You can obtain this trophy during the third DLC mission. After the first tower is destroyed, you will make your way to the second location where you need to plant a beacon.
You will cross a bridge and you will see a turret at the end of it. Take note of this position. Go forward a bit and plant the next orbital beacon. Once you do, enemies will spawn behind you and start coming across the bridge you just crossed. Jump on the turret and start mowing them down. Shoot in bursts! You may need to use the Nano Forge and repair the turret at some point since one of the wankers shooting at you has a gun that disintegrates the turret.
You need to get 10 kills with that turret to get this trophy.