Analysis of image motion for optical remote sensing satellites staring imaging with area-array detectors

Abstract

In this paper, the image motion introduced by the staring action itself during optical remote sensing satellites staring imaging with area-array detectors is studied. The image motion is decomposed into the angle-rotation image motion caused by the change of observation angle, the size-scaling image motion caused by the change of observation distance, and the Earth-rotation image motion caused by the rotation of the ground object with the Earth. The theoretical derivation of the angle-rotation image motion and size-scaling image motion is conducted, and the numerical analysis of the Earth-rotation image motion is carried out. Based on the comparison among the characteristics of the three types of image motions, the conclusion is drawn that, for general staring imaging scenes, the angle-rotation image motion is dominant, followed by the size-scaling image motion and the ignorable Earth-rotation image motion. On the condition that the image motion does not exceed 1 pixel, the allowed maximum exposure time for area-array staring imaging is analyzed. It is found that the large-array satellite is not suitable for long-exposure imaging, as its allowed exposure time decreases rapidly with the increase of roll angle. A satellite with a 12k×12k area-array detector and 500 km orbit is taken as an example. The allowed exposure time is 0.88 s when roll angle of the satellite is 0°; it decreases to 0.02 s when the roll angle increases to 28°.