基于BDS三频信噪比的多径误差检测技术研究

Research on multipath error detection technology based on BDS three-frequency SNR

多径误差指间接波对直接波的破坏性干涉而引起的接收机与卫星的距离误差,具有时变特性,难以通过模型改正或差分技术等方法予以消除.但在存在多径干扰的情况下,同一颗卫星不同频率上的信噪比会发生波动,基于该特征,本文提出一种用信噪比检测多径误差的方法:基于北斗卫星导航系统(BDS)三频信噪比的多径误差数据,建立一个关于信噪比的统计量S■(实验环境)以及计算开阔环境(低多径环境)的检测阈值T,通过比较S■与T的大小关系来检测BDS卫星多径误差.实验结果表明:该方法可以有效探测BDS卫星多径误差,并基于检测阈值和位置精度因子(PDOP)的变化对该某段时间内的卫星予以剔除,获得更好的定位效果.

Multipath error is the distance error of receiver and star caused by the destructive interference of indirect waves on direct waves.The multipath effect has time-varying characteristics,Which is difficult to be eliminated by model correction or differential techniques.In the case of multipath interference,the signal-to-noise ratio fluctuates at different frequencies of the same satellite fluctuates.Therefore,this paper proposes a method to detect multipath by SNR,which establishes a statistic about the signal-to-noise ratio (experimental environment) and calculates the detection threshold of the open environment (low multipath environment),and compareds the statistical values of the experimental environment with the values of the low multipath environment detection threshold to detect the multipath error of the BDS satellite.The experimental results show that the proposed method can effectively detect the multipath error of the BDS satellite,and obtain better positioning effect by remove the satellites in a certain period of time based on the detection threshold and the change of position dilution of precision(PDOP).