Research On Optimization Of Dual-Frequency Positioning Method Based On GPS Trajectory Data Location Anomaly

With the continuous progress of science and technology,research is constantly deepening in response to the development of the times and the progress of science and technology.the BD-2 satellite navigation system has gradually entered the field of vision that people pay close attention to.And since March 2015,BD-3 has gradually revealed a new angle.Each country's defense,if it wants to be stronger,is also necessary to rely on the pre-evolution of technology.For the construction of Beidou system,it can make a great contribution to the national defense security of the country.GPS satellite navigation system has always been an important comparative object of the development of major satellite navigation systems in the world.because of this,this paper analyzes and studies the abnormal situation of trajectory data positioning in the GPS of Beidou satellite.Based on the Beidou satellite system,the theoretical part of the dual-frequency positioning method is studied and the simulation results are analyzed.in this paper,the theoretical part of the dual-frequency positioning method is studied,and the simulation analysis is carried out.In this paper,the composition,function and characteristics of Beidou satellite navigation system are described in detail.for the case of abnormal positioning of GPS trajectory data,The ionospheric model correction method,ionospheric delay correction method,differential positioning method and non-differential positioning method are enumerated.these methods can reduce the influence of ionospheric and other factors on the positioning solution and improve the positioning accuracy.In addition,the Kriging interpolation method is also introduced.in this paper,the interpolation lattice is used to obtain a smoother VTEC distribution map of South China at a certain time.The position solution of dual-frequency can be divided into three kinds of models for processing,including model processing and non-difference model processing and no fuzzy processing,each has its own advantages and disadvantages.By analyzing their advantages and disadvantages,we finally determine which model to use as the final model to be studied in this paper.Through the comparison between different linear combinations of the equation,clean observations can be obtained.of course,it is also necessary to use the method of mixed matching linear combination.in order to master the simple observations,it is necessary tosolve the combination first.Secondly,the ambiguity is solved;and the repaired cycle slip is solved.finally,the detection cycle slip is solved.After that,we find that there will be deviations in positioning,for the actual operation of the deviation,we should find out the causes in time,and analyze and give the solution.In order to confirm the parameters and calculation process of the dual-frequency high-precision positioning algorithm,it is necessary to calculate and deduce several key elements,such as static least square estimation,and discuss its weight matrix.According to the satellite signal-to-noise ratio and other information,the corresponding assumptions are made,and for the dynamic change of the receiver position,it is necessary to consider the state transition at each time,so Kalman filtering method should be used.By analyzing the results and practicability of the above algorithms,it is determined that the estimation method should be used in this paper.Finally,the dual-frequency positioning process is introduced,and then the deviation between the multi-site GPS_TEC and IGS_TEC of the ionospheric operational system in South China is analyzed,and the number of stations involved in the calculation is determined.At the same time,by comparing the VTEC differences in South China before and after the Greater Cold solar term,the research environment background is selected,and the dual-frequency signal from Beidou satellite is received by using the Beidou dual-frequency receiver of the station,and the real-time solution is carried out.Draw the deviation map of the positioning results and draw the relevant conclusions of the accuracy.