After market sat nav problem

[zoros]

I have a 12 yr old SL55 AMG and I can't be bothered to update the CD for the satnav - mainly because I had already bought a Garmin sat nav to swap between all our cars when needed.
Now I have had the problem before in my car with an older Sat nav and also my Iphone maps:

When I plug a sat nav into the cigarette lighter power source to run the satnav - OR simply use google maps on my phone INSIDE the car anytime/anywhere - it can't acquire the satellites??? It works in all our other cars.

Is it because my SL55 has a heated front screen and perhaps the element in the screen is acting a little like a Faraday's cage effect?

Or have MB screened items like this on purpose?

Your observations appreciated.

 

[tec]

The heated screen may also be made from heat reflective glass, sometimes called solar glass, and this also stops radio GPS signals.

Solar glass is more widely used in buildings and trains now, so if you wonder why your phone has a poor signal, this may be the reason.
Most railway carriages are fitted with repeaters that boost phone signals to get around this.

 

[zoros]

Thanks tec