Guilhem Moreaux, Collecte Localisation Satellites (CLS), Ramonville-Saint-Agne, France, Frank G Lemoine, NASA Goddard SFC, Greenbelt, MD, United States, Hugues Capdeville, Collecte Localisation Satellites, Ramonville-Saint-Agne, France, Petr Stepanek, VUGTK, Ondrejov, Czech Republic and Pascale Ferrage, CNES French National Center for Space Studies, Toulouse Cedex 09, France