Modified UKF for integrated orbit and attitude determination based on gyro and magnetometer

A new method for orbit and attitude determination of satellite simultaneously based on three-axis-magnetometer (TAM) and gyro data is presented, which is a breakthrough in traditional pattern of treating orbit and attitude of satellite separately. Considering of the nonlinear system, a modified unscented Kalman filter is developed. The magnetic field components are used to update as measurement and the gyro data are used to propagate the state vector. Because of the constraint of the quaternion, an error vector update approach is proposed. Numerical simulations are given at last, and the algorithm is confirmed to be feasible and effective.