Research On GNSS Precise Single Point Positioning Technology Based On RTKLIB

Precise single point positioning is a technology that uses precise ephemeris and precise clock difference,and uses a single GNSS dual frequency receiver to realize realtime or post precise positioning,which is called PPP for short.Compared with relative positioning,this technology has the characteristics of independence,flexibility and high precision.However,the program structure of precise single point positioning is complex and highly modular.How to design an efficient,reliable and expandable software becomes the turning point of PPP technology's wide application.Rtklib software,provides a good tool for us to study the mathematical model and parameter estimation of precise single point positioning.Specific research contents include:1)Study the basic theory and method of precise single point positioning.The characteristics of linear combination of different observations are studied,and the precise single point positioning principles of ionospheric free combination model,uofc model and non difference non combination model are studied.2)Data preprocessing experiment is carried out based on RTKLIB software.From the analysis results,the constellation layout is the most reasonable,and the visibility of satellites in local areas is equivalent to the GDOP BDS and GPS,which is superior to GLONASS and Galileo systems.3)Based on RTKLIB software package,a precise single point positioning solution strategy is designed.The traditional ionosphere free model is used,the cut-off altitude angle of satellite is 15 °,the saastamoinen model is used to correct the troposphere,the LLI cycle slip detection method is used,and all errors are considered comprehensively to achieve multi system precision The location accuracy is centimeter level.4)Different solution models are designed,which take precise ephemeris,single system and combined system,different solution models and other factors issued by different analysis centers as variables to carry out precise single point positioning solution,and analyze their respective effects on PPP solution accuracy and convergence speed.Figure 22;Table 7;Reference 76...