Research On GPS Singal Tracking Algorithm Under High Dynamic Environment And Desgin Of Baseband IP Core

GPS system has become an indispensable part of living, national security and military construction. With the rapid development of GPS technology, there are increasingly high requirements for the performance of the GPS receiver, providing highly accurate and stable GPS navigation and positioning services is urgently to be solved. High dynamic environment, a common scenario of GPS system in military, which will result in a larger Doppler frequency when the GPS receiver is operating, leads to the GPS receiver easy to unlock and cannot stably track. This paper research on the dynamic GPS tracking algorithms, and implement GPS baseband processors, it is of great significance for application and development of GPS technology.This paper aims to ameliorate the GPS tracking technology under high dynamic environment. At first, the basic structure of the GPS signal is clarified, and a high dynamic GPS intermediate frequency signal source is designed, which can simulate a typical high dynamic signal model; Further, the traditional principle of GPS tracking loop including carrier tracking loop and code tracking loop is analyzed. Next, the paper explores the effect of dynamic stress on conventional tracking loop under high dynamic environment, moreover, a high dynamic GPS tracking algorithm based on maximum likelihood estimation is proposed, which can reduce the computational algorithm by using a two-step approach and improve the tracking accuracy by using interpolation method. Finally, the author designs a GPS baseband processor using Verilog language on the Xilinx Platform to realize the acquisition and tracking of GPS signal and export the GPS signal navigation data. Acquisition and tracking modules are implemented by the correlator, which can reduce hardware design resources. Each tracking channel adopts the same loop structure design, and CORDIC algorithm(IP core) in Xilinx platform is introduced to achieve the carrier discriminator and code discriminator, and two order digital filter is employed by loop filter to filter out the noise in the error signal. Timing simulation results on FPGA show that the design of the GPS baseband IP nuclear energy can acquire and track the GPS signals, which proves that the method introduced by this paper is of strong practicality.