应用延迟累加的微弱GPS信号捕获算法  

Improved Algorithm for Weak GPS Signal Acquisition Based on Delay-accumulation Method

作　　者：李源明[1,2] 李晶 张朋[2] 郑勇[2] 

机构地区：[1]宇航动力学国家重点实验室 [2]中国人民解放军63751部队

出　　处：《测绘学报》2016年第1期44-49,共6页Acta Geodaetica et Cartographica Sinica

基　　金：宇航动力学国家重点实验室开放课题(2014ADL0404)~~

摘　　要：针对在弱信号环境下传统算法无法进行捕获的问题,提出了一种改进算法。该算法在双块零拓展(double block zero padding,DBZP)算法的基础上,采用延迟累加的方法,首先将DBZP算法相关运算结果中被舍弃的部分暂存,然后对延迟1ms的接收信号进行相关运算,得到相应的相关运算结果,将其与存储的运算结果进行相干累加,并将相干累加结果作为捕获模块输出与门限值进行比较。改进算法在增加极少运算量的前提下,通过提高相关运算结果的利用率,增加了数据观测量。仿真结果表明,改进算法能够提高捕获算法处理增益,在捕获载噪比为17dB-Hz的信号时,检测概率能够达到91%。A new improved algorithm is proposed to solve the problem of GPS weak signal capture that the traditional algorithms are unavailable to capture under a weak signal environment. This algorithm is based on the analysis of double block zero padding （DBZP） algorithm and it adopts the delay-accumulation method to retain the operation results temporarily which are discarded in DBZP algorithm. Waiting for delaying 1 ms, the corresponding correlation calculation results are obtained. Then superimpose the obtained results with the operation results retained temporarily and compare the coherent accumulation results with the threshold value. The data measurements are increased by improving the utilization rate of correlation operation results in the improved algorithm on the premise of increasing little computation. Simulation results showed that the improved algorithm can improve the acquisition algorithm processing gain and it is able to capture the signals whose carrier-to-noise ratio（C/N0） is 17 dB-Hz and the detection probability can achieve to 91%.

关 键 词：弱信号捕获 延迟累加 双块零拓展 叠加 FFT 

分 类 号：P228[天文地球—大地测量学与测量工程]