Research On The Autonomous Orbit Determination Of GEO Satellite Based On ISLs With Navigation Constellation

In traditional method,the ground station is used to realize the orbit determination of GEO satellite,there is a problem that the observation geometry among the GEO satellite and MEO satellites is weak,it leads to the result that the error of satellite-ground station observation will be amplified too much.But the BDS satellite navigation system is designed with ISL(Inter-Satellite Link)which measures more accurate and the observation geometry is much better,it has become more suitable to realize the orbit determination of GEO satellite.This paper focused on the autonomous orbit determination of GEO satellite use the ISL with the MEO satellite,and the research mainly included the following aspects:(1)This article established the model of autonomous orbit determination of GEO satellite.The state equation and the observation equation are established,the EKF algorithm is used to achieve the state to be estimated of GEO satellite.In premise of the accuracy and reliability of the algorithm,this paper analyses the effects that the random noise of observation,systematic error,gross error and solar radiation pressure have on orbit determination result.This paper also uses the base satellite orbit covariance to modify the predicted state of GEO satellite and analyses the effect and order that the base satellite orbit error has on orbit of GEO satellite.(2)This article put forward the algorithm aimed to solve the problem about wrong observation and error in dynamics model.The effect of different weight counting method based on the quality of observation.The article also analyses the effect on reducing the error of orbit determination by dynamics error by the adoption method through constructing the state inconformity quantity.(3)This article analyses the accuracy of orbit determination under different ISL resource selection strategy.The PDOP is regarded as the quota of observation geometry quantity.Three resource selection strategies have been put forward based on the contribution of each base MEO satellite,and the effect of three resource selection strategies have been discussed in different error situation.This paper mainly focuses on the autonomous orbit determination of GEO satellite use the ISL with the MEO satellite,it analyses the effect that base MEO orbit error cause in GEO satellite,optimizes the algorithm through robust estimation and adoption estimation and draft the resource selection strategy for GEO satellite to maintain the accuracy and increase the coefficient of ISL.The paper can provide reference for autonomous orbit determination of GEO satellite in our BDS.