Europe’s new age of satellite navigation has passed a milestone: the first determination of a ground location using the four Galileo satellites in orbit. This step confirms the Galileo system works as planned.
A minimum of four satellites is required to make a position fix in three dimensions. The first two were launched in October 2011, with two more following a year later.
“Once testing of the latest two satellites was complete, in recent weeks our effort focused on the generation of navigation messages and their dissemination to receivers on the ground,” said Marco Falcone, ESA’s Galileo system manager.
This first position fix of longitude, latitude and altitude took place at the Navigation Laboratory at ESA’s technical heart ESTEC, in Noordwijk, the Netherlands, on March 12, with an accuracy of between 10 and 15 meters, which was expected due to the limited infrastructure deployed so far.
This fix relies entirely on European infrastructure, from the satellites in space to the two control centers in Italy and Germany linked to a network of ground stations.
“The test of today has a dual significance: historical and technical,” said Javier Benedicto, ESA’s Galileo project manager. “From the historical perspective, this is the first time ever that Europe has been able to determine a position on the ground using only its own independent navigation system, Galileo. From the technical perspective, generation of the Galileo navigation messages is an essential step for beginning the full validation activities, before starting the full deployment of the system by the end of this year.”
With the validation testing activities under way, users might experience breaks in the content of the navigation messages being broadcast. In the coming months the messages will be further elaborated to define the “offset” between Galileo System Time and Coordinated Universal Time, enabling Galileo to be relied on for precision timing applications, as well as the Galileo to GPS Time Offset, ensuring interoperability with GPS.