Ground Surface Calibration Sources for Earth Observation Segmented Telescope

This study focuses on appropriate calibration targets to maintain the imaging performance of an Earth observation segmented telescope. Unlike the case of an astronomical observatory, the telescope is not directed toward space, and thus stars are not the preferable targets, especially in terms of persistency and latency of the observation system. In view of these points, three different types of sources are proposed and considered. The preliminary optical telescope model is presented (with an aperture size of 3.5 meters) and for each type of calibration source, error analysis was performed by simulating the distortion of the point-spread-function (PSF). From this study, we gained a perspective to maintain the optical performance of segmented telescopes by using ground targets.