BDS Receiver Acquisition And Tracking Research Methods

After the global positioning System GPS, Russian GLONASS and European Galileo, BeiDou Navigation Satellite System (BDS) is developed by China.At first, this dissertation studies the method of BDS signal modulation and analyses the characteristics of BDS signal modulation. At the same time, this dissertation analyzes the correlation function and power spectral density of BOC signals modulation by the comparison with the traditional BPSK signal. Although the steep peak of BOC correlation function can improve the precision of the code phase, but there will be a multi-peak phenomenon.Therefore, the methods on eliminating the influence of multi-peak to improve the precision of acquisition is a major research problem.Then this paper researches on the ASPeCT method in-depth. By the experiments on Matlab, it can effectively eliminate multi-peak and improve precision of the acquisition.The use of ASPeCT also can eliminate the fuzzy points and improve the tracking accuracy.Finally, through the contrast of different experiments on Matlab, the results demonstrate that the use of cubic spline interpolation can effectively improve the precision of the code phase.The carrier loop and code loop of the tracking are studied in-depth, the paper mainly studies the phase-locked loop(PLL) and frequency-lock loop(FLL) of carrier loop and the impact of the choice of the order of the loop of tracking, as well as the delay-lock loop(DLL) of the code loop. According to the Factors that affect the dynamics, noise in the loop, this dissertation studies the way to decide the bandwidth and the order of the loop,and then studies the SNR,the phase discriminator and the integration time of the loop. At last,the study researches the graphics of the simulation on Doppler shift and the outputs of code phase discriminator and the immediate correlation peak output error by the comparison of the second-order FLL assisting third-order PLL loop of tracking and the traditional third-order PLL loop, in conclusion,the second-order FLL assisting third-order PLL loop of tracking can improve the tracking performance.