In your home you have a so called satellite dish pointed in various directions, mostly horizontal facing in many cases, but that's one thing.
How many cars do you see with so called satellite dishes on them?
You have a gadget on your dashboard, you tap in your postcode and the post code of your final destination and off you go.
In between time, your so called sat nav picks up mobile speed camera's.....How?
The reason is simple. It's because your sat nav is simply just a part of cells.
It's programmed as a map and it's programmed to receive marker signals which will be scrambled for that specific purpose.
Anyone who says they only lose signals in certain built up areas and not in country side, etc, is a full blown 100% liar.
As soon as you get out of range of towers, your sat nav goes to hell until it can pick up the next signal from the next tower.
The technology is getting better and better because they are building towers into the countryside for the very purpose of keeping a full map of the whole country.