Coordinate Stability Research And Application Of Base Station Of National BDS Augmentation System Based On Fuzzy Fixed Algorithm

Beidou satellite navigation system(hereinafter referred to as Beidou)is one of the most important spatial infrastructure to meet the needs of national security and economic development in the new era.As an important part of Beidou,the stability of Beidou foundation strengthening system is an important guarantee for the normal operation of Beidou.However,in terms of the coordinate stability of the reference station,the Beidou foundation strengthening system has not yet achieved effective monitoring.Whether the base station is stable or not is an important index to consider the service quality of Beidou foundation enhancement system,and it is also the basis for Beidou foundation enhancement system to provide long-term stable and highprecision service.The change of reference station coordinates can comprehensively reflect the stability degree of a reference station.It can be said that most factors affecting the stability of the reference station will ultimately affect the change of the reference station coordinates.Therefore,in order to maintain the frame stability of the base station and fill the gap in the construction of the Beidou foundation strengthening system,this paper studies the coordinate stability of the base station of the Beidou foundation strengthening system,and realizes the stability monitoring of the frame base station by the industrial data processing center of the Chinese Academy of Sciences,which is of great significance to the continuous and stable operation of the Beidou foundation strengthening system and the normal work of the whole Beidou.According to the actual engineering application needs of Beidou foundation strengthening system,this paper analyzes the improvement of the performance of precision point positioning algorithm for precision point positioning from the basic model of precision point positioning(PPP).At the same time,using the original observation data of Beidou foundation strengthening system frame network reference station,the influence of the Yibin 6.0 earthquake on the surrounding Beidou foundation strengthening system reference station on June 18,2019 is evaluated,the concrete effect of the fuzzy fixed precise single point positioning algorithm in the coordinate stability analysis of Beidou Foundation strengthening system reference station is verified,and the Beidou foundation increasing is developed and realized Coordinate stability monitoring software of strong system reference station.The main research contents and achievements of this paper are as follows:(1)Based on the basic model of precise single point positioning,the method of fuzzy degree fixing based on Uncalibrated hardware delay is introduced.Based on the observation model of single difference between satellites,the calculation method and flow of uncalibrated phase delays(UPD)in wide narrow lanes with single difference between satellites are derived.According to the research on the theory of wide and narrow lane UPD,the algorithm of fuzzy degree fixing based on UPD is derived,that is,the single point positioning model of fuzzy degree fixing based on UPD.In general,the flow model of fuzzy fixed precise single point positioning solution by UPD is given.At the same time,the common error sources and error processing methods in precise single point positioning are described,and the error correction model is deduced.At the same time,the quality evaluation and control indexes used in this paper are introduced.(2)Based on the original observation data of IGS,MGEX and Beidou foundation strengthening system frame reference station,the fixed fuzzy degree methods of lambda and fix are analyzed and compared,and the improvement effect of fuzzy degree fixed algorithm on static positioning and pseudo dynamic positioning performance is studied.The results show that the fixed solution of fuzzy degree has a significant improvement on the positioning accuracy in the direction of N and E,and has no obvious influence on the positioning accuracy in the direction of elevation,but at least 11% in the threedimensional direction,and the fixed solution has a greater influence on the single point positioning solution with shorter time.(3)Based on the observation data of seven frame reference stations of Beidou foundation strengthening system,such as Chengdu,Junlian and Pengshui,in June 2019,the fuzzy fixed positioning algorithm is used to precisely locate the reference station,and the influence of short-term strong earthquake on the coordinate stability of frame reference station of Beidou foundation strengthening system is studied.Through data comparison,it is found that the influence of the Yibin earthquake on the coordinates of the reference station is closely related to the relative orientation of the reference station focal fault zone.The necessity of establishing the coordinate stability monitoring system of Beidou foundation enhanced frame network reference station is further demonstrated.At the same time,the research based on the seismic influence further expands the new field for the application of the frame network data of Beidou foundation strengthening system: through the fixed point positioning of the fuzzy degree,the monitoring and analysis of the large-scale geological movement can be realized by using the Beidou foundation strengthening data,and it also proves that the fixed fuzzy degree algorithm can also be used in deformation monitoring,engineering monitoring,geological investigation and other fields ?(4)Based on the fuzzy fixed PPP algorithm,the coordinate stability monitoring software of Beidou foundation enhancement system reference station is developed,which can monitor the transmission status of original observation data,the availability of reference station data,and the coordinate stability of the reference station in the frame network of Beidou foundation enhancement system.The user interface is combined with the data quality analysis software of Beidou foundation enhancement system.This system can be used not only in the coordinate stability monitoring of Beidou foundation strengthening system reference station,but also in deformation monitoring,engineering monitoring and other fields.According to different data sources,it can provide different monitoring services.The software can provide further services for the Chinese Academy of Sciences and the society,develop more application fields,and provide strong support for the smooth operation of Beidou foundation strengthening system.