Click the link to read the article, or just watch the video because they both explain system in detail. The last couple minutes of the video shows the iron curtain system defending against live rpgs, its pretty impressive.
http://www.wired.com/dangerroom/2009/11/new-bomb-resistant-trucks-will-blast-rpgs-before-they-hit/
[ame=http://www.youtube.com/watch?v=qPYlINh8Q_Y]YouTube- iron_curtain.mp4[/ame]