Spacecraft yaw pointing for inclined orbits

Abstract

A method for use in a spacecraft for controlling yaw angle deviations from a desired yaw angle profile. The method includes the steps of: (a) operating a profile generator to output roll angle, pitch angle, yaw momentum, and yaw angle profiles, the profiles being calculated to meet spacecraft pointing requirements while operating in an inclined orbit; (b) inputting to an observer raw roll-axis sensor measurements, commanded and measured yaw-axis wheel momentum storage, measured pitch-axis wheel momentum storage, and external roll-axis and yaw-axis torques, the observer generating a yaw angle estimate and a yaw momentum estimate; (c) subtracting the yaw angle profile from the yaw angle estimate to obtain a difference value; and (d) using the difference value and the yaw momentum estimate to control roll-axis thruster firings to limit spacecraft yaw angle deviations from the yaw angle profile.

Dependencies are inferred from the claim text.