First you will need a sniper rifle. Then go to where the overshield is.

Grab the overshield if you want then look over the ledge and there will be a long gray thing with blue light going across it.

Now very carefully jump over the ledge and make sure you don't land on the blue lights, but on the part without lights.

You cant move that far or you will die and its happend a few times to me, if stay in the same place you will die.