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 123 for “"Satellite system"”.
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Satellite System Safety Analysis Using STPA
… NASA, are inadequate for analyzing safety at the system level. System-Theoretic Accident Model and Processes (STAMP) shifts the focus of safety from preventing failures to that of a dynamic feedback control system that enforces behavioral constraints. System-Theoretic Process Analysis (STPA), the …
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Frame synchronisation methods for digital satellite system
… was carried out in four specific areas, namely, Satellite-Switched Time-Division Multiple-Access (SSTDMA) network synchronisation, frame synchronisers, remote sensing satellite data decommutating systems, and prototype frame synchroniser implementation. In the area of SSTDMA network …
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Remote synchronization method for the quasi-zenith satellite system
This dissertation presents a novel satellite timekeeping system which does not require on-board atomic clocks as used by existing navigation satellite systems such as GPS, GLONASS or the planned GALILEO system. This concept is differentiated by the employment of a synchronization framework combined …
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Design of the control systems operations for the Iridium satellite system
The Iridium satellite system as proposed by Motorola, Inc. provides continuous global communications coverage by supplementing prevailing telephone services. The satellite system is comprised of 66 Low Earth Orbiting (LEO) satellites which are able to accommodate Iridium handsets or existing …
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Integration of satellite system and Stratospheric Communication Platforms (SCP) for weather observation
Submitted to the Information Technology (IT) Department in conformity with the requirements for the degree of Doctor of Philosophy in Information Technology, Durban University of Technology. Durban, South Africa, 2016.
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Integration of Wireless Sensor Network with CubeSat Satellite System for Enhanced Agricultural Monitoring
Direct-to-Satellite (DtS) uplinks by many low-power devices create a classic many-to-one contention problem during short visibility windows. This work proposes a hierarchical mesh→gateway→satellite architecture and a lightweight contention-mitigation protocol that combines randomized backoff with a …
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A Low Power Beacon for Transmitting Location Data via the Globalstar Satellite System
… industries are turning to wireless communication systems to track their assets. One example of such an industry is the shipping industry, where — under the growing emphasis on homeland security — tracking cargo containers and their contents has become a high priority. There are several beacons on …
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A probabilistic model of the effects of satellite system automation on cost and availability
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1997.
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Spectral analysis of earth orientation results from Doppler tracking of the Navy Navigation Satellite System
Doppler tracking of the Navy Navigation Satellite System (NNSS) gives solutions for polar motion as a by-product of the orbital computation process. The polar motion estimation process at the Defense Mapping Agency is reviewed and comparisons of the Doppler results with the polar motion series of …
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Performance evaluation of chirp spread spectrum system and Land Mobile Satellite System by computer simulation
… dissertation examines the performance of two satellite radio communication systems by computer simulation. Two simulations were separately performed for a spread spectrum chirp system as an analog communications system, and for the Land Mobile Satellite System (LMSS) channel as a digital …
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Low-cost and flexible USRP based real-time global navigation satellite system receiver for ionospheric sounder
Made available in DSpace on 2018-03-13T15:28:45Z (GMT). No. of bitstreams: 2 KIM-THESIS-2017.pdf: 2624944 bytes, checksum: 54f94eb1b16a5d22d1bcb586b0c1a959 (MD5) LICENSE.txt: 4207 bytes, checksum: 1a026929318db256d44e97c1d5dc823a (MD5) Previous issue date: 2017-12-15
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Factors That Affect the Global Positioning System and Global Navigation Satellite System in an Urban and Forested Environment.
… time measurements acquired from GPS and GLONASS satellite observations using RTK techniques in an urban and forested environment. To determine this accuracy, 2 data sets of 3-dimensional coordinates were created and compared at 14 stations situated at East Tennessee State University. One data set …
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Design and Simulation of a Planar Crossed-Dipole Global Navigation Satellite System (GNSS) Antenna in the L1 Frequency Band
… of a planar cross-dipole Global Navigation Satellite System (GNSS) receiver antenna to operate in GNSS L1 frequency band with multipath mitigation performance. First, a crossed-half-wavelength dipole antenna was designed to resonate centered at 1.6 GHz, and then various configurations were …
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Path planning and position control and of an underactued [sic] electromagnetic formation flight satellite system in the near field
… Next the thesis limits itself to a two-satellite system and thus is able to perform a state reduction that constrains the motion to an arbitrary two-dimensional plane in 3-dimensional space showing that this is not actually a constraint on the real system for a two satellite formation. A …
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Performance modeling and analysis of parallel processing and low earth orbit satellite communication systems
… analysis of packet-switched data communication systems. The research described in this dissertation examines performance characteristics of two types of packet-switched data communication systems. The first system to be analyzed operates in a parallel processing environment where cooperating …
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A Connection Admission Control Framework for UMTS based Satellite Systems.An Adaptive Admission Control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS.
… growth in the use of multimedia applications. A satellite system offers great potential for multimedia applications with its ability to broadcast and multicast a large amount of data over a very large area as compared to a terrestrial system. However, the limited transmission capacity along with …
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Experimental design for the evaluation of high-Tc superconductive thermal bridges in a sensor satellite
Infrared sensor satellites, which consist of cryogenic infrared sensor detectors, electrical instrumentation, and data acquisition systems, are used to monitor the conditions of the Earth's upper atmosphere in order to evaluate its present and future changes. Currently, the electrical …
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System architecting of a campaign of earth observing satellites
… warming, the ability to collect data on Earth system dynamics is of high importance. This thesis discusses how systems architecture principles can be successfully applied to the scheduling and implementation of large, complex space satellite systems, designed to provide measurements towards the …
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