Just as well that most pedestrians also have hands, then. Pockets, even.
I've got a handheld Garmin GPS unit that's also a two way radio and a weather radio, and if anyone in your party has a similar radio it can magically put their location and heading on your map on your screen, all via FRS or GMRS without the need for cell towers or any infrastructure whatsoever. The technology can clearly be made. It's just that smartphones have stepped in and eaten the lunches of multiple peripherally related markets.