The solution

The DriX used a marine broadband radio link to communicate with the RV Nautilus (and our HPT 3000) to track, position and communicate with (including providing navigation data) the Mesobot and NUI as part of our Mini-Ranger 2 Ultra-Short BaseLine USBL system.

The underwater vehicles Mesobot and NUI were fitted with our AvTrak 6 combined tracking, telemetry and control transponders. The EV Nautilus was also fitted with our Ranger 2 Gyro USBL system, which would have also be able to track, position and communicate with the Mesobot and NUI, if this had been required.

Mini-Ranger 2 is our mid-level USBL tracking system that’s also able to support communications with underwater vehicles. It can track up to 10 targets at a time, at ranges of up to 4,000 m (with an extended range option) and, with our Robotics Pack, enables command and control untethered underwater vehicles.

For the OECI team, it was this combination of communications and positioning – acomms and USBL – that offered the broadest possibilities to the mission, from a single system.

AvTrak 6 is our tracking, communications and relocation transceiver. It allows USBL aiding for your AUV from a surface vessel and robust telemetry for AUV to vessel and AUV-to-AUV communications.

Ranger 2’s Gyro USBL comes pre-calibrated, thanks to its perfectly aligned acoustic transceiver and built-in attitude and heading reference sensor (AHRS), so you don’t need to take the measurements otherwise needed to determine the alignment of the ship’s motion sensors to the acoustic transceiver.

This makes it a very a portable system that the OET can use on vessels of opportunity. On the EV Nautilus, it was fitted through the vessel’s moon pool.

The solution

L3Harris had already used our Mini-Ranger 2 for USBL aiding an iXblue Phins INS, via one of our AvTrak 6 OEM Nanos, on one of its Iver3s on a separate customer project. Read more here.

Mini-Ranger 2 is the ideal USBL system for coastal operations, supporting high-elevation tracking of up to 10 targets simultaneously down to 995 m water depth (extendable to 4,000 m), as well as data harvesting. It offers performance without the cost and complexity of a larger deep water USBL system.

At the heart of the system our HPT 3000, a highly capable surface deployed USBL transceiver which is optimized for performance in shallow water, high elevation and long lay back operating scenarios, as well data telemetry.

To provide INS aiding, L3Harris’ customer chose to integrate our AvTrak 6 OEM Nano, with a remote transducer, into their Iver3.

AvTrak 6 OEM Nano is the smallest variant of our AvTrak transceiver, designed for ease of integration on smaller underwater vehicles. It combines the functions of a transponder, transceiver and telemetry link, enabling communications, tracking and USBL aiding for subsea robotics. It’s also based on our 6G hardware platform, which means it’s interoperable with all our USBL, LBL and INS systems. This provides flexibility, but also performance enhancement, for example when combined with a Sonardyne INS.

As in the earlier project, the AvTrak 6 was programmed to speak the right language to the third-party IXBLUE Phins INS, by sending out an APOS PSIM SSB telegram, instead of our proprietary SPOS. The AvTrak 6 transducer was also supplied on a special Iver3 mounting post design, to make it easy to plug and play into the AUV – and any other Iver3, for that matter.

Mini Ranger 2 was pole-mounted to the support vessel with hemisphere GPS for topside absolute positioning.

The results

L3Harris ran a <5 km-long survey, with six 800 m legs, in challenging <20 m water depth in Narraganset Bay on the north side of Rhode Island Sound.

Real-time USBL-aiding improved the survey accuracy by upwards of 7 m on far end of survey legs through the turns. During the survey, real-time survey performance ranges up to 800m were tested with USBL position standard deviations ranging from 1 – 3 m.

In addition, using Mini-Ranger 2’s robotics pack, the L3Harris team were able to provide the vehicle with information of the acoustic environment, so its autonomy could make decisions to adjust the AvTrak 6 OEM Nano’s power and gain settings to improve acoustics without a human in the loop.

“The standard deviation on the USBL position fixes were accurate allowing real-time position updates to the INS. The ease of operation using the Mini-Ranger 2 topside to track and monitor environmental influences throughout the survey also added a layer of safety for monitoring the UUV.”

“This set up allows surveyors to meet Special Order navigation standards, which is a big deal for small unmanned underwater vehicles (UUVs),” says John Sloat, Application Engineering Lead, L3Harris. “The problem before has been that there’s not a lot of real estate inside smaller UUVs to house the onboard technology required for Special Order navigation capability in. But now they can.

“This capability adds a high level of survey efficiency by reducing the need to frequently surface for a position fix which increases the vehicles endurance, reduces the risk of vehicle entanglement or loss, and allows for larger areas to be surveyed. It also means they have real-time data vehicle positioning, which, when post-processed, could be improved even more. That’s really valuable to survey customers and we do see this as the cusp of a new UUV survey era,” adds John.

What was also hugely valuable to the L3Harris team was the support from Sonardyne’s experts.

“The level of support and service from Sonardyne has been exceptional,” says John. “We are very pleased. It’s been a fantastic experience at every phase of the integration we have done and that’s a big de-risk for us, having a partnership like this.”

The challenge

As they reach the end of their productive life, oil and gas well heads still need to be monitored whilst suspended – for up to five years, before they become fully abandoned / decommissioned. A regime must be in place to monitor the assets ‘in perpetuity’ to meet government regulations. As this is ‘abandonment expenditure’, rather than capital expenditure, any monitoring schedule must be conducted as cost effectively as possible.

Dana Petroleum (Netherlands) was faced with one such challenge in early 2023 when they needed to plan and implement a well annulus monitoring schedule for suspended wells at their Van Ghent and Van Nes subsea wells, situated in the North Sea approximately 60km West of The Hague. The wells were situated alongside others still in operation and although the topside platform remained, communication links with the sensors on the suspended subsea wells had been lost. There was an additional challenge of the system needing to be in place within 12 weeks.

The solution

The ’simple’ solution would have been to lay new communication cables from the suspended well heads to the topside platform to enable the monitoring. But this would have been lengthy, expensive and carbon intensive, involving bringing in large vessels to lay long stretches of subsea cables. A quicker, cost effective and lower carbon solution was needed. Having heard about Sonardyne’s experience and expertise in long-term subsea asset monitoring, Dana Petroleum approached us for a solution.

We have many years’ experience in providing subsea pressure and temperature data directly from well downhole gauges, mostly during the appraisal phase in a field development, providing essential data to the reservoir engineers before connection is made to the offshore or onshore facility.

Although Dana Petroleum’s requirement was well within our capabilities, there were some initial unknowns such as; field layout, pressure gauge model and manufacturer and how the equipment would be mounted to the subsea manifold. Also, which topside would be most suitable for data harvest? Something which is typically dictated by the vessel size, noise profile and water depth. The timeframe was also very challenging.

In the following weeks, Dana Petroleum provided information on the field layout, drawings of the subsea infrastructure and a strong specification for a system capable of monitoring the annulus pressures at both locations. Having received this, we were able to provide illustrations of previously designed bracketry, 3D CAD images of our potential offering and expert advice to work out the optimum placement to enable best line of site for data harvesting. With a firm specification and known time constraints we looked to our off-the-shelf products with a view to creating a semi-custom solution with our projects team.

The obvious choice was to make custom alterations to our Autonomous monitoring transponder (AMT). The AMT has been used in a wide variety of different applications including overburden monitoring and pipeline movement monitoring, all utilising and autonomously logging pressure sensor data. These solutions can operate autonomously over long periods of time, over five years – depending on deployment – logging data and making it accessible for wireless upload.

The topside platform of choice was a Nano topside equipped with a ruggedised laptop running Sonardyne’s Monitor software fitted to a small crew transfer vessel that would pass by the wells at regular intervals, delivering workers to the platforms. The size of the vessel dictated a small portable solution but other options are available for all sizes of vessels.

Once the seabed and topside products were selected, custom modifications were made by the projects team to the AMT, allowing the pressure sensor to be connected to the annulus via a flange – rather than inside the AMT –to give flexibility in the location of the AMT and achieve best line of communication with the Nano transceiver when it passed overhead.

A factory acceptance test was witnessed by Dana Petroleum where our projects team provided documentation and coordinated the testing. Following this the equipment was shipped and ready for installation – all within a few months!

The challenge

Without surface platforms, acoustic data from the subsea sensors had to be harvested by crewed vessels in the early years of the field’s operation. This was costly, carbon heavy and posed a risk to personnel in often challenging sea conditions.

With a company ‘Powering Progress’ strategy to achieve net-zero emissions by 2050, Shell was looking for an alternative data harvest method that would reduce cost and risk as well as its carbon footprint.

The solution

Marine robotic platforms provide the opportunity to remove carbon and personnel risk. Working with the customer and XOCEAN as a sub-contractor we developed a solution that would save time, costs. and carbon, while also eliminating the human risk element, using a USV to conduct the data harvest.

The proposal was to use our HPT 3000 transceiver mounted to an XOCEAN USV to remotely harvest data from the 75 seabed PMTs. The HPT 3000 is perfect in terms of size, weight and power for deployment from a USV and can communicate with seabed transponders at depths up to 995 m (or 4,000 m with an extended range version).

XOCEAN USVs are perfect for the data harvesting mission at Ormen Lange. They enable full over-the-horizon 24/7 operations. This means that operators and data analysts can remain safely onshore whilst the operation takes place and data can be sent ashore and verified in near real-time using the USV’s satellite communications.

This satisfied Shell’s commitment to accelerate the transition of their business to net-zero emissions and to integrate sustainability within their business strategy. Following the successful PMT installation in 2019, a five year project was agreed where Sonardyne are responsible for the data delivery to Shell and XOCEAN are responsible for delivering the transceiver to the field for data collection via their USV.

The results

The project began in January 2020 and this was the first time a remote USV data harvest was completed offshore in Norwegian waters by any operator.

Whilst the USV and HPT 3000 were in Norwegian waters surveying the Ormen Lange site, the Sonardyne and XOCEAN personnel never left their bases in England and Ireland.

The data harvest was monitored in real time, 24/7 and the two teams were in contact with each other as well as the remote equipment. This mean that data was being monitored by our team as it was collected and there was no risk of the USV returning with missing or irrelevant data. Had there been any missed or partially collected data the Sonardyne team could ask the XOCEAN team to return to recollect from a particular PMT whilst still in the field, rather than waiting until the vessel returned and having to send it out again.

Successful data harvests have been conducted yearly since 2020 and continue to be a cost effective, low impact operation. This year we collected data from the Ormen Lange site twice, in Spring and Autumn.

If you think you have a similar challenge for us, contact us today.

The technology

The fleet-level autonomy engine developed by Royal Holloway, University of London served as the mission’s central nervous system, making real-time decisions and replanning when necessary due to factors such as inaccurate mission execution, vehicle faults, changes in the operating environment or the addition and removal of stations. The division of labour enabled by this approach showed significant promise in productivity gains made possible by robotics and AI.

The SoAR Communications Backbone, developed and released by the team at the NOC, acted as a central messaging system which enabled interoperability between the fleet-level autonomy engine, each vehicle-specific command and control system and any other sub-system requiring bi-directional communication. This was key to allowing the seamless introduction of different platforms and sub-systems in diverse combinations to suit a wide range of mission objectives.

We provided inter-medium communications via our AvTrak 6 Nano acoustic transceivers fitted to each AUV. This enabled simultaneous USBL tracking via a surface vessel and robust telemetry for AUV-to-vessel and AUV-to-AUV communications.

A small swarm of four ecoSUB AUVs, each fitted with an AvTrak 6 Nano acoustic transceiver, played a crucial role in rapidly assessing the underwater environment and conducting preliminary evaluations to identify targets of interest.

An Auto-Hover 1 (AH1) AUV, owned and operated by NOC, capable of exceptional precision in maintaining station and navigating vertically within the water column, and fitted with an AvTrak transceiver, was dedicated to close inspection tasks, enabling intricate and comprehensive examination of identified targets.

Our HydroSurv REAV-60 uncrewed surface vessel ‘Decibel’ assumed a pivotal role, serving as a crucial communications gateway to and from the AUV swarm. It was fitted with an HPT 3000 transceiver and ran our well-established Ranger-2 software on its topside, facilitating inter-medium communication and providing navigation support to the AUVs. Decibel was also equipped with various communications devices including 4G/LTE and Iridium satellite communication systems to enable communications between subsea, surface and the Autonomy Engine.

The deployed SoAR fleet was managed and controlled from HydroSurv’s shore-based Remote Operations Centre in Exeter, using 4G/LTE and Iridium communications.

The results

The open-water trials successfully showcased co-ordinated missions designed, monitored and adapted in real-time by an intelligent “Autonomy Engine”. The trials involved several surface and underwater autonomous systems, with mission management conducted from a remote shore-based command and control facility.

SoAR has led to the introduction of several technological innovations, including advanced AI-driven mission planning, open-source communications protocols for heterogenous fleet coordination and a range of new and enhanced platform capabilities for both surface and sub-surface systems. The variety of small form factor robotic platforms involved in the project represented some of the best innovation in UK ocean robotics to date.

The SoAR concept is adaptable to various applications but strategically tailored to address the specific needs of the offshore wind sector, developing an approach that will offer new operating paradigms and substantial long term cost savings for offshore asset construction and maintenance compared to conventional methods.

SoAR received funding from the ‘Next Generation Subsea Technologies’ competition, a joint initiative supported by Innovate UK, the Net Zero Technology Centre and the Royal Navy.

However, despite their importance, locating and monitoring seagrass beds using traditional methods, such as survey boats, presents significant challenges. Seagrass typically grows in shallow waters, which can make it difficult for boats to navigate close enough to the shore to obtain accurate data. Traditional survey boats are often large and cumbersome, making them hard to manoeuvre in shallow or rocky areas. This limitation can result in incomplete or inaccurate assessments of seagrass distribution and health.

Furthermore, the process of using boats for surveying can be time-consuming and labour-intensive. It often requires multiple trips and extensive manual labour to map out the seagrass beds accurately. The visibility in shallow waters can also be poor due to water turbidity, further complicating the survey efforts and leading to potential underestimation of seagrass coverage.

Finding a solution…

This is where Sonardyne and Wavefront Systems come in. The solution, which combines Sonardyne and Wavefront technology, is a survey boat carrying Solstice MAS™ (Multi-Aperture Sonar) as well as a SPRINT-Nav Mini mounted to a pole, deployed over the side of the boat; this maps the chosen area in 200 m wide strips. Once this survey has been completed, the sonar data that has been captured is then processed to create a map of the seagrass in a GIS. A Remotely Operated Vehicle (ROV) is then sent to the same area to ground truth features on the seabed to check that they are how they have been interpreted by Solstice MAS. The ROV is fitted with SPRINT-Nav Mini, allowing us to track its position underwater and guide it, using the map, to the features identified by Solstice; the ROV is also fitted with a camera and the recorded video can be used to create 3D models of the seabed.

Wavefront Systems’ Solstice MAS uses sound signals to produce high-quality images of the seabed, capable of creating images 200 metres wide at high resolution even in shallow water environments, all while consuming very little power. The Solstice family of sonars are built on unique MAS technology and are designed to fill the gap between standard side scan sonars, which are typically simple in design but give low image resolution, and Synthetic Aperture Sonars (SAS), which are expensive, more susceptible to complete data loss due to platform movement and also produce vast amounts of data. In order to execute more detailed mapping, Solstice MAS requires a high quality navigation sensor, which in this case is SPRINT-Nav Mini.

SPRINT-Nav Mini is an all-in-one vehicle guidance and navigation instrument, which combines AHRS data, Doppler Velocity Logger (DVL), Inertial Navigation System (INS) and depth sensor into a single housing. Having SPRINT-Nav Mini fitted onto the ROV provides positioning input, as well as attitude and heading data.

Adopting these technologies on such small versatile platforms opens the possibility of high-grade survey data in shallow waters. As a result of the cross Covelya Group collaboration between Sonardyne and Wavefront Systems, a high-definition map of seagrass beds can be created with a greater degree of accuracy than was previously possible with more traditional methods.

A seagrass restoration project conducted by the Ocean Conservation Trust (OCT) in Plymouth Sound, which involves monitoring, conserving and expanding the existing seagrass beds can be enhanced with the use of an ROV which has SPRINT-Nav Mini fitted to it. To help grow the existing seagrass beds, the OCT are placing seagrass mats on the seabed in Plymouth Sound. A survey boat fitted with Solstice and SPRINT-Nav Mini followed by an ROV fitted with SPRINT-Nav Mini can then be used to monitor and create a map of where these mats have been placed so that they have a better understanding of the success of the restoration and expansion project.

What is possible

Ranger 2 comes with an impressive list of features including our award-winning 6G (sixth generation) acoustic hardware platform and Sonardyne Wideband 2 digital signal architecture. It provides stable and repeatable acoustic position referencing for your ship’s DP system, including those from GE, Kongsberg, MT, Navis, Thrustmaster and Wärtsilä.

As your needs grow and become more complex, bolt-on software packs unlock additional capability and protect your investment. Take the DP pack and enable your acoustic ranging to be aided by our inertial navigation technology (DP-INS). Add the robotics pack and commanding a swarm of up to 99 AUVs is at your fingertips.

Ranger 2 can do even more, it also supports robust two-way data telemetry, allowing you to control our range of seafloor deployed, long-endurance sensors and recover your all-important data.

Track everything, in any depth, from any vessel

Why choose it?

• Tracks multiple targets to 11 km;
• Compatible with all makes of DP system – GE, Kongsberg, MT
• System accuracy: when fully optimised it will deliver 0.04% of slant range
• Works with a global inventory of pre-deployed Sonardyne 6G hardware
• Configurations available for USV and temporary vessel installations
• Valuable features included as standard
• Bolt-on packs available for growth with your operations and ambitions
• Developed and supported by a company with over 50 years of experience in innovative underwater technology

The kit

Transceivers

Our High Performance Transceiver (HPT), is available in a range of different designs to suit your operations whether they are in deep or shallow water or over a long layback.

HPT 5000 / 7000 are acoustic and telemetry transceivers designed for use with Ranger 2 USBL system. HPT 5000 enables targets to be tracked over a wide range of water depths; HPT 7000 is optimised for noisy DP drilling or construction vessels and in deep water.

HPT 5000 offers full hemispherical acoustic coverage so is a popular choice for tracking multiple targets (ROVs, AUVs, towfish, seafloor sensors) over a wide range of depths and elevations. The unit is also suitable for dynamic positioning reference on survey, research and offshore support vessels.

HPT 7000 is engineered for ultra-deepwater operations, tracking targets far below (rather than to the side of) a vessel, and for high vessel noise operating environments such as those typical of DP, drilling and construction where activity from thrusters is liable to cause signal interference.

If you need a solution for a vessel of opportunity, our pre-calibrated, all-in-one Gyro USBL transceiver is perfect. Lighter, smaller and just as capable, our second-generation Gyro USBL transceiver works seamlessly with Ranger 2 to track the position of your subsea targets from a USV, vessel of opportunity or from a pipelay vessel’s stinger over extreme ranges.

• All-in-one instrument; combined 6G acoustic transceiver and AHRS
• Choose between standard or ‘plus’ variants to suit your project’s specifications
• Optimises the performance of Ranger 2; eliminates lever arm offsets, pole bending and ship flexing errors
• Calibrated in-water before delivery – saving you time; install it and go to work

Transponders

The flexibility of the Ranger 2 family is further extended by our range of transponders to support a wide variety of your operations. WMT is a high-power transponder capable of operations to 7,000 m, while AvTrak 6 is our most capable acoustic vehicle instrument, combining the functions of a USBL transponder, LBL transceiver and modem for demanding applications such as AUV command and control.

How it works

Combining our cutting-edge 6G acoustic transceiver with a high-performance AHRS, Gyro USBL eliminates the lever arm offsets, pole bending and ship flexing errors common in traditional USBL systems. Its compact, corrosion-resistant design ensures durability in any marine environment.

Upgrade your operations today

Discover how Gyro USBL can revolutionise your subsea projects. Contact us to learn more about this groundbreaking technology.

What is GNSS-A?

GNSS-A works by combining satellite positioning with underwater acoustics to track seafloor movement with centimetre-level accuracy. An uncrewed surface vessel (USV) with Sonardyne’s GNSS-A payload patrols above an array of Sonardyne Fetch transponders on the seabed.

Combining its known surface position with acoustic pulses down to each Fetch transponder allows it to calculate the precise position of each transponder – and therefore the position of the seabed it’s sitting on.

By repeating these measurements over time, scientists can track the movement of tectonic plates across faults to better understand and estimate earthquake and tsunami hazard.

One of the organisations using this technique to monitor subduction zones, where one plate is sliding under another, is the USGS.

They first started exploring its use in 2017, working in collaboration with the University of Hawaii and Scripps, and using a Wave Glider and seabed sensors, in order to measure how friction between two tectonic plates restricts sliding and causes a build-up of stress – essentially measuring “how stuck are the plates”.

Since then, they’ve continued to contribute to the development of GNSS-A using Sonardyne GNSS-A modules and Fetch transponders.

Critical insights from the Aleutian subduction zone

One of the tectonic sources of large earthquakes that USGS has been monitoring is the Aleutian Subduction Zone. It was here that the Chignik earthquake struck – and USGS was ready for a post-earthquake response mission.

Just a couple of years before, three GNSS-A monitoring sites had been set up on the seafloor off Alaska, in the Aleutian subduction zone, by a team of scientists funded by US National Science Foundation (NSF).

Several Wave Glider surveys had been carried by the USGS and Scripps prior to the M8.2 Chignik earthquake, monitoring the position of the sites in about 1,200 m water depth.

Within weeks of the earthquake, USGS had their Wave Glider back out to measure what movement there had been during and shortly after the earthquake.

Despite challenging weather conditions, the mission collected high-fidelity GNSS and acoustic data with eye-opening results.

“The tsunami was modest, but the seismic event was the largest in the US for nearly six decades,” says Ericksen, “so we expected a large movement. But it was incredible to know exactly how much – and that was 1.4 m.” This was a critical insight into the co- and post-seismic movement, helping to understand subduction zone dynamics.”

The big question was, did the Chignik earthquake increase the state of stress and tsunami potential on the up-dip portion of the fault or not?

“The measurements showed that the fault moved 2 – 3 m horizontally in a shallow part of the fault, less than 20 km below the seabed, helping us to understand how stress builds up along the fault and is released in an earthquake,” he says

“These results suggested that the cumulative slip had relieved stress on the shallow portion of the fault and therefore, the Chignik earthquake likely did not increase tsunami potential of the shallow fault.

“It also showed the effectiveness of the GNSS-A technique and the utility of rapid response GNSS-A measurements to better assess tsunami and earthquake hazards in the region.”

Read more about the Chignik data here.

The origins of GNSS-A

The ability to measure the movement of plates on the seabed is not that new. It’s based on what was originally called the GNSS-A technique, first developed by Scripps, specifically David Chadwell and Fred Spiess.

“Combining GNSS positioning and acoustic measurements to track seabed movement was a clever idea – and it worked,” says Michelle Barnett, Ocean Science Business Development Manager, at Sonardyne.

“But the cost of using crewed ships to do the positioning made it cost prohibitive. It was also technically challenging.”

“So, working with Scripps, in the early 2010s, we developed a combination of our Fetch long-life sensors and an off-the-shelf GNSS-A payload for Wave Gliders that can go out and do the survey work at a much lower cost than using a crewed ship.”

Worth the wait, even when waiting on weather

The technique is not without its challenges, however. After gathering the positions of the Aleutian subduction zone transponders, Ericksen and his team were naturally keen to see the data.

Due to the significant amounts of data involved – we’re talking 25-30 GB per site (comprising three Fetch) – only sub-samples are sent back to shore from the USV, primarily for quality control.

So, they have to wait until the USV comes back – or is brought back – to shore. Low levels of daylight in the Alaskan winter (when the Chignik survey was carried out) meant limited power availability for the USV.

Combined with bad weather, coordinating its recovery proved challenging, resulting in it taking four-months to recover the Wave Glider and offload the data.

Still, the wait was worthwhile and the results are providing greater insights than we’ve ever had before.

Read more

Sonardyne technology chosen for new Canadian seabed observatory.

TL;DR:

Scientists can now monitor underwater earthquake zones using GNSS-A technology—combining satellite positioning with acoustic sensors on the seabed. This breakthrough, developed through collaboration between Sonardyne, Scripps Institution of Oceanography, and the USGS, allows them to track how tectonic plates move and where stress is building up, which was previously a “blind spot” beneath the ocean.

The technology: Sonardyne’s Fetch transponders sit on the seabed in arrays, while Wave Glider robots equipped with Sonardyne’s GNSS-A payload circle above them, using acoustic signals to precisely measure their positions over time. This makes continuous offshore monitoring both feasible and cost-effective for the first time.

Australian vessel operator Tenggara Explorer wanted to see if there was another way. Could DP-level control for ROV-follow capability be achieved on a non-DP class workboat?

Together, maritime autonomy and AI specialist Greenroom Robotics, ourselves and Unique Group equipped the 34 m-long Tenggara Explorer multipurpose vessel with integrated DP-level control and USBL for ROV-follow capability for their client’s medium-size inspection-class ROVs (with the capability to attach the Sonardyne transponder to any unit).

The Solution

The core of the solution was the integration of two key systems, Greenroom Robotics’ autonomy software, GAMA and our Mini-Ranger 2 USBL system.

Greenroom Robotics’ GAMA

GAMA is advanced autonomy software that is hardware agnostic and can be retrofitted to existing vessels to enable remote, hybrid and autonomous control.

GAMA’s Dynamic Predictive Control (DP-C) independently controls thrusters, propellers and rudders using sensor feedback and control algorithms to counter wind, waves and current. This provides DP-level control to smaller more agile workboats, like Tenggara Explorer enabling precision positioning.

As a result, survey teams on smaller vessels can execute complex manoeuvres and survey patterns with high precision, at day rates around 80% less than a DP-class vessel, and with lower risk than manual precision control.

Mini-Ranger 2 USBL

Our industry-leading Mini-Ranger 2 USBL system is engineered for high-performance tracking of underwater targets from surface vessels in shallow waters and coastal environments, providing stable and reliable tracking, even in challenging sea conditions.

It’s lightweight and portable, making it easy to integrate into smaller vessels, even including smaller uncrewed surface vessels (USVs). Installed on the Tenggara Explorer, Mini-Ranger 2 provides the high-accuracy positioning data required to track the ROV during inspection tasks and survey work.

Crucial to successfully integrating these systems onto the Tenggara Explorer was:

• Robust platform integration: direct interfacing with helm, propulsion and auxiliary thruster systems to enable smooth, coordinated actuation.
• Sensor fusion and target tracking: combining GPS, IMU, wind, and USBL subsea positioning data to maintain stable lock on both fixed coordinates and moving underwater assets.

Unique Groups’ team was the crucial integration partner, ensuring the vessel’s complex systems worked together, enabling its transformation to DP-level control and ROV-follow capability.

The Mini-Ranger 2 was expertly integrated into the vessel along with human machine interfaces and GAMA and Sonardyne displays into pre-existing Simrad units on the Bridge. This was followed with extensive in-water testing and performance verification and calibration.

Through this work, Unique Group enabled GAMA to perform critical autonomous functions, including precise ROV following, station-keeping and survey line tracking off Australia’s West Coast.

The Results

Our collaboration with Tenggara Explorer demonstrates how high-precision station-keeping and target-following can be done without the DP price tag. With the integration of GAMA and Mini-Ranger 2, the vessel is proving its ability to deliver DP-level capability, including ROV-follow operations.

Kai Lebens, Director and Operations Manager, at Tenggara Explorer:

“What stood out most was the stability during ROV/AUV following. We consistently held position and heading within DP-equivalent tolerances, even in variable wind and swell, while following a moving subsea target through USBL updates. The feel is ‘DP-like’ – the helm simply stayed where it needed to be, without the constant micro-corrections they were used to.

With GAMA managing fine vessel motion, bridge teams can maintain higher vigilance and focus on project oversight, data quality and safety. It’s also an advancement on the autonomy roadmap – helping to unlock the benefits of autonomy, alongside DP-level control.”

Peter Baker, General Manager of Growth, at Greenroom Robotics:

“Mini-Ranger 2 provided the reliability and fidelity needed for predictive tracking. It provides high update rates, dependable accuracy and stable performance in the shallow-to-midwater environments typical of survey and inspection work.

“That consistency is essential as the autonomy needs trustworthy subsea positioning to predict vessel motion relative to the ROV/AUV. Sonardyne effectively gave us the ‘subsea truth source’ that GAMA’s Dynamic Predictive Control depends on.”

Aidan Thorn, Marine Robotics Business Development Manager at Sonardyne:

“For vessel operators like Tenggara Explorer, it means new mission types – allowing them to use their existing workboat to take on tasks that historically required a DP-class vessel, unlocking a broader variety, and potentially higher-value, jobs.”

“Unique Groups’ integration work was the linchpin that allowed the Tenggara Explorer to fully leverage the GAMA package and Mini-Ranger 2’s capabilities, enhancing operational efficiency and safety while reducing environmental risk,” adds Lebens (at Tenggara Explorer). “Their contribution was fundamental to the success of this project.”