Re: Useful in tunnels?
What DaLo said.
Assuming you are travelling at roughly constant speed in a tunnel is easy. Taking the integral of acceleration to get velocity, and again to get location just makes the sensor errors too big to be practical.... apparently, according to this fella who is smarter than I am on a Google Tech talk: (23 minutes in)
https://www.youtube.com/watch?v=C7JQ7Rpwn2k
Biting the hand that feeds IT
