Research On The Methods Of BDS/GNSS Precise Real-time Kinematic Relative Positioning

With the improvement and development of the Global Navigation Satellite System(GNSS),the application areas of navigation and positioning services continue to expand.However,when the carrier is moving or in a bad observation environment,it is difficult to obtain high-precision and high-reliability positioning results only by relying on a single GNSS.Multi-GNSS integration has become an effective way to achieve precise kinematic relative positioning.Therefore,the paper first establishes a BDS kinematic relative positioning model,and then on this basis,the BDS/GNSS combination precise real-time positioning methods are researched.The BDS/GNSS kinematic relative positioning software is realized,and the usability of the software is verified through measured data.The main work and research contents of this paper are as follows:1.Aiming at the problem of cycle slip detection in the process of dual-frequency positioning,the carrier phase rate method for single-frequency data detection is improved.The simultaneous detection of dual-frequency data is realized through the combination of observations rate,which reduces the amount of calculation.And it has achieved better results in the application of measured dual-frequency data combined the ionospheric residual method.2.BDS constellation contains three types of satellites,and according to the structural characteristics of the BDS satellites constellation,the interpolation accuracy of the various orbit satellite coordinates using precision ephemeris is researched.The lowest order of Lagrange interpolation method and Chebyshev polynomial method that meet the accuracy requirements of satellite coordinate interpolation are respectively given.3.In order to solve the problem that the number of visible satellites of the moving carrier is small and the positioning results is unstable,the BDS/GPS combination relative positioning model is researched.First,the GNSS coordinate system and time system are introduced,and the conversion relationships of the space-time coordinate systems between different systems are given;Then,the post-test weighting Helmert variance component estimation(VCE)method is researched,which can make up for the insufficiency of the pre-test weights method that cannot effectively distinguish the difference in the quality of the observation data of each system.The experiments have verified that the combined positioning accuracy of multi-GNSS is higher than that of any single system.The Helmert variance component estimation method further improves the accuracy and reliability of the combined positioning results of multi-GNSS.4.Based on FORTRAN language,the BDS/GNSS kinematic relative positioning calculation software is realized,and its data processing flow is introduced.In order to verify the usability and reliability of the software,the actual experiments are carried out and the results of a single system or a combination of multiple systems are compared and analyzed.It shows that BDS/GNSS can obtain high positioning results in both static applications and kinematic applications,and realizes precise dynamic positioning.