The AquaShield tactical display showing the long-range tracking of two divers inside a harbour. (all photos : DSIT)
Over the past decade there has been an awakening across government and industry of the vulnerability of deployed maritime platforms, coastal military installations and critical civil/commercial infrastructures to asymmetric attack from terror groups and irregular combatants.
This has generated a flurry of activity among front-line operators, defence research laboratories and industry to devise ways and means to better protect the 'maritime flank'.
In the above-water domain, greater cognisance of threats such as suicide craft and infiltration teams has seen the introduction of layered anti-terror/force-protection (AT/FP) measures designed to detect, classify, identify, and, if necessary, neutralise hostile elements before they can reach their intended targets. These constructs typically combine networked surveillance sensors (principally radar and electro-optical/infrared) with agile and responsive AT/FP platforms (typically patrol craft or unmanned surface vehicles) and improved ship defences.
The provision of subsea surveillance around deployed high-value assets and critical infrastructures is an altogether less mature area, but one that is receiving increased attention as the threat from swimmer delivery vehicles (SDVs) and divers has become better understood.
One industry insider said: "There are billions of dollars-worth of facilities and structures under or adjacent to the sea. Governments, and particularly the energy industry, are finally waking up to their vulnerability to attack."
He added: "Scuba training is relatively cheap and easily accessible. Even a single terrorist equipped with a limpet mine or IED [improvised explosive device] could wreak havoc, with huge financial, environmental and/or political consequences."
Active sonar – the transmission, reception and processing of pulses of acoustic energy – offers the only practical means of surveillance through the water column and the past five years have witnessed a significant increase in activity as a plethora of new sonar surveillance and alerting devices have been brought to market.
Two market niches have appeared: one for larger, multisensor diver-detection sonar (DDS) systems designed to watch over a relatively large area; and a second for more compact, lightweight and mobile devices better suited to confined areas or the protection of high-value vessels deployed into high-threat regions.