Research On Communication Mechanism Of Inter-satellite Link In Satellite Navigation System

With the wide application of satellite navigation system, the requirements for theaccuracy of satellite navigation system and anti-interference ability are increasing. Sorelying on the ground station has been unable to protect autonomous operation of thesystem. Therefore, it is particularly important to realize autonomous operation withinter-satellite communication and inter-satellite measurement, which is navigationconstellation Inter-satellite Link (ISL). Therefore, the communication mechanism andkey technology of ISL which could be able to provide independent operation andupdated has become the focus of research.ISL is studied from the aspects of communication mechanism, signal form,synchronization and anti-jamming performance based on communication mechanism ofGPS. In order to enhance the anti-interference ability in the communication, spreadspectrum technology is regarded as the core of ISL, and the frequency hopping (FH)and direct sequence spread spectrum (DSSS) is the main support of spread spectrumcommunication. Therefore, according to the communication mechanism, ISLcommunication systems have been designed based on DSSS and FH. ISL has twomodes of communication, measurement model and data model, in differentcommunication system information processing of two modes is also different. Hence, asynchronization method is established for BPSK and FSK signals based on FH, whichregards the cyclic correlation synchronized head as the core. Synchronous processing isimplemented for BOC and UQPSK signals based on DSSS, which combinesmeasurement and data information. Further, on the basis of the analysis of interferencefactors existing in space, the signal interference of inter satellite links is determined.Besides, interference test is conducted for different inter satellite link communicationsystem and analyze anti-jamming performance. Based on theoretical research, the intersatellite link communication systems have been designed, which are implemented andanalyzed with MATLAB7.1simulation platform. The correctness and effectiveness ofsystem are verified by simulation.