Autonomous spacecraft navigation system

TLDR: In this article, a method and corresponding apparatus for providing spacecraft attitude, position and orbit data without the need for externally supplied data is presented, using onboard observations of the earth, sun and moon, the system determines spacecraft attitude and instantaneous position, and the orbit based on multiple position estimates.

Abstract: A method and corresponding apparatus for providing spacecraft attitude, position and orbit data without the need for externally supplied data. Using onboard observations of the earth, sun and moon, the system determines spacecraft attitude, instantaneous position, and the orbit based on multiple position estimates. Position and orbit data are derived by multiple deterministic solutions, including some that employ star sensors and gyros, and the multiple solutions are accumulated in a Kalman filter, to provide continuous estimates of position and orbit for use when the sun or moon is not visible. The best estimate of position is selected from the multiple deterministic solutions and the Kalman filter solution, and can be used to control the spacecraft in various ways, without having to rely on ground-based equipment or other spacecraft for the determination of position and orbit.