Diver Detection Sonar - Mature Diver Detection Sonar Technology

Mature Diver Detection Sonar Technology

In the above mentioned study, conducted with the Italian Navy, it was found that diver or intruder detection sonar technology is mature inasmuch as:

1. It has demonstrated 360 degree coverage with detection ranges of 300 to 800 m

against intruders wearing open-circuit breathing equipment. The coverage is significant relative to the area of open water and to the possible entry points for intruders in many harbours.

1. Reduced detection range and track fragmentation, when it occurred, could be

accounted for by environmental (sound propagation) conditions at the time (see below).

1. Random false alarms are rare (when the auto-detection is properly adjusted), and

they are recognizably false because they are of short duration and do not follow a track.

1. Non-random false alarms caused by genuine underwater contacts that happened

not to be intruders—by large fish, or schools of fish, or marine mammals, for instance—can usually be recognized by an experienced operator from the contact’s behaviour, especially the evolution of their track, so these “false” alarms are unlikely to be troublesome in practice. They furthermore provide feedback about the functioning of the sonar and domain awareness.

1. The automatic algorithms are capable of detecting and tracking many contacts

simultaneously. Were the Diver Detection sonar systems to rely strictly on the echograph generated by the sonar units overlaid on a navigation chart, then a diver or SDV would appear as a relatively small moving shape that is refreshed with each transmission or ping of the sonar against a fluctuating background of sound clutter and reverberation. The operator would have to recognize the shape and judge if it represents a threat calling for further action or not. This is problematic in that they would have to be highly trained sonar operators. For this reason, commercial DDS systems use automation to simplify the sonar display by suppressing the echograph and displaying only the chart and detection and tracking information.