I see on TV shows from the US that if a car has a Sat/Nav that the cars position can be determined by others (police, govt agencies etc.), a bit like mobile phone triangulation.

1) Is it true?

If so then ......

2) How does that work? I thought SatNav was passive device.

3) Is there an option to turn this feature off on our cars?


TIA

 

Sat nav just recieves several signals that are all atomically timed from various satalites, it doesnt transmit information. It then triangulates your position by working out the delay from each signal. So no Sat nav cant give you position away. Mobile phone signals can however be traced although I dont think thats instant as such.

 

GPS satellites are transmitters - they don't interrogate transponders or track objects on the ground. A receiver on the ground can use GPS signals to work out where it is; thus a tracking unit installed in a car can let the ?government? know where that object travels perhaps using some form of wireless communications - a spy in the cab not a spy in the sky!

 

When you talk to BMW assist, they confirm your position and direction so they are able to find your position, I also understand if the airbag deploys the rescue services are directed to your car. Don't know how it works, but it's not via my mobile so it must be via satellite or some other wireless signal from the car.

 

But the are talking to you over a mobile signal even though its not your phone. Not many cars with sat nav have that feature.

 

For US models (I don't know about ROW) -

It's not a Sat Nav thing (although the technology is used), but a BMW Assist thing. IIRC, from MY05 forward, BMW Assist can track your car, similar to "Lojack". So if f the car is stolen, BMW Assist can tell you or the police where it's located.

 

Your Pro-Nav car has its own SIM fitted - when connecting to BMW Assist for query/mobile service or SOS the car sends it's position via 'wireless' cell technology.

 

Thanks all, that is a relief. Not a spy in the sky. But some hyperbole from TV.