Europe is building its own global satellite navigation system, Galileo, which will offer very accurate positioning and timing, under civilian responsibility. This system will be compatible with the two other existing systems, GPS and GLONASS. A user will be able to use the same receiver to calculate his position from signals sent out by any satellites combination, however Galileo will offer to all users a bi frequency system that will allow knowing position within one meter of accuracy, which is unprecedented for an openly accessible service. Apart from extreme circumstances, it will always be available and its users will be informed in a few seconds of a potential disruption of one of the satellites. Thus it will be usable for safety of life applications, requiring the highest security level, such as plane landing, train circulation or car guidance.