微弱GPS信号精捕获算法  

Fine Acquisition for Weak GPS Signal

作　　者：王勇松[1] 赵民建[1] 

机构地区：[1]浙江大学信电系,杭州310027

出　　处：《宇航学报》2010年第12期2671-2676,共6页Journal of Astronautics

摘　　要：为了解决微弱GPS信号比特/二次编码(Neumann-Hoffman码)的同步以及频偏精细估计等问题,本文提出了对相关器输出数据进行精捕获的算法。通过对相关器输出数据进行二次变频,对不同频点的信号进行比特/二次编码位置的搜索,从而实现弱信号条件下比特/NH码的同步以及频偏的精捕获。精捕获后,使用频偏补偿后的数据进行频偏的再次精细估计。经过理论推导和仿真验证,在C/N0不低于20dB/Hz时,用1299个相关器输出数据进行精捕获时就有95%以上的检测概率,说明本方法适用于微弱GPS信号条件下比特/NH码的同步和频偏精细估计问题。In order to achieve bit/NH（Nenmann-Hoffman）synchronization,second code synchronization and frequency fine acquisition,a new method named second acquisition using outputs of correlator is proposed.Outputs from correlator are down converted,and then used to perform bit/NH code synchronization.After second acquisition,frequency-compensated data is used to realize fine frequency estimation.Analysis and computer simulation show that this method could realize bit/NH code synchronization and fine frequency acquisition under weak signal environment.When C/N0 is not below 20dB/Hz,the probability of detection can achieve 95% using 1299 correlator outputs.

关 键 词：微弱导航信号 精捕获 比特/NH码同步 频偏精估计 

分 类 号：P228.4[天文地球—大地测量学与测量工程]