Abstract: This paper proposes an accurate orbit determination technique to accurately determine orbit elements of a spacecraft equipped with a GPS receiver according to navigation messages from the receiver. Accurate coordinate system and time system transformations necessary to guarantee the orbit determination accuracy of the order of 10m are presented. A combined navigation method using navigation messages from receiver and the recursive formula of the perturbation motion equation is adopted, and the navigation can still operate normally even if antennas of the receiver is obscured in a short duration.

Key words: orbit determination , orbit elements