By offering dual frequencies as standard, Galileo will deliver real-time positioning accuracy down to the metre range. It will guarantee availability of the service under all but the most extreme circumstances and will inform users within seconds of any satellite failure, making it suitable for safety-critical applications such as guiding cars, running trains and landing aircraft.

ESA’s first two navigation satellites, GIOVE-A and –B, were launched in 2005 and 2008 respectively, reserving radio frequencies set aside for Galileo by the International Telecommunications Union and testing key Galileo technologies.

Then on 21 October 2011 came the first two of four operational satellites designed to validate the Galileo concept in both space and on Earth. Two more will follow in 2012. Once this In-Orbit Validation (IOV) phase has been completed, additional satellites will be launched to reach Initial Operational Capability (IOC) around mid-decade.

Galileo services will come with quality and integrity guarantees which marks the key difference of this first complete civil positioning system from the military systems that have come before.

A range of services will be extended as the system is built up from IOC to reach the Full Operational Capability (FOC) by this decade’s end.

The fully deployed Galileo system consists of 30 satellites (27 operational + 3 active spares), positioned in three circular Medium Earth Orbit (MEO) planes at 23 222 km altitude above the Earth, and at an inclination of the orbital planes of 56 degrees to the equator.