Research On The Multipath Mitigation Techniques For BOC Modulated Signal In Satellite Navigation Systems

With the increasingly widespread application of satellite navigation system,people's requirement on the positioning accuracy is strengthened day by day,and the impact of the major errors of the positioning accuracy: ephemeris error,satellite clock error,ionosphere and troposphere error,multipath error and the receiver noise.Many of the above errors can be well eliminated by methods such as modeling and differential.But the multipath error is closely related to the characteristics of navigation signal itself,environment where the receiver is located and receiver processing algorithms,is hard to be eliminated by the differential method,so multipath error has already become the main factors which affect the performance of satellite navigation system.Techniques about multipath mitigation has become the research hot spot in satellite navigation system filed.This thesis systematically introduces the features of multipath signals,and the effects of multipath on the delay lock loop of navigation receiver firstly,and then detailed analyzes multipath mitigation algorithm's performance under the new signal system in BOC modulated signals.On this basis,This thesis studied the affect of antenna height on the multipath mitigation algorithm's performance for the first time,and then get the optimal height antenna for GNSS-750 antenna under multipath environment.Specifically,the thesis mainly includes the following contents:the characteristics of the multipath signals,the theory of multipath signal and the common models are systematically studied.The effects of the multipath signals on the code tracking loop and carrier tracking loop are analyzed.This thesis introduces the characteristics of the new modulation signal,analyzes the signal generation modes and autocorrelation function,power spectrum density and so on,studies the performance of the traditional BPSK modulation signal which is applied under the new system signal,including narrow correlation technology,Double-Delta technology,code related reference waveform technology.The algorithm principle and Implementation process are also analyzed in detail,The primary influencing factors are studied,such as channel,casing wave width.this thesis also introduces the characteristics of Estimator Double tracking algorithm,analyzes its tracking performance in the multipath environment,and gives some suggestions on the selection of related parameters.