Development of an EKF Based Gyro Calibration Method for High-Precision Attitude Estimation

IIn high resolution remote sensing satellites, meeting stability and pointing requirements are very crucial in mission’s success. In this regard, usually, very accurate gyroscopes are utilized as one of the main attitude sensors. In order to avoid decreasing attitude estimation accuracies, gyroscopes data should be calibrated in appropriate time intervals. In this research an Extended Kalman Filter (EKF) based approach is investigated for gyro calibration. Therefore, at first, a model which contains main gyro parameters, namely, biases, scale factors and misalignments is proposed. Then, an EKF based algorithm for gyro parameters estimation is presented. Next, a Multiplicative Quaternion Extended Kalman Filter (MQEKF) which uses star sensor data as measurement is applied for attitude estimation. Finally, in order to evaluate the performance of the proposed gyro calibration method in attitude control loop, a quaternion feedback controller is implemented. The simulation results show that satellite’s stability and pointing are maintained with accuracies better than 0.005 deg/second and 0.15 deg which demonstrate the proposed method will be beneficial for missions with tight control requirements.