Research And Implement Of Deep Space Communication Demodulation Techninology

With the rapid development of the space industry, the new round of the deep-space exploration booms in recent years. In deep-space exploration system, deep space communication system is the only link of information transmission and target control. The normal operation of the communication system and the accurate data link are the most important guarantee of the success of deep-space exploration missions. Meanwhile, the distant distance of the control communication is also the difficulty of deep-space exploration. Subject to the communication distance and limited resources in satellites, control data transmission rate hovered at Kbps orders of magnitude, for example the highest data transmission rate of China-Russia cooperative space probe YH-1 is only 8Kbps. Due to the development of the relay satellite and the orbiter technology, the deep space communication data transmission rate has been obviously increased, such as the data transmission rate of NASA Deep Space Network has reached 10Mbps under the condition of satellite relay.Based on the research of deep-space communication telemetry demodulation technology, especially the PSK modulation commonly used in deep space communication, an effective digital demodulation scheme which can cover the low speed to the high rate is put forward. The key technology is analyzed theoretically and is simulated in Simulink. Then the demodulator is realized on FPGA, and its performance is tested.In this issue, the core modules carrier and timing synchronization in receiver are analyzed theoretically. The three timing synchronization algorithms IP/MP(DTTL), Early-Late Gate and Gardener Algorithm most commonly used are compared in performance and application, and the best structures of DTTL and Early-Late Gate have been received.Finally, the low and middle rate demodulator and high speed algorithm are realized and tested on FPGA, which proved the rationality and feasibility of the system design. The design of the ground demodulation equipment in this issue, implement the power of 2 adjustable rate general-purpose ground receiving system and verify the high-speed demodulation scheme design, lay the technical foundation which meet the deep-space communication development. The design can be applied to deep space communication system, ground receiving system and integrated testing system.