Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Ephemeris"”.
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GPS ephemeris spoofing
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-20 without embargo terms
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A geometric approach to determination of satellite ephemeris over a limited area
Range and,interferometric observations have been examined for their potential, application in a geometric approach to determination of satellite ephemeri. The approach differs from the normal (dynamic) approach in that each satellite position is treated as an independent state variable or …
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Coupled Dynamics in the Cislunar Region and Spacecraft Attitude Prediction in a Higher-Fidelity Model
… problem (CRF3BP) and a full higher-fidelity ephemeris model that includes perturbations from the sun’s gravity and the eccentricity of the moon’s orbit. The CRF3BP is leveraged as a tool for predicting spacecraft attitude motion in the full ephemeris model using rotation matrices. Extensive …
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STARE CubeSat Communications Testing, Simulation and Analysis
… Telescope for the Actionable Refinement of Ephemeris (STARE) CubeSat will play an important role in contributing to this nations space situational awareness (SSA), perhaps one day becoming an integral part of the space surveillance network (SSN) to track orbital debris and satellites, both …
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Control System Design and Simulation of Spacecraft Formations via Virtual Formation Approach
… effectiveness of the modified control laws. The ephemeris and attitude data files generated via Matlab are exported to Satellite Tool Kit (STK) to create 3D animations. Various formation scenarios are modeled and the formation control strategies studied in this thesis are applied for switching …
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A transit-timing variation study of the extrasolar planet TrES-3
… Sozzetti et al. (2008) [8], are compared to the ephemeris of the planet. The transit timing variation (TTV) of each midtime is calculated. Based on these data the presence of a third body in the TrES-3 system cannot be determined. Mass and period of a hypothetical perturbing body are calculated …
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Astrometria, efemérides e ocultações estelares de satélites irregulares e corpos do sistema solar exterior
… with foreign researchers, the astrometry, ephemeris production and stellar occultation prediction by irregular satellites, the first stellar occultation by an irregular satellite (Phoebe) ever observed, the astrometry of the Neptune- Triton system and the prediction work of the recent …
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Control System Design and Simulation of Spacecraft Formations
… are carried out using Matlab to generate the ephemeris and attitude data, which are exported to Satellite Tool Kit (STK) to create animations. The process by which Matlab is used to produce the data and how the data are used to produce a 3-D animation in STK is explained. Finally, various …
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Location Verification for Spoofing Detection in Non-Terrestrial Networks
… the LVS performance under various satellite ephemeris error conditions, spoofing distances, number of measurements available to the system, and wireless channel properties. The proposed LVS is shown to reliably detect spoofing among malicious users.
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An expert system for processing uncorrelated satellite tracks.
… far Earth orbit. The sensors provide epoch and ephemeris information that is used to update a database of known objects. While a majority of the sensor observations are matched to their corresponding satellites, a small percentage are beyond the capabilities of current software and can not be …
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A Millimeter Wavelength Interferometric Study of Organic Molecules in Comet Hale -Bopp (C/1995 O1)
… the plausibility of yielding arcsecond level ephemeris corrections on a daily basis. (5) A three dimensional, non-spherically symmetric Monte Carlo code has been written to calculate production rates, the results of which, when combined with analysis of the high resolution observations and …
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Space situational awareness CubeSat concept of operations
… Telescope for the Actionable Refinement of Ephemeris (STARE) project was initiated to explore the potential for a cube satellite (CubeSat) to contribute to the current SSN, with an optical payload integrated into a 3U Colony II Bus. The bus and payload data from the CubeSat will be collected …
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Interplanetary mission design with applications to guidance and optimal control of aero-assisted trajectories
… is explored further with the use of a time-free ephemeris to see where minimal energy transfer arcs between Earth and Mars occur, and see if the 2018 opportunity is one such transfer. It turned out that both the 2017 and 2064 candidates found from the 100-year search were the closest to minimum …
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Eclipsing Cataclysmic Variables With TESS
… eclipse minima for all datasets to the standard ephemeris equation. Fully phased light curves were produced, resulting in updated ephemerides for all systems. P dot terms were identified via the observed minus calculated (O–C) diagrams and added to the newly updated ephemerides for all CVs.
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Significance of Specific Force Models in Two Applications: Solar Sails to Sun-Earth L4/L5 and GRAIL Data Analysis Suggesting Lava Tubes and Buried Craters on the Moon
… trajectories are transitioned to higher fidelity ephemeris model to account for additional perturbing accelerations that may dominate the sail-craft dynamics and improve upon the trajectory design process.
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Global non-dynamic refinement of radial orbit error for altimetric earth satellites
… of the radial component of the satellite ephemeris. A non-dynamic technique is proposed as a method of reducing the global radial orbit error of altimetric satellites. This involves the recovery of each coefficient of an analytically derived radial error correction through a refinement of …
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Reappraising the Land Behind Baghdad: Using CORONA Satellite Imagery to Reassess the Archaeological Landscape of the Diyala Plain, Iraq
… This procedure eliminates the need for camera ephemeris data or mathematical models and relies on ground control points. Google Earth was successfully used as the geographic reference. An attempt was also made to utilize the stereographic nature of the product to photogrammetrically extract …
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Risk-resilient GPS-based positioning, navigation, and timing using sensor fusion and multi-agent platforms
… caused by anomalies in the broadcast satellite ephemeris or clock information. Spoofing attacks occur when counterfeit GPS signals are transmitted by malicious sources to overpower authentic ones. This dissertation aims to provide risk-resilient GPS-based positioning and timing against these …
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