Research On Precise Point Positioning Of Beidou Satellite Based On Code Bias Correction

Precise Point Positioning(PPP)high-precision positioning results are based on various error corrections that affect positioning accuracy.It has been found that the pseudo range measurement of the Beidou satellite have systematic deviations related to the satellite elevation angle,which is called "Beidou satellite code bias" in this paper.The existence of the Beidou satellite code bias which has serious impact on the research and application of precision positioning.Therefore,the analysis and correction of the Beidou satellite code bias to improve the positioning accuracy and application performance of Beidou satellite navigation has important significance.In this paper,the Beidou satellite code bias and its correction model are studied,and the effect of the model is verified by PPP experiment.The research methods and conclusions are as follows:(1)The Beidou satellite code bias is extracted based on MP combination observation,and its characteristics were analyzed.(2)According to the characteristics of Beidou IGSO and MEO satellite code bias associated with satellite elevation angle,this paper adopts the method of weighted piecewise linear fitting to model,and analyzes the influence of the number and distribution of stations on modeling.According to the characteristics of GEO satellite code bias,the wavelet transform and wavelet decomposition and reconstruction method are used to correct the code bias.(3)In order to validate the validity of the model,the paper calculated the combination of the MW before and after the error correction of the Beidou satellite.The results show that the pseudo range deviation of the MW is eliminated,and the data utilization is improved in the ambiguity-fixed process of the wide lane.(4)This paper developed the Beidou code bias correction software.And based on RTKLIB open source code,developed the Beidou PPP software,(5)Using the observation data of 10 stations,using the traditional ionospheric model,as well as the precise ephemeris and the precise satellite clock correction,the experimental results show that the corrected code bias after static PPP accuracy in the N,E,the average increased by 6.8%.9.5%and 11.3%in the U direction,average RMS value increase by 1.1 cm,1.3 cm,2.6 cm;The dynamic PPP accuracy increased by 9.1 percent,1.5 percent and 5.2 percent in N,E,and U,and the RMS value increased by 1.7 cm,0.6 cm,and 2.3 cm.The experimental results show that the accuracy of the PPP is improved after the correction of the code bias correction model proposed in this paper.