The PRIMA Astrometric Data Reduction Software

We describe the Astrometric Data Reduction Software (ADRS) for the Phase Referenced Imaging and Micro-Arcsecond Astrometry (PRIMA) instrument, which is being developed by the PRIMA Astrometry Operations and Software (PAOS) Consortium in collaboration with ESO. PRIMA will be commissioned at the VLTI in 2007/2008. The primary objective of the astrometry program with this instrument will be the detection of extra-solar planets and the characterization of their orbits. The goal is to achieve a relative astrometric accuracy of the order of 10 micro-arcseconds. In order to reach this accuracy the ADRS has to analyze all available PRIMA data uniformly and consistently. We describe in this paper how this will be done and what ESO infrastructure requirements must be fulfilled.