What's it for?
Navigation and location satellites
Navigation and location are two different things. The first helps a car, boat or plane know exactly where it is by means of a satellite. Location allows an observation centre, using a satellite, to know where an object is located, which is vital, for example, for the military. But the techniques are the same. Knowing where things are becomes a power play…
© ESA
He who has information has power
At the beginning it was the American and Russian militaries that started these programmes, at the end of the 1960’s and in the 1970’s, with the Transit system for the former and Cosmos for the latter. But a real milestone was achieved by the American armed forces with the Global Positioning System, known as GPS, which has a location precision of about 15 meters. You need a constellation* of 24 satellites located 20,000 km from Earth to cover the entire globe and find the target’s coordinates, using a sophisticated triangulation system. It was only in 2000 that President Bill Clinton authorised the universal use of GPS with the same degree of accuracy. Previously, as with Google Earth today, the information was deliberately fudged.
Towards the end of a sort of monopoly
It’s true that the Russians have their own location system, Glonass, but its use was for a long time limited to the armed forces and has never really enjoyed success in civilian applications. The European Union, by way of the European Space Agency (ESA)*, therefore decided to launch its own location system, Galileo" >Galileo, whose accuracy would be about one metre. A first satellite has already been launched and a second should follow in 2010. Despite stiff opposition from the Americans, the existence of a new system seems a stroke of good luck, both in terms of scientific developments and of multipolar diplomacy.
