Compass star tracker for GPS applications
Additional Document Info
Star trackers are the most accurate attitude sensors to perform the complete 3-axis attitude estimation of spacecraft. However, even though they are specifically designed to estimate attitude, as it will be shown in this paper, they can also be used to estimate the local coordinates of the camera on the Earth as well as the direction of East. This requires us to align the camera with the local direction of the gravity and to have knowledge of the time, that can be provided by an accurate clock. The resulting system is the Compass Star Tracker, that is, a star tracker used as a global surface navigation system. This system would certainly not substitute the Global Positioning System which, in turn, does not suffer of the limitation night-only operation and in clear weather conditions. On the contrary, the Compass Star Tracker does not require any satellite information or other support from ground stations to be used in lieu of the traditional Global Positioning System.