The project was overseen by ESA in its System Prime role managing Galileo’s design, development, qualification and deployment of future upgrades on behalf of the European Commission, Galileo’s owner.

Galileo’s worldwide ground segment has been described as the most complex system ever developed by ESA. It is operated by the Spaceopal company – a joint undertaking between Italian company Telespazio and German firm Gesellschaft für Raumfahrtanwendungen mbH, set up especially for this purpose – under contract to EUSPA, the EU Agency for the Space Programme. The ground segment is divided into two segments: the Galileo Mission Segment, which oversees the functioning of the satellites’ navigation payloads including the generation of their signal messages, and the GCS which oversees the functioning of the satellites themselves.