Sensor Redundancy

Hi all, My 2.1 will be here mid week and I have a few questions about how the sensor redundancy is handled with Ardu.



What one is selected as default and how is switching decided ?


Internal x2 vs external, are are these handled when external is fitted, can it switch back to internal if external goes bad.

If I went for duel GPS how is external compass redundancy handled ?

Thanks in advance.