A star scan/attitude determination experiment conducted on the geostationary meteorological satellite

The paper discusses the results of a star scan test performed on the spin stabilized Geostationary Meteorological Satellite (GMS) and used for the purpose of determining the vehicle's spin state. The test data shows that the payload camera, normally used for imaging the Earth and its cloud cover, sees a sufficient number of stars to provide for a rapid and accurate spin state update and that Earth and Sun blockage constraints have essentially no impact on the star detection process. Also presented are analytical results regarding how many stars constitute an observable set, the accuracy achievable using the five most easily detected stars, how star location affects state uncertainty, and why certain state components are more easily determined than others. The primary test conclusion is that star scan offers an attractive alternative to the presently used Earth horizon and landmark tracking attitude determination methods, as far as accuracy and computational complexity are concerned, provided the occasional star viewing intervals that are required do not interfere with the meteorological scheduling of the camera.