Attitude pointing error correction system and method for geosynchronous satellites

摘要

A system and method for attitude control in a geosynchronous satellite (10) to compensate for roll and yaw pointing errors consequent to orbit inclination variation from the nominal equatorial orbit plane provides for an inertially fixed momentum vector coupled to the satellite (10) through a gimbal system (22) providing a one and preferably two degree-of-freedom relationship with the momentum vector. In a two degree-of-freedom embodiment, the momentum vector is established by spinning the satellite (10) about an axis or providing an independent momentum wheel (54) with the gimbal axes provided along the roll and yaw axes. Gimbal torquers (30,34) torque the satellite (10) about the inertially fixed momentum vector in a time-varying manner to effect correction of the roll and yaw pointing errors. Additionally, a conventional thruster (Tn) system is provided for pitch axis error correction and large orbit corrections attendant to the station-keeping function. Roll and yaw pointing errors consequent to orbit inclination drift from the nominal equatorial orbit are corrected in a fuel-efficient manner to extend the operating life of the satellite (10).