现代GNSS信号捕获性能评估理论与应用

Theoretical assessment and application of modern GNSS signals acquisition performance

全球卫星导航系统(Global Navigation Satellite System,GNSS)的应用越来越广泛,几乎涉及国民经济和社会发展的各个领域.作为导航系统设计的重要环节,GNSS信号性能评估工作受到了广泛关注.本文以单点检测为基础,建立GNSS信号统计检测的理论模型,提出了综合调制方式、搜索步长和捕获算法的捕获性能评估方法.针对BOC(Binary Offset Carrier),MBOC(Multiplexed Binary Offset Carrier)和AltBOC(Alternative BOC)等的匹配捕获、无模糊捕获算法的整体检测性能和主峰、边锋检测性能进行评估,给出定量分析结果.搜索步长固定时,BOC,MBOC和AltBOC调制信号的自相关函数多峰特性会导致捕获性能下降,而且副载波速率越高性能下降越明显.虽然BPSK-like和SCPC(Sub Carrier Phase Cancellation)等无模糊捕获算法会带来一定程度的信号功率损耗,但却能有效提高BOC信号的捕获性能.

The application of the Global Navigation Satellite System(GNSS)is extensive and has widely infiltrated the national economy and social development in various fields.As critical part of the satellite navigation system design process,GNSS signals performance assessment has received tremendous attention for a long period of time.The mathematical model of GNSS signal detection is built based on single point detection test.An improved acquisition performance assessment method that considers the modulation type,code search step-size,and acquisition algorithms is proposed herein.This study investigates the performance of the overall detection and main/side peak detection for Binary Offset Carrier(BOC),Multiplexed Binary Offset Carrier(MBOC),and Alternative BOC(AltBOC)signals using matched and unambiguous acquisition methods,and obtains quantitative results.With a fixed code search step-size,the multi-peaks of the autocorrelation functions of BOC,MBOC,and AltBOC signals will degrade the acquisition performance.The higher the sub-carrier rate,the more serious is the degradation.Although signal-power loss occurs to some extent,Binary PhaseShift Keying-like(BPSK-like)and Sub Carrier Phase Cancelation(SCPC)methods significantly improve the acquisition performance.