No undercarriage? Isn't that sensor package at the front in danger if it hits a rock on landing? Unless of course the troops jump out when it's hovering 6 feet off the ground.... 
Yes it has an undercarriage which does elevate it slightly above floor level (if you look closely there is a gap under the hull and the ramp(s) are angled down. I imagine that the undercarriage could be raised to overcome any difficulties encountered on landing or even hover on the four manoeuvering thrusters to allow troops to disembark.
