PROPOSED DESIGN OF A FAULT-TOLERANCE ATTITUDE ESTIMATOR FOR SMALL EARTH OBSERVATION SATELLITE

Attitude Determination and Control Subsystem (ADCS) is considered as the most complex subsystem on-board on-board an Earth observation satellite. The subsystem functions to point the satellite to the desired target especially for earth imaging task. Its performance is certainly decided by the accurate and reliable data provided by the attitude estimator. However, the estimator which is the fusion of multiple sensors data such as gyroscope and star tracker is heavily impacted by uncertain parameters such as the system noise, measurement noise and sensor unavailability delivering unreliable attitude outputs. This paper will describe a fault-tolerant gyro-stellar estimator (GSE) to effectively fuse the measurements from gyroscope and star tracker and for small Earth observation satellite.