For the CASSINI mission, Officine Galileo are presently developing, under Jet Propulsion Laboratory (JPL) contract, a CCD based star tracker, named Stellar Reference Unit (SRU). The SRU will be used in a new attitude determination approach developed by JPL, in which 'gyroless' operation can be implemented. The unit has a wide angle (15 degree(s) full cone) Field of View (FOV) and a maximum sensitivity up to +6 Visual Magnitude for an integration time of 400 msec. Exposure time can be commanded via Attitude and Articulation Control Subsystem Flight Computer (AFC) from 0 to 65535 msec. Optics characteristics and centroiding algorithm for star position determination, are defined by Officine Galileo, to achieve required performance (total accuracy: 53 (mu) rad, 3(sigma) ). The defined centroiding algorithm will be then implemented on the AFC. In this paper, the SRU architecture, characteristics, and main technological areas are described. Expected performance is reported.
Stellar reference unit for CASSINI mission
Space Optics 1994: Space Instrumentation and Spacecraft Optics ; 1994 ; Garmisch,Federal Republic of Germany
Proc. SPIE ; 2210
1994-09-30
Conference paper
Electronic Resource
English