Research On GNSS Multipath Effect And Observed Noise Reduction Method

With the rapid development of navigation and positioning technology,the demand for real-time,high-precision and high-availability location information is becoming stronger and stronger,and the processing of various error sources becomes an urgent problem.Multipath effect and observation noise are the main Influencing factors,more and more relevant experts at home and abroad attention.In some special applications,multipath effect and observation noise has become the dominant factor affecting the positioning accuracy,we need to give priority to solve.In this paper,we focus on how to reduce the influence of multipath error and observation noise in GNSS positioning measurement.We start from the basic concept and extraction method of multipath error and observation noise,and gradually explore the multipath error and observation noise in signal frequency and change period And finally the above research results are given to reduce the multipath effect and observation noise in GNSS positioning solution.The main work and achievements of this paper are summarized as follows:1?MPC algorithm is used to extract the multipath error and the observation noise combination in the pseudorange measurement to analyze the influence factors and influence rules of the multipath effect and the observed noise,and then summarize the receiver antenna environment,satellite distribution,hardware equipment Performance is the three main factors that affect multipath effects and observed noise.2?The MPC algorithm and the triple-frequency carrier phase combining method are used to extract the pseudorange measurement and the carrier phase measurement multipath error combination items respectively.It is used for the comprehensive evaluation and analysis of the frequency points of GNSS systems in the system and system.The experimental results show that the interference ability of L1 and L2 in GPS is better than that of L5,while in GLONASS,G2 is better than G1,and B3 is optimal in BDS,and E1 is the best in Galileo.In general,the narrower the signal bandwidth,the more likely to be affected.3?This paper proposes a method to calculate the exact period of multipath errorcombination of high frequency observation data by means of Matlab correlation analysis function.The experimental results show that the average exact repetition period of the pseudorang multipath error of the C06(IGSO),C03(GEO)and C12(MEO)satellites in the BDS is 86156 s,86160s,603095s;The average precision repetition period of the pseudorang multipath error of the fixed station under GPS satellites is 86155 s.4?In this paper,the multipath error of the pseudorange single-point positioning is verified by adding the real-time multipath error estimation method.The experiment proves that the method can improve the positioning accuracy by about 9%.According to the periodic characteristics of the multipath error,the results of the PPP positioning are corrected by the additional periodic correction method.The experimental results show that the sidereal filtering method can effectively weaken the positioning results Of the periodic error(mainly refers to the multipath error).