Satellite attitude determination and control system

摘要

Agile (electronically steerable) beam sensing with associated on-board processing, previously used exclusively for positioning of antennas for beam formation and tracking in communications systems, is now also used for satellite active attitude determination and control. A spinning satellite (100) is nadir oriented and precessed at orbit rate using magnetic torquing determined through use of an on-board stored magnetic field model (520) and attitude and orbit estimates (212). A Kalman filter (211) predicts parameters (202, 203) associated with a received signal (204) impinging on the satellite's wide angle beam antenna (201). The antenna system measures the error between the parameter predictions and observed values and sends appropriate errors signals (207) to the Kalman filter for updating its estimation procedures. The Kalman filter additionally outputs the spacecraft attitude error signals (215) to an attitude control law (213), which determines commands to attitude-altering magnetic torque elements (220) to close the control loop via the spacecraft dynamics (230).