Terry
I don't know if you remember but when GPS first came in (with lots of empty spots) the US only allowed high definition to the military and civilian (or foreign military) received a reduced accuracy. Still enough for general navigation but insufficient for such things as close instrument approaches by aircraft or survey calculations.
This of course has now all changed and the day of the surveyor's chainman have gone and you see them wandering around by themselves with a stick holding a GPS receiver for accuracy within inches.
As I said, in the event of a conflict, USA would have to have a serious think about messing with the satellite signals or they stand the risk of losing the lot - permanently
You may be right about the recent Russian problems but I have my doubts USA would risk such an asset in so petty a matter. A bit like killing the roses of the next door neighbour anonymously because their dog barks.
If they messed with the signals they would have to remember that at any time there are dozens of international airliners tracking over Russia using GPS and, although they have back-up systems they certainly would have reported it en mass.
Just my take on the matter.
Lang
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