Research And Hardware Implementation Of High-dynamic Real-time Acquisition Algorithm Based On B1 Signal

The precision and efficiency of BeiDou Navigation System are becoming more of a concern under high dynamic environment, with the improvement of satellite navigation. To deal with Doppler Shift and improve efficiency of acquisition is the research focus. A Bei Dou real-time acquisition system that can eliminate the influence of bite turnover is designed.Firstly, the characteristic of B1 signal and the impact of bite turnover to the ranging code are analyzed. The acquisition range of B1 signal is determined under generally high dynamic environment.Secondly, the performance of common two-dimensional search algorithm is analyzed.Principles of two-dimensional serial search and parallel search algorithm are demonstrated,and they do not apply to B1 signal real-time acquisition. The paper demonstrated the principle of the parallel code phase search algorithm, which improves the acquisition speed.Then algorithm is improved based on asymmetric FFT, the simulation experiment results show that the improved algorithm can eliminate the influence of bite turnover.Then, the principle of algorithm based on parallel search frequency offset is analyzed.The algorithm based on partial matched filter(PMF) realizes parallel search frequency and the code phase short-time parallel correlation. The parallel search algorithm that eliminates bite turnover is proposed in the paper. MATLAB simulation proves the algorithm performance and accuracy.Finally, the new acquisition solution is implemented on FPGA and the design of PMF is improved. The ability and design of each module is analyzed. The experiments that adopt high-dynamic simulation data and real-time data show the effectiveness and feasibility of the algorithm.