Reserch And Implementation On Fast Acquisition Of GNSS Signal Based On FPGA

With the widely use of global navigation satellite system in aerospace, railway monitoring, marine rescue, environmental and disaster monitoring, missile guidance, civil aviation and other areas. China's Beidou system, Russian GLONASS, European Galileo and American GPS all accelerate the research and the development of navigation technology. The real-time and precision performance of navigation positioning are primarily decided on the merits of acquisition algorithm and tracking algorithm. In prior to tracking the signal, the carrier Doppler frequency shift and pseudo random code phase should be estimated, the estimation process is called capture, so capture algorithm is the key technology of the whole navigation system.In order to realize the fast acquisition of GNSS signal and reduce the acquisition time, this paper mainly studies the acquisition algorithm, and finally realizes the fast acquisition of digital IF signal on the FPGA. In the course of the study, on the principle of GNSS signal acquisition algorithm and the traditional acquisition algorithm are introduced and analyzed, the algorithm was improved by comparing the advantages and disadvantages, designed a parallel code phase PMF+FFT acquisition algorithm based on to the one of a plurality of code phase parallel search can improve the efficiency of acquisition.The capture module of the GNSS receiver is designed based on FPGA, the capture module based on PMF+FFT algorithm of parallel code phase is achieved,the design not only improves the capture rate, but also can reduce the cost of the hardware resource of FPGA. In the realization of the project have higher economic and feasible. Based on the thought of modularization, the capture module is divided into several sub modules, and every sub module is realized. the function and performance of the capture module was verified and analyzed based on IUS tool of Cadence Company.The design can achieve the GNSS signal pseudo code phase acquisition and Doppler frequency shift estimation, and reduce the acquisition time, the results prove the practicability and validity of the algorithm. The static timing analysis tool primetime of Synopsys is selected to analyze the design. The results show that the timing design of the acquisition module is integrated and correct.