Abstract: An optical sensor apparatus receives visible light and converts that light to electrical signals for use by a control system. Visible light enters the apparatus through a hemispherical "fisheye" lens which provides a 360.degree. field of view in azimuth and a 180.degree. field of view in elevation. The light exiting the fisheye lens is projected through a shutter mechanism onto a receptor of a camera. The lens, shutter mechanism, camera and a level dector are mounted on a gimbal mounting to maintain a vertical orientation of the lens and camera. When the optical sensor apparatus is called upon by the control system to provide visual information, the shutter mechanism is energized to open when the lens and camera next become vertical. Image processing is then performed to determine the position of the optical sensor apparatus relative to known landmarks in the operating environment.