  The Alpha Magnetic Spectrograph (AMS) is a composite particle detector to be
accommodated on the International Space Station (ISS) in 2008. AMS is mainly
devoted to galactic, charged Cosmic Rays studies, Antimatter and Dark Matter
searches. Besides the main, classical physics goals, capabilities in the field
of GeV and multi-GeV gamma astrophysics have been established and are under
investigation by a number of groups. Due to the unsteadiness of the ISS
platform, a star-mapper device is required in order to fully exploit the
intrinsic arc-min angular resolution provided by the Silicon Tracker. A
star-mapper is conceptually an imaging, optical instrument able to autonomously
recognize a stellar field and to calculate its own orientation with respect to
an inertial reference frame. AMICA (Astro Mapper for Instruments Check of
Attitude) on AMS is responsible for providing real-time information that is
going to be used off-line for compensating the large uncertainties in the ISS
flight attitude and the structural degrees of freedom. In this paper, we
describe in detail the AMICA sub-system and the accommodation/integration
issues and the in-flight alignment procedure adopting identified galactic
(pulsars) and extragalactic (AGNs) sources.
