Grid-based Dynamic Positioning Algorithm Based On GNSS Reference Station Network And Its Software Implementation

Virtual Reference Station(VRS)technology is a mature high-precision positioning method,which is widely used in the continuous operation reference station system at various provincial levels in China.However,in the traditional VRS mode,there is still the problem of small concurrent users of online users.Aiming at this problem,this paper makes effective improvement on the basis of traditional VRS technology,and puts forward a grid-based dynamic positioning algorithm based on GNSS reference network,and makes an in-depth research of its theoretical principles,and analyzes the sources of errors such as atmospheric delay and their processing methods,and introduces the principle and implementation process of grid division,and puts forward the best grid size division method,and carried out experimental verification and analysis of the algorithm's usability,The specific work includes the following aspects:(1)Introduced the relevant theories of GNSS network RTK technology.Including GNSS observations and their observation equations,linearization of observation equations,and linear combinations commonly used in multi-frequency observations;the main sources of errors in network RTK positioning and the corresponding error processing methods,focusing on the analysis of the influence and change characteristics of double-difference atmospheric delay error with strong spatial correlation.(2)Introduced several commonly used spatial error interpolation models,and deducts the generation model of grid point virtual observations,and analyzes the factors that affect the accuracy of grid differential correction data positioning,and gives the theoretical basis for grid size division,and studies the optimal division of grid size by using measured data.It is recommended that users with high-precision positioning requirements choose a grid density of 4?×4? for virtual grid division(3)Introduced the rover station RTK positioning algorithm based on the Kalman filter algorithm with multi-epoch initialization,and conducts field tests on two different types of RTK user terminals,GNSS receivers and smartphones,to analyze and verify the feasibility of the algorithm.Introduced the changes of BDS-3 in terms of signal system and satellite constellation,designed experiments to analyze the positioning accuracy of BDS-3,and verified the support of grid differential correction service for BDS-3 satellites.Experiments show that: according to the grid density of 4?×4?,the grid positioning service is equivalent to the original network RTK software positioning effect,which can effectively increase the concurrent amount of online users on the service platform while ensuring positioning accuracy.Meet the positioning requirements of centimeter-level accuracy;it can provide positioning services with decimeter-level accuracy for smart phones.There are 47 pictures,22 tables and 59 references.