On Guardian grab a carbine rifle and a sniper and go to the ledge by the needler.
You will see a blow up coil at the top of the ramp - stand on top of it.
Point your carbine at the top of it and press A and right trigger at the same time.
When you do you will shoot up in the air.
Press crouch and move forward and you'll be on a ledge high up and it is a perfect sniping spot.