Sentinel IDS – Intruder Detection Sonar

Sentinel IDS – The world’s most deployed Intruder Detection Sonar

Our latest generation Sentinel IDS is capable of detecting, tracking and classifying underwater targets including the new drone threat.

Sentinel IDS is used globally to protect critical national infrastructure, ports and harbours, military operations and ports, private and commercial yachts, commercial vessels and waterside properties.

Sentinel automatically detects, classifies and tracks subsea threats approaching your protected area or asset, such as a diver, swimmer delivery vehicle or unmanned drone. Our latest generation IDS, Sentinel 2, adds advanced Simultaneous In-band Active and Passive Sonar capability (SInAPS®) to identify and protect, at ranges of up to 1500m for mini-subs and divers.

Sentinel is an intuitive system that will automatically inform the end user of any potential threat without the need for any sonar-trained personnel.

Depending on your application, Sentinel can be supplied in either a portable and mobile package for rapid deployment where temporary underwater security is required or as a permanently installed system for continuous protection of a known asset or perimeter.

Sentinel IDS
New Sentinel Screen

Display Controls

Passive View

Passive Track

Active Track

Active PPI

Zoom View

Tracking Information

Control Panel

System Summary

Sentinel at a glance

  • Identifies and classifies threats up to 1500m from any waterside asset or structure
  • Wavefront’s unique SInAPS® technology combines the detection and tracking capabilities of active and passive sonar
  • Simultaneous multiple detections and tracks of subsea threats in a single processing cycle
  • Super-Inheritance to maintain single track across multiple sonar heads
  • Target zoom allows improved target classification via high resolution, enhanced speed replay
  • Historical tracking data for enhanced threat target validity and evaluation
  • Compact and portable for rapid overboard deployment, when and where needed
  • Permanent installation for continuous protection of perimeters and assets
  • Low false alarm rate; no specialist sonar experience required

Sentinel Sonar is suitable for:

Port and harbour security

The reliable detection of underwater targets in the acoustically hostile environment of a seaport, harbour or marine terminal using sonar is a notoriously difficult challenge to overcome. Constant vessel traffic, noise from active depth sounders and a complex thermal structure characterise the scene.

Sentinel has been specifically designed to cope with these conditions, including ‘brown’ water, shallow water and tidal harbours where vessel activity results in a lot of disturbance in the water column. The system’s unique detection, classification and tracking software has been proven to operate in all environmental conditions and is capable of tracking multiple targets in real-time.

Critical National Infrastructure

Due to their strategic and economic importance, critical national infrastructure facilities such as nuclear power plants, dams, LNG terminals and offshore oil platforms represent attractive targets for sabotage.

Whilst these CNI installations have stringent above-the-water security measures, including physical barriers, access control radar and long range opto-electrical sensors, they are not generally equipped to detect intrusions from below the water. That’s why constant, real-time underwater monitoring using Sentinel will help ensure your facility is fully protected.

Naval vessels

Naval ships anchored off the coast or berthed in ports and dockyards are difficult assets to protect because of their size and proximity to commercial shipping traffic, open shipping lanes and leisure users. Physical measures such as floating barriers offer ships protection against surface attack using fast boats, divers using easily acquired scuba equipment remain a significant, yet hard to detect threat.

Sentinel’s compact sonar can be deployed using its own cable over the side of small craft patrolling inland waterways, through the hull of a naval vessel (e.g. Offshore Patrol Vessels) or lowered on a lightweight frame directly onto the seabed. If required, track data can also be exported via an open, industry standard interface to the vessel’s Combat Management System or integrated bridge.

Superyachts, coastal residencies, cruise ships

Sentinel provides reliable, effective and affordable security for properties and vessels considered to be vulnerable to unauthorised access from the water. The moment an intruder enters a monitored underwater exclusion zone, the alarm is raised and the threat is tracked. Sentinel’s advance warning of an attack gives security personnel time to assess the threat, intercept it, or simply move the protected vessel away from it – ensuring the safety of owners, guests and crew always comes first.
Sentinel Screen

The Image Zoom window (top left) shows a full-resolution active sonar image automatically centred on the target. This is shown with range as the Y- Axis and azimuth as the X-Axis. The zoom can be used to help the operator to classify the target; in this case groups of bubbles from the diver’s breathing can clearly be seen, confirming it is an open circuit diver OCD.

Image Zoom Window

Sentinel Screen

Up to 10 sonar heads can be displayed on a single command workstation. The Sentinel UI can display the multi-head view in one window, or can tile images from individual heads in the Overview. A tiled example is shown below. The user can drag and zoom the displays to optimise views in any window.

Sentinel Screen

The Sentinel UI allows for easy fine-tuning of the sonar positions relative to the background images – the operator can move and rotate the sonar location in real-time using built-in tools. Additional point to point measurement scan be made from any area of the UI screen.

Benefits of Sentinel for your operations


For very large sites, such as naval bases and container ports, Sentinel sonar heads can be networked together to provide uninterrupted protection. Integration with C2 systems is standard.

Low false alarms

Sentinel’s advanced algorithms intelligently and reliably discriminate a real threat from fauna and flora removing false alarms, freeing up Security personnel to monitor other critical systems.

Nowhere to hide

Sentinel uses advanced Simultaneous In-band Active and Passive Sonar capability (SInAPS®) to identify and protect, at ranges of up to 1500m for mini-subs and divers.

Sentinel IDS Installation

Wavefront offer a wide variety of installation options for the Sentinel system. This is usually advised after an engineer site visit to assess the perimeter that requires protection and understand the end-user Concept of Operations (CONOPS). Installation options include:

    1. Expeditionary / temporary deployment of the Sentinel sonar via seabed frame or cable
    2. A fixed bracket is a practical, cost-effective solution to deploy the sonar from piles and other suitable structures
    3. A seabed stand provides an optimum sonar deployment method for permanently protecting open areas of water
    4. A seabed frame provides a fast low logistic deployment of the Sentinel system from vessel or quayside for temporary and mobile protection requirements

To discuss mounting options for your specific application please contact us.

As a critical security product, Wavefront offer extensive support and operator and maintenance training to our customers either in the UK or in-country to ensure the Sentinel is providing the required world beating protection 24/7.

Why invest in Sentinel IDS?

At a glance

  • The most deployed Intruder Detection Sonar in the world, in service globally since 2007
  • Simultaneous in-band active and passive sonar (SInAPS®) leaving intruders nowhere to hide
  • Multiple subsea target-type detectors and trackers in a single processing cycle
  • Sets specific identifiable sonar- return characteristics for even lower false alarm rates
  • Super-Inheritance tracking data for improved threat identification across multiple sonar heads
  • One of the most compact IDS solutions on the market; take it and deploy it anywhere
  • Commercial-off-the-shelf (COTS) technology that integrates seamlessly with your existing security systems: radar, CCTV...
  • No specialist sonar experience needed; software automates most of the heavy lifting


  • Up to 3,000m diameter protection zone using a single sonar head
  • Detects divers up to 1000m away
  • Detects underwater vehicles up to 1,500m away
  • 100s of targets can be tracked and classified simultaneously
  • Exports track, status and display image data
  • Automated, user definable alarms
  • Up to 10 sonars can be linked to a single tactical display

Typical system set up

  • Man portable sonar head (or networked multiple sonar heads), cabling (including fibre option), junction boxes, shelters
  • Deployment options: lightweight seabed frame, seabed stand, rail and trolley mount, vessel through-hull/over-the-side, cable suspension, fixed bracket
  • Sonar processor, command workstation, software
  • Optional Syclla underwater loudhailer for deterring intruders. If a diver enters a restricted zone, Scylla can broadcast a pre-recorded or live audio message that can be heard by the diver at up to 600 metres


  • Unrivalled access to our technology and application specialists to configure your tailor-made security solution
  • Each project is backed with site visits, customers demos, FATs and SATs depending on your requirement
  • Comprehensive and flexible training for security system operators and equipment maintainers
  • 24-hour onsite and remote technical support backed with global equipment servicing and repair