The British Ministry of Defense had a briefing on the MoD Grand Challenge in March. A 3-page list of people attended, many from British universities and aerospace companies. Different presentations described the rules, registration process, and practical military views on urban warfare and the kinds of environment the competitors should consider in their designs (terrain, weight a soldier can carry, threats, etc). The winners should be able to enter an area and identify a variety of types of threats.
There are interesting commentaries here and here.
See more here.