Star detection and tracking using CCDs

The design and operation of a star sensor using a CCD imaging array and microprocessor-based data acquisition and processing are briefly discussed. The estimated absolute accuracy of the instrument is 0.1 of the pixel size, corresponding to about 4 arcsec for the present 4 x 3-deg field of view. The use of a light intensifier stage will increase the sensor instrument sensitivity by about a factor of 100. A similar increase in sensitivity can be achieved through a more intense cooling of the detector to allow for larger integration times. The use of a microprocessor for data acquisition, management, and processing makes it possible to adapt the sensor to various mission requirements by simply modifying the software.