Research On Optimal Selection Algorithm Of GNSS Tracking Station

With the continuous development of GNSS technology and the continuous construction and promotion of satellite ground tracking station,the application of GNSS technology in the field of PNT parameter calculation has become the current research hotspot.The geometric distribution,the stability and the observation data quality of GNSS tracking stations seriously affect the precision of both satellite precise orbit determination and the Earth rotation parameters.With the development of global satellite navigation system,there are thousands of GNSS ground tracking stations globally distributed.Obviously,it is not the best strategy to generate GNSS products using all tracking stations without considering the observational geometry of stations as well as the data quality and station stability.Therefore,how to utilize the ground tracking stations to balance the GNSS product accuracy with the real-time service performance becomes a hot research pot.This paper focuses on the precision of GNSS tracking station in solving PNT related parameters,explores the factors affecting the precision of GNSS tracking station in solving PNT related parameters,and optimizes the selection of tracking station and applies it to the work of solving related parameters.The main research contents and innovations include:(1)In this paper,the principle of GNSS tracking station to calculate the satellite orbit determination and the earth rotation parameters is introduced,and the current related calculation methods and the advantages and disadvantages of each method are described.(2)This paper analyzes the factors that affect the precision orbit determination and earth rotation parameters of GNSS,mainly discusses the stability and data quality of tracking station and the accuracy of parameter calculation of combined configuration of tracking station.The optimal configuration of ground tracking station for precise orbit determination and earth rotation parameters of GNSS satellite is derived and given.(3)In view of the current situation that only the uniformity is selected as the evaluation index of GNSS tracking station,considering the influence of various factors on the solution accuracy,the weight function model of tracking station is established by comprehensive evaluation of tracking station performance,and the weighted DOP index is constructed to evaluate the tracking station combination,so that the evaluation standard of tracking station combination is more reasonable.(4)At present,grid method and other deterministic methods are widely used in GNSS tracking station selection strategy.However,at present,the number of tracking stations is huge,which may face the occurrence of ‘combined explosion'.The GNSS tracking station is optimized by using random algorithm(equal probability random algorithm,grid control probability random algorithm,probability space evolution algorithm)and intelligent algorithm(genetic algorithm,discrete particle swarm optimization algorithm).Aiming at the limitations of traditional algorithm,the accuracy of GNSS products and the timeliness of GNSS services are improved.(5)Using the observation data of tracking station issued by IGS official to calculate the precise orbit determination and earth rotation parameters of relevant satellites,the results are compared with those of precise ephemeris and earth rotation parameters issued by IGS official to verify the performance of the tracking selection results proposed in this paper.The experimental results show that the performance of tracking station combination can be more accurately reflected by the ideas and related algorithms proposed in this paper the accuracy of the solution is significantly higher than that of single index and deterministic method.