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Milstar“环”加速了数据向反恐战场的传输
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作者 平良子 《电信技术研究》 2002年第4期35-36,共2页
关键词 Milstar卫星 高优先权信息 四星星座系统 通信卫星网络
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Dynamic Connectivity in Cislunar Communication Networking Based on Geosynchronous Orbit Relay Satellites 被引量:3
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作者 Wu Xiaobo Zhou Xianwei Lin Fuhong 《China Communications》 SCIE CSCD 2012年第11期41-53,共13页
The architecture of cislunar multi-hop communication networks, which focuses on the requirements of lunar full-coverage and continuous cislunar communications, is presented on the basis of Geosynchronous Orbit (GEO) s... The architecture of cislunar multi-hop communication networks, which focuses on the requirements of lunar full-coverage and continuous cislunar communications, is presented on the basis of Geosynchronous Orbit (GEO) satellite network relays. According to the geographical distribution of the forthcoming Chinese Deep Space Measuring and Controlling Network (DSMCN), two networking schemes are proposed and two elevation angle optimization models are established for locating GEO relay satellites. To analyze the dynamic connectivity, a dynamic network model is constructed with respect to the time-varying characteristics of cislunar trunk links. The advantages of the two proposed schemes, in terms of the Connectivity Rate (CR), Interruption Frequency (IF), and Average Length of Connecting Duration (ALCD), are corroborated by several simulations. In the case of the lunar polar orbit constellation case, the gains in the performance of scheme I are observed to be 134.55%, 117.03%, and 217.47% compared with DSMCN for three evaluation indicators, and the gains in the performance of scheme II are observed to be 238. 22%, 240.40%, and 572.71%. The results validate that the connectivity of GEO satellites outperforms that of earth facilities significantly and schemes based on GEO satellite relays are promising options for cislunar multi-hop communication networking. 展开更多
关键词 cislunar communication networking dynamic connectivity dynamic network model GEO relay satellites lunar full coverage
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Time synchronization in communication networks based on the Beidou foundation enhancement system 被引量:7
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作者 LIU Hui ZHANG RuFei +1 位作者 LIU JingNan ZHANG Ming 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2016年第1期9-15,共7页
Communication networks rely on time synchronization information generated by base station equipment(either the Global Navigation Satellite System receiver or rubidium atomic clock) to enable wireless networking and co... Communication networks rely on time synchronization information generated by base station equipment(either the Global Navigation Satellite System receiver or rubidium atomic clock) to enable wireless networking and communications. Meanwhile, the time synchronization among base stations depends on the Network Time Protocol. With the development of mobile communication systems, the corresponding time synchronization accuracy has increased as well. In this case, the use of sparsely distributed-high-precision synchronization points to synchronize time for an entire network with high precision is a key problem and is the foundation of the enhanced network communication. The current receiver equipment for China's digital synchronous network typically includes dedicated multi-channel GPS receivers for communication; however, with the development of GPS by the USA, network security has been destabilized and reliability is low. Nonetheless, network time synchronization based on Beidou satellite navigation system timing devices is an inevitable development trend for China's digital communications network with the establishment of the independently developed BDS, especially the implementation and improvement of the Beidou foundation enhancement system. 展开更多
关键词 Beidou satellite navigation system precision timing time synchronization Beidou foundation enhancement system communication network time synchronization
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