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 14 of 14 for “"Low earth orbit (LEO) satellites"”.
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Low Earth Orbit Spacecraft Slotting: Towards an Implementable Proposal
The growth in the number of proposed low Earth orbit (LEO) satellites is driven primarily by large commercial communications constellations. The launch of even half of the proposed satellites would result in an order-of-magnitude increase in active spacecraft traffic, with significant implications …
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Deep learning for downscaling GOES-18 measurements for wildfire detection
… the Geostationary Operational Environmental Satellites (GOES-R) series containing the Advanced Baseline Imager (ABI) offers high temporal resolution for frequent observations but suffers from low spatial resolution. In contrast, low Earth orbit (LEO) satellites like Suomi-NPP, NOAA-20, and …
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Sensor Package Analysis and Simulation for Direct Sensor-to-Satellite Links
… investigates the design and the performance of low-power microsensors that communicate directly to a satellite or a constellation of satellites. Information is spread using pseudo noise (PN) or Barker codes. The sensors use a single circular microstrip patch element with a wide beamwidth or a …
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Evaluation of Probabilistic Methodology for Predicting Satellite Tracking Resources
… acquisition services to large constellations of satellites. This approach, developed by Hagar is evaluated using Monte Carlo simulations of optimal satellite contact scheduling on a tracking network for a certain class of satellites. The actual results of the scheduled Monte Carlo simulations …
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Joint Localization and Synchronization via User Cooperation in Non-Terrestrial Networks
… Non-terrestrial networks (NTN) with low Earth orbit (LEO) satellites offer a promising alternative for positioning, navigation, and timing (PNT) by providing diversity and increasing the signal-to-noise ratio (SNR) over global navigation satellite systems (GNSS). However, the primary …
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Kinetic modeling of electrodynamic space tethers
… space tethers provide propellant-less orbit boosting and de-orbiting of Low Earth Orbit (LEO) satellites. On the one hand, when driven by a current, their interaction with the Earth's magnetic field creates a thrusting Lorentz force. On the other hand, current can be collected from the …
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A variable-rate modulation and coding scheme for low earth orbit satellites
Low Earth Orbit (LEO) satellites are increasingly being used for a wide variety of communications applications. These satellites have to operate in widely varying channel conditions. These conditions are often significantly better than the 'worst case' situations that are experienced and thus a …
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A Genetic Algorithm Framework using Variable Length Chromosomes for Vehicle Maneuver Planning
… potential in increasing the performance and/or lowering the cost of complex systems. Reconfigurability enables a system to adapt and dynamically respond to the specific objectives it encounters, rather than simply being optimized towards a general case. One such class of reconfigurable systems …
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The Impact of Low-Earth-Orbit Satellites on GNSS Ambiguity Resolution
In this thesis, the impact of low-earth-orbit (LEO) satellites on carrier phase ambiguity resolution is demonstrated through a global covariance simulation and a hardware in-the-loop simulation. Dedicated LEO constellations for GNSS are expected to become operational within the next few years and …
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Understanding how low energy electrons control the variability of the Earth's electron radiation belts
… trapped electrons, surrounding the Earth, presenting hazards to operational satellites. On the timeframe of hours, both the energy and particle flux of the radiation belts can change by orders of magnitude. Variations in the high energy relativistic electron flux depend on transport, …
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Towards Resilient and Secure Beyond-5G Non-Terrestrial Networks (B5G-NTNs): An End-to-End Cloud-Native Framework
… scalable communication services. NTNs, including Low Earth Orbit (LEO) satellites, Unmanned Aerial Vehicles (UAVs), and High Altitude Platform Systems (HAPS), extend traditional terrestrial networks by providing continuous connectivity in remote, underserved, and connection-critical scenarios such …
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Low altitude unmanned aerial vehicles (UAVs) in wireless networks
… of Things networks with high reliability and low latency requirements; and thirdly, their integration into maritime-satellite networks to enable communication between maritime users and satellites, in the absence of onshore base stations. Firstly, we explore a novel cellular-connected UAV …
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Low altitude unmanned aerial vehicles (UAVs) in wireless networks
… of Things networks with high reliability and low latency requirements; and thirdly, their integration into maritime-satellite networks to enable communication between maritime users and satellites, in the absence of onshore base stations. Firstly, we explore a novel cellular-connected UAV …
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An Information-Theoretic Examination of Next Generation Location Systems: The Role of LEOs, RISs and the Near Field
… GPS is vulnerable to failures due to its low received signal power, susceptibility to jamming, and reduced accuracy in dense urban environments and deep fades. A failure of GPS could have severe consequences, making it crucial to explore alternative or supplementary navigation …