Space subsystems design: (navigation, control, structure and…)
Amir Labibian
Volume 17, Issue 1 , March 2024, , Pages 11-20
Abstract
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 ...
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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.
Mohammadvali Arbabmir; Masoud Ebrahimi Kachoei
Volume 12, Issue 3 , September 2019, , Pages 43-54
Abstract
In the last decades, the visual navigation system has been investigated by many researchers as an aided navigation system for Inertial Navigation System (INS) in the Unmanned Aerial Vehicles (UAV). In this research, for improving the INS errors a new approach based on feature tracking algorithm is used. ...
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In the last decades, the visual navigation system has been investigated by many researchers as an aided navigation system for Inertial Navigation System (INS) in the Unmanned Aerial Vehicles (UAV). In this research, for improving the INS errors a new approach based on feature tracking algorithm is used. In this approach, in order to estimate the feature points in the current image, the INS states, the feature points of the previous image and dynamic equations are used. Also, in this approach, for improving the estimation of terrain points, the outlier estimated feature points delete. Furthermore, in this article, for improving the altitude error, a barometer is used by the mentioned vision navigation system. The simulation results illustrate the desirable accuracy of the vision system and barometer observations in the update step of Extended Kalman Filter (EKF) and remarkable performance of integrated navigation system for calculating the UAV navigation parameters.
