Study On Gps Precise Point Positioning Using Un-differenced Carrier Phase

This thesis exhibits a comprehensive investigation on GPS Precise Point Positioning (PPP)with un-differenced carrier phase which includes mathematical models, error mitigations, datapreprocessing and parameter estimation as well as TcorrelativeT experiments, analysis andapplication.A brief introduction of mathematical models, error mitigations and data preprocessingtechniques was presented. Research was emphasized on methods of parameter estimation. A newapproach named"Tow-Way"Kalman Filter was proposed to conquer the disadvantage oftraditional Kalman Filter for kinematic PPP post processing. TA detailed deduction of Square RootInformation Filtering & Smoothing (SRIF&SRIS) and the method to categorise the unknownparameters were presented. A set of more universal Tformulas of Recursive Least Square (RLS)was derived by the author. The new formula using orthogonal transformation algorithm unifiestraditional RLS and SRIF&SRIS.To further our research, a piece of softwareT named"GPS-PPP"with the function for staticand kenamatic precise point positioning post processing was developed by the author. In thisTsoftwareT, varied error mitigations were implemented along with three modules for parameterestimation which include Tow-Way Kalman Filter, SRIF&SRIS and RLS. TFlexible Ttechniquesfor parameter elimination and restoration were employedT Tin all the three estimation modules.Test with plenty of both static and dynamic data demonstrated that an accuracy of 2-3 cmprecision and 10-20 cm precision has been achieved for static and kinematic positioningrespectively. The dynamic data used for test came from land, marine and airborne vehicles.Supported by the software package GPS-PPP, a series of correlative experiments andanalysis were carried out and conclusions were as follows: Firstly, Tow-Way Kalman Filter hassucceeded in overcoming the shortcoming of traditional Kalman Filter, and the result ofkinematic PPP with Tow-Way Kalman Filter is close to that with the other parameter estimationmethods presented by many references. Secondly, PPP results with different estimation moduleswere consistent to each other, and Kalman Filter has the highest calculating efficiency for staticpositioning while SRIF&SRIS enjoys the least time cost for kinematic positioning. Thirdly,Experiments demonstrated that static PPP results using different Orbit & Clock products sharenearly the same precision while using products with 30 sec sample rate Clocks would improvekinematic PPP result by 50% than that using products with 5min Clock. Fourthly, it has beenconcluded that ignoring DCB correction will result in systemic errors for PPP result whichmainly influence receiver clock estimation and the influence of DCB on static positioning is small enough to be ignored, but for kinematic PPP it has to be considered seriously.Last but no least, it occurs to the author to receive a set of data with 1 Hz sample rate from 12 continuous operation stations in Tianjin China on the date of Wenchuan Earthquake 12 May, 2008. Experiment of using PPP for far-field ground motion analysis of Wenchuan Earthquake was carried out and the result was really encouraging that the periodic motion in both east-west and south-north directions of the stations could be distinguished.