Imagine you had the equivalent of a parking sensor installed on the bow of your vessel, just beneath the water line. Imagine that it gave you a live 3D view of the seabed and the water column ahead, on your vessel course. Imagine if that sensor also sent you automated warnings, when something in the water column ahead – hidden from sight, radar or Lidar – presents an obstacle or hazard (the equivalent of a pedestrian or bollard near your car).

We think that would be a powerful tool, de-risking day-to-day as well as the more “off-chart” navigation by the adventurous mariners among us. It would also enable more marine autonomy, providing unmanned craft, surface and sub-surface, with that additional level of situational awareness.

Next generation forward-looking sonar

That’s why we’ve built Vigilant, our next-generation, long-range, forward-looking sonar (FLS). Vigilant FLS is a navigation and obstacle sonar, built by us from the ground up based on our previous system. Vigilant provides automated alarms of objects in the water column out to 1.5 km. It also creates – with unrivalled resolution and detail – a real-time, easy to interpret 3D terrain map of the seabed ahead out to 600 m and down to 100 m water depth.


It’s so good you can literally ‘park’ your vessel with it. Just view your crystal clear terrain data for that ideal anchorage. And, at just 31 cm-wide – comparative with a gaming console – and weighing only 14 kg in air (more than 90% lighter than our previous system), it’s easy to handle and install on a wide range of vessels, from private yachts and harbour patrol vessels to offshore support vessels and research ships. It’s also autonomy ready, coming with a specific mode for use with auto-pilot systems.

“It’s an ideal solution for those with an adventurous streak,” says Rob Crook, Research Director at sister company Wavefront Systems Ltd., who have led the development of Vigilant. “You can fit it to your superyacht or expedition cruise vessel and you’re then prepared for anything, from seeking out a secluded bay or voyaging into the Article Circle to watch the Northern Lights. With our sonar on board, these vessels can navigate through unknown reefs, rocks, icy polar regions or shallow sand bars with confidence. You can even use it to see the seabed topography ahead in order to pick the best anchorage.”

An essential bridge tool

It’s also ideal for those working in busy coastal waters, says Pete Tomlinson, Engineering Manager at Sonardyne. “Coastal shipping is, in fact, where the majority of known marine incidents happen. Groundings are all too common,” he says. “These – and costly recovery operations – can be avoided with Vigilant’s automated alarms. Timely alerts mean crew have time to take avoiding action. Offshore energy and commercial fishing operations, which often take place in busy and frequently shallow waters, would benefit too. As would vessels called upon for disaster relief operations, where they can be going in literally blind following a tsunami, earthquake or hurricane that’ve dramatically changed what may have previously been well charted seabed. With Vigilant, you can see the seafloor. It’s no longer unknown. Even large marine mammals, like whales, can be picked up by Vigilant’s computer aided detection (CAD) markers, which trigger alarms. Regrettably, whale strike happens more than you might think and can result in quite hefty fines and reputation damage.


“For naval operations, with Vigilant, operatives can be prepared for the unexpected, whether they’re in a swimmer delivery vehicle (SDV), or on a coastal patrol vessel or cruiser. With its history mapping capability, which lets you see your past track, they’ve also got great situational awareness for tight manoeuvres or backing out of a confined area. It remembers where it’s been! Combined with our Sentinel intruder detection system, naval facilities and assets at anchor or in port can also protect themselves from underwater threats, including closed and open circuit divers and even man-portable unmanned and autonomous underwater vehicles. That’s a powerful combined package.”

Compact hardware, comprehensive coverage

Vigilant really packs a punch in a compact package because a lot of focused work has gone into its design, of both the hardware and how the sonar works. It’s effectively been designed from the ground up, moving the processing power to the topside and redesigning the sonar array. This has enabled the dramatic reduction in size and means it’s easier to fit, not just in new builds, where it’s relatively easy to design in a hull-mounted sensor, but also retrofits. In fact, our mechanical design teams have developed a novel cassette arrangement that any shipyard can install in the bow during a routine dry dock stopover.

Even more effort has gone into the acoustics involved in Vigilant. It works by transmitting acoustic energy into the water, through a 90 degree azimuth and through a vertical plane down to 100 m water depth – deeper than any other system in the market. It then listens for the sonar returns. These are then used to build an outstanding quality, real-time 3D bathymetry map of the seafloor and enable the CAD detections out to 1.5 km. Sounds simple?

The science of seeing subsea

“Our next-generation Vigilant probably represents the toughest design challenge Wavefront has ever faced,” says Crook. “Multi-beam echo sounders (MBES) are a common type of sonar which seek to map the water column and seabed topography with a fan of beams projected directly beneath the host platform. In terms of the nature of the resulting imagery – maps of the seafloor and water column objects – this seems rather similar to what we have designed Vigilant to deliver. However, whereas MBES has the luxury of mapping directly beneath the host platform, achieving the fundamental operational requirement of an FLS means delivering the same type of information many hundreds of metres ahead of the host platform, often in shallow water. We need to ‘forward look’ and still provide navigationally relevant terrain and object detection data. That’s not easy.

“It means imaging both the surface and the seafloor and anything in-between (two highly reflective surfaces). It means handling high levels of multipath interference caused by multiple reflections off these two interfaces. We have to deal with increased levels of ray-bending, associated with propagation through a predominantly horizontal sound channel. We also need to process and select for real-time display a single meaningful cut through of the dense 3D data point cloud of returns. Finally, the imagery has to be electronically stabilised against significant platform motion. With Vigilant, we’ve overcome these challenges and built the most capable (longest range, highest area coverage, highest resolution), commercially available forward looking sonar on the market.”

Vigilant has two principal operational modes, Depth mode and Sonar mode. Depth mode produces stunning 3D bathymetry and colour coded depth imagery, using our proprietary Altitude Confidence Filter (ACF), out to 600 m and down to 100 m. Sonar mode processes the intensity of the acoustic data to extract long-range positional data out to 1.5 km and over a 90 degree field of view. In this mode, the sonar returns are used to generate our CAD markers which alert the operator (or a third-party AI based processor) to the presence of a navigationally relevant obstacle, such as coral reefs, rocks, containers or even small ice bergs. Both modes use a combination of physical array hardware and a suite of proprietary signal and data processing algorithms, to deliver class leading performance.

Route guidance made easy

Under the hood, it’s not simple. But, you don’t have to be a sonar expert use Vigilant. We’ve focused heavily on making the graphical user interface (GUI) easy to use with automatic obstacle detection and classification. In Sonar mode, Vigilant has CAD markers showing potential obstacles, including objects like ISO containers or small ice-bergs, as well as shallow seabed, which provide the mariner with timely, clear and easy to see warnings. That gives you more time to act. Vigilant even picks out hard objects in sandy or silty seafloor. A warning at 300 m, a typical range of other less capable systems, just doesn’t give the vessel’s crew enough time to respond.

If required, users can also view the raw profile data showing the entire water column, so they can see how deep an object is. If it’s something shallow, for example, divers in a SDV, using Vigilant, would know they could pass underneath it.

Results, when you need them

During our rigorous testing, throughout last year, we’ve been putting these capabilities to the test and even we’re impressed. In really rough and pretty hostile acoustic conditions, in terms of salinity and temperature variations, it’s been performing. During one trial, our vessel was pitching so much that every now and again the frame-mounted sonar actually came out of the water. Yet, it was still seeing things in Sonar mode in these conditions – which it wouldn’t have to contend with on a large ship deployment.

It’s easily picking out marker buoys, more than 1 km away, in Sonar mode. That’s impressive. In 3D mode, it even produces fantastic images in quite enclosed harbours; a space that’s about as challenging as you can get for sonar.

Vigilant is now in production and we’re already working with customers keen to see what it offers. So, if your vessel is still on the drawing board or scheduled for a dry dock this year – wherever that might be – now’s a great time to speak to us about your requirements. We have 3D models and data sets we can share with you and are planning several in-water demos in Europe and the Far East to showcase what it can do. Get in touch to find out more.

Join our webinar


Derek Lynch, our Global Business Manager – Marine Vessel Systems, will give a 30-minute overview of Vigilant, introducing the applications Vigilant is designed for, the technologies inside it, how its performance compares and how it will benefit your operations, whether your vessel is manned, remotely piloted or fully autonomous. We will open the floor for a short Q&A session after the presentation. There are limited spaces so make sure you sign-up to not miss out.