the components of the RTN system including CORSs and central processing facility, the respondent stated that Leica establishes the CORSs and 52 central facility as a stand-alone service, in conjunction with hardware/software procurement, and as part of building a complete GNSS-RTN system. He reported that Leica is a full-service manufacturer from start to finish of the GNSS-RTN system. All of the RTN components can be done, from installation to network adjustment, from design to management. Leica operates their own GNSS-RTN network and provides a total solution inside of SmartNET. SmartNET is a global network of Leica, including CORSs across the United States, which provides real-time location services. The coverage of SmartNET in the United States is shown in Figure 22. Furthermore, the respondent reported three major options for developing, operating, and managing the GNSS-RTN system which is discussed in the following sections. Option - I Leica provides hardware for CORSs and software for the central facility and the state agency is responsible for all charges. The agency is responsible for the installation of COR infrastructure and operating the facility. Regarding the central facility, the interviewee reported that blade servers can be set up to deploy an in-house central facility processing system or host it on cloud-based servers such as Azure environment or Hyland cloud. Hosting the system on Azure/Hyland would discharge the agency from upgrading the servers every two years and the maintenance cost of servers, etc. He suggested that approximately 6 servers and 4 CPUs would be needed for 120 CORSs. 53 Figure 22. SmartNet Network Coverage in the U.S. (Courtesy of Smartnetna.com) The cost of cloud-based servers for the GNSS-RTN system would be approximately $32,000 per year. If the agency wants to set up in-house servers, the server’s life would be 2-3 years and would cost the agency approximately $30,000 to $40,000 every 2-3 years. The respondent reported that the cloud-based servers are very reliable and secure and have a fast backup service, in case, data servers crash. Whereas the inhouse servers may take up to a week on the backup process after a server crash. When asked about the software for the central facility, the Leica representative reported that Spider is a modular and scalable solution offered by Leica that can be upgraded anytime for additional sites (stations) inclusion and functionality. The respondent reported that the cost of Spider depends on the features required by the customer. The respondent also tried to estimate an approximate cost for developing a GNSS- RTN system in Montana comprising 120 CORSs. In the estimation process, the following assumptions/selections were made: ­ The AR10 GNSS Antenna (cost $2750.00) was selected including a longer antenna cable, ­ Ability to use the different GNSS constellations GPS, Baidu, Galileo, and GLONASS, 54 ­ The functionality of monitoring the positions of CORSs at any moment over time, ­ The functionality of billing the contractors and private users and performing analytics, ­ The functionality to allow download of RINEX data for post-processing, ­ The functionality to locate users of the GNSS-RTN system on a map when they are connected to the network, ­ Communication between CORSs and the central facility is mainly based on the internet, but it would include an option of cellular from two networks to fall back on the cellular if internet access stops working, ­ Costs of ground mounts or building mounts are included. Using the above assumptions and functionalities, the total cost of a GNSS-RTN system including CORS, central processing center, software, etc. was estimated at around $5 million. Leica representative reported that if the project goes for competitive bidding, the price may drop to half of the approximate cost. He mentioned that they usually offer significant discounts on the list price during the bidding process and this may bring the cost down to around $2.6 million for the GNSS- RTN system. This cost includes the price of hardware for CORSs, software for the central facility, mounts (ground monument of 8 ft tall), cables, first-year regular maintenance, and network adjustments. The system would be operated by the agency. The annual maintenance (checkup of the hardware) includes visiting every CORS site, checking every cable connection, power supply, ethernet connection, among other services. The annual maintenance cost is approximately 20% of the total cost of hardware of CORSs. The cost of installation of CORSs (construction cost) and the cost of servers are not included in this total cost estimate. In the case of adopting option-I (i.e., in-house GNSS-RTN system development), the agency would be able to provide free access to other public agencies and can sell subscriptions to private users. They can manage this through “Spider Business Center”, a software toolbox by Leica. The cost of it depends on the number of stations in the network and software functionalities the agency needs such as a function of billing the end-users for subscriptions, and data analytics of private user’s 55 utilization. Furthermore, there is an inherent additional cost that one needs to take into consideration when the agency manages the GNSS-RTN network in-house. The network can have issues, a station can be down anytime, and other similar problems. To fix such randomly occurring problems in the network, at least two staff members are required to carry out the routine operations. Option - II In option-II, the agency establishes the complete GNSS-RTN system and Leica host the software and system on their own infrastructure. However, the agency staff operates and manages the system online through Leica system infrastructure. The CORSs of such GNSS-RTN system are only part of that specific network and not connected or incorporated into Leica’s private network (i.e., SmartNET Live). Leica would not have any access to the network either. This would be based on a term of 3 years contract and quarterly/annual payment of an operational fee to Leica. The approximate annual operational cost to pay to Leica would be around $1.2 million. This price can fluctuate based on what Leica would provide and what the agency would be responsible for. Moreover, if the agency wants to manage and operate the GNSS-RTN system in-house on their own infrastructure, Leica can offer support and service contract that helps in managing and maintaining the network, in addition to the annual maintenance. Option - III In this option, Leica would plan and design the network and system requirements for the agency to establish a GNSS-RTN CORS network. After establishing the statewide GNSS-RTN CORS network, Leica would incorporate and host the proposed Montana CORS network in the SmartNet North America network based on 3 years contract. The renewal/continuation of the contract after three years depends on the choice of the agency. The agency would pay for the communication service and the annual maintenance cost of CORSs. Leica would take care of all the operations and maintenance of the system including the network adjustments, maintaining all the hardware and software of the central facility, and operating the network. In response to the network establishment, the agency would receive free full access to real-time data, and access to RINEX data for post-processing. The annual subscription charges to SmartNet Live North America are $2,500. Leica would set up an enterprise license for a number of employees of the agency. The number of free subscriptions depends on the type of use such as an agency surveying crew usage of the network, private contractors who are working for the agency, etc. However, the agency would be responsible for the block of 100-200 licenses and keep track of who is using this license. 56 When asked about the number of free subscriptions/licenses provided to the agency, the respondent replied that it is, usually, one free license per one CORS, but it can be discussed and negotiated in the contract. He also mentioned that the private users would need to buy subscriptions from Leica to access the network. 3.2.2.2 Current and Past Clients To gain information on Leica's expertise and market share in the GNSS-RTN industry, the representative was asked about clients of the company. The respondent reported that Leica has established several statewide GNSS-RTN systems such as networks owned by Oklahoma DOT, New York DOT, Iowa DOT, and Michigan DOT. Regarding operation and contracts with the owner of the GNSS-RTN system, he mentioned that Iowa DOT purchased the hardware and established the statewide network; however, Leica managed and operated the network based on 5- year contract. The contract was continued for two consecutive terms. The 11th year Iowa DOT decided that they would manage and operate the statewide GNSS-RTN system in-house; however, they purchased a yearly-based maintenance service plan. In the following years, they signed a contract of support and services for various options with Leica. Further, he mentioned that another entity purchased all the hardware and software from Leica to establish the statewide network of CORSs, but made a contract with Leica to host the software of the GNSS-RTN system. In addition, one entity purchased all the hardware and software but had a contract of support and services with Leica to help the entity in managing and maintaining the network. 57 4. EXISTING INFRASTRUCTURE This chapter aims to document all existing infrastructure used in providing GNSS-RTN geospatial location service in the state of Montana. Such documentation is deemed important as the existing infrastructure has the potential and is expected to contribute to the future Montana statewide GNSS-RTN system. This chapter presents the current status of the CORSs infrastructure in Montana and provides much relevant information about those stations such as the current hosting arrangements, public and private networks that receive and correct data from CORSs, and station ownership, among other characteristics. Further, out-of-state CORSs currently used to improve location precision in areas near state boundaries are also discussed in this chapter. 4.1 MONTANA CORS INFRASTRUCTURE This chapter identified a total of 69 CORSs within the geographic boundaries of the state of Montana. The stations vary in ownership, networks they contribute to, sampling rate, power source, and means of communication. Figure 23 shows a map with Montana CORS locations. Further, location coordinates along with the mounting type for all CORSs in Montana are provided in APPENDIX D (53). 58 Figure 23. CORSs in the State of Montana 4.1.1 Montana CORSs by Network Montana CORSs are part of different networks, both public and private, providing GNSS location services in Montana. Stations are not limited to being a part of a single network, as many CORSs contribute to multiple networks. Maps of the major GNSS networks along with a list of the contributing CORSs for each respective network are provided in APPENDIX E. The Montana State Reference Network (MTSRN) is a Pilot network currently hosted by the Washington State Reference Network (WSRN). The MTSRN is the largest public network in Montana; currently consisting of 54 CORSs covering different parts of the state – other 7 CORS are to be added to the network in the spring of 2022. All the raw geospatial data collected by the CORSs in the MTSRN are sent to the WSRN central processing facility, where the data is corrected and sent back to the MTSRN users. The users of this public network have access to static files of any station in the network as well as real-time correction services (37). The post-processed data or static files are available for any user to download at no expense. Real- time kinematics (RTK) corrected data, both single base and network, are available for authorized 59 users and possible partners interested in joining the network. Authorized users have access to RTK single base corrections from any station in the network and to RTK network corrections for areas in which subnetworks are present, such as the Fort Peck and Blackfeet areas. Other public networks include the National Oceanic and Atmospheric Administration (NOAA) Continuously Operating Reference Stations (CORSs) Network (NCN), hosted by the NOAA/National Geodetic Survey (NGS) (54). Currently, NGS manages data from around 1900 CORSs located within the US and the UNAVCO network, provided by the Geodetic Facility for the Advancement of Geosciences (GAGE). Funded by the National Science Foundation and NASA, The UNAVCO network currently manages thousands of stations both within and outside the US (55). Post-processed data corrections are available for users of the NCN and the UNAVCO networks. Users of the latter network also have access to real-time GNSS data corrections. Besides the public networks discussed above, private networks are also used to provide GNSS location services in Montana. Specifically, TopNet Live (56), SmartNet North America (57), and Trimble VRS network (58) are the major private networks providing location services in Montana. These networks are hosted by the manufacturers TopCon, Leica, and Trimble, respectively. The network provided by Trimble is the largest private network in Montana with a total of 47 CORSs (59). The services provided by these networks are subscription-based and network users usually have access to post-processed as well as real-time GNSS data corrections. Table 5 includes all CORSs in Montana and the major networks they contribute to, namely: MTSRN, NGS, UNAVCO (60), and Trimble. For the TopCon Live and SmartNet North America, no information was available on Montana CORSs that are part of these networks, and therefore these networks were not included in Table 5. Further, Table 5 also includes five stations in the MTSRN network that are located outside Montana (North Dakota, Wyoming, and Idaho) but contribute to the MTSRN network; and seven stations that will be added in the MTSRN in the spring of 2022. 4.1.2 Montana CORSs by Ownership Currently, 57 CORSs are publicly owned in Montana, which constitute most CORSs in the state. For the vast majority of stations, the location was determined using accurate location coordinates. However, for a couple of stations, the location coordinates were not available and therefore the map location for those stations was estimated (shown in yellow in Figure 23). Table 5 shows the 60 names and ownership types (public or private) for Montana CORSs. 4.1.3 Montana CORSs by Sampling Rate The sampling rate is another property that indicates the frequency with which the receiver is collecting data. Currently, most of the CORSs in Montana provide a sampling rate of 15 seconds or less; with a considerable number of stations providing a sampling rate of 1 second. Table 6 lists the CORSs in Montana providing location name and sampling rate in seconds. Out of the 49 CORSs with known sampling rates in this table, 27 operate with a sampling rate of one second, 20 with a sampling rate of 15 seconds, and one station each with a sampling rate of 5 seconds and 30 seconds. Figure 24 shows a map of Montana CORSs with known sampling rates. The CORSs are marked in light green, light blue, yellow, and orange for sampling rates of 1 second, 5 seconds, 15 seconds, and 30 seconds respectively. Figure 24. Montana CORSs with Known Sampling Rate 61 Table 5. CORSs by Network Affiliation Network Network Station Location Station Location HAML Hamilton, MT • • • P046 Clearwater Junct., MT • • • • LOLO Lolo, MT • • • P047 East Glacier, MT • • • • MSOL Missoula Airport, MT • • P048 Four Corners, MT • • • MTBR Bridger, MT • • • P049 Armington Junct., MT • • • • MTCB Culbertson, MT • • • P050 Sweat Grass Hills, MT • • • • MTCU Cut Bank, MT • • • P051 Billings Airport, MT • • • • MTDT Helena, MT • • • P052 Jordan, MT • • • • MTEI Billings, MT • • P053 Whitewater, MT • • • • MTFV Flathead Valley CC, MT • • • P054 Ekalaka, MT • • • MTGW Glasgow, MT • • • P055 Glendive, MT • • • • MTHC Butte, MT • • • P456 W. Yellowstone, MT • • MTHM Harlem, MT • • • p457 Big Sky, MT • • MTLG Lodge Grass, MT • • • P458 W. Yellowstone, MT • • MTLO Loma, MT • • • P460 Big Sky, MT • • • MTLW Lewistown, MT • • • P461 Merriman, MT • • • MTMS MSU N. Havre, MT • • • P680 W. Yellowstone, MT • • MTOP Opheim, MT • • • P706 Dillon, MT • • • • MTPJ Pendroy Junct., MT • • • P707 Red Rock Lakes, MT • • • MTRC Sidney, MT • • • P712 W. Yellowstone, MT • • MTSU MSU Bozeman, MT • • P714 Gardiner, MT • • Private stations are underlined 62 Trimble UNAVCO NGS MTSRN Trimble UNAVCO NGS MTSRN Table 5. CORSs by Network Affiliation - Continued Network Network Station Location Station Location MTSY Scobey, MT • • • P719 Ennis, MT • • • MTUM Sunset, MT • • P721 Silver Gate, MT • • • MTWP Wolf Point, MT • • • P722 Fishtail, MT • • MTZM Zoteman, MT • • • P818 Fishtail, MT • • MTMI Miles City, MT • • P819 Fishtail, MT • • NOMT Norris, MT • • • • MAWY Mammoth, WY • • BKFB Browning, MT • RYA1 East Hope, ID • FTPP Popular, MT • NDGR Grenora, ND • MTPO Fort Peck RES., MT • P024 Sunset Peak, ID • • YBRA Red lodge, MT • P025 Bonners Ferry, ID • • BUEH Lima, MT • STMY St. Mary, MT • LCLN Lincoln, MT • CSCD Cascade, MT • TWSD Townsend, MT • DUTN Dutton, MT • DRLG Deer Lodge, MT • LBBY Libby, MT • WTHL Whitehall, MT • PLSN Polson, MT • EUKA Eureka, MT • SUPR Superior, MT • P045 Dillon, MT • • • • BTMR Big Timber, MT • Private stations are underlined Stations to be added are presented in italic 4.1.4 Montana CORSs by Communication Type The communication between CORSs and the central processing facility is often achieved using either the internet or mobile cellular networks depending on availability and cost in different areas of the state. This information is unavailable for many Montana CORSs and is only known for part of the MTSRN network stations. Specifically, this information is available for 28 out of the 54 CORSs comprising the MTSRN network. For the 28 CORSs with known communication type, 15 CORSs (around 54%) use mobile cellular networks while the remaining 13 CORSs use the internet 63 Trimble UNAVCO NGS MTSRN Trimble UNAVCO NGS MTSRN as a means of communication with the central processing facility. Figure 25 shows the breakdown of the MTSRN CORSs by communication type for stations with available information. Table 6. Montana CORSs with Respective Sampling Rate Station Location Sampling Station Location Sampling Rate Rate HAML Hamilton, MT 1 sec P046 Clearwater Junct., MT 15 sec LOLO Lolo, MT 1 sec P047 East Glacier, MT 15 sec MSOL Missoula Airport, MT 1 sec P048 Four Corners, MT -- MTBR Bridger, MT 1 sec P049 Armington Junct., MT 15 sec MTCB Culbertson, MT 1 sec P050 Sweat Grass Hills, MT 15 sec MTCU Cut Bank, MT 1 sec P051 Billings Airport, MT 15 sec MTDT Helena, MT 1 sec P052 Jordan, MT 15 sec MTEI Billings, MT 1 sec P053 Whitewater, MT 15 sec MTFV Flathead Valley CC, MT 1 sec P054 Ekalaka, MT 15 sec MTGW Glasgow, MT 1 sec P055 Glendive, MT 15 sec MTHC Butte, MT 30 sec P456 W. Yellowstone, MT 15 sec MTHM Harlem, MT 1 sec p457 Big Sky, MT -- MTLG Lodge Grass, MT 1 sec P458 W. Yellowstone, MT 15 sec MTLO Loma, MT 1 sec P460 Big Sky, MT -- MTLW Lewistown, MT 1 sec P461 Merriman, MT -- MTMS MSU N. Havre, MT 1 sec P680 W. Yellowstone, MT 15 sec MTOP Opheim, MT 1 sec P706 Dillon, MT 15 sec MTPJ Pendroy Junct., MT 1 sec P707 Red Rock Lakes, MT 15 sec MTRC Sidney, MT 15 sec P712 W. Yellowstone, MT -- MTSU MSU Bozeman, MT 5 sec P714 Gardiner, MT -- MTSY Scobey, MT 1 sec P719 Ennis, MT -- MTUM Sunset, MT 1 sec P721 Silver Gate, MT -- MTWP Wolf Point, MT 1 sec P722 Fishtail, MT 15 sec MTZM Zoteman, MT 1 sec P818 Fishtail, MT -- MTMI Miles City, MT 15 sec P819 Fishtail, MT -- NOMT Norris, MT 1 sec MAWY Mammoth, WY -- BKFB Browning, MT -- RYA1 East Hope, ID -- FTPP Popular, MT -- NDGR Grenora, ND -- MTPO Fort Peck RES., MT -- P024 Sunset Peak, ID -- YBRA Red lodge, MT 15 sec P025 Bonners Ferry, ID -- BUEH Lima, MT 15 sec STMY St. Mary, MT 1 sec LCLN Lincoln, MT 1 sec CSCD Cascade, MT 1 sec TWSD Townsend, MT 1 sec DUTN Dutton, MT 1 sec DRLG Deer Lodge, MT 1 sec LBBY Libby, MT 1 sec WTHL Whitehall, MT 1 sec PLSN Polson, MT 1 sec EUKA Eureka, MT 1 sec SUPR Superior, MT 1 sec P045 Dillon, MT 15 sec BTMR Big Timber, MT 1 sec “--” Information unavailable Stations to be added are presented in italic 64 Figure 25. Type of Communication for Stations with Known Information in the MTSRN 4.2 SUMMARY This chapter discussed the current CORSs infrastructure in the state of Montana. This infrastructure is very important for planning the future statewide GNSS-RTN system in the state. Specifically, many of the existing CORSs have the potential of being incorporated in the statewide RTN network thus reducing the capital investment required for establishing the system. Overall, this chapter identified a total of 69 CORSs in Montana owned by both public and private entities. This chapter discussed the different RTN networks, both public and private, that Montana CORSs contribute to. Further, this chapter also summarized other important aspects of CORS operation such as CORS ownership, sampling rate, and type of communication. 65 5. IDENTIFY AND CATALOG VIABLE BUSINESS MODELS FOR STATEWIDE GNSS-RTN This chapter aims at cataloging business models that are used in the current domestic or international practice for providing GNSS-RTN geospatial location, and providing an overview of the merits and demerits of the different business models. The chapter is organized into three parts. The first part provides an overview of the most important business models that were identified in the literature review, the practice survey, or the manufacturers’ interviews discussed in chapters 2 and 3 of this report. The second part of the chapter discusses in more detail the conceptual elements of any business model, i.e., system ownership, costs, and user access charges. The last part of the chapter provides a high-level assessment of the various business models identified in this task. 5.1 EXISTING GNSS-RTN BUSINESS MODELS This section summarizes the most important business models identified in previous project tasks, specifically the literature review and the practice screening. The models are numbered in sequence without necessarily following a specific order. 5.1.1 Business Model 1 In this model, the state owns the GNSS-RTN system and is responsible for all the costs associated with building and operating the system. In a survey conducted by the California Department of Transportation (Caltrans), it was reported that the Minnesota GNSS-RTIN network follows this business model (61). Specifically, the Minnesota Continuously Operating Reference Station (CORS) Network (MnCORS) is primarily composed CORSs and a Central Processing Center (CPC) that are owned and operated by the state DOT. However, several stations that are part of the network in Wisconsin and Iowa are owned by private companies or counties in neighboring states. At the time of the study, the users of the network had free access to all products provided by the MnCORS network. The main advantage of this business model is that the state has full control over the system (the state has almost full ownership of the system). However, the state is responsible for all costs 66 associated with building, operating, and maintaining the system. This model has the potential to improve user engagement by providing end users with free access to all data and system products. The study conducted by Caltrans and published in 2015 estimated this model to have a total annual cost equivalent to roughly $580,000, and an annual benefit equivalent to roughly $38.5M (61). 5.1.2 Business Model 2 In this model, the state owns the CPC facility and part of the CORSs within the state while other CORSs are owned by other state partners including private entities. Operation and maintenance costs are borne by the owners of system components, i.e., the state is responsible for operating and maintaining the CPC and state-owned CORSs, while other partners are responsible for maintaining their CORSs. In a study conducted by Caltrans (61), it was reported that the GNSS-RTN system in the state of Oregon follows this model. Specifically, the study reported that the Oregon Real- Time GPS Network (ORGN) is operated and controlled by the Oregon DOT’s Geometronics Unit. Around 30% of CORSs in this network are owned and maintained by the agency while the remaining 70% CORSs are owned and maintained by ORGN partners. The state DOT monitors all stations and notifies ORGN partners when their stations malfunction or go down. ORGN partners are responsible for the maintenance of their CORSs while the state DOT is responsible for the state-owned CORSs and the CPC’s operation and maintenance costs. At the time of the study, the users of the network had free access to all products provided by the system. In this model, the state still owns the majority of the infrastructure for the network, i.e., the CPC and a part of the CORSs network, which allows the state to have good control over the network. This model involves a public-private partnership in which private entities own, operate, and maintain the remaining CORSs needed to complete the statewide network. The public-private partnership requires agreements in place between the state agency and all other system partners. Similar to the first model, this model provides access to all system users free of charge, which can potentially increase the number of end users. 67 5.1.3 Business Model 3 This business model shares a great deal of similarity with business model 2 except that the public agency which owns and operates the CPC does not necessarily own any notable portion of the CORSs network. In the same study conducted by Caltrans (61), it was found that the GNSS-RTN system in the state of Washington follows this model. The state CORS network, called the Washington State Reference Network (WSRN), is owned by a cooperative of more than 80 partners (cities, counties, utilities, state agencies, and private partners). The Seattle Public Utilities (SPU), one of the partners in the cooperative, owns the CPC and is responsible for its operation and maintenance costs. Operation and Maintenance costs for each CORS are the responsibility of that station’s owner. The WSRN provides free real-time services to partners in the cooperative, while other users have access to real-time services for a subscription fee. This business model proposes a network that is owned and operated by a cooperative. Although public agencies are some of the partners of the cooperative, the network is controlled by all partners, not only the state. In this model, an entity can be a partner of the cooperative by providing, operating, and maintaining one or more CORSs. Similar to the previous two models, a state agency is responsible for addressing any technology-related cost of the network and to implement, operate, and maintain the CPC. This model also requires agreements between all partners of the network and the operating agency. The strategy used to deliver data in this model differs from the first two models by requiring an annual subscription fee to all non-partner end users. The revenues generated by the paid subscriptions are used to cover some of the operating costs of the network. The level of control the state has over the system is still reasonable (but less than the previous two models) given that a state agency is operating and maintaining the CPC. 5.1.4 Business Model 4 In this business model, the state agency has full ownership of the system, i.e., the CORSs network and the CPC, however, the system is operated using a private company/corporate. All costs associated with operating and maintaining the system are the responsibility of the state agency. This was one of the business models proposed by GNSS-RTN manufacturers/vendors to the state of Iowa as part of planning the statewide GNSS-RTN system (62). Specifically, Iowa DOT 68 required that the CORSs and the CPC facility are owned by the state but managed by a private vendor. Operation and maintenance costs for CORSs and the CPC are paid by the state. The state DOT also requested that all users have access to the system services and products free of charge. This model is very similar to business model 1, except that the state would use a private vendor for operating and maintaining the system. Similar to business model 1, this model involves a considerable initial and annual costs borne by the state. As the system is completely owned by the state, the state maintains a high level of control over the system. Contracts and/or agreements between the vendor and the state agency are required. User engagement is estimated to be high with this model, as users have access to system products free of charge. 5.1.5 Business Model 5 The University of New South Wales, Australia, and Leica Geosystems worked together in the analysis of GNSS-RTK network business models. One of the models examined in the study recognized the existence of 90 CORSs that were owned by public entities and suggested that Leica would install 40 more CORSs (63). In this business model, the CPC is owned and operated by the vendor. The study suggested a partnership between public and private entities to address the operation and maintenance costs of the CORSs. All costs related to the CPC are the responsibility of the vendor. This model also considers a subscription fee as a source of revenue to the vendor. Rizos (63) reported that the model was adopted by the U.K.’s Ordnance Survey, who have licensed the CORS data to Leica Geosystems and Trimble. Leica has undertaken to install more than 40 additional GNSS CORS receivers. This model suggests a strong public-private partnership with a vendor, in which the vendor installs all remaining CORSs needed to complete the network and utilizes its own CPC to process and deliver location data to end users. In this model, it’s the vendor’s responsibility to cover all costs the CPC and vendor-owned CORSs may require, leaving only operating and maintenance costs of other CORSs as the responsibility of the state. In another effort to lower state costs, a partnership with private entities was proposed to help cover costs to operate and maintain the CORSs. In this system, data is delivered to the end user for an annual subscription fee. The revenues generated 69 from subscription fees are used to help support the operation and maintenance costs of the CORSs. While this dynamic requires negligible initial investment and annual costs by the state, it also provides the state with lower control over the network. 5.1.6 Business Model 6 This business model is based on public-private partnership and was discussed as part of the interviews with the technology vendors/manufacturers’ representatives conducted in Task 3 of this project (model discussed with both Leica and TopCon representatives) (64). In this model, the state would establish the CORSs network (alone or with partners) while the private vendor would host and manage the network using their infrastructure. The state network in this model would contribute to the private vendor network, and in return, the vendor would provide the state agency with access to the network data and services in the form of an agreed-upon number of network subscriptions. The agency in this model has the freedom to use those subscriptions in any way they see fit including selling some subscriptions to private users. One variation of this model is for the state to control access to the network by purchasing additional subscriptions at discounted prices and selling those to “other” users usually at the higher market price (as proposed by the TopCon representative). The main advantage of this business model is the use of a CPC that is owned, operated, and maintained by a private vendor, to host the network. This will remove a significant proportion of the initial and running costs that would otherwise be borne by the state agency if the system was completely owned and operated by the state. However, this requires that the state enters into an agreement with owners of existing CORSs and may have to provide incentives in the process (e.g., state to pay power and communication costs). The remaining CORSs needed to complete the network are to be implemented by the state. While this model significantly reduces the amount of state investment in the GNSS-RTN system, it provides the state with a lower level of control over the system (compared to model 1 for example). Another advantage of this business model is that technology upgrades and changes can be incorporated on time by the vendor compared to when the state agency is in charge of incorporating these upgrades using state funds. 70 5.1.7 Business Model 7 This business model is also based on a public-private partnership that was discussed during the interviews with technology vendors’ representatives (64). In this model, the state would establish the CORSs network (alone or with partners) and will be responsible for the costs of operating and maintaining the network. The vendor would host and manage the network using their infrastructure but with full state control on operating the statewide network. The state network in this model will not be incorporated/added to the vendor’s private network, and the vendor has no access to the state network. The state will pay the vendor annual fees for hosting and managing the network using a fixed-term agreement. The state is free to decide who can access the network and can impose fees for different products and user types within the state. This business model shares many similarities with the previous model in regard to the ownership of the CORSs network and the network hosting infrastructure. The CORSs needed to complete the network are implemented, operated, and maintained by the state (alone or with partners), and the vendor uses its infrastructure to host the network. In this business model, the vendor has no authority over the network, it simply provides the CPC hosting and management services for an annual fee, allowing the state to hold full control over the network, its products, and users’ fees. The operating costs of the system including network hosting costs, which is borne by the state, could be significant. 5.1.8 Business Model 8 In this business model, a technology vendor would establish, operate and maintain the CORSs network and provide hosting and management services through their own networks. The vendor would develop and use a business model for marketing the RTK services to end users including public and private entities. In this model, the system is 100 percent owned by the vendor and the state plays no role in establishing, operating and maintaining the system. A variation of this model is to have a consortium of private companies as the owners and operators of the GNSS-RTN system instead of a single technology owner such as the CORS-RTK network across the whole of France (63). The main advantage of this model is the lower financial responsibility for the state. Like other end 71 users, state agencies would need to purchase subscriptions to satisfy their RTN data needs. However, this model provides no control to the state over the system, which may not serve the best interests of the state (e.g., inconsistent or incomplete geographic coverage of the state). 5.2 BUSINESS MODELS: CONCEPTUAL ELEMENTS Any business model for establishing and operating a GNSS-RTN system should address three major elements: infrastructure ownership, costs, and user access charges. This section discusses with some detail each of these conceptual elements. 5.2.1 Infrastructure Ownership The ownership of the GNSS-RTN infrastructure largely determines the level of control a state has over the statewide GNSS-RTN system. The earlier section in this document presented business models in which the ownership combination of system components varies among state, partners, and vendors, so does the level of control the state has in each of the models. The GNSS-RTN system infrastructure can be broken down into three main components: The CORSs, the CPC, and the supporting components primarily power and communications. For a better understanding, each infrastructure component is discussed independently in the following sections. i. CORSs A CORS primarily consist of hardware and the physical structure supporting the hardware. The hardware of each CORS is composed of a GNSS receiver along with an antenna to obtain high precision coordinates. Receivers and antennas are offered in a variety of types (different specifications) by most manufacturers such as Leica, Trimble, and TopCon. The GNSS receivers available in the market today come in different types depending on receiver properties such as available storage memory, file size, life expectancy for a given sampling rate, and power-related features. The UNAVCO website provides a summary of receiver types that they 72 consider reliable, and properties for each receiver type are also listed on the platform (65). Antennas also come in different types and costs depending on features and specifications. The different antennas require different calibration methods. Some of the methods follow the guidelines set by the National Geodetic Survey (NGS). The stations for which the antennas are calibrated with the methods that comply with the NGS guidelines are prone to be integrated with the NOAA CORS Network (66). Similar to receivers, UNAVCO summarized all antennas that they consider reliable and provided the calibration method that applies to each of the antennas listed (65). Each CORS needs a physical structure to ensure hardware support at a fixed location. This physical structure (a.k.a. monument) can generally be of two types, building mounts and ground mounts. Within these two categories, there are a number of different sub-types that have been designed to address specific site characteristics (67). Building mounts involve installing the CORS hardware on an existing building using a mounting mechanism. Ground mounts, on the other hand, involves building a physical post on the ground to support CORS hardware. The NGS set forth a set of guidelines for new and existing CORSs in the NOAA CORS Network (NCN). The NGS guidelines are based on monument designs used by the International GNSS Service (IGS), the objective of the NGS guidelines is to avoid monument designs that can negatively affect data precision (68). ii. CPC The central processing center is a major component of any GNSS-RTN system and its design is vital to the success of the RTN operation, i.e. to fully utilize and manage the entire infrastructure, and deliver services reliably in real-time (67). The CPC hardware primarily consists of computers and data servers. The hardware needs to be capable of processing and storing data from all stations in the network, thus the required number of data servers is dependent on the number of stations included in the network. Much like the CORSs, the CPC also needs a physical structure to host the hardware, more specifically a building. All data collected at the stations is sent to the CPC wirelessly, which allows the location of the CPC building to be anywhere. A mirror of the CPC is highly recommended by the NGS (optional). Often for the cost of a few extra servers, the RTN can be mirrored at another physical location to 73 ensure continued service should there be failures of a primary CPC or be utilized for load balancing and archiving redundancy strategies as well (67). Both sites can easily be maintained by the same staff remotely and there are strategies for synchronization of settings. The other major component of a CPC is the software suite used for processing the data received from CORSs in real time. The software suite offered by technology vendors notably varies in capabilities, functionalities, and costs. To comply with the worldwide file format standard, the software used in the CPC to process all data from CORSs in real time should be able to convert the data into a Receiver Independent Exchange Format (RINEX) (69). iii. Supporting Components The CPC and CORSs do not compose a network on their own, other elements are needed for the RTN to function properly. Constant and reliable connectivity between the CORSs and the CPC is needed for the network to ensure optimum functionality. It was found in the survey conducted in Task 3 that the majority of GNSS networks across the country use internet or mobile networks to provide communication between the CORSs and the CPC (4). A radio-based communication can be useful for stations located in areas with low internet and mobile coverage. The NGS guidelines for CORSs consider radio-based communication but notes possible signal interference from other radio frequency sources (67). Receivers should be supplied with continuous power via a reliable source. The national electric grid is the most common source of power for the CORS receiver. However, solar panels, regulators and lead acid batteries are a viable alternative for uninterrupted power in remote locations (67). 5.2.2 Costs This section provides an overview of the costs associated with establishing and operating a GNSS- RTN system. Both initial and running costs will be discussed under each system component. i. CORSs 74 The initial costs involved in building a CORS include the cost of the hardware (receiver and antenna) and the cost of the physical structure and the mounting mechanism. The cost of a single CORS varies widely depending on hardware specifications and whether the hardware is building mounted or ground mounted. The running costs for operating a CORS include costs for communication, power, and regular maintenance for the hardware and structure. ii. CPC The initial costs of a CPC include the costs of the computers and servers, the cost of the software suite to process the GNSS network data, and the cost for the furnished physical building where the CPC is located (space owned or leased by the system operator). The running costs for the CPC primarily include the needed staff to manage/administer the network, regular software updates and license fees, upgrades and regular maintenance required for computers and servers. In the case of hosting all data on cloud servers, usage fees/charges will be part of the running CPC costs. iii. Supporting Elements The costs associated with supporting elements primarily involve the running costs associated with providing power to the CORSs and communication between the CORSs and the CPC. 5.2.3 User Access Charges The GNSS-RTN location data has applications in many fields, which explains the diversity of potential system users, i.e., public agencies, private entities, and individuals. In the previous chapters, it became clear that system access privileges are handled in three different ways: i. Systems that allow all end users, public and private, to access the system data and products free of charge. ii. Systems that allow public agencies to access the system free of charge while requiring usage fees (often in the form of subscription fees) from all other users, namely; private entities and individuals. 75 iii. Systems that require all users public and private to pay usage fees to access the data and products of the system. The scenario (iii) above exists when the technology vendor owns and operates the whole GNSS- RTN system. 5.3 GNSS-RTN SYSTEMS: POSSIBLE BUSINESS MODELS The major business models identified in previous chapters are presented and discussed in section 2 of this chapter. Section 3 provided an overview of the conceptual elements of a GNSS-RTN business model. This section of the chapter attempts to analyze the information presented in the previous sections in order to select 2-3 business models for further analysis. This selection should consider the unique circumstances in the state of Montana such as the size of the network, the existing CORSs, and the potential end users of the prospective GNSS-RTN system. As the use of the GNSS-RTN systems is relatively new in practice (most installations occurred within the past 15 years), and to be comprehensive in our approach, this section will consider all scenarios of business models using various combinations of the conceptual elements, i.e. ownership, costs, and user access charges. Two possible owners for the CPC exist: the state or the vendor. For the CORSs, owners may be the state, other partners, or the vendor. The CPC costs including system management and administration are usually borne by the state or the vendor regardless of ownership. The costs of implementing CORSs are usually borne by the owners which could be the state, the vendor, or other partners. However, other CORSs running costs including power, communication, and maintenance are often borne by the owners or by the CPC owner or RTN operator (as an incentive to incorporate existing stations in statewide networks). For access privileges to system data and products, most of the existing systems either provide free access to all end users (public and private) or provide free access to government agencies but charge individuals and private entities for using the system (in the form of subscription or per-use fees). Only in the instance when the vendor owns the whole system (CORSs and the CPC) that all 76 users private and public have to pay for the service. Considering the three elements above, possible business models for the prospective Montana GNSS-RTN system are presented in Table 7. Table 7. Possible GNSS-RTN Business Models CPC Operations CPC – State CPC – Vendor CPC – Vendor for Fee Network CORSs Operating & Maintenance Costs FA* ---* FA --- FA --- --- State UC* --- UC --- UC --- --- FA FA FA FA FA FA --- State + Partners UC UC UC UC UC UC --- Vendor --- --- --- --- --- --- UC * FA: Free Access; UC: User Charges; “---": Not Applicable As shown in this table, three different scenarios for CPC ownership and operation are provided; CPC owned and operated by the state, CPC owned and operated by the vendor for a fee, or CPC provided as part of the vendor network. The latter scenario requires the statewide network to be incorporated into the vendor’s network. Under each of the CPC scenarios, two different cost possibilities for CORSs are provided; all CORSs are operated and maintained by the state, or CORSs are operated and maintained by owners, i.e., the state and other partners. A third cost possibility was added to the option “CPC – Vendor Network” when the vendor is responsible of CORSs operations and maintenance (vendor 77 CORSs Ownership State State + Partners State State + Partners State State + Partners Vendor owns the whole GNSS-RTN system). The owners of CORSs always pay for building their CORSs, and therefore building costs are not part of the cost scenarios. Regarding CORSs ownership, three different scenarios are provided to cover the different ownership possibilities: the state, the state and partners, and the technology vendor. All cost and ownership scenarios and their combinations in Table 7 may include user access charges or not, except for a system that is fully owned by the vendor where access charges always exist. User access charges are shown in the cells as either free access (FA) or user charges (UC). 5.4 HIGH-LEVEL ASSESSMENT OF THE GNSS-RTN BUSINESS MODELS This section provides a preliminary assessment of the business models discussed in the previous section and outlined in Table 7. To remove some of the subjectivity in the process, a high-level quantitative analysis of the merits or demerits of all possible business models is needed. To provide an objective assessment for the different business models included in Table 7, certain criteria must be considered. Three major criteria are used in this high-level assessment, state control, sustainability, and state/agency costs. State control refers to the level of control the state has on the prospective GNSS-RTN system being planned and built to align with the state’s best interests. A sustainable business model refers to a model that would help the state maintain and provide the desired level of location data service over time within available resources. For sustainability, the lower the running costs the higher the sustainability of the system. Similarly, having user access charges would help the state recover all or some of the operating and maintenance costs, which should result in improved sustainability. For the assessment, the following star scoring scheme will be used for each criterion as follows: Agency (state) control: * Very low control ** Low control *** Moderate control **** High control ***** Very high control 78 Sustainability: * Very low ** Low *** Moderate **** High ***** Very high Agency/state costs (financial obligations): * Very high costs ** High costs *** Relatively high costs **** Average ***** Relatively low costs ****** Low costs ******* Very low costs Summing the number of stars for the three criteria will provide a composite score (out of 17) which refers to the overall merit of a specific business model. Using the star scoring scheme for the criteria above, and considering all possible business model scenarios in Table 7, Table 8 shows a tentative assessment of the different business models considering the three criteria; state control, sustainability, and state/agency costs respectively. In this high-level assessment, it should be kept in mind that while the scoring scheme described above attempts to provide a quantitative and systematic comparison among alternative business models, the process still has some subjectivity, i.e., two individuals using the same scoring scheme may end up having slightly different results. In general, business models in Table 8 show that the higher the level of agency (state) control over the GNSS-RTN system, the higher the financial obligations on the state. The two extremes shown here are: a system that is fully owned and operated by the state where the state has full control over 79 the system and a system that is fully owned and operated by the technology vendor where the state has minimal control (if any) over the system. Further, it is evident that partners’ contribution to the CORSs maintenance and operations costs as well as the user access charges both lead to improved sustainability. However, the partners’ contribution to CORSs maintenance and operation costs may lead to lower state control over the GNSS-RTN system. Table 8. Assessment of Possible Business Models Using the Star Scoring Scheme CPC Operations CPC – State CPC – Vendor CPC – Vendor for Fee Network CORSs Operating & Maintenance Costs ***** ***** **** * NA * NA *** NA NA ** * **** State ***** ***** **** ** NA ** NA **** NA NA *** ** ***** **** *** **** *** *** ** * ** * ** ** ** NA *** **** ** *** ***** ****** State + Partners **** *** **** *** *** ** ** *** ** *** *** *** NA **** ***** *** **** ****** ******* * Vendor NA NA NA NA NA NA *** **** Note: Cells highlighted in grey are for business models with user access charges 5.5 SUMMARY The objective of the current chapter is to catalog possible business models for the prospective Montana GNSS-RTN system and provide an overview of the merits and demerits of the identified 80 CORSs Ownership State State + Partners State State + Partners State State + Partners Vendor models. The chapter started with a description of the major business models that were identified in the previous chapters, namely, the literature review and the practice screening. It was then provided an overview of the conceptual elements of any GNSS-RTN business model to help understand the different models for building and operating the system. Next, conceptual elements were used in laying out all possible business models using four variables: the CPC ownership/operation, CORSs ownership, CORSs operating and maintenance costs, and user access charges. Finally, a high-level assessment of possible business model was performed using the following criteria, agency control over system, sustainability of business model, and agency financial obligations. 81 6. CONCLUSIONS AND RECOMMENDATIONS This project is intended to provide important information that would help the state’s efforts in the planning and implementation of the Montana GNSS-RTN system. This chapter summarizes the major findings of each of the four tasks conducted in the course of this project and culminates with a few recommendations stemming from the project work. Literature Review: A comprehensive literature review was conducted at the onset of this project which focused on the various aspects regarding the planning, design, implementation and operation of statewide GNSS- RTN systems. Recent advancements in GNSS technology and an overview of conventional and emerging applications were briefly discussed to provide familiarity with the system and its potential uses. Further, GNSS-RTN business plans were summarized, and best practices and guidelines were presented. Finally, system design considerations were reviewed by examining characteristics of existing systems and reviewing available guidance. The review included published information on the GNSS-RTN systems in studies, reports, magazines, and websites both in the US and internationally. State-of-the-Practice Assessment: A state of practice survey was conducted to learn about the current practices of operating and managing the GNSS-RTN systems and providing accurate location services in different states around the U.S. Thirty-eight respondents submitted the survey representing 30 states. Additionally, phone interviews were conducted with major vendors/manufacturers of the GNSS-RTN products and services to learn about costs and recent trends in technology and system operations. The major findings of this task are summarized below. • Most of the statewide GNSS-RTN systems surveyed are owned by state agencies (primarily DOTs). Approximately 90% of the systems in the U.S. are based on CORSs with an average spacing of less than 70 km resulting in an accuracy of 2 -4 cm in location data. 82 • The owners of central facilities are responsible for user and IT support service costs in approximately 64% of all the systems surveyed. In addition, the CPC owners are responsible for the cost of communication between the CPC and CORSs and for the cost of CPC maintenance. • Approximately 60 % of GNSS-RTN systems offer entirely free access to both public and private users resulting in the majority of state agencies not generating revenues from user fees. • The GNSS-RTN systems often provide data as corrected coordinates, network corrections, post processed data, and in fewer instances virtual RINEX. • The funding sources for the establishment of most of the statewide GNSS-RTN systems are either only state funds or some federal funds along with state funds. However, the funding sources for the daily operation of GNSS-RTN systems are state funds and users’ fees, when used. • In the process of incorporating privately-owned CORSs to statewide networks, some states provide incentives to the private owners in various forms such as unlimited access to data, access to value-added services, free or discounted subscription(s), and educational opportunities for schools that host CORSs. • The vendors/manufacturers interviews laid down average market prices of GNSS-RTN products and services including CPC and CORS components. It was estimated that approximately 120 CORSs placed across the state are required for Montana’s network to achieve the desired accuracy of 1 to 2 inches in location data. To operate the system, the CPC was estimated to require 6 servers, and 4 CPUs. Existing Infrastructure: An assessment of all existing GNSS-RTN infrastructure in Montana was conducted in this task. The task identified aspects such as CORS ownership, sampling rate, location coordinates, mounting type, and the networks each station contributes to. The major findings of this task are summarized below. 83 • At the time of executing this task, this task identified a total of 62 CORSs in Montana owned by both public and private entities, of which 57 are publicly owned. The Montana State Real Time Network (MTSRN) is the largest public network in Montana; currently consisting of 54 CORSs covering different parts of the state. • Currently, most of the CORSs in Montana provide a sampling rate of 15 seconds or less; with a considerable number of stations providing a sampling rate of 1 second. • For MTSRN stations with known information, the communication between CORSs and the CPC were almost equally split between the internet and the cellular service. Catalog Viable GNSS-RTN Business Models: This task cataloged eight distinct business models that were identified in the previous project tasks, namely, the literature review and the practice screening. The business models were adequately described with a summary of the merits and demerits of each model. The report then provided an overview of the conceptual elements of any GNSS-RTN business model to help understand the different models for building and operating the system. Next, the report used the conceptual elements in laying out all possible business models using four variables: the CPC ownership/operation, CORSs ownership, CORSs operating and maintenance costs, and user access charges. Finally, a high-level assessment of possible business model was performed using the following criteria, agency control over system, sustainability of business model, and agency financial obligations. Recommendations Considering the overall project and findings from project tasks, the researchers would like to make the following recommendations regarding the planning, implementation, and operation of the Montana GNSS-RTN system. 84 I. Building public-private partnerships through incorporating existing CORSs owned by private and other public entities proved to be a cost-effective way for establishing the statewide network within fewer resources and a shorter time span. II. Expanding the user base of the prospective statewide GNSS-RTN system is important for achieving sustainable operations of the system while maximizing benefits to the state’s economy and its citizens. This requires a scheme for user access charges that is competitive with those that already exist in the region and other neighboring states. III. 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(2021). “The NOAA CORS Network (NCN)” National Geodetic Survey. Retrieved September 30, 2021, from https://geodesy.noaa.gov/CORS/ 55. UNAVCO. (2021). “GPS/GNSS Data,” Retrieved September 30, 2021, from https://www.unavco.org/data/gps-gnss/gps-gnss.html 56. TopCon. (2021). “Topnet Live Corrections: GNSS Positioning Correction Service” Retrieved September 30, 2021, from https://www.topconpositioning.com/enterprise-services-and- subscriptions/gnss-correction-services/topnet-live 57. SmartNet North America, (2021). “Why Smartnet” Retrieved September 30, 2021, from https://www.smartnetna.com/smartnet_why.cfm 58. Trimble, (2021). “Trimble Geospatial” Retrieved September 30, 2021, from https://geospatial.trimble.com/ 59. Trimble, (2021). “Trimble Reference Stations” Retrieved September 30, 2021, from https://www.trimble.com/trs/findtrs.asp?Nav=File-14468&Detail=Montana 60. UNAVCO, (2021). “UNAVCO Network Monitoring” Retrieved September 30, 2021, from **INSERT LINK*** 61. Statewide Real-Time GPS or GNSS Network Implementation. Caltrans. (2015). [cited 2022 Jan 4]. Available from: https://dot.ca.gov/-/media/dot-media/programs/research-innovation-system- information/documents/preliminary-investigations/real-time-gps-networks-pi-a11y.pdf 62. Iowa statewide RTK-GPS network deployment project. ROSA P. (2008). [cited 2022 Jan 4]. Available from: https://rosap.ntl.bts.gov/view/dot/17115 63. Rizos, Chris. (2007). Alternatives to current GPS-RTK services and some implications for CORS infrastructure and operations. GPS Solutions. 64. Raza, S., & Al-Kaisy, A. (2021). Analyze Business Models for Implementation and Operation of a Statewide GNSS-RTN, Task 3 Report: State-of-the-Practice Assessment. MDT. Available from: https://www.mdt.mt.gov/other/webdata/external/research/DOCS/RESEARCH_PROJ/GNSS- RTN/Task-3-Report.pdf 65. UNAVCO resources: GNSS antennas - knowledge base [Internet]. UNAVCO. [cited 2022 Jan 4]. Available from: https://kb.unavco.org/kb/article/unavco-resources-gnss-antennas-458.html 91 66. Bilich, A., & Mader, G. (2010). GNSS absolute antenna calibration at the National Geodetic Survey. NGS. [cited 2022 Jan 4]. Available from: https://www.ngs.noaa.gov/CORS/Articles/Bilich-and-Mader_ION2010.pdf 67. Guidelines for new and existing continuously operating Reference Stations (CORS). NGS. (2018). [cited 2022 Jan 4]. Available from: https://www.ngs.noaa.gov/PUBS_LIB/CORS_guidelines.pdf 68. National Geodetic Survey Guidelines for Real-Time GNSS Networks. NGS. (2013). [cited 2022 Jan 4]. Available from: https://www.ngs.noaa.gov/PUBS_LIB/NGSGuidelinesForRealTimeGNSSNetworksV2.2.pdf 69. Prusky, J. (2001). The cooperative CORS program. NGS. [cited 2022 Jan 4]. Available from: https://www.ngs.noaa.gov/CORS/Articles/Coop.pdf 92 APPENDIX A: GNSS-RTN Survey Questionnaire 93 SURVEY QUESTIONNAIRE The purpose of this survey is to understand the state of practice in establishing and operating the Global Navigation Satellite System (GNSS) Real-Time Network (RTN) at the state level. GNSS- RTN may be owned and/or operated by state DOTs, other public agencies, or private entities. Private entities may own some of the Continuously Operating Reference (COR) stations that are part of a larger RTN network. This survey is divided into two sections. Section 1 consists of general questions on the GNSS- RTN system including system ownership, system design, and system users among other aspects. Section 2 of the survey consists of questions related to the operation of the GNSS-RTN system such as system operating costs, system funding, and user’ fees (if any). This survey should be completed by those in your agency who are involved in the development, management, or operation of the GNSS-RTN system. Participation is voluntary, you can choose not to answer any question that you do not want to answer, and you can stop at any time. The survey has 23 questions in total and is expected to take approximately 10 minutes to complete. Thank you in advance for your participation. Please enter your contact information: (We may wish to contact you if we need clarification or desire more information regarding a response) NAME: TITLE: AGENCY: PHONE: EMAIL: 94 1. Your current State: Select from dropdown list: Choose a State Choose a State 2. Does your state have a GNSS real-time network (RTN) system? o Yes o No 3. Does your agency own or operate a GNSS-RTN system? o Yes o No Section 1. System General Information 4. Tell us about the GNSS-RTN system ownership in your state. Central Control/Processing facility is owned by: o Public agency o Private entity COR stations are owned by: o Public agency o Private entity o Both public and private entities 5. What company/vendor did supply hardware for the COR stations [check all that apply]? □ Trimble □ Lieca □ NavCon □ TopCon Other, please specify: 6. What company/vendor did supply hardware for the central facility [check all that apply]? □ Trimble □ Lieca □ NavCon □ TopCon Other, please specify: 95 7. What company/vendor did supply the software [check all that apply]? □ Trimble □ Lieca □ NavCon □ TopCon □ Other, please specify: 8. Total number of COR stations that are part of your GNSS-RTN system (including COR stations owned by entities other than the GNSS-RTN system owner/operator): o Please specify: 9. Your GNSS-RTN system provides coverage in: o Whole State (system covers most of the state geographic area) o Part of the State (system covers a certain region within the state) 10. On average, spacing between COR stations is about: o 30-40 km o 40-50 km o 50-70 km o More than 70 km o Do not know 11. Communication method used to connect COR stations to the central processing station/server [check all that apply]: □ Mobile network □ Internet based □ Radio signals based □ Other, please specify: 12. The accuracy of your GNSS-RTN system is approximately: o 2-4 cm o 4-6 cm o 6-8 cm o More than 8 cm 13. The users of your GNSS-RTN system are [check all that apply]: □ DOT 96 □ State survey department □ Universities □ Construction industries □ Engineering consultants □ Machine guidance (farming equipment, crop management, etc.) □ Private companies purchasing raw data for value-added services □ Other private and/or public entities --- please specify. 14. Does your GNSS-RTN system provide the following products to users [check all that apply]: □ Corrected coordinates (Real-time) □ Network corrections (Real-time) □ Post-processed data (Static) □ Other – please specify: 15. Provide the average number of users of your GNSS-RTN system: Total system users Annual subscriptions Less-than-a-year subscriptions Other Section 2. System Operation 16. Users of your GNSS-RTN access the system [check all that apply]: □ Free of cost / zero charges □ Annual subscription fee □ Less-than-a-year subscriptions fee □ Charges based on access duration □ Charges based on data-size download □ Other, please specify: 97 17. Who is responsible for the following GNSS-RTN system costs? [check all that apply]: RTN components Central facility COR stations Other, please specify owner owner User and IT support Communication b/w central facility and COR stations Maintenance of central facility Maintenance of COR stations 18. Revenue from user fees/charges cover: o Total cost of system operation o 0 % of total system operation cost o 1% to 20% of total system operation cost o 20% to 40% of total system operation cost o 40% to 60% of total system operation cost o 60% to 80% of total system operation cost o 80% to 99% of total system operation cost o Do not know 19. Please specify the system funding sources by checking the applicable boxes in the table below. GNSS-RTN cost Federal State funds Users/subscription fee Other, please component funds specify Establishment of GNSS- RTN system System operation System maintenance 20. How many full-time equivalent (FTE) staff are assigned to the daily operation of the GNSS-RTN system? • E nter approx. number. 98 21. Were already existing COR stations incorporated into your current GNSS-RTN system? o Yes o No o No previous existing stations o Other, please specify: 22. Do you provide any incentives to the owners of COR stations (other than the central facility owner/operator)? o Yes o No 23. Owners of COR stations (other than the central facility owner/operator) get incentives in the form of: □ Reduced subscription charges □ Unlimited access to data □ Other, please specify: 99 APPENDIX B: GNSS-RTN Survey Raw Data 100 Q1 Q2 Q3 Q4a Q4b Q5 5a_TEXT Alabama Yes Yes Public agency Public agency Lieca California Yes Yes Public agency Both public and Trimble, Lieca, TopCon, Other, please Septentrio private entities specify: Colorado Yes Yes Public agency Both public and Trimble, Lieca, NavCon, TopCon, Other, NGS private entities please specify: Connecticut Yes Yes Public agency Public agency Trimble Florida Yes Yes Public agency Public agency Lieca Florida Yes Yes Public agency Public agency Lieca Georgia Yes Yes Private entity Private entity Other, please specify: CHCNAV and HoWAY GIS Hawaii No Illinois Yes Yes Private entity Both public and Lieca, Other, please specify: Mix of Leica and private entities Novatel Indiana Yes Yes Public agency Public agency Lieca Iowa Yes Yes Public agency Public agency Lieca, Other, please specify: Leica ;-) Iowa Yes Yes Public agency Public agency Lieca, Other, please specify: GPS receivers and Antennas only Louisiana Yes Yes Public agency Public agency Trimble Maine Yes Yes Public agency Public agency Trimble Maryland No Massachusetts Yes Yes Private entity Both public and Lieca private entities Michigan Yes Yes Public agency Public agency Lieca Minnesota Yes Yes Public agency Public agency Trimble New Hampshire No Ohio Yes Yes Public agency Public agency Trimble, Lieca, TopCon Ohio Yes Yes Public agency Public agency Trimble, TopCon Oregon Yes Yes Public agency Both public and Trimble, Other, please specify: Septentrio private entities Oregon Yes Yes Public agency Both public and Trimble, Lieca, Other, please specify: Septentrio private entities Pennsylvania Yes Yes Public agency Public agency Trimble Tennessee Yes Yes Public agency Public agency TopCon Texas Yes Yes Public agency Public agency Trimble Utah Yes Yes Public agency Both public and Trimble private entities Vermont Yes Yes Public agency Both public and Trimble private entities Washington Yes Yes Public agency Both public and Trimble, Lieca, TopCon, Other, please Septentrio private entities specify: West Virginia Yes Yes Public agency Public agency Trimble No State Info Yes Yes Public agency Both public and Trimble private entities No State Info No No State Info Yes Yes Public agency Public agency Trimble 101 Q1 Q6 Q6a TEXT Q7 Q7a TEXT Q8 Q8a Alabama Lieca Lieca Please provide number below: 53 California Other, please specify: HP Blade servers for data Trimble Please provide number below: 205 processing and storage Colorado Trimble, Lieca, UNAVCO Trimble, Lieca, UNAVCO Please provide number below: 9 NavCon, TopCon, NavCon, TopCon, Other Other, please specify: Connecticut Trimble Trimble Please provide number below: 9 Florida Lieca Lieca Please provide number below: 100 Florida Lieca Lieca Please provide number below: 99 Georgia Other, please specify: My IT Department Trimble, Other, please 3 processing platforms. Please provide number below: 69 specify: Trimble, Geo++, CHCNAV CPS Hawaii Illinois Lieca Lieca Please provide number below: 58 Indiana Other, please specify: Indiana Office of Lieca Please provide number below: 45 Technology Iowa Other, please specify: We use Iowa DOT servers Lieca Please provide number below: 103 Iowa Other, please specify: That would be Iowa DOT IT Lieca Please provide number below: 101 (State) hardware supplied. Louisiana Trimble Trimble Please provide number below: 122 Maine Trimble Trimble Please provide number below: 19 Maryland Massachusetts Lieca Lieca Please provide number below: 20 Michigan Other, please specify: State-run VM's Lieca Please provide number below: 123 Minnesota Trimble Trimble Please provide number below: 130 New Hampshire Ohio Trimble Trimble Please provide number below: 64 Ohio Trimble Trimble Please provide number below: 61 Oregon Lieca Lieca Oregon Other, please specify: State Data Center Lieca, Other, please Septentrio Please provide number below: 120 specify: Pennsylvania Trimble Trimble Please provide number below: 18 Tennessee TopCon TopCon Please provide number below: 45 Texas Trimble Trimble Please provide number below: 240 Utah Trimble Trimble Please provide number below: 109 Vermont Trimble Trimble Please provide number below: 18 Washington Other, please specify: Seattle Public Utilities Trimble Please provide number below: 150 West Virginia Trimble Trimble Please provide number below: 23 No State Info Trimble Trimble Please provide number below: 125 No State Info No State Info Trimble Trimble Please provide number below: 52 102 Q1 Q9 Q10 Q11 Q11 TEXT Q12 Alabama Whole State (system covers most of the state geographic area) 40-50 km Mobile network, Internet based 2-4 cm California Part of the State (system covers a certain region within the state) 40-50 km Internet based 2-4 cm Colorado Whole State (system covers most of the state geographic area) More than 70 km Radio signals based 4-6 cm Connecticut Whole State (system covers most of the state geographic area) 40-50 km Internet based 2-4 cm Florida Whole State (system covers most of the state geographic area) 30-40 km Mobile network 2-4 cm Florida Whole State (system covers most of the state geographic area) 30-40 km Internet based 2-4 cm Georgia Whole State (system covers most of the state geographic area) 50-70 km Mobile network 2-4 cm Hawaii Illinois Part of the State (system covers a certain region within the state) 30-40 km Internet based, Radio signals based 2-4 cm Indiana Whole State (system covers most of the state geographic area) 30-40 km Internet based 2-4 cm Iowa Whole State (system covers most of the state geographic area) 40-50 km Mobile network, Internet based 2-4 cm Iowa Whole State (system covers most of the state geographic area) 50-70 km Mobile network 2-4 cm Louisiana Whole State (system covers most of the state geographic area) 50-70 km Internet based 2-4 cm Maine Whole State (system covers most of the state geographic area) 50-70 km Internet based 2-4 cm Maryland Massachusetts Whole State (system covers most of the state geographic area) 50-70 km Internet based 2-4 cm Michigan Whole State (system covers most of the state geographic area) 30-40 km 2-4 cm Minnesota Whole State (system covers most of the state geographic area) 40-50 km Internet based 2-4 cm New Hampshire Ohio Whole State (system covers most of the state geographic area) 30-40 km Mobile network, Internet based 2-4 cm Ohio Whole State (system covers most of the state geographic area) 30-40 km Mobile network, Internet based 2-4 cm Oregon Whole State (system covers most of the state geographic area) Do not know Mobile network, Internet based Oregon Part of the State (system covers a certain region within the state) 50-70 km Mobile network, Internet State based, Other, please specify: Network 2-4 cm Pennsylvania Whole State (system covers most of the state geographic area) More than 70 km Internet based 2-4 cm Tennessee Whole State (system covers most of the state geographic area) 40-50 km Internet based 2-4 cm Texas Whole State (system covers most of the state geographic area) 50-70 km Mobile network, Internet based 2-4 cm Utah Whole State (system covers most of the state geographic area) Do not know Internet based 4-6 cm Vermont Whole State (system covers most of the state geographic area) 30-40 km Mobile network 2-4 cm Washington Whole State (system covers most of the state geographic area) 50-70 km Mobile network, Internet based, Radio signals based 2-4 cm West Virginia Whole State (system covers most of the state geographic area) 50-70 km Mobile network, Internet based 2-4 cm No State Info Whole State (system covers most of the state geographic area) 40-50 km Mobile network, Internet based 2-4 cm No State Info No State Info Whole State (system covers most of the state geographic area) 50-70 km Mobile network, Internet based 2-4 cm 103 Q1 Q13 Q13 TEXT Alabama DOT, State survey department, Universities, Construction industries, Engineering NOAA, NGS consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify California DOT, State survey department, Universities, Construction industries, Machine Counties, cities and public water entities. Fields guidance (farming equipment, crop management, etc.), Other private and/or public using the RTN from these entities include Surveys, entities --- please specify GIS, city water departments and irrigation districts. Colorado DOT, State survey department, Universities, Construction industries, Engineering COUNTY AND MUNICIPAL consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Connecticut DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services Florida DOT, Universities, Construction industries, Engineering consultants, Machine guidance System is available to the public. (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Florida DOT, State survey department, Universities, Construction industries, Engineering multiple municipalities, utilities and private consultants, Machine guidance (farming equipment, crop management, etc.), Other companies - no fees private and/or public entities --- please specify Georgia DOT, State survey department, Universities, Construction industries, Engineering Land Surveyors, GIS consultants, Remote Sensing consultants, Machine guidance (farming equipment, crop management, etc.), Private consultants companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Hawaii Illinois DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services Indiana DOT, State survey department, Universities, Construction industries, Engineering Utility, municipalities, etc. consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Iowa DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Iowa DOT, Universities, Construction industries, Engineering consultants, Machine guidance Counties, Cities, DNR, Federal USDA, USACOE, (farming equipment, crop management, etc.), Private companies purchasing raw data etc. for value-added services, Other private and/or public entities --- please specify User base in numerous, given FREE to access. And we do not have a specific State Survey Dept. Louisiana DOT, State survey department, Universities, Construction industries, Engineering USACE, USGS, Plumbers, Land & Hydro consultants, Machine guidance (farming equipment, crop management, etc.), Other Surveyors, UAV Pilots, Public Utilities, and more... private and/or public entities --- please specify Maine DOT, Universities, Construction industries, Engineering consultants, Machine guidance Agricultural Users, robotic mowers (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services, Other private and/or public entities --- please specify Maryland Massachusetts DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) Michigan DOT, State survey department, Universities, Construction industries, Engineering NGS data Gzip consultants, Machine guidance (farming equipment, crop management, etc.), Other private and/or public entities --- please specify Minnesota DOT, State survey department, Universities, Construction industries, Engineering NOAA consultants, Machine guidance (farming equipment, crop management, etc.), Private NGS companies purchasing raw data for value-added services, Other private and/or public entities --- please specify New Hampshire Ohio DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services Ohio DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) Oregon DOT, Universities, Construction industries, Engineering consultants, Machine guidance UNAVCO (farming equipment, crop management, etc.), Other private and/or public entities --- please specify 104 Oregon DOT, State survey department, Universities, Construction industries, Engineering Mapping and GIS services consultants, Machine guidance (farming equipment, crop management, etc.), Other private and/or public entities --- please specify Pennsylvania DOT, State survey department, Other private and/or public entities --- please specify The state has a DOT owned and operated RTN for DOT use only, that also shares data to a Private RTN run by Trimble for subscription users. Tennessee DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) Texas DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) Utah DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) Vermont DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services Washington DOT, State survey department, Universities, Construction industries, Engineering Utilities, agriculture, scientific agencies, federal, consultants, Machine guidance (farming equipment, crop management, etc.), Private autonomous navigation, robotics companies purchasing raw data for value-added services, Other private and/or public entities --- please specify West Virginia DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.), Private companies purchasing raw data for value-added services No State Info DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) No State Info No State Info DOT, State survey department, Universities, Construction industries, Engineering consultants, Machine guidance (farming equipment, crop management, etc.) 105 Q1 Q14 Q14a TEXT Q15a Q15b Q15c Q15d Alabama Corrected coordinates (Real-time), Network Virtual Rinex 1188 corrections (Real-time), Post-processed data (Static), Other, please specify: California Corrected coordinates (Real-time), Network 300 300 corrections (Real-time), Post-processed data (Static) Colorado Other, please specify: ONLY VIA NGS OR Software 10000 0 0 21 Connecticut Corrected coordinates (Real-time), Network corrections (Real-time) Florida Corrected coordinates (Real-time), Network 5900 15600 corrections (Real-time), Post-processed data (Static) Florida Corrected coordinates (Real-time), Network 3600 corrections (Real-time), Post-processed data (Static) Georgia Corrected coordinates (Real-time), Network User statistics 500 200 300 corrections (Real-time), Post-processed data (Static), Other, please specify: Hawaii Illinois Corrected coordinates (Real-time), Network 1000 700 300 corrections (Real-time), Post-processed data (Static) Indiana Network corrections (Real-time), Post-processed data 4500 (Static) Iowa Network corrections (Real-time), Post-processed data Virtual RINEX 3700 (Static), Other, please specify: Iowa Network corrections (Real-time), Post-processed data Adjusted Network Coordinates, last 2036 1781 392 (Static), Other, please specify: derived upon NAD83(2011) upon NAVD88/Geoid12B on Jan. 4th, 2019 Louisiana Corrected coordinates (Real-time), Network Online Post-processing solutions, corrections (Real-time), Post-processed data (Static), Real-time & Historical Tracking of Other, please specify: rovers for clients Maine Corrected coordinates (Real-time), Network 50 600 0 corrections (Real-time), Post-processed data (Static) Maryland Massachusetts Network corrections (Real-time), Post-processed data (Static) Michigan Corrected coordinates (Real-time), Network 5268 5268 0 0 corrections (Real-time), Post-processed data (Static) Minnesota Network corrections (Real-time), Post-processed data we send out a correction to the user 5000 (Static), Other, please specify: in the field via internet. The end user’s equipment supplies the real time coordinate. New Hampshire Ohio Network corrections (Real-time) 3000 Ohio Network corrections (Real-time), Post-processed data 7721 7721 (Static) Oregon Corrected coordinates (Real-time), Network corrections (Real-time) Oregon Corrected coordinates (Real-time), Network 1600 0 0 corrections (Real-time), Post-processed data (Static) Pennsylvania Network corrections (Real-time), Other, please DOT system will provide Real- specify: Time network corrections to users. The private RTN will provide more services. Tennessee Corrected coordinates (Real-time), Network 500 400 20 corrections (Real-time), Post-processed data (Static) Texas Corrected coordinates (Real-time), Network 2000 0 0 corrections (Real-time), Post-processed data (Static) Utah Corrected coordinates (Real-time), Network 130 0 corrections (Real-time), Post-processed data (Static) Vermont Corrected coordinates (Real-time), Network 451 40 25 corrections (Real-time), Post-processed data (Static) Washington Corrected coordinates (Real-time), Network Observation streams for science 4500 288 0 corrections (Real-time), Post-processed data (Static), and industry Other, please specify: West Virginia Corrected coordinates (Real-time), Network 4000 corrections (Real-time), Post-processed data (Static) 106 No State Info Corrected coordinates (Real-time), Network 3500 3500 0 corrections (Real-time), Post-processed data (Static) No State Info No State Info Corrected coordinates (Real-time), Network 1600 corrections (Real-time), Post-processed data (Static) 107 Q1 Q16 Q16a TEXT Q17a Q17b Q17c Q17d Alabama Free of cost Central facility owner Central facility owner Central facility owner Central facility owner Direct access is only available to Municipalities. Central California Other, please specify: Public can access Central facility owner facility Central facility owner, data from state ,CORSs owner owner, Central facility owner CORSs owner owned station via CORSs owner the partner CRTN network. ANNUAL Colorado Free of cost, Annual subscription LICENSING FEE fee, Other, please specify: BY PRIVATELY CORSs owner CORSs owner OWNED VENDORS Connecticut Free of cost Central facility owner Central facility owner Central facility owner Central facility owner Florida Free of cost Central facility owner Central facility owner Other Central facility owner Central facility owner Central Florida Free of cost facility owner Central facility owner Central facility owner Central facility Central Georgia Annual subscription fee, Less- owner Central facility owner facility owner Central facility owner than-a-year subscriptions fee Hawaii Free of cost, Annual subscription Central facility owner Central facility owner Central facility owner Central facility owner Illinois fee, Less-than-a-year subscriptions fee Indiana Free of cost Other Central facility owner Central facility owner Central facility owner Iowa Free of cost Central facility owner Central facility owner Central facility owner Central facility owner Central Iowa Free of cost Central facility owner facility owner, Central facility owner Central facility owner, CORSs owner CORSs owner Free of cost, Annual subscription fee, Less-than-a-year Louisiana subscriptions fee, Charges based Research Central facility owner Central Central facility owner Central facility owner on access duration, Other, please Agreements facility owner specify: Maine Free of cost CORSs owner Central facility owner Central facility owner CORSs owner Maryland Central Massachusetts Free of cost Central facility owner, facility CORSs owner owner, Central facility owner CORSs owner CORSs owner Michigan Free of cost Central facility owner Central facility owner Central facility owner Central facility owner Minnesota Free of cost Central facility owner Central Central facility owner facility owner Central facility owner New Hampshire Ohio Free of cost CORSs owner CORSs owner CORSs owner CORSs owner Ohio Free of cost Central facility owner Central facility owner Central facility owner Central facility owner Central facility owner Central facility owner Central facility owner Central facility owner Oregon Free of cost ,CORSs owner ,CORSs owner Central Oregon Free of cost Central facility owner facility owner, Central facility owner Central facility owner, CORSs owner CORSs owner 108 No access beyond Pennsylvania Other, please specify: DOT. Private RTN Central facility owner Central Central facility owner Central facility owner is subscription facility owner based Central facility Tennessee Annual subscription fee owner Central facility owner Central facility owner Central facility owner Central facility owner, Central Texas Free of cost CORSs owner facility Central facility owner, Central facility owner, owner, CORSs owner CORSs owner CORSs owner Utah Annual subscription fee, Other, 1-year subscription please specify: only Central facility owner CORSs owner Central facility owner CORSs owner Vermont Free of cost Central facility owner, Central Central facility owner, Central facility owner, CORSs owner facility owner Other CORSs owner Central Washington Annual subscription fee, Other, The majority of our please specify: users are Central facility owner facility Central facility owner Central facility owner cooperative partners owner, ,CORSs owner CORSs owner West Virginia Free of cost CORSs owner CORSs owner CORSs owner CORSs owner No State Info Free of cost Central facility owner CORSs owner Central facility owner Central facility owner No State Info No State Info Free of cost Central facility owner Central facility owner Central facility owner Central facility owner 109 Q1 Q18 Q19a Q19b Q19c Q19a Text Q19b Text Q19c Text Alabama 0% of total system operation Federal funds, State Federal funds, State Federal funds, State cost funds funds funds California 0 % of total system operation Federal funds, State State funds Federal funds, State cost funds funds PRIVATELY OWNED Colorado Do not know State funds Other Other STATIONS PRIVATE COST IS VENDORS UNKNOWN Connecticut 0 % of total system operation cost State funds State funds State funds Florida 0 % of total system operation cost State funds State funds State funds Florida 0 % of total system operation State funds State funds State funds cost Private Georgia Total cost of system operation Other Other Other Business Ownership for Self-funded Self-Funded profit Hawaii Illinois 80% to 99% of total system operation cost Users/subscription fee Users/subscription fee Users/subscription fee Indiana 0 % of total system operation Federal funds, State cost funds State funds State funds Iowa 0 % of total system operation cost State funds State funds State funds Iowa 0 % of total system operation cost State funds State funds State funds Louisiana Total cost of system operation Users/subscription fee Users/subscription fee Users/subscription fee Maine 0 % of total system operation cost State funds State funds State funds Maryland Massachusetts 0 % of total system operation Federal funds, State Federal funds, State Federal funds, State cost funds funds funds Michigan 0 % of total system operation cost State funds State funds State funds Minnesota 0 % of total system operation cost State funds State funds State funds New Hampshire Ohio 0 % of total system operation cost State funds State funds State funds Ohio 0 % of total system operation Federal funds cost ,State funds State funds State funds Oregon Do not know State funds State funds State funds Oregon 0 % of total system operation cost State funds State funds State funds Pennsylvania 0 % of total system operation cost State funds State funds State funds Tennessee 1% to 20% of total system State funds, State funds State funds operation cost Users/subscription fee ,Users/subscription fee ,Users/subscription fee 0 % of total system operation State funds State funds State funds Texas cost Utah Total cost of system operation State funds Users/subscription fee Users/subscription fee Vermont 0 % of total system operation Federal funds, State Federal funds, State Federal funds cost funds funds ,State funds While there was no initial state funding, Partner some DOT regions contributions, Some partner have contributed Washington Total cost of system operation Users/subscription fee, Users/subscription fee, Users/subscription and initial constitutions for CORS hardware. Other Other fee, Other investment by software There have been Seattle public upgrades some contributions Utilities, from universities from USGS grant funding. West Virginia Federal funds, State Federal funds, State Federal funds, State funds funds funds No State Info Federal funds, State funds State funds State funds No State Info No State Info 0 % of total system operation cost Federal funds Federal funds Federal funds 110 Q1 Q20 Q21 Q21a TEXT Q22 Q23 Q23a TEXT Alabama 3 Yes No California 1 Yes Yes Unlimited access to data, Access to "value added" data Other, please specify: products like network corrected RTN data streams. Colorado 1 Yes No Connecticut 1 Yes No Florida 3 Yes No Florida 2 Other, please specify: adjacent states No and municipal Georgia 3 No Hawaii Illinois 2 No Indiana 2 Other, please specify: Only 1 No Iowa 1 No previous existing stations Iowa 1 No previous existing stations Louisiana 3 Yes No Maine 0 No Maryland Massachusetts 1.5 No Michigan 3 Yes No Minnesota 3 Yes No New Hampshire Ohio 3 No Ohio 1 No Oregon 2 Yes No Oregon 1.5 Yes No Pennsylvania 1 Yes No Tennessee 1 No Texas 5 Yes No Utah 2 Yes Yes Other, please specify: One free subscription for a station Vermont 2 No previous existing stations Washington 0.75 Yes Yes Unlimited access to data, Education opportunities for Other, please specify: schools that host sites West Virginia 4 No No State Info 1 Yes Yes Reduced subscription charges, Unlimited access to data No State Info No State Info 2 No 111 APPENDIX C: Vendors/Companies Interview Questions 112 Vendors/Companies Phone/Zoom Interview Questions SECTION ONE: PRODUCTS AND SERVICES Which of the following products/services does your company offer? i. CORS hardware Types: Approximate cost 1. – 2. – 3. – ii. Central Processing Center (CPC) hardware Types: Approximate cost 1. – 2. – 3. – iii. Central Processing Center (CPC) software Types: Approximate cost 1. – 2. – 3. – iv. Does your company provide design services for GNSS-RTN systems? If YES, – Design as a stand-alone service – In conjunction with hardware or software procurement – Only for GNSS-RTN systems solely built by your company v. What is the approximate cost paid by clients for your design services and how is it determined? vi. Does your company build and/or establish the following system components? - CORSs - Central Processing Center - Both 113 If YES to any of the above, please indicate the type of service: - Stand-alone service - In conjunction with hardware/software procurement - In conjunction with system operation contracts - In conjunction with system design services - Part of building a complete GNSS-RTN system vii. What are the approximate costs for building system components and how are they determined? viii. Does your company operate GNSS-RTN systems? If YES to the above question, please indicate the type of service - Stand-alone service - Only for systems designed and built by your company ix. How are operation costs paid by clients determined by your company? Any ballpark numbers? x. Does your company provide maintenance services for GNSS-RTN systems? If YES to the above question, please indicate the type of service. - Maintenance of CORSs - Maintenance of Central Processing Centers - Both Is maintenance provided as (check all that apply): - Stand-alone service - Only for systems designed and built by your company - In conjunction with system operation contracts 114 xi. How are maintenance costs estimated by your company? Any ballpark numbers? 115 SECTION TWO: CURRENT AND PAST CLIENTS xii. Which states have your company provided any of the following services? - Complete GNSS-RTN systems operated by your company - Complete GNSS-RTN systems operated by owner or other agency -medium box- - Building the Central Processing Center (both hardware and software) - Provide software for existing GNSS-RTN systems 116 - Supply hardware for CORSs - Providing stand-alone design services for systems built by other companies - Provide system operation services -medium box- - Provide system maintenance services 117 xiii. For GNSS-RTN systems your company helped plan, design, build, and/or operate, have you incorporated already existing CORSs in a larger GNSS-RTN network (e.g., statewide system)? - If YES to the above question, were incentives provided to the owners of the existing CORSs? - If incentives were provided, what are those incentives? 118 119 120 APPENDIX D: Montana CORSs Geospatial Location and Mounting Type 121 Montana CORSs Geospatial Location and Mounting Type Total Stations in Montana Station Location Latitude Longitude Ellipsoid height (m) Mounting Type 1 HAML Hamilton, MT 46 11 42.80313 N 114 10 22.55733 W 1105.200m Ground-based 2 LOLO Lolo, MT 46 45 46.24771 N 114 05 48.67202 W 1109.859m Ground-based 3 MSOL Missoula Airport, MT 46 55 45.83764 N 114 06 31.84491 W 960.611m Ground-based 4 MTBR Bridger, MT 45 16 11.09210 N 108 54 51.42018 W 1106.667m Ground-based 5 MTCB Culbertson, MT 48 08 49.77412 N 104 30 11.22183 W 571.018m Ground-based 6 MTCU Cut Bank, MT 48 38 34.35059 N 112 18 58.49254 W 1134.073m Ground-based 7 MTDT Helena, MT 46 35 18.59145 N 111 59 36.96274 W 1217.743m Ground-based 8 MTEI Billings, MT 45 44 47.03568 N 108 36 00.73636 W 970.852m Ground-based 9 MTFV Flathead Valley CC, MT 48 13 38.89085 N 114 19 36.54279 W 905.671m Roof-based 10 MTGW Glasgow, MT 48 22 11.18755 N 106 47 36.41814 W 672.738m Ground-based 11 MTHC Butte, MT 45 56 16.19774 N 112 30 36.10882 W 1696.543m Roof-based 12 MTHM Harlem, MT 48 32 44.41440 N 108 46 46.76372 W 717.512m Ground-based 13 MTLG Lodge Grass, MT 45 18 44.66277 N 107 20 30.20525 W 1053.010m Ground-based 14 MTLO Loma, MT 47 57 02.41089 N 110 30 17.96950 W 835.250m Ground-based 15 MTLW Lewistown, MT 47 03 14.92966 N 109 26 33.76416 W 1236.960m Ground-based 16 MTMS MSU N. Havre, MT 48 32 27.42647 N 109 41 11.85839 W 773.908m Roof-based 17 MTOP Opheim, MT 48 51 17.11527 N 106 24 22.04353 W 980.556m Ground-based 18 MTPJ Pendroy Junct., MT 48 04 14.81121 N 112 20 09.16623 W 1310.411m Ground-based 19 MTRC Sidney, MT 47 42 38.17615 N 104 10 51.20554 W 584.659m Ground-based 20 MTSU MSU Bozeman, MT 45 39 40.37682 N 111 02 42.00897 W 1495.489m Ground-based 21 MTSY Scobey, MT 48 47 37.61523 N 105 23 55.55138 W 745.944m Ground-based 22 MTUM Sunset, MT 46 57 00.08260 N 113 28 20.62213 W 1122.778m Roof-based 23 MTWP Wolf Point, MT 48 05 58.09697 N 105 40 00.38540 W 617.360m Ground-based 24 MTZM Zoteman, MT 47 57 41.13086 N 108 18 18.92264 W 933.199m Ground-based 25 MTMI Miles City, MT 46 26 49.02766 N 105 47 48.62912 W 709.389m Roof-based 26 NOMT Norris, MT 45 35 48.6336 N 111 37 46.7118 W 1578.634m Ground-based 27 BKFB Browning, MT 48 32 56.35424 N 113 00 43.80884 W 1329.987m Roof-based 28 FTPP Popular, MT 48 06 56.40274 N 105 11 13.02263 W 595.395m -- 29 MTPO Fort Peck RES., MT -- -- -- -- 30 YBRA Red lodge, MT 45 07 19.56 N 109 16 02.64 W 2072.518m Ground-based 31 BUEH Lima, MT -- -- -- -- 32 LCLN Lincoln, MT 46 56 51.7196 N 112 44 34.8798 W -- Ground-based 33 TWSD Townsend, MT 46 18 34.1861 N 111 30 53.2971 W -- Ground-based 34 DRLG Deer Lodge, MT 46 23 19.4530 N 112 44 04.6286 W -- Roof-based 35 WTHL Whitehall, MT -- -- -- Roof-based 36 EUKA Eureka, MT 48 54 42.9881 N 115 03 19.7636 W -- Roof-based 37 P045 Dillon, MT 45 22 58.32584 N 112 37 01.82863 W 1618.799m Ground-based “--” Information unavailable 122 Total Stations in Montana - Continued Station Location Latitude Longitude Ellipsoid height (m) Mounting Type 38 P046 Clearwater Junct., MT 47 01 46.52357 N 113 19 54.18527 W 1290.844m Ground-based 39 P047 East Glacier, MT 48 25 16.78905 N 113 13 11.02622 W 1476.057m Ground-based 40 P048 Four Corners, MT 45 39 10.944 N 111 12 15.156 W 1492.595m Ground-based 41 P049 Armington Junct., MT 47 20 59.85056 N 110 54 22.38306 W 1186.651m Ground-based 42 P050 Sweat Grass Hills, MT 48 48 34.09690 N 111 14 54.29693 W 1267.434m Ground-based 43 P051 Billings Airport, MT 45 48 23.74192 N 108 32 46.07076 W 1081.757m Ground-based 44 P052 Jordan, MT 47 22 29.02686 N 107 01 07.18536 W 859.285m Ground-based 45 P053 Whitewater, MT 48 43 33.86527 N 107 43 31.45675 W 815.608m Ground-based 46 P054 Ekalaka, MT 45 50 46.83313 N 104 26 29.06244 W 1093.859m Ground-based 47 P055 Glendive, MT 47 07 00.14491 N 104 41 06.39476 W 668.450m Ground-based 48 P456 W. Yellowstone, MT 44 51 48.564 N 111 13 30.396 W 2956.339m Ground-based 49 p457 Big Sky, MT 45 02 28.392 N 111 16 21.432 W 2262.54m Ground-based 50 P458 W. Yellowstone, MT 44 45 56.484 N 111 18 05.436 W 2393.924m Ground-based 51 P460 Big Sky, MT 45 08 23.964 N 111 01 42.924 W 2197.818m Ground-based 52 P461 Merriman, MT 45 21 15.3 N 110 45 31.284 W 1544.094m Ground-based 53 P680 W. Yellowstone, MT 44 35 54.096 N 111 05 55.50 W 2315.94m Ground-based 54 P706 Dillon, MT 45 02 36.47248 N 112 31 26.66902 W 1811.325m Ground-based 55 P707 Red Rock Lakes, MT 44 43 07.55322 N 111 50 13.73844 W 2293.445m Ground-based 56 P712 W. Yellowstone, MT 44 57 26.892 N 111 04 20.568 W 2161.49m Ground-based 57 P714 Gardiner, MT 44 53 45.06 N 110 44 39.912 W 2250.18m Ground-based 58 P719 Ennis, MT 45 13 03.936 N 111 47 20.508 W 1706.356m Ground-based 59 P721 Silver Gate, MT 45 00 10.638 N 110 00 07.38 W 2236.31m Ground-based 60 P722 Fishtail, MT 45 27 25.98575 N 109 34 15.58671 W 1453.451m Ground-based 61 P818 Fishtail, MT 45 27 26.424 N 109 34 15.636 W 1463.00m Ground-based 62 P819 Fishtail, MT 45 27 26.208 N 109 34 16.14 W 1463.00m Ground-based 63 MAWY Mammoth, WY 44 58 24.31914 N 110 41 21.43320 W 1824.920m Roof-based 64 RYA1 East Hope, ID -- -- -- -- 65 NDGR Grenora, ND 48 37 14.47271 N 103 55 59.20221 W 642.775m Roof-based 66 P024 Sunset Peak, ID 47 33 43.92 N 115 50 32.784 W 1907.629m Ground-based 67 P025 Bonners Ferry, ID 48 43 51.63211 N 116 17 14.98280 W 695.894m Ground-based 68 STMY St. Mary, MT 48 47 24.4521 N 113 24 28.4052 W -- Ground-based 69 CSCD Cascade, MT 47 15 39.8010 N 111 42 21.3293 W -- Roof-based 70 DUTN Dutton, MT 47 50 34.9700 N 111 42 24.4100 W -- Roof-based 71 LBBY Libby, MT 48 21 04.7988 N 115 31 27.2496 W -- Roof-based 72 PLSN Polson, MT 47 41 09.4416 N 114 07 29.0496 W -- Roof-based 73 SUPR Superior, MT 47 11 13.8800 N 114 52 54.5600 W -- Roof-based 74 BTMR Big Timber, MT 45 50 19.9608 N 109 56 53.3796 W -- Roof-based “--” Information unavailable Stations to be added are presented in italic 123 APPENDIX E: Montana CORS Networks 124 MTSRN – CORSs Map and Table Stations in the MTSRN Station Location Station Location Station Location BKFB Browning, MT LCLN1 Lincoln, MT P051 Billings Airport, MT FTPP Popular, MT TWSD1 Townsend, MT P052 Jordan, MT HAML Hamilton, MT DRLG1 Deer Lodge, MT P053 Whitewater, MT LOLO Lolo, MT WTHL1 Whitehall, MT P055 Glendive, MT MSOL Missoula Airport, MT EUKA1 Eureka, MT P460 Big Sky, MT MTBR Bridger, MT NOMT1 Norris, MT P461 Merriman, MT MTCB Culbertson, MT MTRC Sidney, MT P706 Dillon, MT MTCU Cut Bank, MT MTSU Bozeman, MT P719 Ennis, MT MTDT Helena, MT MTSY Scobey, MT STMY1 St. Mary, MT MTEI Billings, MT MTUM Sunset, MT CSCD1 Cascade, MT MTFV Flathead Valley CC, MT MTWP Wolf Point, MT DUTN1 Dutton, MT MTGW Glasgow, MT MTZM Zoteman, MT LBBY1 Libby, MT MTHC Butte, MT NDGR Grenora, ND PLSN1 Polson, MT MTHM Harlem, MT P025 Sheridan, WY SUPR1 Superior, MT MTLG Lodge Grass, MT P045 Dillon, MT BTMR1 Big Timber, MT MTLO Loma, MT P046 Clearwater Junct., MT MAWY Mammoth, WY MTLW Lewistown, MT P047 East Glacier, MT RYA11 East Hope, ID MTMS MSU N. Havre, MT P048 Four Corners, MT NDGR Grenora, ND MTOP Opheim, MT P049 Armington Junct., MT P024 Sunset Peak, ID MTPJ Pendroy Junct., MT P050 Sweat Grass Hills, MT P025 Bonners Ferry, ID MTPO1 Fort Peck RES., MT Stations to be added are presented in italic 1 Estimated location 125 UNAVCO – CORSs Map and Table Montana CORSs - UNAVCO Network Station Location Station Location P045 Dillon, MT P458 W. Yellowstone, MT P046 Clearwater Junction, MT P460 Big Sky, MT P047 East Glacier, MT P461 Merriman, MT P049 Armington Junct., MT P680 W. Yellowstone, MT P050 Sweat Grass Hills, MT P706 Dillon, MT P051 Billings Airport, MT P707 Red Rock Lakes, MT P052 Jordan, MT P719 Ennis, MT P053 Whitewater, MT P722 Fishtail, MT P054 Ekalaka, MT NOMT Norris, MT P055 Glendive, MT YBRA Red lodge, MT P456 W. Yellowstone, MT BUEH Lima, MT 126 NCN – CORSs Map and Table Montana CORSs - NCN Station Location Station Location Station Location HAML Hamilton, MT MTLO Loma, MT P047 East Glacier, MT LOLO Lolo, MT MTLW Lewistown, MT P049 Armington Junct., MT MSOL Missoula Airport, MT MTMS MSU N. Havre, MT P050 Sweat Grass Hills, MT MTBR Bridger, MT MTOP Opheim, MT P051 Billings Airport, MT MTCB Culbertson, MT MTPJ Pendroy Junct., MT P052 Jordan, MT MTCU Cut Bank, MT MTRC Sidney, MT P053 Whitewater, MT MTDT Helena, MT MTSU MSU Bozeman, MT P055 Glendive, MT MTEI Billings, MT MTSY Scobey, MT P706 Dillon, MT MTFV Flathead Valley CC, MT MTUM Sunset, MT P707 Red Rock Lakes, MT MTGW Glasgow, MT MTWP Wolf Point, MT P054 Ekalaka, MT MTHC Butte, MT MTZM Zoteman, MT MTMI Miles City, MT MTHM Harlem, MT P045 Dillon, MT P722 Fishtail, MT MTLG Lodge Grass, MT P046 Clearwater Junct., MT NOMT Norris, MT 127 TRIMBLE – CORSs Map and Table Montana CORSs - Trimble's Network Station Location Station Location Station Location HAML Hamilton, MT MTRC Sidney, MT P055 Glendive, MT LOLO Lolo, MT MTSY Scobey, MT P456 W. Yellowstone, MT MTBR Bridger, MT MTWP Wolf Point, MT p457 Big Sky, MT MTCB Culbertson, MT MTZM Zortman, MT P458 W. Yellowstone, MT MTCU Cut Bank, MT MTMI Miles City, MT P460 Big Sky, MT MTDT Helena, MT NOMT Norris, MT P461 Merriman, MT MTFV Flathead Valley CC, MT P045 Dillon, MT P680 W. Yellowstone, MT MTGW Glasgow, MT P046 Clearwater Junct., MT P706 Dillon, MT MTHC Butte, MT P047 East Glacier, MT P707 Red Rock Lakes, MT MTHM Harlem, MT P048 Four Corners, MT P712 W. Yellowstone, MT MTLG Lodge Grass, MT P049 Armington Junct., MT P719 Ennis, MT MTLO Loma, MT P050 Sweat Grass Hills, MT P721 Silver Gate, MT MTLW Lewistown, MT P051 Billings Airport, MT P722 Fishtail, MT MTMS MSU N. Havre, MT P052 Jordan, MT P818 Fishtail, MT MTOP Opheim, MT P053 Whitewater, MT P819 Fishtail, MT MTPJ Pendroy Junct., MT P054 Ekalaka, MT 128 This public document was published in electronic format at no cost for printing and distribution.