Geometric parameters analysis of two large FOV space-borne optical imaging systems

Abstract

To precisely calculate geometric parameters of space-borne optical imaging systems, such as object distance, projection angle, ground sampling distance (GSD), swath width, the effect of earth curvature and projection angle, these imaging systems are researched as nadir imaging and roll imaging. In this paper, a precise geometric model is proposed, which is based on earth curvature and projection angle. Two types of space-borne optical imaging systems are simulated by the model. They are single camera and combined camera with large field of view (FOV). They are on 644.5km orbit, with full field of view 64.44°. The analysis shows that, the GSD of combined camera changes rapidly with field angle, the maximum GSD is 2.07 times of the minimum GSD. The GSD of single camera changes less rapidly with field angle, the maximum GSD is 1.75 times of the minimum GSD. The swath widths of sub-cameras of combined camera are different. The two marginal sub-cameras have larger swath width than the two central ones. Therefore precise calculation of geometric parameters is significative to ensure the imaging quality.