| Spread spectrum communication technology has strong abilities of anti-interference,confidentiality, concealment and accurate positioning and velocity measurement. And it hasbeen widely used in the fields of satellite communication and ground communication. Thispaper combines the application of space rendezvous and docking area, and studys the keytechnology of the direct sequence spread spectrum signal detection and tracking, and givesthe design of acquisition and tracking and the analysis of measured datas.The first chapter mainly introduces the research background, purpose, significance andthe domestic and foreign development situation of the key technology of DSSS system, andarranges the work contents of other chapters.The second chapter mainly introduces the key technology of acquisition circuit inDSSS system. Firstly, the basic working principle of DSSS system and the commonly usedmodulation method are given. Secondly, the commonly used search modes of acquisitioncircuit are introduced. Thirdly, the coherent accumulation and non coherent accumulationtechnology are researched. Then, the improvement measures of the sector decline of FFTtransformation are studied. At the end of this chapter, the detection and decision methodsare studied.The third chapter mainly introduces the key technology of tracking loop in DSSSsystem. Orderly, the discriminators and the optimal parameters of PLL, FLL and DLL areresearched. In addition, the carrier auxiliary of DLL is studied.The fourth chapter mainly introduces the design and realization of acquisition circuitand tracking loop in DSSS System. The parameters, procedure, the detection and decisionmethods and the law of motion are designed. The designs of discriminator, loop filter andlock detection method of FLL, PLL and DLL are given. In the end, the realization ofacquisition circuit and tracking loop using FPGA is given, and the measured datas areanalyzed.The end of the paper is summary and prospects. |
