The Galileo project is an attempt to create a network of satellites that will be capable of calculating a location to within a few inches.
On Wednesday, the first Galileo satellite was blasted into orbit on the back of a rocket fired from Kazakhstan. This satellite, called Giove-A, was built by a British firm called Surrey Satellite Technology. The complete network will eventually consist of 30 satellites when it is completed in 2010, and will cost an estimated £2.2bn.
Galileo is a joint venture between the European Union and the European Space Agency. The UK is playing a major role, and has already contributed £92m to the project.
Galileo will help provide new services, such as advanced satellite navigation and better mobile location information.