A Conical Lens For Earth Sensor Application

A low attitude infrared earth sensor for 3-axis stabilised satellite needs wide angle field of view of the order of 120°. Since the requirement of the optics is only to image the earth as a sharp circular disc, it can be achieved by a conical lens which can be fabricated by generating an axially symmetric cone into a near hemispherical lens. The angle of the cone is same as the earth's subtended angle. The design of the lens was verified by fabricating a lens for the visible region.