The Algorithms And Program Implementation Of Precise Point Positioning Based On GPS Tri-frequency Carrier Phase Observations

Based on high-precision GPS carrier phase observations which are collected by asingle GPS receiver, The Precise Point Positioning(PPP) can achieve decimeter-leveleven centimeter-level positioning accuracy combined with the IGS precise orbit andsatellite clocks data. Due to its low costs and relatively high positioning accuracy, PPPhas broad application prospects in various fields. So far, PPP based on tri-frequencyobservations have become an important research area because of all GNSS systemshave the ability to broadcast tri-frequency carriers in the future as well as tri-frequencyobservations have a higher ionospheric correction precision, stronger anti-interferenceability, better quality of data preprocessing, faster ambiguity fixed speed and otheradvantages than the dual-frequency observations.This paper systematically studys PPP theory based on GPS tri-frequency carrierphase observations. Meanwhile, some key technologies, such as ionospheric andtropospheric errors correction, cycle slips detection, precise ephemeris and clockinterpolation and the rapid fixation of ambiguity are discussed in detail and verified byexperiments. Finally, using the Visual C#3.0programming language, the author hasdeveloped a software to do instance validate and analyse.The main research contents and results are as follows:Firstly, this paper has a detailed analysis of GPS un-differenced observationequation, errors and their correction model which need to be considered. At the sametime, this paper has done instance validation and analysis of the ionospheric delaycorrection model, tropospheric delay correction model and the Earth solid tide effect.Secondly, this paper analyses the combination theory of GPS tri-frequency carrier phaseobservations detailedly, and picks out a lot of combinations with long wavelength, lowionospheric errors and small observation noise errors. Thirdly, the simulation theoriesand methods of L5carrier based on L1and L2carrier observations has been done, andthe correctness of the simulation data has been proved indirectly through the followingvarious instances. Fourthly, this paper analyse about the principle of tri-frequency codepseudorange/carrier phase combination method for the cycle slip detection in detaile,and has proved that this method can detect cycle slips under any circumstances quicklyand accurately by an example. Fifthly, this paper introduce the principle of The Generalized Extended Interpolation Method. Through its precision clock errorinterpolation instance, we can see this method can meet the requirements of the0.1nsinterpolation accuracy. Sixthly, mathematical model of tri-frequency ambiguitydecomposition is derived in detail and verified by an example that its single epochresults error is less than four cycles. This paper also analyses the principle of the TCARmethod, and expounds that it is not suitable for the un-differenced observationsprocessing through the theory and examples. Finally, a PPP program has beendeveloped and through the calculation of the measured data, we get the result that thepositioning accuracy of a single epoch data of30s sampling interval is0.2m~0.3m andthe positioning accuracy of a single epoch data of1s sampling interval is0.1m around.It also verifies the correctness of this theory and algorithms and laids a foundation forthe improving and studying of PPP in future.