A lowcost attitude estimation method using Extended Kalman Filter (EKF) was proposed for satcomonthemove (SOTM)which taking Quaternion as state variablesand the attitude information was estimated by fusing the angular output of gyrosthe acceleration output of accelerometers and the position and velocity output of twoantenna GPS.The GPSmeasured velocity was used to compensate for the maneuvering accelerationand the sideslip angle was used to further correct the maneuvering acceleration when the vehicle was turning.Experiment results show that the proposed method can combine together the good shortterm accuracy of gyrosthe good longterm stability of accelerometersand the precise position and velocity of GPSwhich is feasible for attitude stabilization of SOTM with the dynamic estimation error controlled within ±0.5°.