These measurements would complement those of the Gravesspace surveillance radar, also designed by ONERA, which determines the orbits of satellites flying over France. The Nostradamus radar antenna network
ONERA's teams have designed and developed the GRAVESspace surveillance system to establish and maintain a database of satellites flying over France at altitudes of less than 1 000 kilometers... GRAVESSpace Surveillance System: the receiving antennas... Based on this brand-new concept, the GRAVESradar network provides angular and radial velocity measurements