Research On GNSS-Based Orbit Determination Of High Earth Orbit Satellites

The high earth orbit (HEO) satellites are playing an increasingly important role in the field ofmilitary and civilian. Currently the orbit determination of HEO satellites is achieved mainly throughthe continuous observation of the Monitoring network. But the method requires the complexequipments and the high running costs. Therefore, the research on the use of spaceborne GNSSreceivers for orbit determination has become a new research direction. In this paper, the main researchis on the Multi-constellation Integrated Navigation System performance, nonlinear filter for orbitdetermination and the algorithm for weak signal acquisition.Firstly, the dissertation introduces an overview about GNSS and the development of orbitdetermination technology based on GNSS. Then the visibility of spaceborne GNSS receivers isanalyzed by the STK simulation. The mathematical model of the HEO satellites orbit determinationsystem is established. A complete simulation process is given for the follow-up research foundation.Based on the visibility analysis, the further simulation for orbit determination performance of HEOsatellites using multi-constellation integrated navigation system is carried. Because the systemmathematical model is nonlinear, the extended Kalman filter is used for orbit determinationcalculation. But there is the linear error caused by the EKF, which will impact the final orbitdetermination accuracy in some cases.For the lack of the EKF, other nonlinear filters are used for replace it. One of them is the UKFalgorithm which doesn’t need approximate the nonlinear function. And the improved algorithm isobtained by combining the Runge-Kutta method and the EKF algorithm. In the case of using themulti-constellation integrated navigation system，the correctness of the improved algorithm isvalidated. And the orbit determination performance of the two nonlinear filters is simulated.The study of the receiver algorithm for weak signal acquisition is also the important part of orbitdetermination of HEO satellites based on GNSS. The article describes the conventional GPS signalacquisition methods and the traditional algorithms for weak signal acquisition. Then combined withthe thinking of cumulative data block，it presents the fast improved algorithm for weak signalacquisition. Its performance is verified by capturing the simulated signal and the real signal.