Research On Real-Time Kinematic Algorithm Of BDS/GPS And Its Implement Of Software

BeiDou Satellite Navigation System is the global satellite navigation system developed by China independtly. After Chinese BeiDou System (BDS) provided the services in the Asia-Pacific regional area,its research and application in Traffic,Surveying and Mapping industry etc are developped rapidly. Obtaining high precision coordinate is a vary important aspect for the application of BeiDou Navigation Satellite System.It is necessary to use the carrier phase such as RTK,PPP,etc.This dissertation studies the positioning algorithm and mathematical model of BDS-RTK and BDS/GPS-RTK deeply. And the RTK software based on this algorithm is developed.Through real-time experiments,quasi-kinematic experiments and dynamic experiments, the positioning accuracy and reliability of BDS-RTK,GPS-RTK and BDS/GPS-RTK are verified.In this dissertation,the main work are summarized as follows:1.BDS-RTK algorithms comparison, implementation and experimental analysisThe differnce of BDS and GPS positioning algorithm include:the satellite types is different cause the difference of satellite position calculation,these satellites position calculation formulas are given; Time systems and coordinate systems are different,and analyzes the relationship between different space-time system.frequencies are different,and this has little effect on orginal mathematical model.the concrete numerical value of BDS frequencies are given at BDS ICD.Based on the above BDS location Algorithm,the RTK platform is extended to apply to dual-frequency BDS-RTK.2.Combined BDS/GPS RTK algorithm and accuracy assessmentOn the basis of RTK for single GNSS system, the functional and stochastic models of combined BDS/GPS RTK are introduced. This RTK algorithm integrates dual-frequency GPS and BDS observations in observational domain. By introducing an estimable parameter of biased time difference, the time difference between GPS and BDS are correctly compensated. The positioning capability of combined RTK is verified in static,dynamic mode.main conclusions are:it can improve the location precision of RTK if single system has bad geometric configuration but it contributes only marginally to the GNSS-only positioning if single system already has good geometric configuration.