yep, its AT-AT...
now, hardest award, well i'm a terrible sniper so the marksman really is hard, also the rockets award is hard, even though i know where the spots are, the rocket award is also boring to do..
do what I do, use it as a battle rifle, it works great eventually you will get use to it and be popping 10+ marksman a round.
and when I say the rocket on is the hardest for me its cause I get t boed doing it lol.