Aberration effects in orbital imaging

Abstract

ABSTRACTAberrations exist in any moving system that transmits or receives electromagnetic waves. In orbital imaging, these aberrations were ignored before the development of the high-resolution Earth observation system and the high-orbit Earth observation system. In this paper, a two-step model is presented to evaluate the difference between the hypothetical ‘stop-go’ geometry and the real geometry, which is continuously changing. This model is robust in dealing with both Earth ellipsoid and different Earth orbits. Simplified equations are also given for circular orbit and nadir looking. Two consequences of these aberrations, including pointing deviations and image distortions, are analysed. The simulated results indicate that the pointing deviation can exceed 1% of the footprint of the field of view, while the image distortion at a tilted attitude can achieve the same order of magnitude as the image resolution.