A new autonomous orbit determination algorithm based on inter-satellite ranging measurements

Abstract

Due to the limitation of onboard computers relatively low storage and processing ability, current autonomous orbit determination (OD) algorithms mostly adopt sequential and distributed method for navigation satellite. Such algorithms can save computing resources, however have met the problem of filter divergence and rapid accuracy decline especially under the condition of less inter-satellite links (ISLs). This paper proposes a new rapid and stable centralized algorithm based on powerful high frequency inter-satellite measurement capability under the space/time-division multiple access (STDMA) system. This approach describes the difference between the real and long term forecasting orbit as the simple higher order polynomials, which needs no complex dynamic modeling, trajectory integration and the state transition matrix calculation, thus greatly saves computing resources. Meanwhile, this paper advances to make full use of the longitude of the ascending node information of forecast orbit so as to reduce the dependence on ground support system. Finally, we simulate the Beidou global constellation structure and ISL measurements, demonstrate the impact of the number of ISL, the noise of ISL on the performance of autonomous OD, and analyze the total amount of computation theoretically. The simulation results show that the algorithm with high stability has no error accumulation, and can run normally even with 3 ISLs, and under the condition of no less than 5 ISLs, the orbit user orbit error (URE) is about 0.9 m after 60 days autonomous operation. The total amount of calculation of the new method is theoretically one-seventh of the distributed extended Kalman filter algorithm.