GPS信号的码相位与多普勒频率联合捕获  

Joint Code Phase Acquisition and Doppler Frequency Shift Estimation for GPS Signals

作　　者：李小捷[1] 许录平[1] 郑文松[2] 

机构地区：[1]西安电子科技大学电子工程学院,西安710071 [2]西安航天动力研究所,西安710100

出　　处：《宇航学报》2012年第12期1768-1773,共6页Journal of Astronautics

基　　金：国家863高科技发展计划(2007AA12Z323);国家自然科学基金(61172138)

摘　　要：分析了PMF-FFT码捕获算法在不同频偏下的性能,针对其频率估计精度较低引起的部分频偏下的检测性能下降,提出了一种改进的码相位与多普勒频偏联合捕获方法。首先基于部分匹配滤波(PMF)相关算法得到一组匹配滤波输出;然后在PMF-FFT算法基础上提出了一种利用FFT幅度差求解的低复杂度高精度迭代频偏估计算法,并利用此高精度的频率估计值补偿PMF输出,进行相干检测,从而在提高频率估计精度的同时提高了信号的检测概率,实现了高精度的频率估计与码相位捕获的联合处理。仿真结果表明检测算法可以有效改善频偏估计精度,提升检测概率,并且具有极低的复杂度。The performance of PMF-FFT code acquisition algorithm under different frequency offsets is analyzed in this paper. Focusing on the detection performance degradation under partial frequency offset caused by the low frequency estimation accuracy, an improved code phase and Doppler shift united acquisition method is proposed. First, a set of matched filter outputs are obtained based on the partial matching filter （PMF） algorithm; then a low complexity and high- accuracy iterative frequency estimation algorithm is proposed by using the magnitude difference of the PMF-FFT output, and the frequency offset estimation is used to compensate the PMF output, thus improving the accuracy of frequency estimation and signal detection probability at the same time. Simulation results show that the algorithm can effectively improve the frequency estimation accuracy and the detection probability, and has very low complexity.

关 键 词：码捕获 频率估计 快速傅立叶变换 克拉美罗界 

分 类 号：TN96[电子电信—信号与信息处理]