Method And Realization Of GPS Precise Point Positioning Using Un-differenced Phase Observation

Precise Point Positioning(PPP) uses un-differenced dual-frequency psedorange and carrier phase observations along with IGS precise orbit and satellite clocks, for satand-alone precise geodetic point positioning (static or kinematic) with centimeter precision. This paper describes the approach of PPP in detail, and discusses some problems in data processing. The main contents and conclusions of this paper are as follows:1. The thesis adopts Chebyshev polynomial and lagelary polynomial to work out satellite coordinates and clock error at the observation time. The accuracy of satellite coordinates reaches centimeter and the accuracy of satellite clock error correction reaches subnimsecond.2. The thesis does researches on three kinds of the un-dfferenced positioning model, such as the traditional model, the UofC model and the nonambiguity model. The thesis studies the errors and the ways to eliminate or weaken them.3. The kalman filtering and the least square are studied. The least square is just suitable for processing the GPS data after the event. The kalman filtering is more suitable for processing the GPS data dynamically.4. The thesis studies the random walk to model the troposphere error. The receiver clock is modeled as white noise.5. Pretreating the GPS data in the PPP is studied. It involves cycle slips detecting and removing, ambiguity fixing and so on. It is very important for the PPP.6. The PPP soft is developed. Several data sets of IGS tracking stations are computed. The results show that after the initial time of PPP the accuracies of serial epoch positioning can be better than 0.5m.