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 18 of 18 for “"space communications"”.
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Next-Generation Space Communications Technologies for Building Future Mars Connectivity
… of vital importance, both for in-situ and deep-space communications. Hence, this PhD dissertation aims to introduce innovation on this multi-faceted topic, to propose a new set of solutions which we refer to as Next Generation Communications on Mars (NGC-M). First, we discuss through extensive …
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Energy allocation and transmission scheduling for wireless and space communications
This thesis presents two innovations to geophysical inversion. The first provides a framework and an algorithm for combining linear deconvolution methods with geostatistical interpolation techniques. This allows for sparsely sampled data to aid in image deblurring problems, or, conversely, noisy …
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Optimal locations for the ground segment of optical space communications networks
Optical communications are envisioned as a key technology for space communication in the near future. This transition to optical terminals is being pushed by the higher data volume demand of certain missions and by the spectrum encroachment in current RF bands. In addition, optical systems present …
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Enabling Hybrid Optical-Microwave Space Communications with Optically Transparent RF Components Using Indium Tin Oxide (ITO)
<p>Over the last decade, spacecraft have increasingly integrated both microwave and optical communication systems, driving the need for electrically conductive and optically transparent materials. This study presents a comprehensive examination of advanced electromagnetic characterization …
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A simple model for the depolarizing effects of rain and ice on earth satellite links in the 10 to 30 GHz frequency range
… on the polarization reuse technique for earth-space communications. Precipitation in the form of rain and ice leads to significant depolarization and attenuation of dual polarized signals above about 10 GHz. The depolarization versus attenuation relationship is examined in depth using a …
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Integrated optical phased arrays for three-dimensional display applications
… for light detection and ranging (LiDAR) and free-space communications. However, silicon is limited to operating at infrared wavelengths since its bandgap prevents visible light transmission. The development of integrated OPAs for arbitrary complex wavefront synthesis in the visible spectrum would …
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Link Adaptation for Mitigating Earth-to-Space Propagation Effects on the NASA SCaN Testbed
In Earth-to-Space communications, well-known propagation effects such as path loss and atmospheric loss can lead to fluctuations in the strength of the communications link between a satellite and its ground station. Additionally, a less-often considered effect of shadowing due to the geometry of …
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Space Communication Channel Emulation Using Digital and Analog Signal Processing
… large distances, including low orbit and deep space, can be inherently difficult to evaluate since trial implementations are often impractical. In order to accurately measure the performance of a new protocol, it is important to evaluate it in an environment that most closely matchs that in …
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Design of a photonic crystal planar Luneburg lens for optical beam steering
… (LIDAR) for three-dimensional (3D) sensing, free space communications, additive manufacturing, and remote sensing. In particular, there is an increasing demand for LIDAR in a variety of applications including autonomous vehicles, unammaned aerial vehicles (UAVs), robotics, and remote sensing. …
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Design and optimisation of a low cost Cognitive Mesh Network
… networks. Recent developments in TV white space communications technology and the emergence of Cognitive radio devices that facilitate Dynamic Spectrum Access (DSA) have provided an opportunity to mitigate the spectrum scarcity problem. To solve the scarcity problem, this thesis reconsiders …
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Architectures for a space-based information network with shared on-orbit processing
… design choices for the architecture of a space-based information network with shared on-orbit processing. Networking is an efficient method of sharing communications and lowering the cost of communications, providing better interoperability and data integration for multiple satellites. The …
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Dynamic Code Selection Method for Content Transfer in Deep Space Network
Space communications feature large round-trip time delays (for example, between 6.5 and 44 minutes for Mars to Earth and return, depending on the actual distance between the two planets) and highly variable data error rates, for example, bit error rate (BER) of 10−5 is very comand even higher BERs …
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Perspectives on the satellite services industry : analysis of challenges and opportunities in the market, policy and regulatory environments
This thesis focuses on Space Communications and combines engineering, economics, market, and policy analyses to identify challenges and opportunities in the industry that are beyond the scope of any one isolated discipline. This work is divided in two parts. The first part begins by discussing the …
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On a Viterbi decoder design for low power dissipation
… coding is a coding scheme often employed in deep space communications and recently in digital wireless communications. Viterbi decoders are used to decode convolutional codes. Viterbi decoders employed in digital wireless communications are complex and dissipate large power. With the proliferation …
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A variable threshold for an energy detector using GNU radio
… systems, transport, smart city applications and space communications and exploration. Next Generation Networks (NGNs) are designed to connect millions of devices seamlessly and with high throughput rates in the aforementioned sectors and others not mentioned. The use of spectrum has to be …
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The Quest for Ideal Quantum Amplifiers
… and dark matter detection to metrology and space communications. The increasingly complex systems for computing, metrology, and communication require more robust, performant, and scalable components. As a prominent example, quantum computing holds the potential to solve computational …
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Development of high-performance front-illumination III-N avalanche photodiodes by metalorganic chemical vapor deposition
… transmission for many applications such as in-space communications, detection of missile plumes, portable biochemical threat detectors, flame detectors, and environmental monitoring. Metalorganic chemical vapor deposition (MOCVD) is a growth technique well-suited to the growth of advanced III-N …
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Stealth technologies based on thin microwave FSS absorbers
… dielectric clad foil backed outermost layer of space blankets. Simulated reflectivity results are presented for five close packed hexagonal patch FSS based absorber designs, ranging in thickness 140 µm − 112 µm (λ/213 − λ/25 at 10 GHz). These are suitable for Mechanical integration into the top …