Maritime ViDAR tackles surveillance challenges

Published on: March 2021

Early in 2021 two important pieces of news broke in the maritime patrol world. Firstly, US defence giant Lockheed Martin announced it would explore the world’s first Optical Radar system, ViDAR™, with a view to integrating it into the mission system of its MH-60R Seahawk naval helicopter.

And then, a few weeks later, Fisheries and Oceans Canada announced it had adopted ViDAR as part of the integrated sensor suite on its De Havilland Canada Dash-8 fisheries patrol aircraft to detect Illegal, Unregulated and Unreported (IUU) fishing.

Why were these news items important? Because they confirm the value of the Australian-designed ViDAR in both the naval and para-military Law Enforcement (LE) domains.

ViDAR, for Visual Detection and Ranging, is manufactured by Melbourne-based Sentient Vision Systems. An Optical Radar, it is an imagery analysis system that examines the feed from a platform’s Electro Optical and Infrared (EO/IR) sensor suite in real time to identify targets that might be impossible for a human operator or radar to spot.

The performance edge that ViDAR bestows on operators is significant. In Search and Rescue (SAR) missions it has a very high detection rate for human head-size objects in the water, the most difficult targets to spot, even in Sea State 6.

Equally importantly, it can easily detect small wooden, glass fibre or rubber boats with a small radar cross-section. These are the types favoured by IUU fishers and criminals. Terrorists and hostile naval forces attempting asymmetric warfare tactics might use swarms of small, stealthy attack craft which can also be very difficult to spot using a radar. And of course it’s passive, so the surveillance effort can’t be detected by the target, which makes it possible to spot and shadow discreetly larger ships by day and night.

On an airborne platform ViDAR consists of multiple fixed EO/IR cameras with a combined field of view of around 180 degrees. Its imagery analysis software turns that sensor array into a passive, persistent wide area Optical Radar. Depending on airspeed and altitude, ViDAR can help an operator cover a specific area up to 300 times larger than a similar aerial platform using traditional EO/IR sensors and visual search techniques. A helicopter flying at about 90kt at 1,500ft can scan a surface swath 3.2 nautical miles wide in search of a small, semi-submerged target such as the float from an illegal drift net or a Fish Aggregation Device – it has demonstrated detection rates of up to 96%. If the target is bigger and easier to detect – a small boat, for example – flying at 5,000ft increases the swath width to about 16nm. A single aircraft such as the MH60R or UAV, operating off a frigate, can build up situational awareness very quickly and provide early warning of emerging threats around the ship itself.

The ViDAR processor analyses the imagery from this sensor suite, detects targets and places a thumbnail image on the operator’s main display showing the target itself and its location. The operator can then slew the primary sensor towards the target to examine it in more detail and then take whatever action is required, whether it’s an immediate gun or missile attack or a routine report to a ground station. By contrast, the field of view of a turreted EO/IR sensor can be as little as 2-3 degrees, which means the operator needs to scan a huge sea area to find targets, with a low probability of detecting them unless their rough location is already known.

The difference this makes to task planning and situational awareness is enormous. Searches can be completed much quicker; search areas can be extended significantly. Situational awareness and a Common Operating Picture (COP) are achieved much faster and maintained more easily. Targets are detected which would otherwise almost certainly be overlooked.

ViDAR is a passive sensor: unlike radar, it doesn’t emit RF signals. Targets, whether conventional warships or stealthy fast attack craft controlled from a mother ship or shore base, don’t know they’re the subject of a search, or being tracked once detected. Anything within the visual horizon of the surveillance platform is visible – and if that target is a conventional warship that is not using its radar in order to avoid RF emissions, or just a rogue fishing fleet plundering another country’s maritime resources, it is still being watched from far enough away that the surveillance platform is inaudible and invisible, especially at night.

The integration complexity and Size, Weight and Power (SWaP) impact of ViDAR are both low. It can be mounted in the nose of an aircraft or helicopter or incorporated into the payload bay of a UAV; Sentient Vision’s own field teams help install and integrate the system and train operators and maintainers. The image processing and analysis software is easily integrated with the existing mission management system: ViDAR has been integrated with CarteNav’s AIMS-ISR system, for example, as well as the mission system used by the US Coastguard for its Insitu ScanEagle® UAVs – and potentially soon the mission system of Lockheed Martin’s MH-60R Seahawk helicopter.

ViDAR also transforms the economics of deploying an airborne surveillance platform. It enables aircraft to achieve more in a single sortie and to conduct their tasks faster, reducing wear and tear. Its ability to spot hard-to-detect targets instantaneously significantly reduces operator fatigue and task saturation, meaning surveillance operators can sustain a certain level of effort for longer and surge more quickly. This also increases the situational awareness and therefore security and safety of an aircraft and ship.

Operator experience shows that ViDAR can make a maritime patrol effort more successful and efficient as well as much more cost-effective, just by achieving results that weren’t possible before.