On the far south-west coast of the UK, Plymouth has long been shaped by the sea. That same sea has also helped to shape marine technology.

We know it well. Plymouth Sound has been an ideal trials site since the company’s early days. We opened a permanent base at Turnchapel in 1982, with two survey and trials vessels operating out of Mayflower Marina, trialing our and others’ technologies in real-world conditions.

This year has been no different. In the first half of the year we’ve welcomed many customers and partners to our facilities to trial new technologies, systems and integrations, helping to push marine technology to the next level.

That’s all been alongside a constant throughput of Long BaseLine (LBL), Ultra-Short BaseLine (USBL) and related training in our recently upgraded training suite at Turnchapel (overlooking Plymouth Yacht Haven).

We’re also a key part of Smart Sound Plymouth’s Smart Sound Connect Subsurface (SSCS), which we helped put to the test earlier this year through a multi-organisation and supplier robotics demonstration.

We like to see this all as part of Plymouth’s role as a centre for marine science, autonomy and underwater technology, building on its naval and maritime heritage.

To find out more about some of this year’s demonstrations, read on.

Dynamic positioning resilience

Dynamic positioning resilience has also been a strong theme in Plymouth this year, as vessel operators look for ways to maintain trusted positioning when GNSS is unavailable, degraded or untrusted.

One demonstration, carried out aboard Sonardyne’s Sound Surveyor from Mayflower Marina, brought together Guidance Marine, Sonardyne and Veripos to test a resilient, multi-sensor DP reference architecture in real-world conditions. The set-up included Guidance Marine radar positioning technology, Sonardyne’s SPRINT-Nav DP navigation reference, Ranger 2 USBL acoustic positioning and Veripos LD900 GNSS positioning with INS capability.

The trial showed how independent radar, inertial, acoustic and GNSS references can work together within a single DP architecture. It also demonstrated different routes to non-GNSS initialisation of SPRINT-Nav DP, including use of Ranger 2 USBL with a pre-calibrated seabed transponder to establish vessel position independent of satellite signals, and radar-based positioning from Guidance Marine as an alternative absolute position source.

That matters because resilient DP is not about one sensor replacing another. It is about giving operators multiple independent references that can be combined as conditions change, helping maintain confidence in vessel positioning when satellite signals are challenged.

In a separate trial, Navis Engineering conducted live validation trials in Plymouth Sound aboard Sonardyne’s Echo Explorer, working with Sonardyne’s SPRINT-Nav DP and Furlong Sensing’s Unity position reference sensor. That mission stress-tested emerging sonar- and laser-based positioning technologies against live currents, dynamic vessel motion and variable weather, generating operational data to support their safe use within the Navis DP ecosystem.

For offshore vessels, those kinds of trials are increasingly important as the industry pays closer attention to the risks of GNSS jamming, spoofing or signal loss.

Demonstrating capability

Some of this year’s activity has also been about bringing people closer to the systems themselves: not just showing what the technology can do on paper, but putting it into live operating scenarios where customers, partners and technical teams can see how it behaves in the water.

That has included SPRINT-Nav DP and Fusion 2 demonstrations and hands-on training, giving visitors the opportunity to work through real use cases and understand how our navigation, positioning and software capabilities come together in practice. Plymouth is well suited to that kind of work because it allows a system to move quickly from classroom explanation or workshop set-up to a live vessel environment.

Nothing beats hands-on user experience in real-word settings. This is why our training is so valuable to our attendees.

It has also provided a useful setting for wider capability demonstrations around marine security and critical national infrastructure protection. Alongside Sonardyne’s own underwater positioning, communications and navigation technologies, we have been able to demonstrate complementary systems such as Sentinel Intruder Detection Sonar, part of Kraken Robotic’s Sonar Systems portfolio.

As with the DP and autonomy trials, the value comes from testing capability in the real environment. Plymouth gives us and our partners a place to demonstrate systems, gather feedback, refine integrations and build confidence before technologies are deployed in more operational settings.

Smart Sound Connect Subsurface

A major focus this year has been another test site we’ve been instrumental in delivering and also putting to use. Smart Sound Connect Subsurface (SSCS), part of Smart Sound Plymouth. Led by the University of Plymouth with Plymouth Marine Laboratory, and delivered by Sonardyne, the SSCS extends the area’s existing surface trials capability below the waterline.

At its heart is a seabed node array that provides underwater positioning and acoustic communications, helping autonomous underwater vehicles and other subsea systems navigate, communicate and operate in a characterised real-world environment without relying on GNSS.

The infrastructure also includes a permanently deployed Sonardyne Origin 600 acoustic Doppler current profiler (ADCP), providing environmental data such as currents, with data links back to shore through existing oceanographic monitoring infrastructure.

Learn more about Smart Sound Connect Subsurface here.

Early ecoSUB trials

Earlier this year, we supported ecoSUB Robotics in trials of passive USBL navigation for small AUVs. The work used the SSCS seabed infrastructure to provide position aiding from below the surface, rather than relying solely on a surface USBL transceiver.

The seabed nodes at the SSCS include a Compatt 6 co-located with a passive USBL system, while an ecoSUB AUV carried a Nano transponder. Bearing information was passed back via Compatt, enabling the vehicle to calculate its own position.

It is the kind of lower-logistics, seabed-mounted aided navigation that could help small AUVs launch, localise and operate with less dependence on surface assets — and it helped build towards June’s Smart Sound Connect Subsurface demonstration.

Multi-robot demonstration

In June, the SSCS completed its first major demonstration with a live multi-robot trial in Plymouth Sound. The event brought together platforms from ACUA Ocean, ecoSUB Robotics and Seaber.

The University of Plymouth’s Seaber AUV and an ecoSUB AUV navigated using the seabed node array. At the surface, ACUA Ocean’s PIONEER uncrewed surface vessel tracked and controlled an ecoSUB AUV using one of our Ranger 2 Gyro USBL systems installed on the USV.

The PIONEER USV also wirelessly harvested data from the Origin 600 ADCP at the site, while Marine AI demonstrated continued navigation when GNSS drops out using Sonardyne’s SPRINT-Nav. Together, it showed surface and subsea platforms, seabed infrastructure, environmental sensors and shore-based monitoring working as one connected system.

Sonardyne’s training and trials facilities in Plymouth

Behind those trials is a mix of Sonardyne-owned capability and wider Smart Sound infrastructure. Sonardyne’s Plymouth capability starts with our own long-established base at Pier House, Turnchapel.

Here we have offices, training rooms, workshops and practical support space for trials, testing and customer training. That shore base is supported by experienced local engineers and access to our vessel fleet at Mayflower Marina.

Those vessels are an important part of the facility. Echo Explorer is a 12 m commercial catamaran and survey, trials and training vessel, MCA-classified for charter operations out to 60 nautical miles, day or night.

She has a large interior, generous back deck, moonpools and a remotely controlled crane to support safe deployment and recovery of subsea equipment, underwater vehicles and autonomous surface vessels.

Sound Surveyor is also a 12 m vessel and is similarly coded for operations out to 60 nautical miles, 24 hours a day. She is used for subsea instrumentation deployments, surveys, diver-supported work, autonomous underwater vehicle operations and rehearsing more complex offshore projects.

We also have Decibel, a long-endurance, hybrid-powered uncrewed surface vessel (USV), for trials and testing.

Together these facilities allow us and our partners to put technology through its paces in a real-world, but fully supported environment.

Smart Sound Plymouth and Smart Sound Connect Subsurface

Smart Sound Plymouth and Smart Sound Connect Subsurface are different but complementary. They are part of the wider Plymouth marine technology ecosystem, led by the University of Plymouth and Plymouth Marine Laboratory.

Smart Sound provides the authorised, characterised and deconflicted trials environment, while Smart Sound Connect Subsurface extends that capability below the surface through seabed nodes, acoustic communications, positioning infrastructure and environmental sensing.

Sonardyne’s role in Smart Sound Connect Subsurface is as delivery partner and technology provider. We supplied and delivered the subsea acoustic positioning and communications infrastructure, including the seabed node array and Origin 600 ADCP.

Combined with our own shore base, vessels, people and equipment, that creates a powerful local capability: a place where systems can be prepared, deployed, tested, demonstrated, recovered and refined in real operating conditions.

Prove it in Plymouth

This year’s activity shows the value of having a trials facility embedded in a wider marine technology ecosystem. The early ecoSUB work showed how seabed-based acoustic infrastructure can support small AUV navigation with less reliance on surface assets.

The multi-robot demonstration showed connected surface and subsea systems working together in Plymouth Sound. The DP trials showed how vessel operators can test new ways to maintain safe positioning when traditional inputs are challenged.

Together, they point to a future where marine operations are more connected, collaborative and autonomous.

To get there, companies need places where systems can be tested honestly, in the water, with all the complexity that brings.

For Sonardyne and our partners, Plymouth is one of those places: a base for learning quickly, reducing risk and turning promising technology into trusted operational capability.