Design And Implementation Of Digital Transceiver System For Proximity-1 Space

Proximity-1 space link is an important part of the planet network in deep space communication. Research and design of the proximity-1 space wireless transceiver system gets significantly meaning for the development on the proximity-1 space communications, deep space communications network and study on deep space transceiver in China. According to the architecture of the general digital transceiver systems and proximity-1 space link protocol developed by CCSDS, we design and implement a proximity-1 space digital transceiver system based on an FPGA & DSP digital signal processing platform. Not only includes the analysis of the classical theory of digital communication, but also the application of proximity-1 space link protocol and the innovative realization methods.Firstly, we make reasonable design of the whole system scheme and communication process combined with the proximity-1 space communication system requirements. The theoretical derivation of the transmitter and the receiver, detailed analysis and process of parameters design are given.Secondly, we analyse the principle of traditional Costas loop for carrier synchronization and the cause of phase ambiguity of coherent demodulation. Combined with the communication process recommended by the protocol and the classic methods of phase discrimination, we propose to realize the carrier synchronization without phase ambiguity by phase detecting in stages. Analyse and compare the performance of the table look-up method and CORDIC algorithm. Efficient carrier synchronization method and the simulation results of the circuits are given.Thirdly, on the basis of conventional early-late-gate synchronization theory, combined with the simulation results, an innovative design method is proposed to avoid the instability of the sampling point. Then, we design and implement the Gardner timing synchronization, compare the improved early-late-gate with Gardner on hardware system. In addition, a frame synchronization circuit realized by partial combinational logic design is designed.Finally, we simulate the whole digital transceiver system for proximity-1 space, and design the test system with different hardware and software platforms. Complete tests on the output signals of the transmitter and the key signals of each function module in digital receiver are conducted. The testing results verify the correctness of the system design and indicate it meets the requirements of the proximity-1 space communication protocol.