Increasing the Pace of Ocean Exploration Through Multi-Vehicle Collaboration

The Ocean Exploration Cooperative Institute (OECI) Technology Challenge, which took place from May 6 – 22, 2022 in the Pacific Ocean, set out to test collaborative capabilities of multiple uncrewed vessels for ocean exploration expeditions, with the aim of increasing the pace of ocean exploration and finding ways of improving exploration efficiency.

OECI is 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 underlying aim of the Challenge was to develop approaches to having multiple uncrewed vehicles communicate with each other and collaborate with each other, improving the efficiency of operations and expanding the overall exploration footprint. A key objective was also to find out if it was possible to make deliberate adjustments to the mission plan of a robotic vehicle from a significant distance away from the mother ship.

Historically, the offshore use of uncrewed assets would typically be limited to one scientific operation at a time. Even when it was possible to launch several vehicles from the one command ship, it was only ever truly possible to control them individually, and the mother ship would always need to suspend mapping operations in order to deploy a vehicle. However, the OECI Technology Challenge sought to validate a new way of sending complex marine robotic systems on independent missions at the same time, without disrupting the support vessel’s ongoing ocean mapping operations.

Four vehicles were showcased in the Challenge: UNH’s DriX USV (developed by Exail, previously iXblue); WHOI’s mid-water slow-moving Mesobot ROV designed to explore the mesosphere; WHOI’s remotely operated hybrid vehicle Nereid Under-Ice, or NUI for short, which is supported by a fiber optic cable, allowing it to act as a standard ROV as well as an AUV if the cable breaks; and last but not least, the Ocean Exploration Trust’s E/V Nautilus, the principal research platform.

With each of the robots being deployed from the E/V Nautilus, the real challenge was to have these vehicles in the water at the same time and communicating with each other even though they didn’t all have the same protocols. This was the perfect opportunity to test the viability of the interoperability of the four uncrewed assets and, therefore, the genuine possibility of multi-vehicle tracking and positioning.

EXPLORING VAST AREAS IN A SINGLE MISSION

The DriX USV was launched on its own to map the water column and, in doing so, track diurnal migration of the deep scattering layer. To do this DriX used its Kongsberg EK80 multibeam echosounder within its gondola, 2 meters below the hull and so clear of any wave activity and surface bubbles, the necessary conditions for optimum data acquisition.

DriX’s Marine Broadband Radio (MBR) enabled the USV to send real-time data to the E/V Nautilus from up to 20 km away. The MBR enabled the vessel and DriX to sail independently at considerable distance from each, executing mapping procedures in different areas simultaneously, and so effectively multiplying the size of the area covered in each timeframe.

When DriX identified a target during its mapping operations, the Mesobot AUV is automatically sent to the target in order to sample the diurnal vertical migration. DriX was able to track, monitor, and even re-task Mesobot by circling above it, maintaining its acoustic communication with real-time data links established between them. DriX essentially acts as an “aircraft control tower” by maintaining clear acoustic communication with the Mesobot AUV.

Thanks to this acoustic communication link via a USBL system installed within DriX’s gondola, teams were able to monitor Mesobot’s position in real time and send the information to the display systems onboard the E/V Nautilus, giving full situational awareness of all participating vehicles. DriX can then redirect Mesobot in real-time, from miles away, to new features revealed by DriX and obtain real-time information on water column properties and areas of interest.

Thanks to this acoustic communication capability, DriX can also retrieve the data collected by the AUV without having to wait for it to resurface, enabling fast data transmission to the operations center through high-bandwidth communication.

INTELLIGENT UNCREWED COLLABORATION

WHOI’s NUI was able to dive down below Mesobot to explore the seabed, supported by the fiber optic tether linking it to the E/V Nautilus. DriX then acoustically tracked the NUI and reported its positions to the Nautilus’ display systems, offering complete situational awareness to the onboard crew. As with Mesobot, DriX sent acoustic commands to NUI and received acoustic data from NUI in return, which was then forwarded to the mother ship.

When NUI was in full AUV mode, and therefore no longer attached to E/V Nautilus via the tether and free to perform other missions, DriX was able to provide long-range tracking for NUI, and long-range relay between NUI and Nautilus. In other words, Nautilus can receive real-time data mapping from NUI via DriX without NUI needing to resurface, greatly improving efficiency.

EXPANDING MISSION CAPABILITIES

The mission was a great success, exceeding expectations. It illustrates how it is possible to explore the ocean’s seafloor, mid-water and surface simultaneously, leaving the topside support vessel free to perform other mapping tasks and in-field operations, drastically reducing any mission downtime.

Research teams and oceanographers can now use autonomous systems such as the DriX USV in conjunction with manned vessels, significantly increasing their potential mapping coverage while also optimizing mission efficiency and the volume of data gathered in a set period.

The OECI Technology Challenge gave observers an insight into the countless possibilities that multi-vehicle collaboration presents, all of which help to extend the reach of ocean exploration. Jason Fahy, Expedition Lead, NA1389 Technology Challenge, OECI perhaps said it best: “These technologies are already great on their own but so much more powerful when working together.”

For more information about the OECI Technology Challenge, visit: www.web.uri.edu/oeci.

For more information about Exail, visit: www.exail.com.

To read the full article, which was featured in ON&T March 2023, click here.