Galileo, Europe's rival to the US Global Positioning System
(GPS), passed a milestone Tuesday when it pinpointed its first-
ever ground location, the European Space Agency said. The
spot—ESA's research and technology centre in Noordwijk in the
Netherlands—was determined with an accuracy of between 10 and 15
metres (32 to 49 feet), using four satellites already in orbit.
"This is the first time ever that Europe has been able to
determine a position on the ground using only its own
independent navigation system," Galileo project manager Javier
Benedicto said. "This fundamental step confirms the Galileo
system works as planned," added an ESA statement. A minimum of
four satellites are required to fix a position in three
dimensions—longitude, latitude and altitude. The first two
Galileo satellites were launched in October 2011, and two more
last year. The system's accuracy will improve as more
infrastructure is added, said the agency. ESA is set to launch
four more Galileo satellites this year, contributing to an