一种GPS软件接收机信号快速捕获算法研究  

A Fast Signal Acquisition Algorithm for Software-Defined GPS Receivers

作　　者：李亚峰[1] 王新龙[1] 纪新春[1] 

机构地区：[1]北京航空航天大学宇航学院,北京100191

出　　处：《航空兵器》2013年第1期20-26,共7页Aero Weaponry

基　　金：国家自然科学基金(61074157);航空科学基金(20090151004)

摘　　要：利用实测数据,对全采样点循环相关、1023点和1024点平均相关三种GPS信号捕获算法进行了峰-峰比、捕获概率、捕获精度和执行时间的定量对比分析。针对1024点平均相关捕获算法执行速度快,但对弱信号捕获灵敏度差的问题,提出一种基于多码长数据段叠加的1024点平均相关改进算法。该算法对载波剥离后的多码长数据段叠加后再进行1024点平均采样,从而使其既满足FFT快速计算的要求,又提高了信噪比。测试结果表明该算法在保持捕获快速性的同时,能够显著提高GPS弱信号的捕获概率,克服了传统1024点平均相关导致的相关峰-峰比损失问题,具有实际应用价值。The quantitative comparison and analysis of peak-to-peak ratio, acquisition probability, acquisition accuracy and execution time are implemented by utilizing the measured data, with respect to three GPS signal acquisition algorithms including full size circular correlation, 1023-point and 1024-point averaging correlation. Considering the problem of 1024-point averaging correlation which has fast acquisi- tion speed but is limited by its poor sensitivity to weak signal acquisition, an improved algorithm is pro- posed. The proposed method firstly wipes off the carrier form the incoming signal, and then adds the ob- tained multi-period C/A codes to implement 1024-point averaging sampling. Consequently, it can not on- ly satisfy the rapid computation requirement of FFI＇, but also improve the signal-to-noise ratio. The test results show that this algorithm can significantly improve the acquisition probability of weak GPS signal and maintain rapid acquisition performance as well, which overcomes the peak-to-peak ratio losing of tra- ditional 1024-point averaging correlation and has wide practical application values.

关 键 词：GPS 快速捕获 循环相关 FFT 

分 类 号：TN973.3[电子电信—信号与信息处理]