Abstract: To improve the attitude stability of the GF-7 spacecraft under disturbances from moving appendages，especially those induced by dualaxis directional antennae, a motion smoothing method was proposed and the corresponding disturbance mitigation technique was investigated. Firstly, as the attitude disturbances were usually caused by the data transmission antennae′s rapid capturing of ground targets for communications, a motion planning method with global smooth angular velocity was presented. Secondly, the general attitude dynamic equations of spacecraft with dualaxis antennae, which held true under any angular velocities, were developed and verified by comparison simulations. Then, feedforward compensation was developed and applied in the attitude control loop for reducing the disturbances from the antennae. Simulation results show that the proposed methods mitigate the disturbances of moving appendages by 90% while the antenna was working.

Key words: GF-7, antenna drive assembly, all-frequencies-disturbance mitigation, coordinate control, motion smoothing, torque compensation