Please note where I aimed - it has to be that face if the camper is next to the wall up there. The Javelin is the most potent anti-open-air-camper tool you can have on that level.
Here's a map of it:
I was roughly at the yellow position. I aimed at the red. The green area is the kill zone.
You know what? That might be a good starter. Next time someone gets Fallen as Team US, try to hit that shot with the Jav and see if it gets anything.
Simmilarly, I find that moving towards the courtyard and then targetting the the front of the red building on the side closer to that area you are going for also works, plus it has the bonus of taking out people below.