Study On Fast Orbit Determination And Prediction For Navigation Satellite

The model of long-arc orbit determination and prediction is used in the ordinary precise orbit determination and prediction.Its theory is sound, so the method is used abroad.Fast orbit determination and prediction refers to the method by which satellite precise orbit is achieved in short time and a definite arc-length precise orbit prediction can also go along. And the method,which is precise orbit determination and prediction under some certain conditions, is mostly used in orbit determination after satellite maneuvers.When navigation satellite is moving in the space, periodic maneuvers is often carried out for keeping special orbit and pose.Because of maneuvers,the old dynamic model is affected, the accumulation of continuous days'observation data is broken in, and precise orbit and prediction cann't be gained from ordinary precise orbit determination and prediction.For solving the problem of discontinuity caused by maneuvers in the process of ordinary precise orbit determination,main focus is payed on the method of fast orbit determination and prediction of navigation satellite.The purpose is to gain satellite precise orbit and prediction in short time,to assure satellite navigation system to be fine and stable and to improve system availability.On the basis of research,an antitype software for fast orbit determination and prediction is developed by the author. The main works and contributions as follows:1,Satellte motion equations are discussed,and the main perturbation force is introduced simply.On the basis of motion equations,variational equations and the form of unite integration of motion equations and variational equations are derived.The ordinary numerical solution of motion equations and variational equations is introduced.And then,the method of orbit simulation is presented, orbit simulation module of the antitype software is made and simulation analysis is done to the orbits of Medium Earth Orbit Satellite(MEO) and Geosynchronous Earth Orbit Satellite(GEO).2,According to the requirement of fast orbit determination,the kinds of observation data are selected.A method of assessing the results of error correction is presented,and error correction module of the antitype software is made.Through numerical examples,the results of observation error correction are analyzed.3,A method of getting synchronous observation data from different stations is presented,and geometric fast orbit determination of navigation satellites is designed and realized.By this method,single-epoch real time and post fast orbit determination is achieved.The fitting method of geometric orbit determination is improved and the method of orbit prediction of geometric orbit determination is discussed. The module of geometric fast orbit determination and prediction is developed.Through MEO/GEO simulation and real observation data,the method is validated and different proceeding strategies are compared.Meanwhile,the precision of MEO and GEO is compared.4,Short-arc dynamic fast orbit determination and prediction is discussed.Smooth orbit and orbit prediction can be gained after short interval(5 minutes) by the method. The module of Short-arc dynamic fast orbit determination and prediction is developed. Through MEO/GEO simulation and real observation data,the method is validated and compared with geometric orbit determination.5,The advantage and shortcoming of geometric orbit determination and short-arc dynamic orbit determination is analyzed,and considering the thought of dynamic smoothing,the advantage of geometric orbit determination and dynamic orbit determination is combined to achieve greater precision than geometric real-time orbit determination,and after a while(the filter is constringent),more high accuracy and more stable state can be achieved.Considering the background of fast orbit determination,A method of orbit prediction is presented. The module is developed. Through MEO/GEO simulation and real observation data,the method is validated.Meanwhile,the method is compared with geometric orbit determination and short-arc dynamic orbit determination.