Research On GPS/BDS Combination Of Precise Point Positioning

With the further advancement of the third generation of China's BeiDou Navigation Satellite System,the number of navigation satellites is increasing rapidly over the earth.It has created more favorable conditions for multi-system integrated navigation.Based on some previous researches on the current multi-system combination of precise point positioning,although precise point positioning has shown great advantages in many fields,However,from the point of view of the researcher's acquisition of differential data and the positioning accuracy and convergence time that the user's positioning is most concerned about,some problems still worth exploring are found.This paper attempts to study the GPS/BDS combination precise point positioning from the following three aspects.This paper focuses on the basic theories including the mathematical model involved in the precise point positioning of GNSS,the main error of precise point positioning,and the parameter estimation method in the precision point positioning.In addition,different kinds of errors in precise point positioning are introduced in detail.The analysis of single-system positioning model also deduced the precise point positioning model of multi-navigation system combination.In order to realize the effective sharing application of GNSS data,this paper makes the value of the existing data resources can be made more and more convenient for more users to make full use of it,It solves the problem that the general users are mainly the student group's insufficient data for learning and research,and reduces the collection of data resources.The repetitive labors such as sorting and preliminary evaluation of data quality,while providing relatively comprehensive data while avoiding the disadvantages of redundant storage of data,have designed a data sharing platform.The platform realizes "one-stop" data sharing and"visual" analysis results display.This paper proposes a star selection method in a typical environment.The weights of GPS satellites in GPS/BDS dual system integrated navigation are increased.Experiments show that the new star selection method can increase the effectiveness of positioning and speed up the convergence.Using the seven days data of seven stations in IGS,using GAMP open source software,the single GPS system,single BDS system,and GPS/BDS combination precise point positioning performance are compared and analyzed from three observation indexes of positioning accuracy,convergence time and satellite GDOP value.And discussed the results of the solution:From the combination of GPS/BDS,it can be seen that the number of visible satellites can be increased by combination and the geometric configuration of the effective satellite is optimized.It can enhance the positioning performance of satellite navigation.Compared with single-system navigation and positioning,it also has great improvement in positioning accuracy,especially for the performance of BDS;The seven day positioning results from each station can be seen in RMS analysis of ENU and position deviation S.The GPS\BDS dual system precise point positioning mode performs best in both static positioning accuracy and static convergence speed.Comparison and analysis of single GPS and single BDS precise point positioning,BDS positioning accuracy only a few stations can obtain the same positioning precision as GPS even better than GPS,but the overall performance of the seven stations is inferior to single GPS.