AN/WQX-2

The AN/WQX-2 is a diver detection sonar used in anti-frogman precautions. It is in service with the US Navy. It uses Kongsberg Mesotech components. It can detect divers up to 2400 feet (= nearly half a mile) away.
The AN/WQX-2 finds range and bearing of the detected target relative to the sonar. The C3D console developed by SPAWAR converts this to a GPS position. It has software to distinguish diver echoes from shoals of fish, marine mammals, debris, bubbles from boat wakes, etc.