Update on Ifremer technological developments and operational feedbacks with underwater systems
This paper reports on the status of Ifremer Underwater systems. It will focus on recent innovations, improvements and operational references of the remotely operated vehicle “Victor 6000”, of the autonomous underwater vehicles “AsterX” and “IdefX”, of the new “Sysif” seismic tool and some hints about RanD in the domain of Advanced Intervention AUVs.
Design and Experimental Validation of a USBL Underwater Acoustic Positioning System
This paper presents the steps for developing a low-cost POrtableNavigation Tool for Underwater Scenarios (PONTUS) to be used as a localization device for subsea targets. PONTUS consists of an integrated ultra-short baseline acoustic positioning system aided by an inertial navigation system. Built on a practical design, it can be mounted on an underwater robotic vehicle or be operated by a scuba diver. It also features a graphical user interface that provides information on the tracking of the designated target, in addition to some details on the physical properties inside PONTUS. A full disclosure of the architecture of the tool is first presented, followed by thorough technical descriptions of the hardware components ensemble and the software development process. A series of experiments was carried out to validate the developed prototype, and the results are presented herein, which allow assessing its overall performance.
Extensive volcaniclastic deposits at the Mid‐Atlantic Ridge axis: results of deep‐water basaltic explosive volcanic activity?
A recent mapping survey followed by submersible diving investigations revealed the existence of extensive volcaniclastic deposits on three adjoining, progressively deeper, segments of the Mid‐Atlantic Ridge, south‐west of the Azores. The maximum water depth at which subaqueous magmatic and hydro‐magmatic explosive processes can occur is controversial. This discovery provides fundamental constraints on the dynamics of deep subaqueous volcanic eruptions. Using multibeam bathymetry, sonar image interpretations, submersible observations, volcaniclastic sample descriptions and chemical analysis, evidence of extensive deep water (up to –1700 m) magmatic explosive activity of basalt at the axis of a spreading Mid‐Ocean Ridge is documented for the first time.