Real-time drift angle compensation based on speed vector model for space camera on circular orbit

Drift angle is an important factor which disturbs image quality of linear array CCD camera in push broom imaging mode. In order to realize fast calculation to drift angle under limited computational resource condition on orbit, a drift angle expression applied to remote sensor with straight, forward and backward sight on circular orbit was constructed, based on character of relative motion between velocity of camera on round orbit and of ground target which moved with rotation of the earth. Mathematical expression of angular vibration of the velocity vector of satellite relative to target during satellite's flight was given. The real-time adjusting method based on CCD rotating was presented and verified by constructing imaging testbed of real-time drift compensation. Simulation and test results indicate that speed vector model has higher calculation efficiency, and calculation accuracy and stability are as much as method of coordinate transformation and orbital element. MTF degradation can be suppressed to 5% with drift compensated by speed vector model. The method can be further used for development of drift angle real time adjustment mechanism of TDICCD camera and three-line CCD 3-D photography camera.