Research On High Precision Positioning Algorithm And System Based On BDS_GPS Dual System

In recent years,the satellite navigation and positioning technology has developed rapidly,especially China's self-developed BDS,which has been widely concerned since the government had announced its official start of the operation in 2012.With the continuous improvement of the BDS,satellite navigation and positioning technology has gradually penetrated into people's daily life and production.At the same time,people's demand for positioning accuracy is also getting higher and higher.Therefore,it is very necessary to study the high precision location service platform based on the BDS and GPS dual system.This dissertation focuses on the high precision positioning algorithm based on the BDS_GPS dual system,including pseudo-range differential positioning algorithm and satellite selecting algorithm.Combined with the characteristics of high precision location service system and the advantages and disadvantages of the common algorithms,the selection algorithm of BDS_GPS dual system is improved,and used in the high precision location service system.The main research contents of this dissertation include:(1)Analyzing the compatibility of time system,coordinate system,and the position calculation methods of different satellites between the BDS and the GPS,which it to determine the solutions in the BDS_GPS integrated positioning system.(2)Researching and analyzing the principle of the single point positioning and the pseudo-range differential positioning of the BDS_GPS dual system,and comparing the pseudo-range differential positioning algorithm based on the least square algorithm and the pseudo-range differential positioning algorithm based on Kalman filter.At the same time,the positioning performances of BDS single mode,GPS single mode and the BDS_GPS dual mode are compared by the outdoor satellite positioning test results.(3)Researching on several common satellite selecting algorithms and the geometric dilution of precision(GDOP)which is an important criterion of this satellite selection.Then,designing an improved satellite selecting algorithm based on the satellite's altitude angle and its contribution of GDOP,combined with the characteristics of the high precision location service system and BDS_GPS dual system,the advantages and disadvantages of common satellite selecting algorithm.At last,the performance of the proposed satellite selecting algorithm is analyzed.(4)We design and implement a high precision location service system based on BDS_GPS dual system.Apply the pseudo range differential positioning algorithm based on Kalman filter and the proposed satellite selecting algorithm to the system.Then,validating the performance of the satellite selecting algorithm proposed by this dissertation from multiple point of view,including the visible satellites number,the computation and the GDOP value of improved satellite selecting algorithm and common method,the static position results and the dynamic position results.