CU3: Core Data Processing

The task of CU3 is to organise and implement the data processing chain all the way from receiving Gaia’s raw telemetry down to the core astrometric solution. Thanks to our expertise and deep knowledge of the mission, our group is in charge, from the beginning of DPAC, of the design and most of the implementation of the IDT and IDU systems. The IDT system (Initial Data Treatment) carries out the reconstruction and initial processing of the raw data as soon as it arrives on ground, including a first reconstruction of the satellite attitude (or pointing of its telescopes), the determination of the locations and brightness of the objects measured, the Cross-Match (linking the observations to their corresponding catalogue sources and creating new ones if necessary), and a first treatment of the image distortion caused by the radiation on the CCDs. Its operation is accurately monitored on a daily basis with thousands of plots and statistics, as well as automated reports.

The IDU system (Intermediate Data Updating) reprocesses all the accumulated raw data using the most up-to-date calibrations obtained by AGIS (the core astrometric solution) and other systems, giving a higher coherence between all the scientific data and correcting any possible errors or bad approximations from previous iterations. Probably the most complex and hardest task in IDU (in terms of computation) will be the calibration of the instrument response including the correction of the radiation damage which will be carried out with the highest possible detail.