Q&A: how Galileo will take on America's GPS - World - Times Online: "Q&A: how Galileo will take on America's GPS



Mark Henderson, Science Correspondent of The Times, explains why Europe has decided to go it alone with its own satellite navigation system

How long has the EU's satellite navigation programme been in development?

The EU and the European Space Agency formally agreed to go ahead with the project in 2002. A second test satellite will be launched next year, and an entire network of 30 satellites - 27 active ones and three spares - should be operational by 2010.

What problems have arisen and could arise as a result of Europe's reliance on the American GPS network?

The US Global Positioning System is primarily a military network, and public signals are provided as a spin-off. These could in theory be turned off at any time, if the US fears they are being used by terrorists or hostile countries. The GPS public signal is also weak, and offers less than optimal coverage in Europe. It is accurate only to 10 to 20 metres, which is fine for sailing or car navigation but not good enough for road-pricing, air traffic control or other complex applications.

How will the Galileo system benefit European citizens?

Galileo will offer guaranteed accuracy of 1 metre throughout Europe, and will provide centimetre precision in "