Research On The Method Of Precise Satellite Clock Error Estimation And Precise Point Positioning Ambiguity Resolution

Precise point positioning(PPP)is a new technology that can use a single receiver to achieve static or dynamic independent positioning in the world,and can directly obtain the static centimeter level or dynamic decimeter to centimeter level high-precision coordinate position.Real time and high accuracy have always been the key research contents of PPP.As one of the main factors affecting the positioning accuracy,precision satellite clock error products have some problems,such as poor prediction accuracy and difficult prediction,long delay time of post event products,which limit the real-time PPP technology.In addition,in the standard PPP model,due to the influence of uncalibrated hardware delay,the ambiguity are out of integer which can only be estimated by floating solution without integer property,which also limits the convergence speed and positioning accuracy of PPP.For this reason,this paper focuses on three aspects of precision satellite clock error estimation,fractional cycle bias(FCB)modeling and estimation accuracy,PPP-AR,and major contents and achievements have been induced:1.Aiming at the problems of poor prediction accuracy,difficult prediction and long delay time of precision satellite clock error products,the precision satellite clock error solution method is studied in detail,and the formulas based on Un-differenced(UD),satellite differenced(SD)and epoch differenced(ED)and hybrid difference model which derived mathematical model of precise satellite clock error based on is solved by self-programming,and also the advantages and disadvantages of different models is analyzed.The experimental results show that the PPP positioning accuracy of IGS products can be achieved by using self-estimation clock error,and the convergence time can be further optimized.2.In order to realize the estimation and modeling of FCB,the FCB solution method under un-differenced model is studied based on IGS orbit and self-estimation clock error products.Through IGS observation data,the FCB sequences of wide lane and narrow lane are obtained and analyzed statistically.The results show that,the self-estimated FCB product has better internal coincidence accuracy,and the wide lane FCB has better external coincidence accuracy.How to improve the data utilization rate is the next research focus.3.In order to achieve PPP-AR,this paper studies the client PPP ambiguity fixed method based on FCB.Through the self-made software,combined with the generated precise clock error and FCB products,IGS observation data not involved in FCB solution are selected for static and dynamic PPP experiments,and the positioning accuracy and convergence time of ambiguity floating solution and ambiguity fixed solution are calculated respectively.The experimental results show that:after the ambiguity is fixed successfully,the overall deviation series in E,N and U directions are more stable,and the accuracy is significantly improved.However,there are still some errors in fixing ambiguity in some epoch which need to be further solved.Figure[32]table[16]reference[99]...