*sits up*
GPS is used quite a bit in military. Obviously when we soldiers are out on the field we need to be able to navigate through it. Back in the old days, we'd have been given military grade maps but nowadays most modern soldiers use GPS systems specifically designed for military use.
Of course, we're still taught to use a map and personally, I rather use maps. The digital warfront is a sneaky bastard and sometimes technology can fail you. I'll admit though that it is pretty damn convenient. If you ever watched Jormungand, the battle with Seal Team Seven, Night Nine, is a prime example of what I mean, albeit unlikely to happen.
Not entirely sure about this but I'm pretty sure that cruise missiles like the American BMG-109 Tomahawk uses GPS for navigation. Unsure about that since I don't work with that stuff. That being said, if Tomahawk does work like that then I imagine a lot of the other high-tech gizmos like UAVs and such work like that as well.
*hops off the tea cabinet*
Well, I suppose if I'm gonna snooze, I should snooze in my airship. I'll be back sometime.
*boards a VTOL and flies off*