Satellite measurements have problems because of calibration changes when they are replaced every few years.
卫星测量方法也有问题，因为每隔几年卫星测量设备更换后，校准就改变了。
2
The calibration targets are larger than might have been expected, he said, suggesting that the satellite cameras they are being used to calibrate have surprisingly poor ground resolution.
校准目标有可能比预料的要大，他说，这表明被校准卫星上的照相机的地面分辨率是很低的。
3
The department of satellite design and the staff on the ground have conducted a way of thruster calibration execution in terms of the data of the attitude and the nutation principle.