The first two, KOERI in Turkey and the Atomic Energy Centre in France, should be operational some time in 2012 when a more exhaustive test will be conducted.
The Cadarache site lies about 60km (37 miles) inland from Marseille, and has been a nuclear research centre ever since President Charles de Gaulle launched France's atomic energy programme in 1959.
Astrium's role, at its UK centre in Portsmouth, was to integrate all the payload components, including hydrogen-maser atomic clocks, the ultra-precise time-pieces on which Galileo's performance depends.