Multi-GNSS Data Analysis In Complex Environment

With the application of BDS-3,the advancement of GPS modernization,the improvement of GLONASS and the construction of the Galileo system,the future satellite navigation constellation will contain more than 140 satellites.The coexistence,compatibility and interoperability of multi-GNSS have become a hot issue in the field of satellite navigation.The original observation data reflect the situation of the surrounding environment and the receiver equipment and it is of great significance to perform quality assessment on the observation data before data pre-processing.Therefore,this paper focuses on the observation data of GPS/BDS/GLONASS,a study of multi-GNSS data quality analysis and evaluation methods is conducted,and develops multi-system GNSS data quality analysis software based on Python platform,focusing on the quality analysis of multi-GNSS data in complex environments.The main research contents and achievements of this article are as follows:(1)The main error sources which have a great influence on the positioning accuracy are analyzed,And the methods to eliminate and correct errors in GNSS data are given.Focusing on the quality inspection of observation data,we focused on multi-path effects,satellite PDOP values,signal-to-noise ratio,and utilization of observation data.(2)Multi-system GNSS data quality analysis software was developed.Based on the open source code of Anubis,the code was recompiled and the processing function of new signal data of BDS was expanded.Then the code was packaged with an interface based on the Python platform and the checking results would visualize output of checking result.Meanwhile,the function of software and the reliability of this results was also verified.The experimental results showed that the improved Anubis software could effectively check the GNSS data with multiple quality indexes to meet the requirement of checking the data quality of the new generation multi-GNSS receiver.(3)The indexes and methods of multi-system GNSS data quality analysis under complex environment are studied.From the number of visible satellites and the PDOP value,we analyze the improvement effect of comparing the combined system with that of a single system on the constellation of satellite constellations.The calculation method of multi-path effect is studied and multi-system combination of multi-paths is obviously less than single-system GPS,with an average of 17.5%and 5.5%reduction respectively and the multi-GNSS combination can weaken the effect of multi-path effect on positioning results.The data utilization index reflecting the epoch and observation data loss situation is elaborated and analyzed.The data shows that the combined system can make each system compensate each other,expand the range of satellite positioning,and help improve the reliability of high-precision positioning in complex environments.