I thought the same, but I was pretty surprised how bad my phone's GPS performance was next to cliffs. Especially altitude was off significantly.
When thinking of turn-by-turn navigation, keep in mind that car navigation will snap your position to roads. For a better comparison, try e.g. Google Maps in pedestrian or bicycle navigation mode. At least in my experience, the perceived "accuracy" drops significantly.
When thinking of turn-by-turn navigation, keep in mind that car navigation will snap your position to roads. For a better comparison, try e.g. Google Maps in pedestrian or bicycle navigation mode. At least in my experience, the perceived "accuracy" drops significantly.