Research On The Ambiguity Resolution Method Of BDS/GPS Precise Single Point Positioning

Precise Point Positioning(PPP)technology can use precision ephemeris and precision clock products to achieve high-precision positioning through a single receiver.However,with the development and progress of today's society,users' demand for timeliness in obtaining high-precision positioning services has increased.Traditional PPP technology has been unable to meet the needs of users in today's society due to the long convergence time.The reason for this phenomenon is that there are uncalibrated hardware delays(Uncalibrated Phase Delays,UPD)in the observations,which makes the resolved PPP ambiguities unable to be fixed.In theory,if the influence of the hardware delays can be successfully separated,it is estimated When the ambiguity parameter is fixed,the convergence speed and positioning accuracy of PPP can be improved.This paper studies the theory and method of PPP ambiguity fixation.Based on this,an optimized partial ambiguity fixation strategy is proposed,which increases the number of ambiguity fixation epochs,and designs a better fixed solution transfer method to make the PPP convergence process Become faster and smoother.And use FCB products to realize the fixation of ambiguity according to the fixation theory,and test the positioning effect of the fixed solution for the single GPS system,BDS system,and PPP of the dual system combination.In general,the main research contents of this article are as follows:1.Research and analyze the PPP theory and ambiguity fixation methods,as well as the causes and processing methods of various errors,and introduce and learn the commonly used data processing methods and parameter estimation methods.At the same time,the pseudorange observations and carrier waves are also studied.The separation of the hardware delay in the observation and measurement provides a theoretical basis for the subsequent correction of this part of the parameters.2.On the basis of using the single difference between satellites to eliminate the hardware delay of the receiver,using FCB products,the ambiguity fixation method of narrow lane and wide term is designed,and the solution of the ionospheric ambiguity fixed solution is realized.3.Based on the partial ambiguity fixation method to fix the PPP floating-point ambiguity,based on the ratio test and Bayesian posterior probability method,some improvement strategies for the partial ambiguity fixation method are proposed to optimize the narrow lane ambiguity fixation Inspection strategy.4.A better fixed solution transfer strategy is proposed,so that effective fixed fixed solutions can be transferred,avoiding positioning deviation fluctuations caused by floating-point solutions for unfixed epochs.5.Based on the partial ambiguity fixation theory proposed in this paper,the random pair model of different orbit satellites in the BDS system is introduced,and the fusion positioning method of the BDS/GPS system is analyzed.Based on the BDS/GPS observation data,the static and imitation dynamics are used.This model analyzes the ambiguity fixation rate,convergence data,positioning accuracy,etc.The results show that: in a single GPS system 1.In the static mode,the time required for the 3D accuracy of the PPP fixed solution to converge to 10 cm is increased by an average of 7min and 1h for the solution.The positioning accuracy in the E,N,and U directions increased by an average of 28.8%,45.5% and 49.3%.2.In the imitation dynamic mode,the time required for the 3D accuracy of the PPP fixed solution to converge to 15 cm is increased by an average of 15 minutes,and the average positioning accuracy of the PPP fixed solution is increased by 40.9%,20.2%,and 44.4% compared with the PPP floating solution.For the BDS system,this article only fixes the ambiguity of Beidou-2 satellites(except GEO satellites).The convergence time is improved but not as good as GPS,and the positioning accuracy is also improved.The dual-system combined fixed solution effect is equivalent to the GPS single-system fixed solution effect,and will be partially improved.6.Based on the C# environment of Visual Studio 2019 version,the PPP-AR positioning software has been developed,which realizes the solution of ambiguity fixed solution and the output of various parameter files during calculation,which is convenient for analysis and research on the effect of PPP fixed solution.