ECA Group demonstrates high performance of its mid-size AUV during deep survey missions

As announced in early 2018, ECA Group signed a cooperation agreement for subsea robotics services to Oil & Gas companies with a leasing offer of its latest generation A18D AUV creating a new dimension for its AUV Services activity.

ECA Group demonstrates high performance of its mid size AUV during deep survey missions The A18D is the most compact multi-sensor AUV on the market for long endurance deep water survey (up to 3,000m) (Picture source: ECA Group)

Throughout 2018 ECA Group conducted with success several deep survey missions. This new generation AUV demonstrated its capabilities to perform multi-sensors surveys during deep operations (around 2,500 m below to the sea) in the Mediterranean Sea.

The A18D is the most compact multi-sensor AUV on the market for long endurance deep water survey (up to 3,000m). This long endurance AUV performs up to 40 km² of high-resolution imagery per mission.

Thanks to its unique 3D navigation accuracy, outstanding data (MBES, SAS, SBP) were gathered in a single survey at a depth over 2,500m, with a perfect bottom altitude tracking at 25m. In the same survey, multi-sensors are used to obtain the best information.

MBES is used for the bathymetry and Synthetic Aperture Sonar (SAS) for high-resolution imagery.

With its highly accurate inertial navigation, the A18D provides centimetric XY resolutions of the bathymetry data. Unlike deep-sea surveys with a boat, the measurement is much more accurate and less sensitive to the effect of sound velocity profile (eg no effect of surface thermocline).

Environmental data (in particular Sound velocity) are acquired throughout the mission (descent/survey/reassembly) in order to be taken into account during the Post Mission Analysis with the best accuracy.

Thanks to internal synchronization features, all sensors are working together providing localized bathymetry and imagery data of the same objects.
Without moving parts or hydraulics, the LARS of the A18D is particularly reliable and easy to maintain or repair and requires no complex preventive maintenance.

The A18D can be also recovered very simply even when it is switched off thanks to an internal emergency rope, offering to the operators several contingency plan, reducing risks.

Mission-driven design

Compact, reliable and extremely stable, the A18D offers the best platform for deepwater survey enhancing the data quality while reducing integration and expenditure costs.

Measuring 5 meters and weighing 500 kg, the A18D can be easily operated form different kinds of vessels: from 18 meters multitask catamaran to 75 meters and over offshore supply ship.

Reliable, endurant (more than 20 hours at depth) and stable (roll and pitch <<0,15°/s) the A18D is the perfect platform to collect high-resolution data from very performant sensors such as Synthetic Aperture Sonar and Multi-Beam Echo Sounder.

Its unique design and advanced navigation features guarantee a high level of stability and positioning to provide the best quality of gathered data. Over its own central navigation system, it is linked with the surface control station and through dedicated acoustic means it can be regularly repositioned to achieve unsurpassed positioning accuracy.

Its smart Altitude Following Mode (AFM) allows the vehicle to keep gathering high-quality data even on rough bottoms of the seabed.

Fitted in standard with Side Scan Sonar (SAS in option), Multi-Beam Echo Sounder, Sub Bottom Profiler, Physical and Acoustic sensors. ,

ECA Group proposes the A18D vehicle with a sensor suite based on the best products available on the market. Nevertheless, this suite can be configured according to customers’ specific requirements.

The vehicle design provides the AUV with a high level of reliability. Like an ROV, the A18D AUV has a modular design composed of several removable parts with quick access to electronic modules, which is a significant asset for day to day operations and maintenance as well as for repairs onboard a mothership during operations.

In addition to the LARS, the A18D is equipped with a patented underwater catching system securing the AUV recovery in harshest conditions. This unique solution enables the operator to recover the AUV in safer conditions before surfacing, reducing risks to the personnel and the asset.