The European Commission has announced the launch date of the next pair of ESA-procured Galileo satellites. These will be launched together on a Soyuz from French Guiana on 28 September, joining the two satellites already in orbit.

Antonio Tajani, Vice President of the European Commission, responsible for industry and entrepreneurship, announced the launch on 2 May in Brussels, together with Jean Yves Le Gall, Chairman and CEO of Arianespace, in the presence of industrial leaders involved in the programme, and in agreement with ESA's Director of the Galileo Program and Navigation-related Activities Didier Faivre.

The new launch will take place within a year of the first two Galileo In-Orbit Validation satellites, which reached orbit on 21 October 2011.

Four navigation satellites are the minimum needed for satellite navigation - to measure latitude, longitude and altitude while checking ranging accuracy - so these four Galileo satellites can be used to assess the performance of Galileo's world-spanning ground system that serves to maintain the precision of the Galileo system.

In addition European industry should be able to test their own prototype Galileo-based receivers and services realistically against actual satellite signals.

Galileo is an initiative of the European Commission and ESA to provide Europe with an independent global satnav system. The Commission and ESA have signed a delegation agreement by which ESA acts as design and procurement agent on behalf of the Commission.

The full Galileo system will consist of 30 satellites in orbit overseen by control centres located in Europe and a global network of sensor stations and uplink stations.

Each satellite combines the best atomic clock ever flown for navigation - accurate to one second in three million years - with a powerful transmitter to broadcast precise navigation data worldwide.

The Galileo programme is structured in two phases, with the initial In-Orbit Validation phase consisting of deployment tests and the operation of four satellites and their associated ground infrastructure.

This is followed by the Full Operational Capability phase, consisting of the deployment of the remaining ground and space infrastructure.

The definition phase and the development and In-Orbit Validation phase of the Galileo programme were carried out by ESA and co-funded by ESA and the European Commission.

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.