"navigation aids" is right. I wouldn't want to give anyone the impression that I've run foul (yet) of relying on a GPS. Being somewhat oldfashioned I tell the time with my tum a lot and with the sun if it's hot. Maps on paper (and, if in the bush on foot, compasses) are my preferred tools but I do coach students on the strengths and weaknesses of GPSs.

Cheers, Rowan