I may be repeating myself - it wouldn't be the first time. I think I'm right in saying vehicles in Northern Ireland used to have screens either side to record the passage of a bullet over the top - a screen inside showed an arrow, pretty simple technology. The footage from Afghanistan shows lengthy engagements where nobody is entirely sure where the enemy is, and small patrols with large numbers of ANA can be pinned down for ages. Suppose you had a thin mat - say twenty feet unrolled, with two sensors at the edges. A processor knows the difference between the two edges, and the difference between two sections not directly opposite one another. Virtually everything being fired at the troops is 7.62X39, which has a known muzzle velocity. So you throw the trap across the middle of the position. F*ckwit fires a round over. From the recorded velocity and initial velocity you know the distance, to within a couple of metres, and from the angle between the cells it crosses you know the direction. With GPS integrated you could bring down fire bang on. Problems? Different calibres, but that's solvable. Their response would be to fanny about by taking powder out, or putting a bit extra in, which would causemassive problems, or to move, which would be even better.