Europe’s Galileo satnav system

First results

The first orbital elements of Europe’s global satellite navigation system are in place. On 21 October 2011 a Soyuz rocket from French Guiana launched two satellites, with two more following on 12 October 2012: these four Galileo In-Orbit Validation (IOV) satellites currently in orbit represent the operational nucleus of the full 30-satellite constellation.

Fully representative of the others that will follow them into orbit, these first four IOV satellites have served to prove that the satellites and ground segment meet many of Galileo’s requirements and validate the system’s design in advance of completing and launching the rest of the constellation.

On 12 March 2013, Galileo’s space and ground infrastructure came together for the very first time to perform the historic first determination of a ground location, taking place at ESA’s Navigation Laboratory in the ESTEC technical centre, in Noordwijk, the Netherlands. From this point, generation of navigation messages enabled full testing of the entire Galileo system. A wide variety of tests followed, carried out all across Europe.

ESA and its industrial partners had teams deployed in the field continuously for test operations. More than 10 000 km were driven by test vehicles in the process of picking up signals, along with pedestrian and fixed receiver testing. Many terabytes of IOV data were gathered in all.

Galileo positioning performance

The single most important finding from the test results? Galileo works, and it works well. The entire self-sufficient system has been shown as capable of performing positioning fixes across the planet.

Galileo’s observed dual-frequency positioning accuracy is an average 8 m horizontal and 9 m vertical, 95% of the time. Its average timing accuracy is 10 billionths of a second – and its performance is set to sharpen as more satellites are launched and ground stations come on line.

For Galileo’s search and rescue function – operating as part of the existing international Cospas–Sarsat programme – 77% simulated distress locations can be pinpointed within 2 km, and 95% within 5 km.

All alerts are detected and forwarded to the Mission Control Centre within a minute and a half, compared to a design requirement of 10 minutes.

Following this success, the build-up of the Galileo system can proceed to placing the remaining 'Full Operational Capability' satellites into orbit and deploying further ground stations.

Last update: 27 June 2014

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