Considering that NDBs are jammed each time there's lightning in the area, I still think that we're moving in the right direction...
Also considering that the GPS signal is only one of the many inputs in a RNAV system, a terrorist would have to knock out all the VORs, DMEs and other augmentation systems in that area.
Concerning the risk that a plane might be "mislead" or something like that, this would also be difficult as you need RAIM to operate on GPS as a stand alone navigation system.
This report doesn’t tell the whole story…
[ 11 September 2001: Message edited by: Knold ]