Research On Key Technologies Of Isl Data Communication In Space-Based Network

From the 1970s to the middle of 90's in the 20th century, satellite communication system attracted much attention to, especially the research of space-based network has been a very active field because of the military needing. Strategic position of Space-based network in political, military and economic fields has made more improvement with the rapid development of space technology and application, taking up the advantage of space has become a primary task of developing space military strength for countries all over the world. At the same time, the development of information technology such as Mobile Communication and Computer Network prompt people to study how to combine the information technology with aerospace technology from a new perspective. Constructing space-based network as the strategy of entering space, using space and controlling space, as the approach of obtain, fused, distribute and process battlefield information.The basis of Constitute the space-based network is to build the communication link between the corresponding satellite nodes - Inter Satellite Link. Using the Inter Satellite Link we can combine the satellite orbiting the earth in different levels to component multilayer satellite networks, then can use all sorts of orbital altitude satellite constellation advantage and play the advantage in coverage, links, and transmission delay, etc, to ,meet various demands of service quality of different business.This paper mainly studied some key technologies of space-based network inter-satellite link communication, including routing, frequency synchronization, joint coding modulation techniques. The main research topic of issue is:(1) Network system structure designing and system building Including the design of constellation and build of multi-layer satellite network topology. We designed a network structure of double satellite extreme orbit to form a more efficient and reliable satellite network structure, making full use of the GEO satellite wider coverage and LEO satellite low delay.(2) Based on the dynamic network topology, we proposed a DT satellite network routing algorithm based on time-sharing. This method puts the discrete network topology into a series of static topology. Its advantage is low complexity and high efficiency.(3) Aiming at the big doppler of satellite communication system, we proposed the carrier frequency estimation in binary correction based on FFT frequency estimation to solve this problem, achieving greater range and high frequency estimation.(4) In the high-speed digital satellite communication. we need a reliable decoding technology and modulation scheme. Encoding and modulation were considered separately in traditional communication systems. TCM grid coding modulation combines the encoding with modulation creatively, and uses the secondary decoding algorithm. This method improves the frequency utilization and increases the reliability of system, which solves the contradiction between the satellite communication bandwidth utilization rate and reliability.(5) The building of ISL data communication system in space-based network is primer content in this thesis. To realize the multimedia data transmission, we megered all sorts of key technologies, build the whole ISL data communication system in space-based. To some degree, it provides available reference certainly for the research in the future with high significance.