Just sharing a news snippet... (source AvWeb)
Nate WY0X
--------
No More Dumbing Down GPS
The Department of Defense says its next generation of GPS satellites won’t come with an on/off switch for civilian users. Because the system was originally deployed as a military system, the military wanted the ability to degrade the accuracy of the signal or eliminate it entirely to prevent it from being used against them. But with GPS in everything from cellphones to tracking chips in store merchandise, the DoD long ago gave up any hope of keeping it a discretionary asset and effectively turned off the "selective ability" function in 2000.
However, beginning with satellites deployed in 2013, even that capability won’t be included in the system, something that should calm the fears of some that their moving map could suddenly disappear without warning. "This action to permanently remove SA eliminates a source of uncertainty in GPS performance that has been of concern to civil GPS users worldwide for some time," DoD said in a news release. That undoubtedly means the military has something even better than GPS to run its own systems and it will be interesting to see what trickles down to the civilian market.