1. open the Eden editor
2. place a drone operator and an allied UAV/UGV drone (Darter or Stomper RCWS)
3. preview the mission and connect with the drone (use the UAV Terminal)
4. start the engine of the UAV/UGV and fly into the sky (take a stable position / auto hovering) or drive to an overwatch position
5. change to the gunner view
6. aim on your player and lock the view on him (Left CTRL+T by default)
7. Now run around with the player and try to get out of the sight of the UAV (get in houses, try to hide behind rocks, trees, under water or the landscape).

You can even jump to different positions on the map (map view press Left Alt+Left Mouse Button), the gunner turret will find you, no matter what you are trying to do.

I have even tried it with allied and friendly AI. Just randomly pick one of the guys and follow their movement. If they hide behind a wall or get in a house, no problem, once you have locked on the target the gunner turret knows the exact position of the AI/player.