The Research Of Baseband BOC Signal Synchronization In GNSS Receiver

With vigorous development of Global Navigation Satellite System, the BOC signal synchronous system becomes critical. BOC signal spectrum crack into two parts with cave in center and raise the utilization ratio of frequency bandwidth. BOC signal relieve the problem of frequency bandwidth resource shortage in some ways. BOC signal’s autocorrelation function has sharp correlation peak. BOC signal can achieve more accurate tracking performance, better security and multi-path resistance. Considering about these advantages, BOC signal gets a really nice reception in Global Navigation Satellite System.The research of BOC(15,2.5) signal synchronization system is very important in the paper, which include signal acquisition and signal tracking. Firstly, to simulate BOC signal using MATLAB and compared to BPSK signal. The characteristics and basic theory of BOC signal are analyzed. Based on the study of BOC signal’s theory, the BOC(15,2.5) signal is implemented on FPGA board and measured. Secondly, to study the research of BPSK signal synchronization system. Because of BOC signal’s autocorrelation function has many correlation peak, it can lead to error acquisition. Summarize some BOC signal synchronization system which previous scholars have proposed. BOC signal’s acquisition method is BPSK-like and FFT. BOC signal’s tracking method is three loops architecture. Thirdly, according to the requirements and performance of this paper, choose the FPGA and DSP to build the hardware platform. The chip of AD9516-1 provides clock signal for some chips, such as FPGA, DSP and AD54RF63. AD54RF63 chip implement A/D sampling of intermediate frequency analog signals. Mutual cooperation between FPGA and DSP realize the digital processing. Last, to realize BOC(15,2.5) signal synchronization system on the hardware platform and complete the required navigation data extraction. DSP and PC complete the information interaction, and displayed on the PC interface.