@Tony: Can you give me some details how you used Marble during the ride? I guess with GPS turned on and the screen turned off? In offline mode missing tiles do not cause network queries. Losing the GPS connection however does trigger the connection dialog since we run it in agps mode which queries for a network connection when no satellites are in view.

@Dennis, You're right about the way I use it. It always appeared to have acquired a fix whenever I looked at it, but of course I've no idea whether or not it had lost sight of the satellites in between. If you've got any suggestions for diagnostics that might be useful, let me know.