Design And Implementation Of Reliable Communication In Inter-satellite Link Of Micro-nano Satellites

With the rapid development of micro-spacecraft technology,the application of micro-nano satellite formation technology has become more and more widespread,which has become a hot topic in the field of aerospace technology at home and abroad in recent years.In some Low Earth Orbit satellite formation missions,the inter-satellite link has large microwave interference due to its proximity to the ground,and it is difficult to give consideration to both the quality and efficiency of communication due to the fixed data transmission rate.In this case,the existing digital baseband processing module can no longer fully meet the mission requirements of reliable communication between satellites.Therefore,the reliable communication design of inter-satellite links should focus on the research of anti-interference and variable rate communication.The main work of this thesis is as follows:(1)According to the research status of microsatellite formations and related literature on inter-satellite communication technology at home and abroad,anti-jamming design and variable rate communication are the key research content of reliable communication.This thesis introduces the principle of spread-spectrum communication and designs the synchronization scheme of the received signal in detail.The spread-spectrum communication module is implemented in FPGA and its function is verified.(2)For strong narrow-band interference,this thesis analyzes the characteristics of the time-domain and frequency-domain interference detection algorithms and selects the FFT interference detection scheme to design narrow-band communication mode,which is simulated and verified.The process of variable-rate signal processing is introduced and the differential Welch cycle diagram method is used to detect the loop signal-to-noise ratio.According to the actual needs,the variable rate communication scheme is designed.(3)The hardware test of reliable communication design verifies the synchronization scheme of spread-spectrum communication,anti-interference design of narrow-band mode and variable rate communication scheme.Test results show that spread-spectrum communication can resist 15 d B narrowband interference and narrowband communication can avoid interference.The communication rate is adjustable within the range of 1.2kbps ? 9.6kbps.The bit error rate is better than 10-6,and all the data can meet the design requirements.In summary,the research of reliable communication design of the micro-nano satellite based on FPGA in this thesis can meet the requirements of Low Earth Orbit satellite formation missions.The inter-satellite communication payload has the characteristics of adjustable data rate,low-power consumption and the ability to avoid its own interference and ground interference.The reliable transmission of inter-satellite information can be ensured.