I think, for what it's worth, that Guppy & Pace are about as right as it is going to get.
SA is not just about knowing in 3D where you are, it is about being aware of everything around that could affect you in any way. Frinstance, We have just bought a pup, (young dog) situational awareness involves, where is he? Are all the doors shut? Where's the cat? Does he look like he wants a pee, or worse? The dog that is! etc. Flying SA involves eveything from. Have I got enough fuel for this trip? Is the a/c serviceable? Is the correct tank selected? Where is everyone else in the sky, & where are they going relative to me? I know I have right of way but has he seen me & what is he going to do if he hasn't? How far & what direction is the nearest alternate? what was ATC saying? Were they talking to me? Is my pax ok? Where are we exactly? When is sunset? etc. GPS is only a tool to help with one question. Planning just reduces the number of un-answered questions.