Gps Software Receiver Capture Key Technology Research

GPS software receiver technology is a new technology in the field of satellite navigation in recent years. Acquisition is one of the key technologies of the software receiver study. It has been developed based on L1C / A code single-frequency GPS software receiver abroad. The current moving is in high sensitivity, multi-direction signal and developing a practical of high-performance satellite navigation software receiver. GPS software receiver technology starts late in mainland. GPS software receiver acquisition is facing more time and low sensitivity defect. Thus, breakthroughs in key technologies for enhancing the competitiveness in the field of satellite navigation is of great significance.The main topic studies the baseband signal processing section of GPS software receiver. It introduces a weak GPS signal acquisition research, software receiver acquisition and tracking fast.(1)For weak signal the software receiver acquisition, it integrates the advantages of differential acquisition and more data points .It studies an improved acquisition method of coherent and non-coherent. It make up incoherent and coherent Shortcomings .It resolves that the data bits can not transitions, noise superposition problem. Simulation results show that the improved algorithm can capture the signal as low as 20dB signal to noise ratio and improve the software to capture the receiver sensitivity.(2)In terms of speed, the software receiver tracking method using code storage, code generation in software receiver of tracking is the most time-consuming. Experimental results show that the code storage method eliminates the time code generation, saving half of the tracking speed.(3)FPGA fast acquisition is a realization of acquisition using FPGA. In the personal computer acquisition is used to acquire signals of the correlation processing pipeline operations. While the FPGA in parallel correlate operation, it greatly enhances the rate of acquisition. The implementation methods are used in the sampling Method, 5714 points to 1024 points in the sampling FFT transform. The FFT and anti-FFT transform are realized using FPGA IP cores. Based on qurtus software, each module to acquisition is analyzed. The results of code phase and carrier frequency are obtained, and it is applied to the tracking to verify the results of experiments. The results proved the correctness of the acquisition.