The Plymouth Breakwater
Plymouth is set to become home to a real-world testing and demonstration environment that will significantly boost what the city can offer businesses and researchers in underwater innovation, marine autonomy and ocean sensing.
Smart Sound Connect Subsurface (SSCS) extends the existing capabilities offered by Smart Sound Plymouth – the UK's premier marine autonomy testbed – and the Western Channel Observatory beneath the ocean surface.
Through an array of nodes positioned on the seabed, the SSCS system enables real-time tracking and telemetry for deployed payloads, autonomous platforms, and subsea technologies.
This will allow scientists and businesses to conduct trials of navigation, communication, sensing, and data transfer systems under operational marine conditions.
The new system also endeavours to serve as an early step towards permanent subsea infrastructure capable of overcoming the persistent challenges in underwater technology, namely knowing exactly where something is and communicating with it without a physical cable.
The development of SSCS has been achieved through a three-year £1.2million project led by the University of Plymouth in partnership with Plymouth Marine Laboratory (PML), and delivered by underwater technology and engineering company Sonardyne.
It combines the organisations’ expertise in developing, deploying and operating novel marine technologies to deliver real-world ocean intelligence.
It also enhances the city’s reputation as a global leader in marine autonomous systems, something evidenced through its recent designation as the UK’s National Centre for Marine Autonomy.
Aaron Barrett and Dr Lilian Lieber, from the University of Plymouth, preparing to deploy one of the University's Seaber devices during a demonstration event for Smart Sound Connect Subsurface (SSCS) in June 2026

SSCS provides a unique opportunity to test new ocean observing technologies.

For me, its value lies in turning prototypes and field-tested technologies into trusted data streams, accelerating ocean observing towards autonomous sensing and near-real-time insight. This helps turn ocean data into actionable intelligence for climate resilience, early warning and preparedness, while the infrastructure itself enables technology innovation and stronger industry collaboration.

Lilian LieberDr Lilian Lieber
Senior Research Fellow

SSCS is about building the infrastructure needed to locate, track and connect subsea technologies in the real world.

One of the persistent challenges in underwater technology is knowing exactly where something is and communicating with it without a physical cable. SSCS is an early step towards permanent subsea infrastructure capable of addressing both challenges. It is, in ambition, the subsea equivalent of moving from a chart, compass and VHF radio towards a GNSS satellite constellation and 5G network. There is much that can already be trialled, and the lessons learned will help shape bigger and better capabilities in the future.

Aaron BarrettMr Aaron Barrett
Lecturer in Autonomy

Smart Sound Plymouth is going from strength to strength. The addition of the subsurface network enables even greater integration between platforms and supports our state-of-the-art testing capabilities for autonomous vehicles and advanced technologies. It complements the high speed military-encrypted network above the surface and helps provide a fully connected environment. This successful technology demonstration further reflects Plymouth’s place as a world-leading hub for marine autonomy.

Professor James Fishwick
Head of Innovation for Smart Sound Plymouth (Plymouth Marine Laboratory)

Showcasing the network through a multi-robot demo

The first major test of Smart Sound Connect Subsurface (SSCS) was completed during a live, multi-marine surface and subsea robotic platform demonstration.
A key element of SSCS is the seabed node array, which provides absolute positioning and communications using passive Ultra-Short BaseLine (USBL) technology for testing underwater systems in a real-world highly characterised testing environment.
During the demonstration, the University’s Seaber autonomous underwater vehicles (AUVs) navigated using only the seabed node array.
At the surface, a PIONEER uncrewed surface vessel (USV) from Plymouth-based ACUA Ocean tracked and controlled an AUV from Southampton-based ecoSUB using a Sonardyne Ranger 2 Gyro USBL positioning system on the USV.
The USV also wirelessly harvested data from a permanently deployed Sonardyne Origin 600 acoustic Doppler current profiler (ADCP) in the SSCS, which also transmits real-time data to shore – and a live internet feed as part of the Western Channel Observatory – via the long-running L4 oceanographic monitoring station.
In addition, marine software engineering firm Marine AI showed the ability to continue navigating, even when GNSS drops out, using Sonardyne’s SPRINT-Nav, based on trials in the SSCS earlier this year.
The first major test of Smart Sound Connect Subsurface (SSCS) was completed during a live, multi-marine surface and subsea robotic platform demonstration - it was viewed live by guests from the UK and overseas from within the onshore remote operations centre at Plymouth Marine Laboratory (PML)
The demonstrations were viewed live by guests from the UK and overseas from within PML’s onshore remote operations centre

“This ability to test and accelerate marine autonomous system innovation in a known environment with the type of infrastructure we now have in the SSCS is a real boost not just for Plymouth. The demonstration had interest from around the UK and internationally, with visitors from North America and Asia and from a wide range of stakeholders, military, commercial, science and industry. It just shows the reputation Plymouth now has and continues to build for marine autonomy, thanks to the environment, ecosystem and collaboration we have in the city and on the sound.

Geraint West
Business Development Advisor at Sonardyne

Work with us

The Smart Sound Connect Subsurface team is currently seeking additional R&D partners to collaborate in further trials of the SSCS testing environment. 
Whether your interest is in testing new subsea vehicle operations, underwater data telemetry or any other use of the novel infrastructure, please contact Mr Aaron Barrett to discuss how your organisation can join this pioneering marine technology project.
Aaron Barrett, from the University of Plymouth, preparing to deploy one of the University's Seaber devices during a demonstration event for Smart Sound Connect Subsurface (SSCS) in June 2026