The Gaia-FUN-SSO observation campaign of 99942 Apophis: A preliminary test for the network

In order to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO, an observation campaign on the Potentially Hazardous Asteroid (99 942) Apophis was conducted from 12/21/2012 to 5/2/2013 providing 2732 high quality astrometric observations. We show that a consistent reduction of astrometric campaigns with reliable stellar catalogs substantially improves the quality of astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029.