Micro. For when good is good enough

Describing underwater ecosystems requires detailed information that can be accurately tied to specific locations. The impact of marine pests, litter, marine industries and other issues needs to be tracked over time with confidence. What’s more, the changeable nature of the sea and weather systems in coastal areas means equipment used for the assessment and monitoring of marine life, reef systems and sea fauna must be quick to deploy and simple to set up.

The challenge

Port Phillip Bay is home to a host of unique and iconic marine life and is one of the most diverse places on the planet for seaweeds and reef systems that support a diverse array of sponges and other invertebrates. It’s also shadowed by the city of Melbourne which has a growing population of nearly 5 million people and experiences particularly challenging conditions – the large embayment is exposed to strong winds and has periods of low underwater visibility.

To protect the Bay, the Victorian Department of Environment, Land, Water and Planning (DELWP) is implementing the Port Phillip Bay Environmental Management Plan 2017-2027 (EMP). The team at Fathom Pacific Pty Ltd have been tasked with carrying out studies and surveys in Port Phillip Bay to inform the decisions and recommendations made by the EMP.

To do this they need to create reliable models and maps, along with reports detailing the bay’s marine biotopes – areas that provide habitats for specific species – for the protection of the Bay to be effective. The data gathered has to be quantitative and accurately geo-referenced, and it must be gathered in increasingly cost-efficient ways.

The solution

Firsthand ecological research and environmental monitoring are key building blocks of the models and maps needed for supporting the EMP decisions. The BlueROV2 remotely operated vehicle (ROV) from Blue Robotics and a Micro-Ranger 2 USBL from Sonardyne have enabled Fathom Pacific Ltd to capture incredibly detailed HD imagery from the camera they’ve mounted on it. Importantly, the USBL tells them exactly where it was recorded. If divers and other assets are in the water, it can track them as well.

The Micro-Ranger 2 is extremely portable and easy to mobilise making it the ideal solution for small-boat coastal operations and short-notice surveys.

The MRT – the part of the system that communicates with transponders fitted to underwater targets – is so small and light, it has been mounted to the bottom of the stern diver ladder. The range and coverage of the transponder is impressive. Equally impressive are the Nano transponders, these can be strapped to the frame of the ROV or a diver’s tank without affecting balance or freedom of movement. The rechargeable battery lasts for a full day of operations.

Thanks to the instructional videos available on YouTube, the whole system was simple to install and calibrate. Once the software was set up and tested on the laptop, it was put straight to work supporting surveys throughout last winter and spring. The whole set up was often mobilised at very short notice, due to the unpredictable weather windows experienced in Port Phillip Bay.

The Micro-Ranger 2 system has accurately and consistently tracked the BlueROV2 in the bay’s shallow waters, even when it has been transecting some 50-100 m from the small MRT transceiver. This is important for the assessment of the bay’s biotopes during which images of the key structural and functional components of temperate reef and sediment biotopes are taken using the ROV mounted HD camera.

ROV transects typically operate in two modes. The first is a ‘video inspection mode’, detailing the canopy, sub-canopy, lower strata and turfing components and identifying the associated macrofaunal biodiversity. The second is a ‘still image mosaicking mode’, where fixed-altitude planar stills are taken to create biotope mosaics.

Using Micro-Ranger 2, Fathom Pacific Ltd were also able to place their analyses of reef biodiversity and biotopes into a spatial context by correlating the imagery data with real world coordinates. This means ground-truth data for biotope modelling can be provided, while also establishing biotope conditions and informing ecosystem models. Exactly the same locations can be visited time and again for future surveys.

The results

The investment in Sonardyne’s USBL technology is paying enormous dividends. Better monitoring of the Bay is enabling targeted and faster responses to issues like the spread of marine pests, loss of canopy-forming algae to urchin grazing, biodiversity loss, eutrophication, litter and impacts from marine industries. These are just some of the threats facing Port Phillip Bay’s marine systems that are now being curtailed.

Speak with one of our experts to learn how you can protect coastal environments with Sonardyne’s technology.

Underpinning the Indian Tsunami early warning system

Sonardyne Bottom Pressure Recorders (BPR) have been at the heart of the Indian Tsunami Early Warning System (ITEWS) since its establishment in 2007. Based on Sonardyne’s workhorse Compatt transponder, our BPR instrument was developed in direct response to the devastating 2004 Indian Ocean Tsunami.

The challenge

30% of India’s population (ca. 420 million) live on its 7,500 km long coast and are consequently highly vulnerable to devastating Tsunamis such as the one that occurred on 26th December 2004. This killed over 230,000 people in the Indian Ocean region, with 10,749 confirmed deaths in India and another 5,640 missing. While seismometers are an important component of Tsunami warning, only Bottom Pressure Recorders can detect the passage of an actual Tsunami. Indeed, Tsunami warnings based purely on seismic data have the potential to produce false alarms, which are costly in wasted evacuations and undermine public confidence.

The essential elements of a Tsunami Detection System (TDS) are:

1. The capability to detect a Tsunami – While a Tsunami may arrive at the coast many metres high, in open ocean they pass almost imperceptibly and may only be a few centimetres in height, although this elevation in sea-level can be maintained for as long as 20 minutes.

2. The functionality to provide this detection ashore with sufficient warning time – A Tsunami travels (in ms^-1) at roughly the square root of the depth of the water (in m) multiplied by the acceleration due to gravity (9.81ms^-1): In short, it travels faster in deeper water, so for example, in 1,000m of water it will be travelling at over 1,100 kmh^-1. In India’s case, the Andaman-Sumatra and Makran subduction zones are located within a few hours Tsunami travel time of the Indian coastline

3. High reliability in delivering the detection information ashore – BPRs, as the name implies are deployed on the seabed, so rely on robust telemetry, which has to operate even in poor weather conditions continuously 24/7/365.

The solution

The catastrophic 2004 Indian Ocean Tsunami led Sonardyne’s founder, John Partridge, to initiate development of a variant of the Compatt 5 seabed transponder to detect a Tsunami passing overhead.

With an extensive track record in the oil and gas industry, this instrument was ideal to form the heart of a TDS requiring very high reliability. Nevertheless, integration of a Digiquartz pressure sensor to enable the Compatt 5 as a BPR, required significant development. This particularly involved reduction of the power required for continuous operation on battery power. Similarly, a new transceiver with low quiescent power, capable of long endurance deployment on a surface telemetry buoy, also had to be developed.

Development was so rapid that when India’s National Institute of Ocean Technology (NIOT) in Chennai, started looking for a TDS in 2005, it was ready for competitive field trial. Sonardyne’s solution was subsequently selected in 2006, leading to deployment of operational systems in the Bay of Bengal and Arabian Sea in 2007.

In normal operation the Digiquartz pressure sensor in the BPR continuously measures water pressure and this data is stored every 15 seconds. The pressure data is then acoustically transmitted every hour to the surface, where an acoustically baffled transceiver, mounted beneath a buoy, receives this data. The buoy is linked to NIOT’s Mission Control Centre (MCC) by satellite communications, so that not only can data be transmitted ashore quickly, but also the health of the BPR is remotely monitored and, if necessary, reconfigured.

Embedded in the BPR is the National Oceanic and Atmospheric Administration’s (NOAA) Tsunami detection algorithm, which compares each measurement to the predicted pressure [Figure]. This predicted pressure uses the previous 3-hour history to take account of tide, weather and temperature variation. Should the difference between the two exceed a programmable default threshold of 3 cm for two consecutive samples, the BPR switches into Tsunami Alert Mode, which then initiates a sequence of data transmissions for the next few hours.

Sonardyne’s Wideband acoustics are central to the functioning of the system, and with the subsequent replacement of the Compatt 5 with Compatt 6, Sonardyne’s latest TDS offering is equipped with the most robust and efficient wideband acoustic telemetry available.

The results

Soon after the first batch of BPRs were deployed, on the 12^th September 2007, the system detected its first Tsunami, which was triggered by an 8.2 magnitude event off the coast of Sumatra at 04° 30’ S 101° 18’ E. How the Tsunami generated was tracked across three of the Indian Tsunami Buoys (ITB) is shown in the gallery.

Located between 1,760 – 2,300 km away, all three stations recorded the seismic ground wave arrival between 7 – 12 mins after the event started. Between 2 – 3 hrs later, the wave itself, which was less than 10 cm in height, passed over the three BPRs, indicating that it had travelled at between 740 – 800 km/h over this period.

Today, Sonardyne’s TDS continues to deliver bottom pressure and event data to NIOT, which is responsible for delivering sea-level data to the Indian Tsunami Early Warning Center (ITEWC) at the Indian National Centre for Ocean Information Sciences (INCOIS) in Hyderabad. In 2014, NIOT reported that system data availability had been 98.83%, with a Mean Time Between Failure (MTBF) of 1.62 years, noting that the majority of these failures were due to external impacts, including weather and human interference with the surface buoys, resulting in damage to surface communication and data systems.

A new world of multi-robot ocean exploration

The OECI’s Technology Integration Challenge made major strides in multi-robot operations, on the surface and underwater, unlocking ways to explore our ocean – and far more efficiently. Find out how and the role our acoustics played.

The challenge

Ocean exploration is costly. Operations involving single underwater platforms, such as remotely operated vehicles (ROVs) or autonomous underwater vehicles (AUVs), often take up an entire cruise. Even when multiple underwater robots can be accommodated on a vessel, only one tends to be deployed at any one time, due to the complexity involved in its deployment, operations and recovery. It makes ocean exploration expensive and limits how much science can be conducted on any one cruise. But what if uncrewed surface vessels (USVs) could be used, not just as force multipliers for mapping operations, but as a remote shepherd, coordinating multiple underwater vehicles, they would be able to operate entirely freely from a mother ship.

This was a key objective of the US’ Ocean Exploration Cooperative Institute (OECI) 2022 Technology Integration expedition NA139 on the Exploration Vessel (EV) Nautilus.

Enhancing ocean exploration through the use of remote and autonomous operations is a key objective of the OECI, a partnership between The University of Rhode Island, The Ocean Exploration Trust (OET), The University of Southern Mississippi, the University of New Hampshire (UNH), Woods Hole Oceanographic Institution (WHOI) and primary funding partner National Oceanic and Atmospheric Administration (NOAA) Ocean Exploration.

The expedition brought together OECI partner robots together with OET’s EV Nautilus for a ground-breaking technology demonstration in the Pacific Ocean during May 2022. These were:

Mesbot – WHOI’s mid-water robot that is designed to image and sample plankton layers.

NUI – WHOI’s hybrid ROV-AUV, designed initially to work under ice, that can operate out to about 20km on a fibre optic cable for high data rate data, but can also continue to operate without the fibre link.

DriX – UNH’s 7 m-long USV capable of supporting a variety of payloads such as multibeam echo sounders, acoustic communications and tracking and surface communications.

Their goal was to have all three platforms operating together, sharing information and situational awareness and relaying their information, via the DriX, back to the EV Nautilus, enabling scientists onboard to remotely control subsurface operations up to 20 km away from the ship.

Key to meeting their goal was inter-vehicle communications, tracking and positioning.

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 results

“This was a real first for us,” – Professor Larry Mayer, Director of the Center for Coastal and Ocean Mapping, University of New Hampshire.

Over the course of the 16-day expedition near the island of Oahu, off Hawaii, the team tested and demonstrated operational capabilities. Over 30 dives were performed, totaling 210 hours in the water.

The team established a common control system, based on the robot operating system (ROS) for the vehicles and then set out, each time proving out more and more capabilities.

First, they had DriX track and communicate with Mesobot, using Mini-Ranger 2. Because the DriX has GNSS data at the surface, this meant it could position the Mesobot in the real-world and relay this data back to the RV Nautilus.

Next, they sent commands, via the DriX to Mesobot, from EV Nautilus to open and close its samplers, as well as to move up or down or to the right or left as well as change speed through the water column.

But then the most exciting thing happened, explains Professor Mayer:

“Mesobot is designed to sample layers in the water column. But it doesn’t know where they are. DriX has a sonar (EK-80) that could see those layers. So we could get DriX sonar data back on the ship and in real-time see what’s called the scattering layer of plankton and command the Mesobot to go to that layer to sample it.

“Because Drix is circling above, it can actually see the Mesobot in the layer. This was a whole new world. Normally, Mesobot is sampling blindly. We could now direct it into the layer, know it’s in the layer and see if its entrance causes the layer to scatter. All these were unknowns before.”

The team were then able to repeat these activities with NUI, including using DriX to map the seafloor east of Maui and then relay a mission to NUI for further investigation. In addition, CTD data, as well as snippets of imagery and bathymetry were transmitted acoustically up to the DriX, using Mini-Ranger 2, and then via the radio link back to the Nautilus.

“By the end of the cruise we were able to have both vehicles in the water with the DriX circulating above, communicating with each of the vehicles, giving each other situational awareness, and the mothership, it was off do its own thing. I couldn’t have asked for a more successful cruise,” says Larry.

“We are really opening up a new world of multi-vehicle operations. In the old days, we would schedule a cruise and just use the Mesobot or schedule a cruise and just the NUI or an ROV. Even if they would all fit on one ship at the same time, you only use one at a time, so the $60,000 a day would be clicking away and you’re only doing a single science operation.

“Now we can do 2-3 science operations, the efficiencies are tremendous and it allows us to explore the seafloor, water column and surface all at once.

“The Mini-Ranger 2 system gave us the broadest base of possibilities with having both the acoustic communications and the positioning, USBL and acoustic communications, from the same system and that combined set of capabilities was so important to us.

“The standardization and ease at which we were able to send messages across from our programmers made it easy to use. The cooperativeness and responsiveness of the team at Sonardyne was also really helpful. They didn’t see it as disruption, they saw the possibilities.”

The expedition was funded by NOAA Ocean Exploration via the Ocean Exploration Cooperative Institute.

For more information and to watch other videos from Nautilus, click here.

Autonomous robots prepare to storm the ocean depths

Sonardyne were delighted to be part of the trials of a fleet of marine robots able to tackle complex offshore tasks as part of a ground-breaking project funded by Innovate UK, which is poised to change approaches to ocean exploration. Autonomous marine systems are being developed and deployed in increasing numbers. However, as maritime operations become ever more complex and expensive, and installed energy infrastructure increases in scale and distance from shore, there is a rapidly emerging need for more sophisticated multi-platform capabilities in the offshore renewable energy (ORE) market.

Squads of Adaptive Robots (SoAR) is a two-year collaborative research project, led by the developer of ecoSUB autonomous underwater vehicles (AUVs), Planet Ocean. The project kicked off in September 2021 and culminated this summer with full system testing at Smart Sound Plymouth on England’s south coast.

The SoAR team’s aim was to demonstrate how large-scale survey and exploration missions can be achieved by going beyond the limitations of individual AUVs. We worked alongside industry and academic partners; Planet Ocean, HydroSurv, the National Oceanography Centre (NOC), Royal Holloway University and the Offshore Renewable Energy (ORE) Catapult to develop advanced AI-driven mission planning, communications protocols for fleet coordination and significant improvements in underwater navigation and communications technology.

The trials simulated an offshore windfarm concession survey mission informed by a comprehensive business case analysis by the team at ORE Catapult.

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.

Pinpointing Precision: Arctia chooses Sonardyne system for subsea surveys

When Finnish state-owned hydrographic services and icebreaking company Arctia need to accurately and reliably position their subsea survey equipment there is only one logical solution.

Arctia provide a wide range of services for Finland’s maritime industry including icebreaking, hydraulic engineering, planning and permit services, fairway maintenance and survey services, hydrographic services and research.

Their services all rely on precise subsea navigation and tracking, especially those using towed survey equipment. This is where Sonardyne come in, Arctia have chosen their Mini-Ranger 2 Ultra Short BaseLine (USBL) system with WSM 6+ transponders for their marine survey services.

Many of their marine surveys are conducted around offshore wind farms where teams of internationally certified hydrographic surveyors and shallow water experts provide tailor-made survey, analysing and planning solutions to meet even the most demanding of customer needs.

Mini-Ranger 2 is one of Sonardyne’s most popular USBL systems, chosen for its small size, value and dependable performance in all underwater environments. It’s the perfect choice for fitting to small survey vessels, moored barges and uncrewed vessels.

For Arctia, it is the perfect partner for towed hydrographic survey equipment such as magnetometers and sidescan sonars used as part of their survey services. With depth ratings of up to 1000 metres and able to operate in temperatures as low as -5 degrees Celsius, it’s ideal for the Baltic Sea and offers the opportunity to upgrade to other versions for depths up to 4,000 metres should Arctia and their customers operate at greater depths in future.

If you have a similar challenge in your subsea navigation and tracking operations, contact us to see how we can help.

Mapping the future for seagrass beds in Plymouth Sound

Seagrass beds are incredibly important ecosystems that offer a range of ecological benefits. Not only do they provide crucial habitats for a diverse array of marine wildlife, especially in coastal areas like Plymouth Sound, they can also store carbon, helping to mitigate the effects of climate change. These underwater meadows serve as nurseries for many species of fish in the early stages of their life, offering them protection and abundant food sources. Additionally, seagrass beds help to stabilise the seabed with their root systems, preventing coastal erosion and maintaining water quality by trapping sediments and nutrients.

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.

Revolutionising small ROV navigation

Operating a small robotic platform in any marine environment is not without its challenges. Reliability and precision with accurate positioning data are key for safe operations and where repeat inspections or surveys are needed.

The size of the platform may present its own limitations, restricting the size and weight of any payload and therefore the extent of its operational capabilities. Environmental or locational factors may also play a part in the reliability of operations. Most navigational and positioning payloads use magnetic compasses to provide heading.

This reliance on magnetic heading makes the platform susceptible to interference from ferrous materials in its surroundings. These could be wind turbine or energy platform monopiles, wreckage or unexploded ordnance (UXO) on the seabed, the presence of vessels / submerged infrastructure in harbours and coastal locations or even just naturally occurring ferrous minerals in the seabed.

These factors introduce heading errors that compromise the supervised autonomous functions of the platform, particularly when following line headings between reciprocal bearings. Even minor heading inaccuracies can cause cumulative deviations over extended missions, leading to imprecise data and potentially requiring time-consuming survey line re-runs.

Any inaccuracies during survey when locating UXOs are particularly unwelcome, by their nature most UXOs are located based on magnetic signature. So, any poor navigation during the wide area or detailed UXO survey can be misleading and potentially dangerous. With repeat inspections of monopiles, for example, ensuring the survey platform returns to the exact same spot on each visit is important to ensure no anomalies or potential problems are missed.

“Historically, smaller electric vehicles have been limited in the amount of work they are capable of due to size, power and operational limits presented by weather conditions and surroundings.

Recent iterations of handheld ROVs such as the VideoRay Defender have looked to change what electric ROVs are capable of, while maintaining a platform that is easy to mobilise, operate and maintain. That said, the ROV is only as powerful as the tooling that it holds, so it still requires support from companies such as Sonardyne, to reduce the form factor and weight of their tools and sensors, to enable their integration and deployment offshore.

Atlantas Marine have already been utilising the SPRINT Nav Mini to great success on our Ocean Modules V8 M500 platform, but the latest SPRINT-Nav U will allow us to go further and integrate it onto our VideoRay Defender ROVs, and provide another service that we can offer our customers – a hand-launched ROV, that can be mobilised in as little as half an hour, transported to site in the back of an car” Mark Salter, Senior Project Manager, Atlantas Marine.

“Like the other hybrid navigators in the SPRINT-Nav family, SPRINT-Nav U’s true north seeking gyrocompass means that it delivers reliable subsea navigation even when in close contact with the types of environmental factors outlined above. With its ultra-compact form factor (135mm X 114mm) and a weight in water of just 0.6kg, SPRINT-Nav U gives unrivalled navigation capability to small marine robotic system allowing users to maintain a heading accuracy of 0.15° regardless of environmental factors.

“SPRINT-Nav U has been designed with our customers in mind. We’ve been speaking to them for a number of years about their aspirations for operations with small platforms. With the help of valued customers like Atlantas Marine, our trials have demonstrated a variety of use cases for this new, compact navigator and we’re excited to work on many more innovative uses in future.” Aidan Thorn, Business Development Manager – Marine Robotics, Sonardyne.

Small, light, precise

SPRINT-Nav U is simple to integrate into any marine vehicle along with other payload sensors and uses same field-proven web user interface found on the SPRINT-Nav Mini. Pre-calibration in the factory also means that SPRINT-Nav U is incredibly quick to set up and deploy on site with an alignment time of as little as five minutes, compared to the standard 15-20 minutes of other gyrocompassing inertial navigation systems, making it the world’s fastest aligning hybrid navigator.

“SPRINT-Nav U can turn any marine robot into a survey grade platform. For UXO and asset inspection it drastically improves deliverable data quality. As part of the proven Sonardyne SPRINT-Nav family, customers can be assured of reliable, accurate navigation and positioning every time, no matter the operating environment.” John Houlder, Senior Product Manager, Sonardyne.

What the customers thought

Mark Salter, Senior Project Manager at Atlantas Marine – “Of particular significance to us, is the work we undertake on offshore wind turbines. With a high AC voltage running through the subsea cabling, and the strong magnetic signatures associated with that, plus the ferrous nature of the turbines themselves, the SPRINT-Nav U allows us to offer our customers a level of accuracy and precision that was previously not possible. It allows us to state with much higher confidence the location of any faults and anomalies, and allows us to repeat inspections, year on year, as we document the changing condition of those faults. With the positioning and control managed through Greensea, we can set up autonomous routes and sea patterns with more accuracy and precision than even before, especially in the environments we most commonly find ourselves.”

Richard Stanley, Project Leader at Atlantas Marine – “Providing improved accuracy when operating in ports and areas where large metallic objects are buried on or beneath the seabed, improves not only the reciprocal bearings of the lanes the ROV is flying, but feeds a more accurate heading into the navigation solution which is streamed to the surveyor. Beyond seabed surveys, the ability to maintain a stable heading while piloting a compact inspection-class ROV through culverts with rebar or complex subterranean tunnels is a key advantage. It reduces the need for frequent heading corrections and ensures precise navigation when traversing long distances. This ultimately enhances the quality of deliverables for our clients, providing us with a competitive edge when deploying our equipment.”

Navigating new waters: How real-time current monitoring can transform port operations

Port of Aberdeen, Scotland's largest berthage port – previously known as Aberdeen Harbour, was established in 1136 by King David I of Scotland. It is the oldest existing business in Britain, with a history spanning almost 900 years.

Construction of the port’s South Harbour started in 2017 after years of planning. Completed in August 2023, the £420 million expanded port was the largest marine infrastructure project in Trust Port history. It offers 2,800 metres of deep-water berths to a maximum depth of 14.8 metres (MWHS).

The harbour extension is aimed at attracting vessels and project activity – such as cruise ships and offshore renewable energy (ORE) operations – which would have previously gone to European ports capable of handling their requirements. This increased activity will support local jobs, attract local supply chain spend and investment.

A key feature of South Harbour is its ability to berth large ships. To ensure safe passage for these vessels, it’s important to have accurate and detailed data within the harbour. With its long history, Port of Aberdeen has this information for the North Harbour and is continuing to build a comprehensive understanding of the water movements within South Harbour. This data can then be used to enhance navigational safety and operability within the port.

Sonardyne’s Origin^® 600 Acoustic Doppler Current Profiler (ADCP) enables users to monitor waves, currents and turbulence. Its built-in acoustic modem enables remote access while it’s deployed. This allows battery and storage checks, the opportunity to inspect and upload data, reconfigure schedules and run quality control, all whilst the ADCP is on the seabed. Enabling users to make time-critical decisions with near real-time data delivery.

Realising the potential for gathering valuable, high quality data to support their operations, Port of Aberdeen approached Sonardyne’s Aberdeen office to hire an Origin 600 for an initial six month period.

“We’re delighted that Port of Aberdeen chose to hire an Origin 600 to monitor the water movement within South Harbour. The knowledge they will gain from the data is vital to help them provide the best possible service for their customers and operators within the port. We look forward to working with them on this project and beyond.” Thomas Blair, Operations Manager, Sonardyne, Aberdeen.

The Origin 600 was deployed, using Sonardyne RT 6 1000 and 3000 release transponders, in the port district on 20^th March 2025. Its onboard data processing via implementation of Edge ‘apps’ enable it to deliver information on the wave environment, together with the speed and direction of water column currents, and the timing of tides – fundamentally slack tides. All the data is processed and stored on the unit until Port of Aberdeen are ready to harvest it. This can be done without retrieving the ADCP via its onboard acoustic modem.

In June 2025 the unit was temporarily retrieved to recharge the battery and will be redeployed for a further three months in an alternative, suitable location.

“Origin 600’s ability to monitor and report on the behaviour of currents throughout the water column whilst remaining on the seabed makes it an ideal choice for projects where actionable information is critical for operational safety, just as we have seen with Port of Aberdeen’s South Harbour. What’s more, Origin 600’s real-time reporting capability can be used to support and inform dredging activities, opening up a further avenue where this instrument can help Port of Aberdeen. I’m truly excited to see the full extent of the outputs from this project and how the Origin ADCP data will be applied moving forward.” Michelle Barnett, Business Development Manager – Ocean Science, Sonardyne.

As more current and tidal data is gathered, Port of Aberdeen will be able to use it to enhance operability within the port.

“Port of Aberdeen relies on accurate, reliable data to drive informed decision-making. Having a company with this technology right on our doorstep is a significant advantage – not only in helping us achieve our own objectives, but also in supporting our customers, stakeholders, and port users in delivering their work scopes and projects efficiently and effectively.” Benji Morrison, Harbour Master, Port of Aberdeen

Origin 600 being deployed in Port of Aberdeen South Harbour

If you have a similar project or challenge, talk to us about how Origin ADCPs or other Sonardyne technology can help.

Origin 65 holds the key to help unlock Gulf of Mexico loop current eddy mysteries

The Gulf of Mexico is home to the highly energetic ocean circulation feature known as the Gulf Loop Current System (LCS). This current system influences all ocean processes in the gulf, characterised by highly disruptive Loop Current Eddy (LCE) events. LCEs are rings of warm water which rotate at speeds of up to four knots in a clockwise direction, measuring approximately 100-200 km in diameter, reaching down to depths of 500–1,000 m, and breaking away from the extended Loop Current around every 8-9 months. Loop Current Eddy events have serious implications for a great range of natural and human activities, from ecosystem dynamics and hurricane intensification to fishing operations and oil and gas exploration.

The challenge

The behaviour of the LCS remains difficult to forecast with sufficient accuracy to guide operations beyond a few days, yet its significance for processes and operations in the Gulf of Mexico drives a need to improve and extend forecasts of the LCS and LCEs. The difficulty has arisen partly because interactions of the upper currents with deep eddies have not been detectable in real time to guide numerical models.

Unlocking the Gulf current – a continuance

Sonardyne were introduced to this challenge back in 2018 when the University of Rhode Island launched a multi-year scientific study that included deployment of five Sonardyne Current Pressure Inverted Echo Sounders (CPIES) at depths down to 3,500 m in the area of the extended LCS.

The Sonardyne solution

Sonardyne’s modem-enabled CPIES were a key element in the initial two-year project. These instruments were part of a mass deployment to measure two-way travel time (or tau) over an extended area in order to map the local horizontal velocity and density fields in the extended LCS, as can be read at https://www.sonardyne.com/case-study/unlocking-the-gulf-loop-current/.

Soon after the 2018 deployment, Sonardyne began the development of Origin 65, a combined PIES and ADCP with acoustic modem to enable adaptive data harvesting. The benefit of Origin 65 over CPIES is that it not only supports but augments density/current mapping projects.

Where CPIES use a separate single point current meter to provide a deep reference velocity for calculated geostrophic currents, Origin 65 measures a whole profile of currents over a greater range. Being an all-in-one instrument, Origin 65 also removes the risk and expense of combining separate devices for a single application.

What’s more, by utilising Origin 65’s onboard Edge data processing capability, PIES data is time-synchronised and fused with the ADCP measurements for simpler analysis. After extensive trials, Origin 65 was launched in 2023.

“Pulses of strong currents pose a hazard to industry along steep escarpments in the deep Gulf. Moreover, their unexpected arrival compounds the hazard: satellite and near-surface observations and numerical models do not predict them reliably. We needed a forecast tool grounded in observations with adaptive reporting capability. We had a tall order for the observations: We needed to profile currents from the bottom through hundreds of meters above the bottom and we required fast acoustic telemetry capability. Sonardyne committed the engineering capability to develop a combined PIES and upward-looking low frequency ADCP with a vertical range of 800 m. It was an outstanding match to our needs, and Sonardyne’s fast acoustic telemetry capability was key to being able to harvest the data and report it ashore in near-real time.”

Professor D. Randolph (Randy) Watts, Professor of Oceanography, University of Rhode Island

The 2024 deployment

In 2024, funded by the US National Academies of Science, Engineering, and Medicine Gulf Research Programme and led by a team of scientists from the University of Rhode Island, five Sonardyne Origin 65 units were deployed alongside the original Sonardyne CPIES in the Gulf of Mexico (depth range of 1,800 – 3,200 m) for an initial 18-month measurement campaign.

Both the Origin 65s and CPIES have integrated acoustic modems enabling high-speed (up to 9,000 bps) acoustic telemetry to support wireless retrieval of data by an uncrewed surface vessel (USV) in addition to remote control of the instruments.

Despite similar telemetry capability, the volume of data generated by Origin 65 compared to CPIES is much greater, and therefore limited acoustic bandwidth presents a challenge when looking to transfer this substantial data via acoustic telemetry.

This is where Origin 65’s Edge onboard data processing capability comes into play to condense the bulky raw data into small packets of actionable information, easily exportable via the acoustic modem.

The five Origin 65 units were deployed with an Edge application (app) installed to perform combined onboard processing of the ADCP and PIES data. More specifically, the Edge app implemented a custom algorithm that produced an hourly compact (24 bytes) binary output containing a timestamp, the mean current speed and bearing in six depth-bins above the bottom, plus the mean of the PIES results.

The beauty of the onboard data processing was apparent during planned USV visits, where it took less than 20 minutes to acoustically harvest more than two months’ worth of data

An assessment was conducted whereby the integrated acoustic release on one of the Origin 65 instruments was triggered after 66 days of deployment to allow recovery (Figure 1) of the device and complete data download for a thorough evaluation. This instrument was located in a water depth of 2,142 m.

Figure 1: Retrieval of the Origin 65 aboard the R/V Pelican.

Pies

The PIES portion of the Origin 65 performed consistently (Figure 2). Periods of increased scatter in the sound speed measurements are observable, but these are a result of higher ambient noise levels (pretrigger RMS), which correspond to higher sea states (local wave activity is a dominant source of acoustic noise given that in higher sea states the surface return from the PIES chirp is more spread out).

Figure 2: PIES sound speed and ambient noise (pretrigger RMS) measurements for the  deployment. The bottom plot compares ambient noise (pretrigger RMS) to the level of local wave activity using wind speed (as recorded by station Green Canyon 338, 124 km to the WNW of the deployment site) as a proxy for sea state.

ADCP

Velocity data demonstrates expected current behaviour (Figure 3), with velocities much larger in the Eastward and Northward directions than in the upward direction. The lack of significant apparent velocity in the vertical direction indicates that there is no systematic bias in the beam-frame Doppler velocities.

In addition, the observed velocity signals (large blue and red patches) vary on timescales between days and weeks, which is expected.

Of particular interest, it can be seen around 6th June, the prevailing current changed from South-Easterly to North-Westerly over the course of around two days.

This corresponded with a sudden increase in scatter density, thought to be an indication that the seabed was disturbed by the changing current.

Figure 3: Components of the Earth-frame velocities for the 66-day deployment (60-ping ensembles).

Low scatterer concentration in the deep waters (>2000 m) of the Gulf of Mexico reduced the effective profiling range of the Origin 65 from its achieved maximum range of > 800 m. However, with a sufficiently long averaging period it can been seen that the current velocity signal is present for the entire 800 m range of the Origin 65 (Figure 4).

Figure 4: Comparison of 24-hour averages of Eastward current velocity for different altitude bins. Performing increased averaging shows that a consistent current velocity signal is exhibited across the 800 m range of Origin 65.

“Our collaboration with the University of Rhode Island has been instrumental in augmenting our PIES technology in the form of Origin 65, a combined ADCP and PIES, for oceanographic study of geostrophic currents fields like that found in the Gulf of Mexico. We’re delighted to see Origin 65 being applied in this vital study, and by extension, to be able to support research efforts to improve and extend forecasting of the LCS and LCE behaviour with the accuracy desired. We look forward to continuing our relationship with the University of Rhode Island, and to seeing further successful USV data harvests from the Origin 65 units over their deployment period in the Gulf of Mexico.”

Michelle Barnett, Business Development Manager – Ocean Science, Sonardyne

What’s more, evidence of diel plankton migration is apparent with the repeated appearance and disappearance of a scattering layer between 500 m and 800 m height above the bottom. This pattern has a period of roughly 24 hours with the scattering layer clearly visible in daylight hours, as is consistent with the cycle of diel vertical migration observed ubiquitously in aquatic systems throughout the world.

This is nicely demonstrated in cross-correlation data, where values increased to around 80% on a daily cycle in response to the plankton migration (Figure 5). This cross-correlation data helps to indicate the effective maximum range of the system of around 800 m.

Figure 5: An excerpt (4 – 7th June) of unaveraged cross-correlation data for each of the four beams of the Origin 65 demonstrating a clearly observable diel vertical migration pattern. The lower plot represents the local time, with the colour being a function of the local solar altitude.

“This suite of instrumentation and platforms will help refine predictive tools for future applications in the Gulf. Looking ahead, the combination of Sonardyne Origin 65 current profilers and adaptive data-harvesting technology opens the door for long-term deployments in deep water – anywhere in the world. This is very exciting: we could access remote and critically important regions supporting sustained observations and advancing science.”

Professor Kathleen (Kathy) Donohue, Professor of Oceanography, University of Rhode Island

What’s next?

Two successful data harvests by a SeaTrac SP-48 USV equipped with a Sonardyne HPT 7000 L transceiver head have already been conducted. A third data harvest is scheduled for the end of July and the instruments will be recovered in September 2025. Keep an eye on our website and social media for further information about this and the data captured.

If you have an operational challenge for Origin 65, or any other Sonardyne product, please contact us.

Compact navigation solutions enhance Sulmara’s advanced marine geophysical surveys

The drive towards greener offshore energy generation begins well before the first wind turbine blade turns. Geophysical marine survey company Sulmara are innovating the way they work with the offshore energy sector, leveraging technology wherever possible to help offshore wind projects be developed in the most efficient and environmentally sound ways possible. Founded in 2019, they are an international services provider specialising in site investigation, construction support, subsea survey and inspection across the offshore energy and utilities sectors.

The challenge

With a focus on unexploded ordnance (UXO), boulder and linear infrastructure mapping, Sulmara are pushing the boundaries of technologies to deliver depth of burial surveys and identify obstacles in and around potential offshore development sites across the energy sector.

By integrating an ROTV with an Edgetech Buried Object Sonar System (eBOSS) and Micro-Fabricated Atomic Magnetometers (MFAMs) from Geometrics and then layering custom software and delivery packages on top, Sulmara have developed a technology stack capable of enhancing site investigation and asset inspection campaigns. To deliver high quality data with the system that is deployable from a range of vessels and subsea vehicles, Sulmara required very high accuracy positioning and navigation inputs. They were also looking for a way to lighten the payload for towed operations. Sulmara approached Sonardyne as a world-leading supplier of acoustic positioning and hybrid inertial-acoustic navigation technologies to help them rise to this challenge.

The solution

In February 2025, as part of their continuing commitment to pre-commercialisation development, Sulmara mobilised a vessel and survey setup in Norfolk, Virginia USA to perform various trials and data acquisition tasks with a range of sensor equipment. The integrated eBOSS, MFAMs, and ROTV were mobilised and extensively trialled over a range of seabed conditions. For a positioning solution to support the towed platform, Sulmara selected Sonardyne’s Mini Ranger 2 USBL system.

For navigation, Sulmara had opted for an integrated Sonardyne SPRINT-Nav Mini hybrid inertial-acoustic navigator, and they were happy with the navigation performance provided. However, in their drive to make their technologies more compact, any savings on size, weight and power were considered, and Sonardyne sent out members of their engineering team with a prototype of the SPRINT-Nav U hybrid inertial-acoustic navigator to work with Sulmara and utilise this new smaller, lighter and lower powered navigator to the test on the towed platform.

Small, light, precise

Measuring just 134 mm in height, 114 mm in diameter and weighing a mere 600 grams in water, SPRINT-Nav U is the world’s smallest hybrid acoustic-inertial navigator.

Its small form factor packs the full, trusted, SPRINT-Nav capability into a space traditionally filled by just a DVL on a small robotic platform to deliver USBL aided performance up to 4x better than standard, with just 8W of power consumption. SPRINT-Nav U is simple to integrate into any marine vehicle along with other payload sensors and uses same field-proven web user interface found on the SPRINT-Nav Mini. Pre-calibration in the factory also means it’s incredibly quick to set up and deploy on site. An alignment time of as little as five minutes, compared to the standard 15-20 minutes of other gyro compassing inertial navigation systems, also makes it the world’s fastest aligning hybrid navigator.

“The all-in-one and compact nature of SPRINT-Nav Mini and SPRINT-Nav U make them ideal for integration into towfish platforms. Towfish are currently positioned either using magnetic heading sensors or course made good, which may lead to large positioning and heading errors. Affecting both data at nadir and at the edge of a sonar swath. The combination of high-grade fibre optic gyro based IMU and DVL means that our small SPRINT-Nav products provide class leading navigation inputs into the wider towfish system, ensuring reliable data outputs and eliminating any need to re-run lines because of poor navigation.” John Houlder, Senior Product Manager, Sonardyne.

When paired with a Sonardyne Ranger 2 USBL system, in Sulmara’s case the Mini-Ranger 2, the combination of precision navigation and positioning, is second to none.

As our mainstay USBL system for nearshore operations, Mini-Ranger 2 is a tracking, positioning, and communications system with robotic capability that tracks up to 995m out of the box, expandable to 4,000m with an extension pack. It’s suitable for AUVs, divers, ROVs, towfish, USVs, and vessels in shallow to mid-depth waters and features a large array with excellent rear noise blocking, making it ideal for quick vessel mobilisations and long layback tracking in towed surveys.

The results

The combination of Sonardyne Mini Ranger 2 USBL with the new SPRINT-Nav U hybrid inertial-acoustic navigator gave the towed platform a heading accuracy of 0.15°. This was well within the required performance for the geophysical survey specifications that Sulmara are looking to achieve for their clients. Due to the need for location of ferrous materials, such as UXO, having the fibre optic gyrocompass (FOG) inertial measurement unit (IMU) within the SPRINT-Nav U meant that the navigation performance was not compromised in the same way that it would be if the ROTV was using a magnetic heading sensor or course made good for navigation.

“The introduction of the SPRINT-Nav U as a navigation solution for our towed platform provides us with a solution that is not only accurate and reliable in all environments, it also ensured high quality geophysical datasets. It’s low power, size and weight meets our requirement to provide increased manoeuvrability on the ROTV. Pairing the navigation capabilities of SPRINT-Nav U with the Mini-Ranger 2 gives us a great option, as having this one vendor solution means that integration is simplified. The use of a fibre optic gyro is also key; this stops our heading being impacted by any nearby magnetic fields.” Dennis Wilson, Development Scientist, Sulmara.

“Having integrated SPRINT-Nav Mini and SPRINT-Nav U, we’ve been really impressed with the performance of both navigators. The performance of SPRINT-Nav U is really striking for equipment with such a small form factor. This is something we value at Sulmara, as we’re always seeking efficient hardware options to support our innovative survey efforts. We’re increasing the adoption of uncrewed and remote technologies, and it is essential that we do not compromise on the quality of the data we collect when reducing the size of the payload. Having the power of Sonardyne’s SPRINT-Nav products paired with their Mini-Ranger 2 USBL available to deliver guidance for our ROTV operations gives us the reliability needed.” Dennis Wilson, Development Scientist, Sulmara.

If you have a similar challenge in your small robotic platform operations, talk to us about how we might help you to find the solution. Click on the link below and let’s start a conversation…