Research And Implementation On Technology Of Precise Point Positioning Based On Triple-Frequency Ambiguity Resolution

PPP can achieve the advantages of high-precise positioning based on stand-alone operation and unrestricted distance.With these advantages,it has been widely concerned by a lot of scholars and used in the fields of high-precision navigation and positioning.After the modernization,some GPS satellites have been broadcasted triple-frequency signal.Compared with dual-frequency observational combination,triple-frequency observation combination has more advantages on weakening the atmosphere delay,resistance to interference and ambiguity fixed efficiency.With these advantages,triple-frequency PPP has been frontier direction on GPS positioning field.In PPP,the occurrence of cycle slip will make the ambiguity can't be fixed accurately,which will lead to at least the positioning error of the decimeter.And the methods to fix ambiguity will also have a great impact on PPP.To improve positioning accuracy of real-time PPP,this paper mainly focuses on the research of cycle slip detection methods and the methods to fix ambiguity.Firstly,this paper expounds the basic observational equation of PPP briefly and summarize the observational combination mathematical model.Besides,this paper introduces the origin,feature,influence level of error and the methods of weakening error in PPP in detail.Secondly,this paper classifies and summarizes common algorithm and mainly research dualfrequency and triple-frequency methods of current cycle slip detection and correction.And then this paper proposes a new triple-frequency method of cycle slip detection with TECR based on existing methods.And then,this method is validated and analyzed by using triplefrequency data.The experiment results show that this method can detect and repair all the cycle slip.Besides this method has smaller threshold value and can work properly under high ionospheric activity.Then,this paper introduces the reason why ambiguity isn't integer and summarizes two methods estimating the fractional cycle bias which are single difference method and undifference method respectively.This paper mainly researches dual-frequency ambiguity fixed methods with undifferenced combination and traditional triple-frequency ambiguity fixed method.Considering the time variation characteristics of the NL FCBs,this paper proposes a new ambiguity fixed model which called EWL-WL-WL-WL.And then,this method is validated and analyzed by using triple-frequency data.The experiment results show that this method can improve the convergent rate of ambiguity compared with methods to fix dual-frequency ambiguity and reduce the burden of network.Finally,based on database of RTKLIB,this paper achieved PPP software with C/C++ language.The software is based on RINEX observations and realize the function of triplefrequency cycle slip detection and repair.Besides the software realize the function of correcting the triple-frequency FCBs and the function of fixing triple-frequency ambiguity rapidly.And then,this method is validated and analyzed by using observation data from IGS stations.The experiment results show that the software can realize static PPP and the positioning accuracy can achieve cm level with data of one day.