Sat Nav
How does Sat Nav continue to track your position underground?
We've got Sat Nav in our car and last night we were driving in a tunnel under a river and it was still able to tell us what turns to take. How does it do this?
Also, does anyone know how you get updates for Sat Nav systems? Our Sat Nav is the Audi installed one but the Audi dealer didn't have a clue when we asked about updates....
Magician - you cheeky so & so! Did it occur to you that I don't live in the UK? Why do some people assume that eveyone on here is in the UK? There is a long tunnel in Cologne which goes under the river our Sat Nav advised us to Keep Left and Turn Slighty Right whist we navigated that very tunnel last night - so ner!
duh - meant to say Dusseldorf not Cologne - am tired this week from excesses at the weekend!
factory fit sat/nav systems receive a square wave pulse
when the vehicle is moving and as it knows the direction you are heading when you enter the tunnel it calculates the speed at which you are moving,therefore it knows your location at any given time.
 
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