Space signal demonstrates Galileo interoperability with GPS

First two Galileo IOV satellites
12 July 2012

ESA’s first two Galileo navigation satellites in space have achieved their latest milestone, transmitting dummy signals in a modulation scheme designed to allow full interoperability with the US GPS once operational services start.

“This is an advanced modulation technique that offers robust protection against signal interference and the misleading signal reflections known as ‘multipath’,” said Marco Falcone, Head of Galileo System Services.

“Significantly, this is also the European version of the Multiplexed Binary Offset Code signal standard agreed with the United States for the interoperability of Galileo and GPS.

“So this transmission helps demonstrate how the two systems will work together in future with no risk of signal interference.”

Galileo CBOC modulation

The first two Galileo satellites were launched from Europe’s Spaceport in French Guiana into medium orbits on 21 October 2011, and since then have been progressively put through their paces in a series of tests.

These satellites are serving to validate the Galileo system design as well as being fully functional elements of the full 30-strong constellation that will follow.

Four satellites, the minimum number needed to achieve a position fix at user level, will become available later on this year.

This autumn the next two satellites will be launched together from French Guiana.

Once they are commissioned, Galileo will have its operational nucleus complete, able to perform actual ranging when all four satellites are visible from a receiver.

For technical details of the Galileo signal currently being transmitted, see the right-hand link.

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