November 17, 2016


Equivalent to the U.S. GPS, Galileo will be built around a constellation of 30 satellites orbiting at an altitude of 23,222 km. It will offer a level of precision of a few metres, unequalled until GPS III is deployed.

The Galileo programme was decided at the start of the 2000s to assure Europe’s independence from the U.S. Global Positioning System (GPS). The European system would be based on a constellation of 30 satellites designed to compete with the U.S. GPS, Russian Glonass and Chinese Beidou systems.

Launched in tandem in 2011 and 2012, the first 4 Galileo satellites validated the new geopositioning system, followed by 3 successful dual launches in 2015 and another dual launch in May 2016, taking the number of satellites in orbit to 12 (of which 11 are operational). All of these launches were performed by Soyuz from the Guiana Space Centre. On 17 November 2016, 4 more satellites were launched, this time by a European Ariane 5ES, followed by 2 more dual launches in 2017 and 2018.

Initial Galileo services are scheduled to come on stream late 2016, with 15 operational satellites to be complemented progressively by future launches. The full range of services requiring 30 satellites is planned for 2020. Galileo will support a broad range of applications in domains such as maritime, air and land transport, agriculture, public works, search-and-rescue operations and government, as well as applications that we increasingly use in our daily lives, notably on smartphones. A Galileo satellite should be visible from anywhere on the globe 90% of the time and the system is expected to generate numerous social and economic spin-offs.

CNES was closely involved in the preliminary phases of Galileo and in defining its signals, and CNES’s Launch Vehicles Directorate (DLA) contributed to the Ariane 5ES launcher’s qualification. The agency’s space centre in Toulouse also plans and conducts satellite positioning operations in partnership with the European Space Operations Centre (ESOC), as part of ‘CNESOC’. Orbit and manoeuvre calculations, operation of flight systems and management of control centres and the ground station network will all call on the expertise at the two space agencies.