"navigatio eccere necessis" - that's what the ancient Romans said when hitting the Mediterranean sea to conquer foreign countries.
Today's navigational systems work much more precisely than their (Romans) compasses and coastal lighting systems.
Just for comparison: GPS has a position accuracy of 10m and a height accuracy of 35m.
Galileo has a position accuracy of 4m and a height accuracy of 8m.
These values are valid for any public navigational system.
The NASA did not like the European precision (giving the required accuracy to drop weapons at full impact power hitting bull's eye), but now a marriage is due.
NASA and European space technologies will join for better navigation of vehicles.
Galileo offers accuracy to a DIN-A4 size paper sheet for military and puplic services, such as land measuring (of course for extra payment)
