The Algorithm Research And Implementation Of BDS/GNSS Real-time Precise Point Positioning

With the development of GNSS technology,and the coming of the era of multi-GNSS coexistence,precise point positioning with multi-system fusion has gradually become an important issue of research.Real-time precise point positioning technology has the advantage of high positioning accuracy,convenient location,without being limited by reference stations,etc,and it will become an important means of high precision navigation and positioning in the future.Muti-GNSS provide more visible satellite and better satellite geometry structure,which is conducive to improving positioning accuracy,reliability,convergence time for real-time precise point positioning.Thereforce,through researching on theory and method of real-time precise point positioning with multi-system,based on real-time orbit and clock data streams,as well as real-time multi-GNSS observation data streams,this paper realizes real-time precise point positioning for single frequency and dual-frequency that supports three systems,GPS,GLONASS and BDS.The main contents are summarized as follows:(1)This paper carries out an detailed analysis of the pseudorange gross error detection,detecting and repairing method of clock jump,and cycle slip detection method.Firstly,using difference value between different pseudorange detect the pseudorange gross error is analyzed.Then according to different types of clock jump,detecting and repairing method of clock jump based on single epoch observation is analyzed.The end,according to the theory of triple frequency combination observations,Optimizing the GPS and BDS three frequency cycle slip detection combination without geometric distance,and based on the practical examples,Validity is analyzed using two groups of BDS linear combination coefficients by optimizing to detect cycle slip without geometric distance.(2)This paper analyzes the characteristics of system deviation value from different systems and different stations.The results showed that system error value after convergence within a day keeps relatively stable,and the size of system deviation value shows features associated with stations.(3)This paper analyses the precision of orbit and clock for three systems which is restored in real time,using real-time SSR corrections provided by the German federal bureau of surveying and mapping.Meanwhile,the impact of the issue of data ephemeris and the interrupted corrections on real-time precise point positioning,and the solution is given.(4)According to the theory of real-time precise point positioning with multi-system,real-time precise point positioning for single frequency and dual frequency that supports three systems,GPS,GLONASS and BDS is realised by writing programs.Dynamic test simulated by static for dual frequency,dynamic test simulated by static for single frequency and vehicle dynamic test are carried out to analyses the positioning performance of the software.