ATC
Agreement on Galileo seen as enhancing GPS
It took several years for the U.S.

It took several years for the U.S. and the European Union to reach agreement about satellite navigation systems, but the cooperation agreement the parties signed in June that paves the way for the Galileo and GPS satellite navigation systems should be beneficial to both sides, and to aviation worldwide.

Essentially, the agreement says that while each system will be owned and managed independently, the two systems will be compatible and interoperable, so that users anywhere can choose to use either, or a combination of both, based on their needs. And despite fears to the contrary, neither the U.S. nor the European Union will mandate use of its own system in its own airspace.