不同相干积分方法对GPS弱信号捕获的影响  

Effect of Different Noncoherent Integration Alternatives on Weak GPS Signal Acquisition

作　　者：张文[1] 饶谷音[1] 韩松来[1] 袁保伦[1] 

机构地区：[1]国防科学技术大学光电科学与工程学院,长沙410073

出　　处：《数据采集与处理》2012年第1期38-44,共7页Journal of Data Acquisition and Processing

摘　　要：无外界辅助的GPS弱信号捕获,需要长的相干积分时间和多的非相干积分次数,还要考虑未知的导航数据位和数据位分界对相干积分的影响。本文针对无外界辅助的GPS弱信号捕获方法,从非相干积分入手,提出了一种新的非相干积分方法,并在此基础上分析了包含新方法在内的4种非相干积分方法在相同捕获条件下的捕获概率情况。这些方法在每步非相干积分操作上使用不同的计算方式来计算非相干积分,能达到节约计算量和存储空间的目的。在相同相干积分时间、非相干积分次数和导航数据位边界下,结合不同载噪比条件的弱信号捕获的蒙特卡罗仿真,给出了4种非相干积分方法的捕获概率的实验验证和对比分析。Unaided acquisition of weak GPS signals requires both long coherent integration time and a great amount of noncoherent integration operations. The unknown navigation data bits and bit edges should also be considered. From the point of noncoherent integration of unaided weak GPS signal acquisition method, a new alternative is proposed. Besides the new one, four different noncoherent integration alternatives are introduced. They use different approaches to compute the noncoherent integration at each step to reduce calculation and save memory space. Under the same coherent integration time, the same noncoherent integration operation number and the same navigation data bit edge number, with different carrier-to-noise ratio, Monte Car- lo method is applied to verify the probability of detection and the results of the four alternatives are compared.

关 键 词：GPS 信号捕获 弱信号 非相干积分 捕获概率 

分 类 号：P228.4[天文地球—大地测量学与测量工程]