Subsea observatories: Improvement on the deployment, position accuracies and communication to the surface

Subsea observatories are key structures to study underwater environments and monitor physical phenomena. Those structures embed sensors for environmental data acquisition but also smart beacons and inertial systems to get precise position and ensure communication to the surface.

As part of the CPPM Antares, iXblue beacons and USBL antennas allowed to deploy structures on the seabed within 10cm. This accuracy is "essential for a good reconstruction of particle tracks".

Recently in the Focus project, we managed to deploy 8 tripods equipped with smart LBL beacons to measure the drift of the North Alfeo Fault in Sicily and compare them to the measurements from optical cable deployed on the same fault. By interfacing external sensors to the beacons, first results showed an accuracy better than 10cm. Accurate distance measurements and position is again a key figure.

Rovs and AUV are very useful vehicles in such complex environments to deploy, recover, monitor gears but also to acquire bathymetric or geophysical data to build 3D imaging of the seafloor. The positioning of the vehicle for navigation but also the georeferencing of data collected requires once again a high level of accuracy for positioning and is essential to save acquisition time. Sparse LBL method allows operation time reduction while keeping high standard of accuracy.

In this presentation, we are going to demonstrate how improvements on simulation and integration of various sensors into smart systems help to improve the data quality acquired by subsea observatories.