It takes a few minutes to lock onto the GPS initially.

If you want to test it, then go outside or right by a window, applications->maps, and select your wifi as the access point. dont touch anything after that and it will download the map and zoom into your position automatically. Give it a few minutes more and it will lock onto the satellite and the red X will disappear from the symbol in the bottom right.
Once its initially locked on its not too bad at updating and tracking your position.

GPS will work with no memory card and with network access point set to off and will give you your location (but confusingly with no map if not installed and no network connection. It will just show you on a blank screen.)
Sat nav/directions won't work with the access point set to off if you don't have a card with the maps on installed- it needs to access the network to download the maps on the fly and plan the route. This is why buying a card is essential.
Once you have the maps downloaded onto the card you shouldnt need to connect at all when using the gps or nav (unless you want the voice directions in which case you do need to connect I believe) so should be able to set it to off.


Im still learning this thing myself but thats what I have found out so far