The Trawl Alignment Sensor installs on the middle of the headline and communicates to sensors on the doors. For current customers, this means that no additional door sensors are needed. As Notus sensors are omnidirectional (360˚) one sensor on the headline can communicate to sensors on the doors without being aligned perfectly.
The following distances are calculated: from the starboard door to the center of the headline and from the port door to the center of the headline. Subtracting these two distances provides an adjustment to align the trawl. In addition, the trawl angles are calculated.