Dipartimento di Fisica - Universita' di Roma La Sapienza
B2K: The Attitude Control System

The Attitude Control System developed in Firenze and Rome has been completed with two new high precision sensors: a tracking sun sensor developed in Rome and a tracking star camera developed in Toronto.
Using information from these sensors and from the CWRU differential GPS we plan to reach sub-arcmin attitude reconstruction precision. You can see the ACS in action during our scan tests here.

star camera

The pointed star camera (Toronto) is able to lock on magnitude 4 stars in daytime at float. Its orientation with respect to the payload is measured by two absolute encoders (16 bit).
sun sensor

The pointed star sensor (INGV + La Sapienza) locks on the sun center and tracks it by means of two 4 quadrants photodiodes. Its orientation is measured by two absolute encoders (16 bit). It is mounted on the sun side of the gondola, and is covered and painted white to avoid overheating.
The azimuth scans are obtained by means of an azimuth pivot developed at IFAC-CNR and mounted between the payload and the flight chain.
The pivot has a top motor acting against the flight chain, and a lower motor spinning a flywheel. During normal scans, only the lower flywheel works. Acting against the flight chain is needed only to dump momentum when needed, or to reorient the payload towards a distant direction.

See also the other BOOMERanG web pages
University of Toronto