A new underwater trials site designed to accelerate UK marine autonomy and ocean sensing has completed its first major test thanks to a live, multi-marine surface and subsea robotic platform demonstration.
The Smart Sound Connect Subsurface (SSCS) project, part of Smart Sound Plymouth, led by the University of Plymouth, with Plymouth Marine Laboratory (PML), saw platforms from ACUA Ocean, ecoSUB Robotics, Seaber and Sonardyne working together above and below the surface.
The all-day collaborative demonstration enabled visitors from business, science, defence and national bodies to view the potential of the three-year, £1.2 million SSCS project.
Delivered by Sonardyne, the SSCS’ infrastructure extends Smart Sound Plymouth – already the UK’s premier marine autonomy testbed – and the Western Channel Observatory, through a seabed node array for absolute positioning and communications, alongside other intelligent sensors within a highly characterised environment.
Professor James Fishwick, head of innovation for Smart Sound Plymouth (at PML), said: “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.”
Dr Lilian Lieber, senior research fellow at the University of Plymouth, said: “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.”
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, both the University of Plymouth’s Seaber autonomous underwater vehicle (AUV) and an ecoSUB AUV navigated simultaneously 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 demonstrations were viewed live by guests from the UK and overseas from within PML’s onshore remote operations centre at its campus in Plymouth.
Geraint West, business development advisor at Sonardyne, said, “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 in Plymouth Sound.”
ACUA Ocean’s John Hunnibell, chief product officer, said, “This demonstration provided an excellent opportunity to demonstrate the persistent mission utility and seagoing characteristics of our USV Pioneer as a ‘mothership’ for nested robotics, data harvesting and data transfer at sea.
“Specifically, we used this event to demonstrate that the USV Pioneer can deliver subsea monitoring and security for critical underwater infrastructure by teaming with multi-static seabed sensor nodes.
“It was also a great way to develop our relationships with capable, credible technical partners: Sonardyne, ecoSUB, PML and the University of Plymouth in Smart Sound Plymouth.”
Iain Vincent, director and general manager at ecoSUB Robotics said, “Smart Sound and the SSCS environment has already been an extremely useful resource for ecoSUB Robotics. Most recently we have collaborated with Sonardyne on the development of a subsea AUV launch and navigation solution.
“Smart Sound provided the perfect place to test this technology, with easy access to open water, vessels and subsea nodes, and an outgoing and helpful community who support activity.”
The Smart Sound Connect Subsurface team is currently seeking additional research and development partners to collaborate in further trials of the SSCS testing environment.
It encourages anyone interested in testing new subsea vehicle operations, underwater data telemetry or any other use of the new infrastructure to contact Aaron Barrett, Lecturer in Autonomy at the University of Plymouth to learn how they can get involved.
Facts Only
* The Smart Sound Connect Subsurface (SSCS) project was a new underwater trials site for UK marine autonomy and ocean sensing.
* Platforms from ACUA Ocean, ecoSUB Robotics, Seaber, and Sonardyne collaborated during a demonstration.
* The demonstration involved platforms working above and below the surface.
* The SSCS infrastructure extends Smart Sound Plymouth and the Western Channel Observatory using a seabed node array for positioning and communications.
* The system includes other intelligent sensors in a highly characterized environment.
* Professor James Fishwick stated that the subsurface network enables greater integration between platforms and supports testing autonomous vehicles.
* Dr Lilian Lieber noted SSCS allows testing new ocean observing technologies to turn prototypes into trusted data streams for actionable intelligence.
* The seabed node array uses passive Ultra-Short BaseLine (USBL) technology for absolute positioning and communications.
* A University of Plymouth Seaber AUV and an ecoSUB AUV navigated simultaneously using the seabed node array.
* A PIONEER USV from ACUA Ocean tracked an ecoSUB AUV using a Sonardyne Ranger 2 Gyro USBL system.
* The USV harvested data from a deployed Sonardyne Origin 600 ADCP, which transmitted real-time data to shore via the L4 oceanographic monitoring station.
* Marine AI demonstrated navigation without GNSS using Sonardyne’s Sprint-Nav technology in SSCS trials.
Executive Summary
A multi-marine platform demonstration occurred at a new underwater trials site designed for UK marine autonomy and ocean sensing, called the Smart Sound Connect Subsurface (SSCS) project. The demonstration involved platforms from ACUA Ocean, ecoSUB Robotics, Seaber, and Sonardyne working together above and below the surface. This all-day event showcased the potential of the three-year, £1.2 million SSCS project to business, science, defence, and national bodies. The SSCS infrastructure extends Smart Sound Plymouth and the Western Channel Observatory via a seabed node array for positioning and communications, along with intelligent sensors in a characterized environment.
The integration of subsurface networking allows for greater platform interaction and supports testing autonomous vehicles and advanced technologies alongside high-speed surface networks. This infrastructure facilitates turning prototypes into trusted data streams, accelerating ocean observing toward autonomous sensing and real-time insight for climate resilience and early warning. The system utilized passive Ultra-Short BaseLine (USBL) technology for absolute positioning via seabed nodes. During the demonstration, an Autonomous Underwater Vehicle (AUV) from the University of Plymouth and an ecoSUB AUV navigated using the seabed node array simultaneously. A surface Uncrewed Surface Vessel (USV) tracked and controlled a subsea AUV using a Sonardyne Ranger 2 Gyro USBL positioning system. Data was harvested wirelessly from a deployed acoustic Doppler current profiler, which also transmitted real-time data ashore. Furthermore, marine software engineering firm Marine AI demonstrated navigation capabilities even when GNSS was unavailable using Sonardyne’s Sprint-Nav technology in the SSCS environment.
Full Take
The narrative centers on the tangible creation of an integrated, highly characterized testing environment—the SSCS infrastructure—as a catalyst for advancing marine autonomy and ocean sensing. The mechanism driving this development appears to be the convergence of physical infrastructure (seabed nodes) with advanced, redundant communication technologies (USBL positioning, acoustic sensors) to create a "fully connected" ecosystem capable of supporting complex autonomous operations. The shift is from isolated testing to integrated, real-world validation, moving from prototypes to actionable data streams for climate resilience and preparedness.
The pattern suggests that value accrues not just from the technology itself, but from the *interoperability* facilitated by the physical framework. The success hinges on creating an environment where disparate technologies (AUVs, USVs, surface networks, subsea sensors) can communicate reliably within a known spatial context. This infrastructure acts as a critical multiplier, turning individual technological achievements into systemic capabilities—a reputation build-up for Plymouth in marine autonomy.
The implication is that future progress in autonomous systems will be bottlenecked not by sensor capability alone, but by the robustness and connectivity of the underlying physical testbed. If this integrated infrastructure proves scalable, it establishes a new benchmark where collaborative testing environments become as valuable as the tested technology itself. The missing piece to consider is the sustainability and security implications of operating such complex, interconnected systems in operational marine environments, and whether the emphasis on rapid demonstration does not overshadow the necessary long-term regulatory and ethical frameworks required for fully autonomous sensing and data utilization.
Bridge Questions: If this infrastructure proves successful in accelerating innovation, what mechanisms must be established to ensure equitable access and prevent this capability from becoming an exclusive domain? What are the potential negative externalities associated with creating high-fidelity, real-time ocean intelligence systems that drive climate response? How should collaboration agreements evolve to govern shared data streams generated by interconnected autonomous platforms?
Sentinel — Human
This appears to be a factual report based on documented events and stakeholder statements regarding a specific scientific and industrial demonstration.