Abstract:

The positioning accuracy is directly affected by the change of the angle between star sensor and earth observation camera of the optical mapping satellite in the orbit, without the support of ground control point data. Aiming at the practical application problems of low attitude stability and the long calibration period of the earth observation camera, this paper proposes a real-time method for the calibration of the angle between star sensor and earth observation camera, based on the self-collimation method. First, we install collimated light sources, the spot imaging array and other devices inside the satellite load system. Then, we convert changes in the camera's optical axes into changes in the spot images. Finally, the angle variation between the cameras’ optical axes can be solved. Simulation analysis shows that this method can obtain the calibration accuracy of 0.1 arc second-time in both the pitch angle and roll angle. This method requires no ground calibration field and it is not affected by external conditions. It can realize real-time autonomous calibration in-orbit. This method has a good feasibility and practical value.

Key words: on-orbit real-time calibration, angles of camera, optical self-collimation, error analysis, attitude angle