3-axis ultraviolet attitude reference sensor

As emphasis shifts from large, expensive multipurpose satellites to lighter and less expensive vehicles dedicated to a narrower range of activities, the size, weight and cost of housekeeping components become increasingly significant. This is particularly the case for the attitude reference system. If a traditional system is used for a small satellite, its cost and weight can become a significant fraction of the satellite´s total. The ERADS (Earth Reference Attitude Determination System) sensor was designed to provide a significantly lighter and lower cost three axis reference with an accuracy adequate for most missions. The approach was to image a wide field of view with a small optical assembly to achieve a combination of Earth and star viewing. Achievement of this objective required some innovative technical developments