Abstract: A method for on-orbit calibration of center of mass for gravity satellite was proposed， based on a predictive filter fusing extended Kalman filter estimation algorithm．Firstly，a periodic magnetic torque which was more larger than other external torques was applied to the satellite．Secondly，the observation of gyro was used to estimate angular acceleration based on the predictive filter．Finally，an extended Kalman filter was used to estimate the satellite′s center of mass．The numerical results indicate that the angular acceleration and center of mass can be real-time estimated. The calibration accuracy of three axes is [0.0628 0.0324 0.0414] mm, which demonstrates the effectiveness of the proposed method．

Key words: Centerofmass, On-orbitcalibration, PredictivefilterfusingextendedKalmanfilter, Electrostaticaccelerometer, Magnetictorque, Gyroscope, Gravitysatellite