Sharpening eyes, ears, and teeth in a dangerous subsea environment

Dominance of the undersea domain – the underwater battlespace – will be achieved by the side best able to understand and exploit the environment and maintain superior situational awareness. Maintaining that network requires reliable and flexible data exchange.

Justin Hains MBE, Business Development Manager, Forcys

In the 21st century, combat divers pose significant threats to sailors and their assets. A well-trained team can execute an attack on unsuspecting and unprepared navies. Divers will use their environment to cover their tracks by swimming alongside harbour walls and hiding their signatures by using the high returns from those walls, or swimming erratically in an attempt to confuse trackers.

Elsewhere, unmanned, Underwater Vehicle Systems (UUVs) have significantly evolved. Capable of moving faster than divers, many UUVs will stay below the detection threshold of active sonars at longer ranges due to their negligible returns.

We know that, to counter these threats, tools are needed to help detect, track, and identify targets in harbours. For example, active and passive sonar technology can be used to help classify targets, distinguishing between UUVs and divers using opencircuit or closed-circuit breathing equipment. Using passive signals either alone or combined with active sonar, a tracker will obtain precise bearing observations of a threat like a diver or a UUV by listening to the noise they make and analysing the behaviour of the contact.

The majority of navies have some sort of homeland defence requirement so that they can maintain and prepare ships for operations. They also have a requirement to enter or leave their bases at the time of their choosing. Freedom of manoeuvre, to be able to do what they need to do, is key. In expeditionary terms that means going through choke points like the Bab el Mandeb or Straits of Hormuz and being able to operate and defend in proximity to a hostile shore and likewise being able to defend a foreign harbour used for maintenance and resupply.

The ability to monitor ports and harbours is required both at home and away. Many potential adversaries can interfere with GPS signals, but to some extent, the subsurface environment has always been GPS-denied. A fixed installation of a diver and UUV detection array can be augmented by an acoustic positioning network to ensure that there is no impact on operations in a GPS-denied environment. The UK Royal Navy for example is showing keen interest in this area.

Responding to new threats in a networked battlespace

In the Second World War, we were worried about U-Boats stopping the transportation of food, ammunition, and medical supplies. Now, however, we are worried more about an interruption of global commerce if communications cables are corrupted. Oil and gas attacks remain a threat, as highlighted by the recent events on the Nord Stream 2 gas pipeline. Whilst in the end it seems to have had a minor impact on overall supply, the attack shows capability and intent, and capability plus intent equals threat. Imagine the various stock exchanges not being able to talk to one another at the speed they require. In that scenario it would be about sitting on the data, hoovering it up and then potentially manipulating it rather than just cutting it off. The threat has been recognised, and it is real.

Meanwhile, advances in drone use in the air environment are driving navies to look again at the art of the possible underwater, namely submarines operating or being supported by UUVs as either offboard active sensor platforms or weapon carriers; the next generation of micro-processor-controlled sea mines; kamikaze autonomous Unmanned Surface Vehicles; and hyper-enabled combat divers operating at greater ranges and depths, enhanced with propulsion devices and better environmental protection. All of this is evolving a challenging and risky operating environment into an adversarial one.

Until now, the subsea environment has been treated in a piecemeal fashion and the subsea picture as a separate entity. Air-surface integration, however, has been achieved at pace because the technical challenges, I would argue, are lower in the air and the nature of conflicts in Iraq and Afghanistan focused money and development in that direction.

Iver4 580 is a small diameter unmanned underwater vehicle (UUV).

Photo courtesy L3Harris

Underwater networking for the communication of data is significantly harder. In basic terms, data transmission rates are lower, and signals are attenuated faster underwater, leading to reduced operating ranges.

However, improvements in technology mean there is now an increasing ability to transmit large data packets through water with confidence. Assured communication links are improving and this delivers the ability to have a networked battle space. The next trick, however, is to give it a better range, and to improve the level of cryptographic security possible with higher bandwidth radio transmissions, as well as improve the data update rate to fuse with the above-the-water environment.

Working with defence, science, and technology laboratories

Forcys is working with Defence, Science and Technology Laboratories (DSTL) to further improve the security aspects of underwater communications. The step change now, however, is the high-level encryption required to provide security of throughwater communications, an area where the UK MoD is driving change. DSTL has developed Phorcys, an open standard for secure acoustic communications that will enable navies to collaborate and interoperate, assuring secure transmissions and communications. Similar work is taking place at the Centre of Maritime Research and Experimentation (CMRE) in the Italian port of La Spezia – a NATO facility.

Intruder detection sonar.

Photo courtesy Sonardyne

So, while the air-surface domain is benefiting from secure networks to exploit the possibilities of drones and conventional forces as a synchronized capability, the focus of this work underwater is to ensure that we can replicate similar operations as in the air. The ultimate step is to reduce underwater data latency to an extent that there is a truly real-time multi-domain picture, in which a distributed network of Autonomous Underwater Vehicles and Unmanned Aerial Vehicles work in support of larger, possibly crewed, platforms to deliver battlewinning effect while being capable of withstanding higher levels of attrition than a small number of crewed platforms can do today.

This is why going forward, being able to establish a network that communicates with everyone is vital. Interoperability is a key theme for a networked battlespace, and most maritime operations are conducted by coalitions, either of the willing or under pre-established defence agreements. Anything we can do to enable that is ideal.

The key is being able to establish a network that communicates with everyone and everything. Being at the centre of that technological development is exciting and demanding, but ultimately rewarding, as we put greater capability in the hands of our armed forces and security agencies.

Sentinel deployment.

Photo courtesy Sonardyne