Spacecraft Navigation Using Stellar Aberration and Gravitational Deflection of Light

Abstract

An autonomous spacecraft navigation scheme based on the stellar aberration and the starlight gravitational deflection is presented in the paper. The stellar aberration provides spacecraft velocity information in the plane perpendicular to the star line-of-sight unit vector, while the starlight gravitational deflection is sensitive to the spacecraft position relative to celestial bodies. For autonomous spacecraft navigation, a practical approach to collect measurements is to observe the change of inter-star angles caused by the stellar aberration and the starlight gravitational deflection through an optical interferometer. A measurement equation is established to describe the relation between the state vector and the observations. Then it is used together with the dynamical model for the design of an extended Kalman filter that provides spacecraft kinematic state estimation. To improve the navigation performance, an optical path delay bias estimation and compensation are implemented in the extended Kalman filter. It is shown via simulation that, for a medium Earth orbit (MEO) satellite, the position and velocity errors of the presented scheme are on the order of 150 m and 0.02 m/s with the inter-star angle measurement accuracy of about 1 mas.