This will almost certainly be due to a failed GPS Shark's Fin antenna mounted on the roof of yours and Alanjay's tourers. It's becoming a very common fault as our cars get older. Look at the globe symbol in the top right corner of your sat nav map screen, if there are no stars or picture of a satellite, but just a globe, you've lost satellite reception.
Have a look at this thread on the subject for more (especially posts 10 and 14)
Hi-Line shows "Vehicle position outside map limits" message
You'll probably need to replace the roof mounted shark's fin antenna and that should cure the problem.
For info on removing the antenna look here
