Research On The Theory And Methodology For The Application Of VLBI2010 In The Precise Orbit Determination Of GNSS Navigation Satellites

With the continuous improvement of VLBI2010(Very Long Baseline Interferometry 2010)technology,besides the system construction work is imminent,the research on its practical application in all aspects is also gradually on the agenda.As one of the most cutting-edge directions,receiving and processing GNSS(Global Navigation Satellite System)satellite signals with the VLBI2010 system has received special attention from domestic and foreign scholars.This paper aims at the development status of VLBI2010 and GNSS observation technologies,and discusses the joint processing methods of VLBI2010 and GNSS data in the world.It focuses on the exploration of the space-time coordinate reference and mutual transformation relationship in the application of GNSS satellite precision orbit determination,and establishes a joint orbit determination model based on the original observations.Through simulation experiments of application methods,the results show that VLBI data can effectively improve the trajectory accuracy of GNSS navigation satellites,laying the foundation for the application of joint data.The main work and contribution of the dissertation are summarized as follows:1.Based on the analysis of the fundamental characteristics of electromagnetic signals,the main working principles,characteristics and parameter variables in the VLBI observation and observation process were summarized,the characteristics of GNSS signals and the main technical methods were summarized,and the basic observations of GNSS were summarized and analyzed,analyzing the physical basis of signal joint processing.2.The technical standards of VLBI2010 system design were deeply discussed,and the architecture design and principles of the system were studied and analyzed.On this basis,the technical possibilities of the VLBI2010 system for observing the GNSS satellite signals were discussed in detail;the scheme of the VLBI2010 system receiving and processing GNSS signals was summarized,and the working principles of each scheme were researched and their respective advantages and disadvantages were compared.3.Based on the relativistic effect,a strict space-time reference was constructed,and on this basis,a strict and complete spatial-temporal reference frame was researched,and the conversion relationship was systematically analyzed and given.Based on the space-time reference framework,the time system involved in satellite precision orbit determination was studied.Inside,the the links of the two were analyzed and the conversion relationships among various time systems and coordinate systems were given.4.Aiming at the complicated conversion relations caused by the non-Cartesian Cartesian coordinate characteristics in the commonly used geodetic coordinate system,the shortcomings of the existing approximation method,iterative method and closed method were summarized and analyzed,and a new non-singular algorithm for fast transformation from Cartesian coordinate to geodetic coordinates was given by rigorous derivation.5.The mathematic model and equation used in satellite precision orbit determination and the principle of orbit determination were studied.The application of adaptively robust Kalman Filter in satellite precision orbit determination was analyzed and the robust weight function and adaptive factors were improved.6.The principle and superiority of the GNSS non-difference observation model in place of the differential observation model were analyzed.The navigation satellite delay calculation method for the VLBI spherical wave tight delay model considering the relativistic effect was studied.7.The module structure and working principle of VieVS data processing software were introduced and analyzed.Based on the software,a method of simulating GNSS satellite data at the VLBI2010 station was proposed,and a preliminary short-time simulation experiment with joint orbit determination was carried out.By comparing with the results of GNSS alone,the results show that the VLBI data can effectively improve the integrated accuracy of satellite orbit determination,especially the tangential accuracy.