U.S. Taxes Pay for GPS
The American taxpayer pays for the GPS service enjoyed throughout the world. All GPS program funding comes from general U.S. tax revenues.
The bulk of the program is budgeted through the Department of Defense, which has primary responsibility for developing, acquiring, operating, sustaining, and modernizing GPS.
U.S. policy assigns the Department of Transportation responsibility for funding the extra costs associated with new, civilian GPS upgrades beyond the second and third civil signals. Agencies with unique requirements for GPS are responsible for funding them. http://www.gps.gov/policy/funding/