Galileo satellite

Galileo is a joint initiative of the European Commission (EC) and the European Space Agency (ESA).
 
The EC is responsible for the political dimension and the high-level mission requirements. The EC initiated in particular studies on the overall architecture, the economic benefits and the user needs. These include the GALILEI studies that address the local architectures, interoperability and signals and frequencies. Moreover, they provide a market observatory and cater for investigations into legal, institutional, standardisation, certification and regulatory issues.
 
ESA’s responsibility covers the definition, development, and in-orbit validation of the space segment and related ground element. Work on the new technologies needed for the satellite constellation and the ground segment has been continuing at ESA's European Space Research and Technology Centre (ESTEC), at Noordwijk, in the Netherlands for a number of years. These critical technologies include the high precision clocks to be carried on-board the satellites (rubidium and passive hydrogen maser frequency standards), on-board timing units for synchronising the individual clocks to a common Galileo system time, signal generators to produce the positioning signals that the Galileo spacecraft will broadcast, power amplifiers, radio-frequency multiplexers & antennas and telecommand & telemetry transponders. Through its GNSS Evolution programme, ESA maintains and improves continuously the European competences and the technologies requested for the future.

The definition phase and the development and In-Orbit Validation phase of the Galileo programme were carried out by the European Space Agency (ESA) and co-funded by ESA and the European Community.

The Full Operational Capability phase of the Galileo programme is managed and fully funded by the European Commission. The Commission and ESA have signed a delegation agreement by which ESA acts as design and procurement agent on behalf of the Commission.