Autonomous Orbit Determination using Observations of a Sodium Guide-Star Network

Mark L. Psiaki

Abstract:	A new method of spacecraft orbit determination is developed based on position information from the observation of fluorescing streaks in the atomic sodium of the Earth’s upper atmosphere. This concept has the potential to provide an autonomous orbit determination capability independent of GNSS signals, and it may prove useful for GPS constellation Autonomous Navigation (AutoNav). This new orbit determination method uses a spacecraftmounted camera to observe fluorescing line segments in the sodium layer. The fluorescence is excited by ground-based sodium guide-star lasers. Such lasers are currently used in adaptive optics systems for ground-based telescopes. Their use for orbit determination represents a novel application. The system also uses a star tracker in order to reference the measured guide-star directions to inertial coordinates. The measured direction to an unknown point on a known guide-star segment at a known time defines a plane on which the spacecraft must lie. Seven or more independent measurements should suffice to determine a Keplerian orbit and the spacecraft clock offset. Cramer-Rao analysis of this concept indicates that 1-? per-axis orbit determination accuracies on the order of 20 m or better may be achievable for filtering intervals of several days.
Published in:	Proceedings of the 30th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2017) September 25 - 29, 2017 Oregon Convention Center Portland, Oregon
Pages:	1155 - 1168
Cite this article:	Updated citation: Published in NAVIGATION: Journal of the Institute of Navigation
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