Let's start with my gate construction first.
We are in the Southwest-corner and the gate is controlled by 2 proximity sensors.
the power source is on the left
the first sensor (left) is triggered by enemies and has a very wide range (1800) and cuts the power to close the gate
the second sensor (right) is triggered by allies and has a very narrow range (400) to open the gate, when my settlers or I are close to the gate.
The gate area is still under construction a