北斗二代导航信号抗多径性能分析与仿真

针对北斗二代导航信号抗多径性能的分析需求,推导了基于相干超前减滞后延迟锁定环的码跟踪多径误差评估方法,运用该方法分析了北斗二代导航信号的抗多径性能,仿真表明在多径直达信号幅度比为-6 dB,相关间距为24 ns,信号带宽为24 MHz时,北斗二代导航信号都能区分大于300 m的多径延迟。以MBOC信号为例对不同的多径直达信号幅度比、相关器间距、信号接收带宽、信号组成时导航信号的多径性能进行了仿真。结果表明:在多径直达信号幅度比一定时,提升信号的高频分量,在接收端采用窄相关技术和宽的接收带宽可将北斗二代导航信号的多径误差限制在4 m以内,且衰减速度更快,从而改善信号的抗多径性能。

Analysis and simulation on anti-multipath performance of Beidou2 navigation

An evaluation method of code tracking multipath error envelope based on coherent Early minus late delay lock loop is derived to analyze the anti-multipath performance of Beidou2 navigation signal.The simulation shows that all Beidou2 navigation signals are able to discriminate the multipath delay more than 300 m under conditions of multipath-to-direct ratio(MDR)=-6 dB,correlation distance d=24 ns and receiving bandwith =24 MHz.The anti-multipath performance of navigation signal is simulated under different multipath-to-direct ratio(MDR),correlation distance,signal received bandwidth and signal composition.The results show when MDR is a constant,the signal multipath error will be limited to 4 m and decline fast if increasing the high frequency component of Beidou2 navigation signal and utilizing narrow correlation distance and wide receiving bandwidth.So the signal’s anti-multipath performance can be improved.