Unscented Kalman filtering (UKF) based combined attitude determining method and satellite attitude control system

The invention discloses a UKF based combined attitude determining method and satellite attitude control system, and belongs to the technical field of satellite attitude determining. A nonlinear stateequation in the differential form is constructed based on a star sensor of UKF and a gyro combined pose determining algorithm, a four-order Runge-Kutta integration method is used to solve time updateof a state variable, and discretization of the nonlinear differential state equation is avoided; and the UKF algorithm is used to filter and correct a quaternion of the star sensor and the gyro angular speed. The four-order Runge-Kutta integration method is used to update the time, a quaternion multiplication error is used to calculate the weighted mean value and covariance, the UKF algorithm is used, an observed value of the star sensor is introduced to implement filtering and updating, and the estimated error quaternion is used to correct attitude data. The attitude determining performance when a measurement error of