Sat Nav Speed monitoring

  lil27 17:45 11 Mar 2008

Silly Question probably but here goes.

My Sat Nav system shows the speed I am going (albeit a few mph slower than my car speedo shows).

Is there any way i can be charged with speeding via sattelite GPS if i exceed the speed limit on a given road.

Maybe just being paranoid but maybe George Orwell was onto something.


  Al94 18:18 11 Mar 2008

I don't think you are correct - my speedo and sat nav usually show the same. I think you are confusing the fact that a 3% is anecdotally allowed as a margin of error by the police rather than all speedos set at 3% too fast.

  Al94 19:15 11 Mar 2008

Confirms what I said although Wikipedia is very subjective.

  laurie53 20:08 11 Mar 2008

"All speedo's on UK Vehicles are set 3% to fast."

Speedos are not that accurate. Most of them are calibrated for each car by calculating how many revolutions the wheels are making, even gearbox drives.

As the tyre wears this varies, infinitesimally admittedly, but quantifiably.

  anchor 13:27 12 Mar 2008

From reading SatNav forums, it is generally agreed that the speed indicated on the Satnav is the correct one.

  natdoor 20:39 12 Mar 2008

The discussion of the relative accuracy of speedometers and SatNav is all very interesting but it does not address the point which I believe lil27 was raising. The reference to George Orwell makes me believe that lil27 is concerned that breaking the speed limit and having this demonstrated by SatNav might mean that the police could somehow access this data remotely.

The satellites provide timing information which enables the SatNav to calcul position. The calculation of speed would be based upon change of position with time and computed in the SatNav. There would not be a time history of speed stored within the SatNav. So I believe the answer to what I take to be the question is no.

  jack 08:48 13 Mar 2008

No as Natdoor mentioned.
to be able to use data such as this 'your' should be able ro record asnd store the information it was calculating at the time.
I dont think this facility exists...... or does it?

  Covergirl 12:17 13 Mar 2008

Surely in-car sat navs only have recieve ability and don't transmit to the satellite.

If they did transmit, then they would have to transmit with a serial number or unique code. A bit like a mobile phone does.

Then the police would have to be able to access the database of unique codes of all the sat navs sold in order to link YOU to the record.

(Some of the Sat Navs with advanced features may transmit / receive for things like traffic updates etc, but I would think this would be done via RDS radio or phone connection).

So in summary, I don't think so either . . .

However, if the police were to stop me with my Garmin 200 and press the right button, there is a Max Speed display on there which would instantly prove me guilty (if I had been speeding, that is) !!

  laurie53 20:00 13 Mar 2008

On the mainland the police to the same with truckers.

They just look at the tachograph print and if it shows the truck has been been speeding, even hours before, the driver gets fined (or worse).

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