The solution

Atlantas Marine, a global supplier and operator of underwater ROVs, integrated a complete UXO detection package on a VideoRay Defender. Configured to provide robust navigation and high‑fidelity sensing within a compact, low‑logistics footprint, the system was put to the test in Portland Harbour, England.

The package:

• VideoRay Defender — compact UXO‑capable ROV

Atlantas Marine selected the Defender for its stability, power and proven use in UXO/EOD. The platform offers seven vectored thrusters, autonomous flight modes and weighs <25 kg, making it single‑person deployable and ideal for rapid mobilisation in port environments.

• ELWAVE EPULSE – TETRAPULSE — Electric‑field sensing for metallic and non‑metallic UXO

Detection was provided by subsea electric field sensor specialist ELWAVE’s EPULSE- TETRAPULSE electric‑field sensing system. Unlike magnetic sensors, EPULSE is unaffected by background ferrous clutter, allowing it to detect and classify both metallic and non‑metallic subsea targets—including those buried beneath the seabed.

Real‑time electric‑field mapping provides operators immediate situational awareness through an OWLIA software platform, fusing EPULSE and SPRINT-Nav navigation data.

• SPRINT‑Nav U — survey‑grade INS for Small ROVs

For the ability to position detection and provide georeferenced, charted results suitable for operational planning, Atlantas chose our SPRINT‑Nav U.

SPRINT-Nav U is the world’s smallest hybrid navigator for small underwater vehicles and platforms. Combining INS, DVL and a pressure sensor in one factory calibrated unit, it’s compact in size, but delivers big in terms of navigation.

With 0.1% drift specification, it provides accurate tracking over long subsea distances and, crucially, the positional accuracy required for UXO workflows.

Its embedded fibre‑optic gyro (FOG) technology is also immune to magnetic interference, making it an ideal navigator for GNSS‑denied and magnetically noisy environments.

For advanced position detection and georeferenced, charted results essential to operational planning, Atlantas selected Sonardyne’s SPRINT‑Nav U.

The Defender’s course stability and systematic coverage are improved, allowing operators to execute repeatable surveys without the risk of drifting or losing track.

For UXO, because SPRINT-Nav U’s fiber‑optic gyro (FOG) technology is immune to magnetic interference, it’s an ideal navigator for GNSS‑denied and magnetically noisy environments.

Integration

Atlantas Marine handled the mechanical and electrical integration of the sensors, mission planning, in‑water piloting and the cross‑discipline coordination required to ensure navigation, sensing and positioning data aligned seamlessly.

The results

The trial targeted an inert mine supplied by ECS Special Projects, placed on the seabed in Portland Harbour. This provided a representative operational test environment characterised by magnetic disturbance, GNSS shadowing and real‑world vessel movements.

The integrated system performed strongly across all objectives, demonstrating that inspection‑class ROVs can now achieve the accuracy and reliability required for UXO detection and localisation.

SPRINT‑Nav U+ EPULSE: A Proven UXO Localisation Workflow

“The ROV provided a stable, agile platform for the integrated payload, while the EPULSE sensor successfully detected and classified the target, generating clear electric‑field signatures even in the presence of magnetic interference,” says Richard Stanley, Pilot Leader – ROV Operations, at Atlantas Marine. “This is an environment where traditional magnetometer‑based systems would struggle.

“The ability to detect non‑metallic and buried objects proved particularly valuable, confirming the suitability of electric‑field technology for harbours and industrial seabeds.

“However, without positional accuracy, the data has limited application. This is where SPRINT-Nav comes in.

“The SPRINT‑Nav U’s navigation performance exceeded our expectations. Over a 1.776 km GNSS‑denied offshore track, the unit remained within its 0.1% drift specification, resulting in positioning differences of 0.8 m.

“The higher update rate and stability of the navigation solution, fed directly into Greensea IQ, allowed the ROV to hold lines and maintain lane keeping much more effectively, particularly in tidal conditions. That’s a key operational benefit.”

A summary of the positional performance is shown below: 

The Defender platform maintained excellent flight stability despite the compact multi‑sensor payload. Atlantas Marine’s pilots were able to re‑acquire the target consistently, reflecting both the system’s intrinsic reliability and their precise operational control.

“Overall, the exercise demonstrated that a small, rapidly deployable ROV can deliver high‑confidence detection and repeatable target positioning in a survey-grade capacity, rather than purely observation/inspection,” says Scott Macintyre, Project Engineer at Atlantas Marine. “This is thanks to the survey‑grade navigation of SPRINT-Nav U—all within the constraints of a realistic harbour environment.”

Summary and next steps

The Portland Harbour trials confirm that compact, inspection‑class ROVs are now capable of delivering high‑accuracy UXO detection and localisation.

• Sonardyne’s SPRINT‑Nav U provided accurate, drift‑controlled navigation.
• ELWAVE EPULSE/TETRAPULSE provided reliable detection of buried and non‑metallic UXO

The integrated solution offers a credible, low‑logistics alternative to larger survey platforms, reducing project cost and risk while enabling operators to work effectively in challenging marine environments.

“Atlantas Marine has translated, through their integration and piloting expertise, sensor and navigation capability into reliable field results,” says Aidan Thorn, Marine Robotics Business Development Manager. “SPRINT-Nav U and their successful integration and execution provides the foundation for future UXO workflows using compact robotic platforms.”

The findings of the Portland trials were presented at the UXO Symposium in Manchester in February 2026, with contributions from Atlantas Marine, ECS Special Projects, Sonardyne and ELWAVE.