Scholarship & Research
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Item RadPC@Scale: an approach to mitigate single event upsets in the memory of space computers(Montana State University - Bozeman, College of Engineering, 2022) Williams, Justin Patrick; Chairperson, Graduate Committee: Brock LaMeresThis thesis presents the flight test results of a single event upset (SEU) mitigation strategy for computer data memory. This memory fault mitigation strategy is part of a larger effort to build a radiation tolerant computing system using commercial-off-the-shelf (COTS) field programmable gate arrays (FPGAs) called RadPC. While previous iterations of RadPC used FPGA block RAM (BRAM) for its data memory, the specific component of RadPC that is presented in this paper is a novel external memory scheme with accompanying systems that can detect, and correct faults that occur in the proposed data memory of the computer while allowing the computer to continue foreground operation. A prototype implementation of this memory protection scheme was flown on a Raven Aerostar Thunderhead high-altitude balloon system in July of 2021. This flight carried the experiment to an altitude of 75,000 feet for 50 hours allowing the memory in the experiment to be bombarded with ionizing radiation without being attenuated by the majority of Earth's atmosphere. This thesis discusses the details of the fault mitigation strategy, the design-of-experiments for the flight demonstration, and the results from the flight data. This thesis may be of interest to engineers that are designing flight computer systems that will be exposed to ionizing radiation and are looking for a lower cost SEU mitigation strategy compared to existing radiation- hardened solutions.Item Optimization of error correcting codes in FPGA fabric onboard cube satellites(Montana State University - Bozeman, College of Engineering, 2019) Tamke, Skylar Anthony; Chairperson, Graduate Committee: Brock LaMeresThe harmful effects of radiation on electronics in space is a difficult problem for the aerospace industry. Radiation can cause faults in electronics systems like memory corruption or logic flips. One possible solution to combat these effects is to use FPGAs with radiation mitigation techniques. The following Masters of Science thesis details the design and testing of a radiation tolerant computing system at MSU. The computer is implemented on a field programmable gate array (FPGA), the reconfigurable nature of FPGAs allows for novel fault mitigation techniques on commercial devices. Some common fault mitigation techniques involve triple modular redundancy, memory scrubbing, and error correction codes which when paired with the partial reconfiguration. Our radiation tolerant computer has been in development for over a decade at MSU and is continuously being developed to expand its radiation mitigation techniques. This thesis will discuss the benefits of adding error correcting codes to the ever developing radiation tolerant computing system. Error correcting codes have been around since the late 1940's when Richard Hamming decided that the Bell computers he did his work on could automate their own error correcting capabilities. Since then a variety of error correcting codes have been developed for use in different situations. This thesis will cover several popular error correcting method for RF communication and look at using them in memory in our radiation tolerant computing system.Item A radiation tolerant computer mission to the International Space Station(Montana State University - Bozeman, College of Engineering, 2017) Julien, Connor Russell; Chairperson, Graduate Committee: Brock LaMeresThe harmful effects of radiation on electronics used in space poses a difficult problem for the aerospace industry. Memory corruption and other faults caused by the harsh radiation environment are difficult to mitigate. The following Masters of Science thesis describes the design and testing of a radiation tolerant, low-cost computer system to meet the increasing demand of fault tolerant space computing. The computer is implemented on a modern Field Programmable Gate Array (FPGA), which enables a novel fault mitigation strategy to be deployed on a commercial part, thus reducing the cost of the system. Using modern processing nodes as small as 28nm, FPGAs can provide increased computational performance and power efficiency. Common mitigation techniques like triple modular redundancy and memory scrubbing are expanded by utilizing partial reconfiguration on the FPGA and by introducing extra spare processors. Our computer system has been in development at Montana State University for the past 10 years and has undergone a series of technology demonstrations to increase its technical readiness level. These include high energy particle bombardment at the Texas A&M Radiation Effects Facility, 8 high altitude balloon flights to 30km, and two sounding rocket flights to altitudes greater than 120km. This computer is currently being demonstrated onboard the International Space Station and will be the payload for two stand-alone small satellite missions in low Earth orbit in 2018. This Masters of Science thesis presents improvements to the system by moving the design to a new, low power FPGA with a new processor synchronization method. This thesis will present the design, testing, and characterization of the computer system along with conveying data collected by the experiment on the International Space Station.Item Infrared cloud imaging systems characterization(Montana State University - Bozeman, College of Engineering, 2016) Riesland, David Walter; Chairperson, Graduate Committee: Joseph A. ShawInfrared cloud imaging (ICI) is a useful tool for characterizing cloud cover for a variety of fields. Clouds play an important role in free-space high frequency (optical and mm-wave) terrestrial communications. Ground-based infrared imagers are used to provide long-term, high resolution (spatial and temporal) cloud data without the need for sunlight. This thesis describes the development and characterization of two ICI systems for deployment at remote field sites in support of Earth-to-space mm-wave and optical communication experiments. The hardware upgrades, calibration process, sensitivity analysis, system validation, and algorithm developments are all discussed for these systems. Relative spectral response sensitivity analysis is discussed in detail, showing as much as 35% calibrated scene radiance uncertainties when using generic manufacturer data in comparison with measured spectral responses. Cloud discrimination algorithms, as well as cloud phase (ice or water discrimination) algorithms are also discussed.Item Implementation of a radiation-tolerant computer based on a LEON3 architecture(Montana State University - Bozeman, College of Engineering, 2015) Turner, David Lee Douglas; Chairperson, Graduate Committee: Brock LaMeresIt is desired to create an inexpensive, open-source, radiation-tolerant computer for space applications using commercial, off-the-shelf parts and a proven space-grade processor. Building upon previous work to develop the triplicate architecture using MicroBlaze soft-processors, this implementation, using a modification of the popular open-source space-grade LEON3 soft processor from Cobham Gaisler, enables more compatibility with NASA and existing space computing resources. A partially reconfigurable, triple modular redundant LEON3 processor was successfully implemented in a four-core design on an Artix-7 Field Programmable Gate Array to demonstrate an inexpensive and open-source method of developing radiation-hardened-by-architecture computer systems.Item Two dimensional radiation sensor development for use in space bound reconfigurable computers(Montana State University - Bozeman, College of Engineering, 2011) Gowens, Eric Christopher; Chairperson, Graduate Committee: Todd KaiserSpace bound computers are exposed to damaging radiation once they leave the safety of the Earth's atmosphere, which is a significant hindrance to the development of digital space systems. While most digital systems can be radiation hardened, the development time in making them less susceptible to radiation keeps the hardened systems behind the cutting edge. A better solution for this problem is to provide an early warning that a digital microchip may have been struck by radiation in the form of a spatially aware sensor. The focus of this thesis is the design, fabrication, and testing of a two-dimensional silicon-based radiation sensor capable of detecting the location of a potentially damaging radiation strike on a microchip. It is demonstrated that by using a strip sensor design, the spatial detection of incident radiation is possible. Simulations of performance are presented that predict the functionality of the strip sensor. The capabilities of a commercially available sensor are investigated. Additionally, a sensor is designed, fabricated, tested, and compared to the performance of the commercially available sensor. Recommendations for future research of the sensor design are discussed.Item Remote sensing applications of uncooled long-wave infrared thermal imagers(Montana State University - Bozeman, College of Engineering, 2012) Johnson, Jennifer Erin; Chairperson, Graduate Committee: Joseph A. ShawThe commercial development of microbolometer uncooled long-wave thermal infrared imagers in conjuncture with advanced radiometric calibration methods developed at Montana State University has led to new uses of thermal imagery in remote sensing applications. As a result of being uncooled, microbolometer imagers are notably lighter and cheaper than typical cooled imagers, making them ideal for remote sensing. Two novel uses are discussed in the work presented here. The first is the imaging of beehives in order to remotely determine the hive vitality. Bees thermally regulate their hives to a narrow range of temperatures that creates a thermal signature seen in thermal infrared images. For each of the hives imaged, frame counts (or the number of full frames of bees in each hive) were found by manual inspection. Linear regressions of the normalized frame counts of the hives were performed versus the measured hive thermal radiance values. The resulting plots showed a strong relationship between the normalized frame count and the mean radiance of each hive, particularly in images taken just prior to dawn. The second novel use was imaging vegetation exposed to large ground concentrations of CO ₂ over a four-week period in summer for use in leak detection. A CO ₂ leak was simulated in a test field run by the Zero Emissions Research and Technology Center. Thermal infrared images were acquired along with visible and near-infrared reflectance images of the exposed vegetation and healthy control vegetation. Thermal radiance statistics were measured and a regression was performed versus the day of the experiment. The infrared data were found to have a strong R ² value and clearly show the effect of the CO ₂ on the vegetation. An additional regression was run on the infrared data combined with the reflectance data, and this was found to not add any unique information to the vegetation reflectance data. Both methods were found to independently indicate the potential of a CO ₂ leak before it was detected visually.