关键词: 快速傅里叶变换, 多普勒频率, 捕获性能, 数学模型, 全球定位系统

Abstract: L5 signal is a new civil navigation signal adopted by Global Position System since it has better navigation performance because of higher code rate and longer code length.The traditional acquisition method results in long acquisition time,especially under high dynamic circumstance on board,so a matched filter combined with FFT acquisition method was proposed,which could search the code phase and Doppler frequency at the same time,therefore reduced the acquisition time.The theoretical analysis and simulation results show that,this acquisition method is suitable to long code in large Doppler offset situation.Based on the comparison among various subsection methods,an appropriate subsection method which could satisfy the acquisition demand of L5 signal in GPS system was chosen.Finally,the acquisition experiment was implemented using a FPGA,tests were then conducted to verify and validate the method.