Correction Model of BeiDou Code Systematic Multipath Errors and Its Impacts on Single-frequency PPP

• Main Authors: WANG Jie, HE Xiyang
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2017-07-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: BeiDou; single-frequency precise point positioning; Kalman filter; multipath; pseudo-range; accuracy analysis
• Online Access: http://html.rhhz.net/CHXB/html/2017-7-841.htm

There are systematic multipath errors on BeiDou code measurements, which are range from several decimeters to larger than 1 meter. They can be divided into two categories, which are systematic variances in IGSO/MEO code measurement and in GEO code measurement. In this contribution, a methodology of correcting BeiDou GEO code multipath is proposed base on Kalman filter algorithm. The standard deviation of GEO MP Series decreases about 10%~16% after correction. The weight of code in single-frequency PPP is great, therefore, code systematic multipath errors have impact on single-frequency PPP. Our analysis indicate that about 1 m bias will be caused by these systematic errors. Then, we evaluated the improvement of single-frequency PPP accuracy after code multipath correction. The systematic errors of GEO code measurements are corrected by applying our proposed Kalman filter method. The systematic errors of IGSO and MEO code measurements are corrected by applying elevation-dependent model proposed by Wanninger and Beer. Ten days observations of four MGEX (Multi-GNSS Experiment) stations are processed. The results indicate that the single-frequency PPP accuracy can be improved remarkably by applying code multipath correction. The accuracy in up direction can be improved by 65% after IGSO and MEO code multipath correction. By applying GEO code multipath correction, the accuracy in up direction can be further improved by 15%.