While I agree with you, you then need to worry about the opposite problem: Car drives onto ferry, GPS signal is lost, car drives off to ferry, dead reckoning f

While I agree with you, you then need to worry about the opposite problem: Car drives onto ferry, GPS signal is lost, car drives off to ferry, dead reckoning figures the car is lost in the water, GPS is regained placing the car very much somewhere else. Do you trust dead reckoning or the GPS? In this case, you trust the GPS, one assumes, since dead reckoning places you in the middle of a body of water, though there And this isn't a made up scenario. My car fights this every weekday. It's always entertaining to watch it figure this out as the GPS recovers badly and it starts to place me inside buildings in an area with poor GPS coverage.