Spacecraft Attitude Determination
摘要
Many spacecraft use star cameras to determine their orientation. A star camera takes an image of the star field. The first step is to determine what in the image is a star. Bright areas in the image are aggregated into “blobs” that are assumed to be stars. A star camera usually is slightly defocused so that a star image is smeared over multiple pixels. The next step is to find the centroid of each blob. Once this is done, the patterns seen in the image can be compared with the image created by an onboard star catalog.