Tom Tom working in tunnels

White_Fox · Posted: Sat Jul 10, 2004 9:40 am Post subject: Tom Tom working in tunnels

Four times this week, I went through the tunnel under the runway leading into Heathrow Airport T123.

The amazing thing is that TT3 continued to plot my position through the tunnel, even though there were no sats received, it kept plotting my position all the way 'til I came out the other end then sats received OK and it just carried on.

How does it do that? is there a predictor using the speed going into the tunnel and assuming the momentum and direction are maintained? or is it something else.

Strange thing is when I am driving through woods or forest, the same system just stays at the last place it had a reading 'til signal is relaiable again.

Any ideas

masterd2 · Posted: Sat Jul 10, 2004 9:49 am Post subject:

I get the same on TTN2. I think you are right it is predicting somehow.

fergyuk · Occasional Visitor Joined: Oct 18, 2003 Posts: 45

Hi

when you enter a tunnel TT notices the loss of a Sat fixes and continues to plot your position with the last know direction and speed

It continues to do this for about 30 seconds , but this does seem to be speed related ie the slower you were travelling the longer it plots with no fix.

Have a go at slowing down when you go through a tunnel and you will see that you speed remains constant.

Hope this helps

All the best

Fergy

Happy

White_Fox · Posted: Sat Jul 10, 2004 4:01 pm Post subject:

Cheers Fergy

As I suspected eh?

Well that's a cool feature from TT.

There is too much on this site complaining about TT, refreshing to have some good words

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