乘性噪声下的弱GPS信号捕获

摘要

乘性噪声对弱GPS信号的检测与捕获具有重要影响.在分析乘性噪声的循环平稳特性的基础上,提出一种在乘性噪声条件下的弱GPS信号检测方法.首先通过本地产生的伪随机码与接收到的GPS信号进行位乘,以尝试性地消除伪码对GPS信号二阶统计量的周期性的影响；然后利用去伪码后的GPS信号的循环平稳特性估计GPS信号的载频,从而进一步地完成对GPS信号的检测.同时还提出了一种乘性噪声条件下的弱GPS信号检测结构,分析了基于该检测结构的检测性能.最后通过仿真验证了该方法的有效性.%Multiplicative noise has important impact on weak GPS signal detection and acquisition.In this paper we propose a new weak GPS signal detection method based on the analysis of circulation stability property of multiplicative noise.First we make bit-multiplying on GPS signal received through locally generated pseudo-random code to attempt to eliminate the periodical impact of pseudo code on secondorder statistics of GPS single； Then we make use of the circulation stability property of GPS signal after the pseudo-code being eliminated to estimate the carrier frequency of GPS signal,so as to further fulfil the detection of GPS signal.Also a detection structure of weak GPS signal is proposed in condition of the multiplicative noise,the detection capability based on the structure is analysed as well.Simulation results verify the effectiveness of the proposed method in end of this paper.