By turning the cables into sensors, it’s possible to detect nearby maritime activities that could cause damage, so that operators are able to take action before it happens – perhaps contacting those vessels to warn them. We are also engaging with cable companies and operators to discuss how, as a community, this can be done consistently across undersea infrastructure.Tim O’Neill
We are developing a new approach to turn the infrastructure itself into a sensing asset, using existing fibre-optic cables to create a persistent, wide-area sensor network.
To do this we are using an existing technology, off-the-shelf distributed acoustic sensing (DAS) modules, but tailoring them for undersea use. By analysing light pulses sent through standard fibre-optic cables, it’s possible to detect minute vibrations caused by acoustic pressure waves.
This turns a cable running along the ocean floor into a continuous sensing array, capable of detecting everything from environmental shifts to the movement of vessels and even marine life.
From vulnerability to vigilance
The project began by exploring how to monitor power cables to provide early warning of faults and seismic activity, as well as accidental damage from maritime traffic. However, the application has evolved significantly.
“By turning the cables into sensors, it’s possible to detect nearby maritime activities that could cause damage, so that operators are able to take action before it happens – perhaps contacting those vessels to warn them. We are also engaging with cable companies and operators to discuss how, as a community, this can be done consistently across undersea infrastructure,” explains Tim, the project lead.
For an island nation like the UK, we are dependent upon a dense network of power and data cables, which provide much of our internet connectivity and electricity. Any technology that helps protect this infrastructure could offer substantial cost savings, from reducing repair bills to avoiding the economic impact from outages. It could also support broader government needs, such as detecting illegal fishing in protected zones or smuggling.
The data challenge
While the sensing technology we’re tailoring for undersea use is already used in land-based applications, deploying it in the subsea environment presents a major data management challenge. A single DAS unit can generate up to a petabyte of data per day, which is the equivalent of streaming 57 continuous years of high definition video.
“The sheer amount of processing required to analyse all of this data is immense,” Tim notes. “We are building the systems to store, access and retrieve the data over time. Alongside this, we are developing tools to autonomously detect signals of interest as they appear and alert the operator.”
We are using our experience in machine learning in conjunction with software partners to automate this analysis, developing algorithms to classify signatures and distinguish between things like whales, drifting containers, fishing trawlers or vessels of interest.
Visualising the underwater battlespace
To make this data usable for command teams, we’ve integrated the output with our wider intelligence system. This fuses the DAS data with other inputs such as radar, ship identification beacons (AIS) and satellite feeds, providing a comprehensive picture of the maritime environment.
Future deployment and integration
The project is currently preparing for a long-term data gathering trial. DAS sensors will be deployed on a commercial cable for three months to capture data. This real-world data will be used to further train and refine the classification algorithms, moving the capability closer to operational readiness.
This work forms a key pillar of our broader subsea intelligence campaign. By integrating persistent cable monitoring with other surveillance assets, defence forces will be able to build a resilient, multi-layered picture of the underwater domain, helping ensure that critical infrastructure remains secure in an increasingly contested environment.