I_FORD is completely wrong. GPS is still the responsibility of the US Department of Defense although GPS is now overseen by a committee co-chaired by the Secretary of Defense and the Secretary of Transportation.
See
http://gps.faa.gov/GPSBasics/index.htm
then follow links to
Interagency GPS Executive Board (IGEB)
followed by
U.S. Space-Based Positioning, Navigation, and Timing Policy
This is the full text for the new arrangements for the control of GPS.