Re: GPS ASL
I believe ILS wasn't part of the spec because it's supposed to be capable of operation from austere strips so the added weight* wouldn't be worth the few times it'd get used.
I believe the problem with GPS is that the altitude output is the least accurate reading so it wouldn't be reliable enough on its own to get you back down, although the recovery is mainly done by GPS the final few feet need something more accurate to avoid flaring to late or as in this case too early. Personally I'd suggest making the undercarriage stronger and allowing it to do a no flare landing like a carrier aircraft.
*It's really quite small.
Biting the hand that feeds IT
