Research And Implementation Of BDS/GPS Mesh Pseudorange Difference Service And Mobile Terminal Real-time Location Algrithm

With the wide use of BDS,BDS mobile terminals have been rapidly developed,such as BDS vehicle terminals,smart phones,ship terminals,and shared bicycle terminals.At present,the mobile terminal mainly adopts the single-point positioning method for positioning.Since the single-point positioning accuracy is affected by the satellite ephemeris error,the satellite clock error,the atmospheric delay error in the satellite signal propagation process,and the measurement random error and so on,it is adopted.The single-point positioning method generally can only achieve the positioning accuracy of meters,which can no longer meet the user's demand for positioning accuracy.In the current opportunity period for the development of BDS,how to improve the positioning accuracy of smart logistics terminals,shared bicycles,wearable devices,outdoor tourism,and intelligent parking,and realize its fine and intelligent management are problems that need to be solved urgently.Therefore,it is very important to study and implement the BDS/GPS high-accuracy pseudo-range differential positioning software.This article relies mainly on the CORS network in Hunan Province and Hebei Province to develop a dynamic real-time location system R&D project for mobile terminals.The purpose of this project is to establish a BDS/GPS decimeter-level real-time differential location service system.Based on the increasingly perfect CORS network and stable CORS data,the BDS/GPS pseudo range differential method is studied in depth.The BDS/GPS grid pseudorange difference service software,BDS/GPS grid pseudo-range difference service software,BDS/GPS Kalman filter grid pseudo-range differential positioning software and completeness monitoring software are implemented.A lot of experiments were conducted through the mobile terminal dynamic test and the completeness monitoring of the BDS/GPS grid pseudorange differential system,verifying the availability,reliability and stability,of BDS/GPS grid pseudorange differential system software and geting some useful conclusions.The main research contents and research results of this paper are as follows:1.Through the unified BDS/GPS dual-system space-time reference,the unified method of space-time of each system and the principle of network pseudo-range difference are studied in detailand and BDS/GPS grid pseudo-range differential positioning model and BDS/GPS Kalman filtering grid pseudo-range differential positioning model are deduced.2.The BDS/GPS grid pseudorange differential system is implemented,including BDS/GPS grid pseudorange differential correction generation service software and mobile terminal BDS/GPS grid pseudorange differential positioning software.The BDS/GPS grid pseudorange differential correction generates broadcast service software to provide reliable differential correction information for the mobile terminal in real time;the mobile terminal BDS/GPS grid pseudorange differential positioning software includes the Windows system and the Andriod system mobile terminal BDS/GPS grid pseudo-range differential positioning software,the mobile terminal performs differential real-time positioning solution to obtain real-time location3,Using the data of CORS station in Hebei Province,through the completeness monitoring method,the complete monitoring of the differential corrections of grids by the monitoring stations of the differential software system is realized,which ensures the correctness and availability of grid corrections,and the difference between monitoring stations is effective.The epoch rate has increased by 0.23%;completeness monitoring of the mobile tenrninal handset grid differential positioning has been implemented,and the difference results using completeness monitoring and without completeness monitoring have been compared and analyzed.The results show that the difference result with completeness monitoring have higher accuracy and stability,the horizontal RMS optimization rate increased by 13.07%.4.The influence of the grid division in the coverage area of CORS network on the BDS/GPS pseudo-range differential positioning results is compared and analyzed.The results show that when performing BDS/GPS grid pseudo-range differential positioning and using a 1°×1° grid division method,will have higher positioning accuracy and stability.5.The usability of the BDS/GPS grid pseudo range differential system was verified by the Andriod system three defense mobile phone tests.Experiments show that the accuracy of the three-anticipation mobile phone static test differential system can reach sub-meter level,and the system has high reliability and Stability;dynamic test positioning accuracy of up to 1.8m horizontal direction,mobile phone dynamic real-time positioning accuracy still need to be improved.6.Using CORS network data of Hunan Province,the usability of BDS/GPS Kalman filter grid pseudorange differential system was verified by the mobile terminal handset test of Windows system,and The BDS/GPS grid pseudo range differential and BDS/GPS Kalman filter grid pseudo range differential positioning performance are compared and analyzed.Experiments show that the BDS/GPS Kalman filter grid pseudorange differential positioning achieves better filtering results,smoother curves,and system positioning accuracy can be achieved regardless of whether it is a static test or a dynamic test,with high reliability and stability.