Research Of Baseband BOC Signal Synchronization Based On FPGA

Binary Offset Carrier (BOC) modulation is an essential technique in the future satellite navigation system, European Commission and United States had decided to implement the BOC on the Galileo open service (OS) and the GPS IIA civil signal in the future. The synchronization system affects the performance of the satellite signal receiver directly, so the research the BOC signal synchronization system is very important.In this dissertation, BOC signal is firstly analyzed, including the time domain performance, power spectral density and autocorrelation function. Then BOC(1,1) signal is simulated and characteristics of BOC are verified using MATLAB. MBOC is one important implementation of BOC signal, so a detailed analysis of MBOC is given with simulation results.Then, this paper analyzes the synchronization techniques used by satellite signal receiver, which include signal acquisition and signal tracking. The purpose of synchronization is to get the accurate estimation of Doppler frequency and PRN code delay. Signal acquisition process is a coarse estimation of the two parameters mentioned above, common ways of acquisition are discussed and simulation results of BOC(1,1) acquisition are performed. Signal tracking is aimed to get the accurate estimation of the two parameters, this process contains carrier tracking loop and code tracking loop. A detailed discussion and analysis of this two loops are given and tracking performance of costas carrier tracking loop is simulated. Ambiguity is one important factor affecting the synchronization accuracy, in order to alleviated the impact of ambiguity for CBOC signal, a new correlation function is proposed.Based on the previous theoretical analysis and simulation results, the essential modules for BOC signal synchronization are implemented on FPGA board, which include the signal generation module, the carrier tracking module and the code tracking module. The signal generation module can generate the repetition of BOC signal, the carrier tracking module can track the carrier frequency in certain accuracy and the code tracking module can extract the symbol information from the input signal.This paper also presents the results of simulation and design.