Originally Posted by
G-CPTN
My (Volvo) car satnav can obviously identify where it is and uses a DVD-loaded map to direct me - however it recently went 'off-grid' when I decided to drive directly between two locations rather than use the main roads.
I obviously missed a turning (I was on country roads with few signposts) but, instead of recalculating (as usual when I divert from the specified route) it just went dumb until I retraced my steps and regained the designated route.
I don't know whether this was a GPS communication failure or whether the roads weren't on the mapping system - it could have been that the roads were unadopted as they led to private properties (though not signposted at such - just country farms.
Does my satnav communicate with the US system or the European system?
Depending on the age of your car, it will certainly use the original GPS - the US system. It might also use the Russian Glonass. Unless it is very new it will probably not be able to use Galileo. Your receiver won't switch between systems, it will use any and all of those it was programmed for. Obviously when it comes to getting a good fix, more is better especially in urban canyons or in wooded areas where much of the sky is obscured.
Under the forthcoming EU regulations that mandate auto-location of vehicles in accident or emergency situations, car equipment must be able to get a fix from Galileo. So new cars will be fitted accordingly.