Research Of Spread Spectrum Code Fast Acquisition And Its Digital Implement In Complex Spread Spectrum System

The direct-sequence spread-spectrum (DS/SS) technique has been applied for mobile communication, telemetry and orinentetion, radar system since it offers many advantages including anti-interference, anti-eavesdropping, multiple access anti-fading and so on. The complex system has the function of communication and telemetry simultaneously because the DS/SS has the ability of strong discrimination and ranging.In this paper, the structure of complex system is ameliorated so that the inconsistent of technique parameters has been conciliated in traditional complex system. These parameters include the range of telemetre, the precision of telemetre, the real time ability and the velocity of communication. The need of complex code including code characteristic, the speed of code and the length of code is analyzed stressly in complex system. In order to improve the real time ability of the comples system and shorten the time of code acquisition, the novel sequential estimation is proposed. The mean acquisition time of the novel sequential estimation in white Caussian noise (AWGN) is derived. Compared with many methods of acquisition throuth a lot of simulation experiments, numerical results show that the novel sequential estimation performs better in the real time ability of complex system. Some function modules of this complex system have been carried out on FPGA+DSP digital high-speed platform in this paper. Especially many researchs have been done in the part of digital matched filter in FPGA All this work will pay strong matting on application of this technique.