Research On Modeling And Correction Method Of Beidou Satellite-induced Multipath Error

With the Beidou system application gradually developed,the user's requirements of the Beidou satellite precision positioning performance are getting higher and higher.However,there are some systematic errors associated with the satellite elevation in the original pseudorange observations,which are called satellite-induced multipath errors.Satellite-induced multipath error can't be eliminated or weakened by traditional error processing method,which seriously affects the positioning accuracy and reliability of Beidou system.In view of the above problems,this paper aims to eliminate or weaken the multipath error of Beidou satellite.According to the satellite multipath error generation mechanism and error characteristics,this paper uses a variety of data processing methods to establish a simple and accurate satellite-induced multipath error correction model,and the validity of the model is verified by the measured data.The main work and contribution of the paper are as follows:1.The mechanism of multipath error generation of Beidou satellite is studied.Then this paper introduced the multi-frequency multipath error calculation method.By comparing the multipath error sequence of Beidou and other satellite navigation systems,it is found that the multipath error variation of Beidou has some connection with the satellite elevation,The difference between the multipath error of the satellite end and the multipath error of the receiver is analyzed,and the influence of the multipath error on the satellite terminal is analyzed and summarized;2.The algorithm of elevation-based multipath error fitting is proposed,and the CEEMD filter denoising technique is introduced to improve the fitting accuracy.The fitting algorithm is extended to the GEO satellite,The fitting of the multipath error variation trend of the Beidou GEO,IGSO and MEO satellites provides data support for the next error characteristic analysis;3.The error characteristics of satellite-induced multipath error are analyzed,and the corresponding control variables are designed.The relationship between multipath error and receiver type,receiver antenna type,satellite type,station location,satellite azimuth,error stability and other factors is studied,which lay the foundation for the next model;4.A satellite-induced multipath error correction model is constructed in this paper,and all applicable conditions are given.Carried out the pseudorange single point positioning,relative positioning,precise point positioning experiments,relatively comprehensive analysis and comparison of the model in this paper,Wanninger model and traditional methods(satellite-induced multipath error are not correction)three different handling strategies.Results show that compared with the tradi-tional method,corrected the satellite-induced multipath error can effectively improve the positioning precision and stability of single point positioning,precise point positioning and the convergence rate of the long distance relative positioning.Using this model can obtain better improvement effect than Wanninger model.