The Research And Implement Of Baseband Acquisition And Tracking For GPS Receiver

With the wide range of applications of the global positioning system (GPS) in the maritime, aviation, aerospace, transportation mapping, resource exploration, communication, weather and so on, satellite navigation receiver development has become a hot research topic in the world. GPS receiver is a time and distance measuring system by receiving satellite navigation signal, which consists of RF front-end unit, baseband processing unit and positioning estimation and application unit. Acquisition and tracking is the most important signal processing in the base band unit, so it is one of the key technologies to achieve the navigation and positioning capabilities.This project focuses on the research of the baseband acquisition and tracking algorithm of GPS receiver, as well as the design and implement of signal processing on Field Programmable Gate Array (FPGA). It achieves the full algorithm capabilities on the chip.In the main part of this paper, it analyzes and compares these three acquisition algorithms:serial algorithm, fast Fourier transform (FFT) based parallel algorithm, FFT based parallel algorithm with pre-correlation process. It gives the algorithm process used in this thesis, and by the method of using two sets of the samples instead of the 16 average samples, it reduces system implementation complexity in cost of smaller decline in acquisition error performance. By using a coordinate parallel work control signal timing of the behind and front modules, it makes the acquisition units work together, and results in reduction of the acquisition time. In the design of the tracking module, a simple method of acquisition and tracking switch is used to achieve the recombination of acquisition results. By initializing the single-channel tracking unit, it completes the precise tracking of GPS signal. The overall test results of the acquisition and tracking modules verify the feasibility and effectiveness of these designs. Finally, this paper gives the overall structural design of the base-band system of GPS receiver.