The distance measurment is calculated by subtracting the time between the sent pulse and the received light. Together with the detection angle and the distance the exact position of the object can be determined. If the position falls within the predetermined safety zone "warning" the automatic speed reduction is initiated. If the position falls within the safety zone "danger" an e-stop is initiated to bring the vehicle to a complete halt.. 

When entering the working aisle in the forward direction the front scanner becomes active when the vehicle enters the aisle (eg. guide rail detection - wire guidance detection - magnetic codes at the beginning of the aisle). The laser scanner detecting reverse travel direction, even though active will only be evaluated once its travel direction is selected within the aisle. 

The control aspect assures for reduntant detection in a fail safe manner. The switching of the active scanning device ensures authentic obstacle detection avoiding as an example pedestrian and traffic in the intersecting aisle when the vehicle is heading away from this zone. The working aisle detecting scanner always remains active until the absolute end of the aisle has been obtained.