Investigation on Centralized Autonomous Orbit Determination Using Inter-satellite Ranging

Abstract

Autonomous operation capability is essential to improve the overall satellite constellation in terms of stability, reliability and timeliness. In this paper, we assume a miniature constellation based on BeiDou satellite navigation system, including Inclined Geosynchronous Orbit (IGSO) satellites and Medium Earth Satellites (MEO). The performance of autonomous orbit determination (AOD) of the constellation is investigated, with inter-satellite ranging. AOD is accomplished with Extended Kalman Filter (EKF). The process noise is considered modeled with a Gauss-Markov process. The filtering process is implemented using purely analytical state transition matrix (STM) and process noise transition matrix. The centralized orbit determination in this paper is based on the concepts of reference satellites and satellite grouping (by visibility). Within each group where member satellites are directly or indirectly linked, AOD is achieved by designating at least one reference satellite whose Right Ascension of Ascending Node (RAAN) is dynamically propagated but not filtered. Although one reference satellite is theoretically enough to sustain AOD, it may still be insufficient, from the practical point of view, to constrain the whole constellation within only one satellite. On the other hand, introducing too many reference satellites with unfiltered RAANs. In this paper, we also investigate AOD performance with one or two reference satellites. Especially how two reference satellites with different initial errors, different orbital altitudes and different geometries affect the AOD performance.