卫星导航信号无模糊抗多径码相关参考波形设计技术

Design technique of GNSS unambiguous and anti-multipath code correlation reference waveform

针对目前卫星导航接收机码环多径抑制技术在二进制偏移副载波类信号下鉴别曲线可能出现多个稳定跟踪位置,导致接收机存在伪距测量的系统性误差的问题,提出最优鉴别曲线设计技术,采用奇异值优化的最小二乘方法,设计无多余跟踪点的本地码相关参考波形。从多径误差包络和跟踪精度两方面,对基于最优鉴别曲线的二进制偏移副载波信号码相关参考波形的设计性能进行验证评估。仿真结果表明:该方法可实现二进制偏移副载波信号在有限接收带宽下的无模糊鉴别曲线设计。以前端带宽为8.184MHz时的BOC(1,1)信号为例,设计的码相关参考波形相比W2波形,多径误差包络面积增加了61.8%,而跟踪精度提高了4~5dB。

In the code delay lock loop of GNSS receiver,the false-lock problem of binary offset carrier signal was caused by its multi-peak characteristic for the present multipath mitigation technique.An optimal discriminator curve design technique was proposed by using the least squares method combined with the truncated singular value decomposition.As a result,the local code correlation reference waveforms which have no ambiguity points in tracking the BOC signals can be derived.The simulation results show that the proposed method can realize coherent and non-coherent binary offset carrier signal discriminators without false lock points.Generally,there is a performance degradation in the tracking jitter.However,there are performance promotions for the BOC(1,1) signal,which has a 8.184 MHz front-bandwidth,with 61.8% increase in the multipath error envelope area,and 4 to 5 dB increase in the tracking precision compared with W2 waveform.Thus,the selection of waveform parameters involves a trade-off between the tracking ambiguity and tracking performances obtained under multipath and thermal noise conditions.