Diver Detection Sonar for Maritime Security

Nowadays, naval bases, commercial ports, oil platforms, terminals and other similar valuable offshore installations, become more and more targets of terrorists, saboteurs and spies.

Undesired "visitors" tend to approach from sea and submerged, as this line of attack is rather difficult and expensive to survey and to protect. Thus, such an approach route remains unprotected and enables intruders to execute an attack with relatively little risk.

To provide the responsible authorities with a reliable and powerful tool for the protection of vital installations against submerged aggressors, the Diver Detection Sonar (DDS) as a port surveillance system has been designed by arsTECH. This surveillance system enables the automatic detection of intruders and the generation of an early warning which is a prerequisite for an effective counter-measure.

The DDS Diver Detection Sonar is designed to counter the threat of sabotage and terrorism for naval bases, commercial ports, oil platforms etc.

Therefore, the system has to perform the following tasks:

• Detection of divers, swimmers and swimmer delivery vehicles (SDV) in automatic and manual modes;
• Automatic target tracking;
• Depth classification of detected targets;
• Determination of target data like bearing, range, course, depth, speed, aspect angle, length and level;
• Display of processed detection and classification echoes together or alternative to acoustic "raw" data;
• Display of tactical information on the surveillance display with graphical picture of the protected area, sector coverage of the sonar head, target markers, track symbols, track history;
• Interfaces to external communication and radar equipment (option);
• Alarm recordings with the aid of a mass-memory unit (option);
• Guiding of a patrol boat with the underwater attack force to the location of the intruder;
• Initiating an electronic countermeasure (low frequency high power sources).

Diver Detection System (DDS) Detection Range

Diver Detection System Transmitting Array

• Structure: Vertical Line Array, made up of 4 sectors, 90° each;
• Each of the 4 sectors is a Line Array consisting of 2 x 64 Transducer Elements;
• Element Type: Tonpiltz;
• Array Length: 80 cm;
• Horizontal Coverage: 4 x 150° (Overlapping);
• Vertical Beam Width: Fixed in the range of 1.6° - 10°;
• Vertical Beamformer.

Diver Detection System (DDS) Receiving Array

• Structure: 4 Horizontal Linear Arrays, arranged as a Cross; every 2 Arrays are mounted back to back;
• Each Linear Array is made of 3 x 96 Hydrophones;
• Linear Array Length: 125 cm;
• Vertical Coverage: 50°;
• Horizontal Coverage: 90° (±45°) per Line Array (Horizontal Beam Former); total of 360°;
• Number of Receive Beams: 360;
• Horizontal Beam Width: 1.06 ° at 60 kHz;

Diver Detection System (DDS) Acoustic Dome

An Acoustic Dome, made of transparent plastic acoustic material, protects the Acoustic Node. The Dome is filled with purified sea water.

Diver Detection System (DDS) Transmitter

• Transmitted Signal: CW, FM selectable;
• Pulse Length: 0,5 ms to 50 ms (Selectable);
• Source Level: 226 dB re 1 microPa at 1 meter;
• Number of Transmitters: 4, one per Transmit Array.

Diver Detection System (DDS) Detection Receiver

• Two Types, selectable by the Operator;
• Non-Coherent: Energy Detection in the frequency domain (Works best with CW pulse);
• Coherent: Replica Correlator (Works best with LFM pulse);
• Both Receivers include post processing for bearing interpolation and normalization;
• Range: 1 meter
• Bearing: 0.25°

Diver Detection System (DDS) Anti-Reverberation Features

• Very Narrow Horizontal and Vertical Beam Width;
• Uses Short Pulses;
• Uses Replica Correlator;
• Low Side Lobe Level of Vertical Transmit Beam;
• Mutual Operation of Multiple Acoustic Nodes without Mutual Interference;
• Sonar Performance Prediction System (Model): Support function to predict expected detection range.

Diver Detection System (DDS) Automatic Target Tracking

• 3 Dimensions (Range, Azimuth, Depth) ;
• Number of Trackers: 20;
• Tracker Output: Target Range, Bearing, Depth, Doppler Speed;
• Trackers are not affected by strong reverberation or large targets, including surface vessel wake.

Diver Detection System (DDS) Target Classification

The DDS system's Target Classification is based on the target's image characteristics and sophisticated image-processing techniques. The system provides automatic target classifications, and enables operator intervention and final decision. Advanced features enable the differentiation between noise and fish, and between different target types (surface swimmers, divers with closed circuit breathing systems, divers with open circuit breathing systems, SDVs, surface boats, etc.).

Diver Detection System (DDS) Displays

• High Resolution Color Monitor;
• Range Scales: 100 m to 6000 m, selectable;
• Target Intensity: Color Coded or Gray Scale Coded (Operator Selectable);
• Range vs. Bearing (B - Scan/Scope);
• Depth vs. Range;
• Amplitude vs. Range (A-Scan/Scope);
• Doppler vs. Range of Tracked Target;
• Sonar Performance Prediction;
• Geographic Map Background (ECDIS).

Diver Detection System (DDS) Display Features

• Scan-to-Scan Integration;
• Zoom: Up to 3 zoom areas to enable investigation of "areas of interest" ;
• Display of previous detection picture for reference;
• Automatic Target Detection of target above threshold set by the operator; when target is detected, an alarm is generated and the target is graphically marked on the display;
• Suppression Zones: Operator-selected areas are excluded from alarm;
• Static Suppressed Image: Static images are excluded from alarm and/or display.

Operating Multiple Acoustic Nodes

• Operator Consoles with two monitors;
• 2 or 4 nodes are displayed on one monitor;
• In normal time: one operator/one console, monitoring all nodes, up to 8;
• In high alert time: two operators, two consoles, each monitoring half of the nodes.

Diver Detection System (DDS) Additional Features

• Automatic Detection of Jamming;
• Automatic Bandwidth Adaptation and Adaptive Noise Cancellation (ANC) when jamming is detected.

Diver Detection System (DDS) Specifications

• Power Supply: 220 V AC; 50 Hz; one phase; 0.8 KVA (average) / node to 2 KVA / node (worst case);
• Cable Distance between Acoustic Node & Shore Unit: Up to 10 km;
• Resistance to Underwater Explosion: 0.5 Kg TNT at a distance of 2 m ;
• Horizontal Coverage:
  • 1.4 Transmit/Receive Arrays - 360°
  • 2.3 Transmit/Receive Arrays - 270°
  • 3.2 Transmit/Receive Arrays - 280°
  • 4.1 Transmit/Receive Arrays - 90°

To view this full product as a PDF please click here.

To view our related DDS-J Diver Detection Sonar product as a PDF please click DDS-J Diver Detection Sonar.

To view our related Pulsar-3D Advanced Diver Detection product as a PDF please click Pulsar 3D.

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To view our related Underwater Net product as a PDF please click Underwater Security Net.

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To view our related Autonomous Underwater Surveillance Vessel product as a PDF please click here.

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