The Study Of Precise Point Position Based On Multi-signal

Precise Point Position(PPP)is a single-point positioning method that uses high-precision satellite ephemeris and clock difference to perform non-difference models.It has more accurate real-time availability than the GPS control segment.Unlike the double-difference position,PPP uses non-difference observations.Its delay deviation of satellite and receiver's hardware and initial phase deviation are absorbed by the ambiguity parameter.PPP processing has reached the accuracy of decimeter(dm)to millimeter(mm)level.Generally,the static processing conforms to the accuracy of centimeter(cm)and the dynamic processing accuracy is dm.The common problem of satellite positioning is still an important issue that affects the stability of PPP accuracy.In that way,the temporary interruption of satellite signals will affect the ambiguity of the whole week and lead to re-fixing.In order to save the fixing time,it fixes the cycle slip directly to solve it.Therefore,in this thesis,we propose a multi-signal-assisted PPP positioning model to systematically improve the PPP technology algorithm,with the assistance of other signals,based on the analyzing of optimization.The main contents of the research are as follows:(1)The real-time dynamic PPP positioning model is analyzed in detail.In order to solve the problem that the receiver signal is completely interrupted by external occlusion and the output phase observations have cycle slips,an INS-assisted PPP/INS loose combination real-time dynamic positioning model is proposed.MATLAB simulation results based on rtkpost show that the PPP/INS compact combination model proposed in this paper can effectively fix the cycle-slips and improve the positioning accuracy of real-time PPP.(2)Based on the improved dynamic PPP positioning model and the existing PPP static positioning algorithm,a determination algorithm for PPP state post-processing is proposed in the application scenario.The model is based on the assistance of the DTV and IMU loose coupling model,and its threshold is used to determine the carrier.The motion state is solved by using the relevant PPP algorithm.Based on MATLAB simulation results,the opportunistic signal-assisted PPP state separation model proposed in this paper can basically determine the state of the carrier in general scenes and use the relevant PPP algorithm to perform positioning calculation.