Nokia Drive 3.1 - Can I disable A-GPS positioning in my Lumia phone?

There's no separate option to turn off A-GPS (Assisted GPS) in Nokia Lumia phones. If you want to disable A-GPS and prevent it from accessing the network, you can switch the mobile data connection off in Settings > Mobile network > Data connection. In that case only the integrated GPS is used for positioning. Note that it may then take a longer time to get a GPS fix.