Integrated SVD/EKF for Small Satellite Attitude Determination and Rate Gyro Bias Estimation

In this study an integrated singular value decomposition (SVD)/ Extended Kalman filter (EKF) attitude determination system is presented, in which the SVD and EKF algorithms are combined to estimate the attitude angles and angular velocities and gyro biases, respectively. As a reference directions for SVD, the unit vectors toward the Sun and Earth's Magnetic Field are used. The Euler angles produced SVD are provided as input to the EKF along with angular rate data. The parameters of satellite's rotational motion and rate gyro biases are estimated using EKF. In comparison to more traditional approaches, this preprocessing step significantly reduces the complexity of filter design by allowing the use of linear measurement equations.