14,417 research outputs found

    Satellite communication system and method Patent

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    Earth satellite relay station for frequency multiplexed voice transmissio

    Multichannel demultiplexer/demodulator technologies for future satellite communication systems

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    NASA-Lewis' Space Electronics Div. supports ongoing research in advanced satellite communication architectures, onboard processing, and technology development. Recent studies indicate that meshed VSAT (very small aperture terminal) satellite communication networks using FDMA (frequency division multiple access) uplinks and TDMA (time division multiplexed) downlinks are required to meet future communication needs. One of the critical advancements in such a satellite communication network is the multichannel demultiplexer/demodulator (MCDD). The progress is described which was made in MCDD development using either acousto-optical, optical, or digital technologies

    Satellite Communications: Impact on Developing Economies

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    Access to information and communication infrastructure greatly enhances economic growth. When a reliable and affordable medium for information exchange is available, previously unanticipated developments ensue. Most areas in developing countries are sparsely populated and highly rural. Satellite communication is an excellent option for meeting this and many other pressing communication needs of developing economies. This paper examines the impact of satellite communication on developing economies, using popular examples as case study

    Advanced Algorithms for Satellite Communication Signal Processing

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    Dizertační práce je zaměřena na softwarově definované přijímače určené k úzkopásmové družicové komunikaci. Komunikační kanály družicových spojů zahrnujících komunikaci s hlubokým vesmírem jsou zatíženy vysokými úrovněmi šumu, typicky modelovaného AWGN, a silným Dopplerovým posuvem signálu způsobeným mimořádnou rychlostí pohybu objektu. Dizertační práce představuje možné postupy řešení výpočetně efektivní digitální downkonverze úzkopásmových signálů a systému odhadu kmitočtu nosné úzkopásmových signálů zatížených Dopplerovým posuvem v řádu násobků šířky pásma signálu. Popis navrhovaných algoritmů zahrnuje analytický postup jejich vývoje a tam, kde je to možné, i analytické hodnocení jejich chování. Algoritmy jsou modelovány v prostředí MATLAB Simulink a tyto modely jsou využity pro ověření vlastností simulacemi. Modely byly také využity k experimentálním testům na reálném signálu přijatém z družice PSAT v laboratoři experimentálních družic na ústavu radioelektroniky.The dissertation is focused on software defined receivers intended for narrowband satellite communication. The satellite communication channel including deep space communication suffers from a high level of noise, typically modeled by AWGN, and from a strong Doppler shift of a signal caused by the unprecedented speed of an object in motion. The dissertation shows possible approaches to the issues of computationally efficient digital downconversion of narrowband signals and the carrier frequency estimation of narrowband signals distorted by the Doppler shift in the order of multiples of the signal bandwidth. The description of the proposed algorithms includes an analytical approach of its development and, if possible, the analytical performance assessment. The algorithms are modeled in MATLAB Simulink and the models are used for validating the performance by the simulation. The models were also used for experimental tests on the real signal received from the PSAT satellite at the laboratory of experimental satellites at the department of radio electronics.

    ETS-5, ETS-6, and COMETS projects in Japan

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    Three satellite communication projects now in progress in Japan are described. The first is a project to establish a telecommunication network for tele-education, TV conference, and tele-medicine in the Asia-Pacific region by using the Japan's Engineering Test Satellite-5 (ETS-5). The second is a project of the ETS-6 satellite, to be launched in 1993, for inter-satellite communication, mobile and fixed communication, and millimeter wave personal communication experiments. The third is a project of the Communications and Broadcasting Engineering Test Satellite (COMETS), to be launched in 1997, for advanced mobile satellite communication, inter-satellite link, and advanced broadcasting experiments at higher frequencies

    Network emulation focusing on QoS-Oriented satellite communication

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    This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication

    Satellite communication and navigation for mobile users

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    Efforts made to utilize space technology for solving communication and navigation problems faced by mobile users in earth orientated situations are outlined. Applications include transoceanic airline communications, reliable long range ship-shore communications, emergency communications in regions with rough terrain, and military operations

    Development of a metalised carbon fiber reinforced plastic (CFRP) antenna reflector for satellite communication

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    The Antenna reflectors made of Carbon Fibre Reinforced Plastics (CFRP) are used in spacecrafts for Satellite Communication in C, S and Ku bands. For futuristic Satellite Communication applications in x2018;Kax2019; band, there is a need of improving the reflectivity for Radio Frequency (RF) signals by metallising the surface of CFRP reflectors. The space qualified CFRP reflectors have been developed by ISRO for various GEOSAT projects but the process for developing a space qualified reflector having a metallized surface has not been established in the country. Recently, efforts in this hither to fore unexplored domain have been made jointly by Space Application Center, Ahemadabad and National Aerospace lab, Bangalore to develop reflectors with metallized surface

    Possible application of remote-sensing techniques and satellite communications for earthquake studies

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    Passive and active remote sensing techniques used with satellite communication for earthquake studie
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