Running AIM: initial data treatment and μ-arcsec level calibration procedures for Gaia within the astrometric verification unit

Abstract

The Gaia payload is a highly sophisticated system and much of its instrumental behaviour is tested to proper accuracy during the Commissioning and Early Operations phase. The Astrometric Instrument Modelling (AIM) belongs to the Core Processing, or CU3, software systems devoted to astrometric data processing, instrumental monitoring and calibration.; it was developed in the context of a special unit of CU3 devoted to Astrometric Verification. While waiting for nominal scientific operations, we present the challenges phased in the Gaia initial data treatment and real-time instrument health monitoring and diagnostic, during the non-standard conditions of the Commissioning phase. We describe the dedicated diagnostic and correction procedures implemented for Commissioning and Early Operations and we show some results obtain during still on-going Commissioning activities.