Six State Kalman Filtering for LEO Microsatellite Attitude Determination

Abstract— The attitude determination and control subsystem (ADCS) requirement of payload on the Algerian Satellite (Alsat-1) is stringent enough to demand some type of data processing in order to meet attitude determination requirements. Two vector magnetometers and four dual sun sensors are carried in order to determine the attitude. This paper describes the various steps of the design and the implementation of the reduced model of the extended Kalman filter (6-state EKF) for small Euler angles on the Alsat-1. For the 6state filter, the state vector defines not only the attitude of the satellite, but also the rates at which the attitude is changing. This paper examines the six state Kalman filter from a theoretical standpoint before examining practical implementation.