Software Development Based On Multi-frequency Multi-GNSS Precise Point Positioning Algorithm

The increasing maturity of the Global Navigation Satellite System(GNSS),in particular the establishment of the Beidou-3 navigation satellite(BDS-3)system and Galileo system,has driven the progressive development of precise point positioning(PPP)technology to multi-frequency and multi-systems.However,the addition of multi-frequency and multi-systems would bring some problems to the traditional PPP model,such as differential code bias(DCB)at the satellite end,inter-frequency bias(IFB)and BDS-2/BDS-3 time delay bias(TDB),and the traditional floating point solution accuracy is not enough to meet the increasing demand for positioning,how to achieve high accuracy positioning over a wide area using ambiguity resolution in precise point positioning(PPP-AR)technology is the problem we need to face.Therefore,in order to address the context of future multi-frequency applications,to consider the deep integration and full utilization of multi-GNSS signals,and to evaluate the effectiveness of different PPP-AR products for multi-GNSS ambiguity fixing,the main researches of this thesis is as follows:(1)For the multi-frequency signals broadcast by the BDS-3 satellite,the threefrequency PPP models using B1C/B2a/B2 b and the five-frequency PPP models using B1C/B2a/B1I/B3I/B2 b are constructed respectively,the processing of the deviation terms in the multi-frequency PPP models is explained in detail,and the usability and positioning performance of those models are verified and evaluated through the corresponding MGEX experimental data,providing some reference for future research related to BDS multi-frequency positioning.(2)In view of the current research status of multi-frequency and multi-systems,the multi-frequency and multi-GNSS adaptive PPP models applicable to inconsistent satellite broadcast frequencies is derived on the basis of the original observation equations,and the innovative points of the model are explained in detail.The usability of the proposed adaptive PPP models is then verified by corresponding experimental data,and its positioning performance are analyzed,the characteristics of the multifrequency and multi-GNSS adaptive PPP models are also concluded.(3)For various agencies offering PPP-AR products with different strategies in distinct forms,the principle steps of ambiguity fixing are introduced in detail,the usage of each PPP-AR product is explained,and a ambiguity fixing software compatible with all types of PPP-AR products is developed and the performance of single Global Positioning System(GPS),single Galileo and multi-GNSS converged PPP including BDS-3 using different products is studied through this software,providing a reference for multi-product and multi-system PPP-AR technology.(4)A set of multi-frequency multi-GNSS PPP and dual-frequency multi-GNSS PPP-AR positioning software has been developed,and the usability of the developed software in kinematic and static positioning scenarios has been verified through measured data respectively.There are 61 figures,14 ables and 99 references in this thesis.