Design of Fault Detection, Isolation and Accommodation Algorithm for Attitude Determination System of a 3-Axis Satellite

In this study, a fault tolerant Attitude Determination System (ADS) has been designed which provides fault detection, isolation and tolerant abilities in this system. Suggested approach is based on derivation of all possible rotations between body and orbital frames and comparison of Euler angles provided by them. In this regard, significant changes in the variance of Euler angles set are considered as criteria for fault detection. Moreover, fault isolation and tolerant mechanisms are based on classification of rotation matrices which are not affected by faulty components. The above features present a quite analytical and computational approach which does not impose additional mass, power consumption and cost in the satellite. Also, designed diagnosis and fault correction algorithms are model-free based mechanisms which always provide tolerated attitude angles for the attitude control subsystem. The mentioned abilities combined with the model based FDI mechanisms utilized in the attitude control system, provide an advanced decision support system capable of isolation of faults which have been simultaneously occurred in the satellite sensors and actuators. Finally, performance of the designed algorithm is approved by simulation results.