A Novel Methodology for Deployment and Retrieval of Autonomous Deep Ocean Distributed Acoustic Sensing Landers and Submarine Cable Layout

This study presents an innovative approach for the deployment and retrieval of autonomous deep ocean landers equipped with Distributed Acoustic Sensing (DAS) systems and associated fiber optic cables. The methodology utilizes the LanderPick system, a Remote Operated Towed Vehicle (ROTV), to facilitate precise placement and recovery of the lander and measuring cable on the seafloor. The integrated DAS system employs fiber optic technology to provide high-resolution acoustic monitoring along the cable's length, facilitating long-range detection of various underwater phenomena.

The autonomous lander design incorporates a frame structure and pressure-resistant housing designed to withstand depths of up to 6,000 meters. A key feature of the method is the lander’s hitching mesh and attached fiber optic reel mechanism, which enables controlled deployment and laying of the measured fiber. A specialized housing protects the DAS interrogator and associated electronics from the harsh deep-sea environment, ensuring long-term operational reliability.

The LanderPick deployment system, an ROTV, enables precise placement and recovery of the lander on the seafloor, while the attach reel mechanism allows to steer the cable layout as required. This approach significantly enhances the survivability and accuracy of the deployment process while allowing for continuous monitoring of the optic fiber deployment.

This novel approach addresses limitations of onshore installations utilizing submarine telecommunication cables, which often lack the location and fiber layout flexibility required for measuring specific ocean areas of interest. By enabling the deployment of autonomous platforms with customizable cable layouts, this solution significantly expands the potential applications of distributed sensing techniques in undersea environments.

Field trials have successfully demonstrated the LanderPick's capability to conduct deployment and retrieval missions with real time visual feedback. The adaptation of this controlled deployment method to the distributed sensing requirements represents an opportunity for deep-sea observation techniques, offering new opportunities for long-term monitoring of benthic ecosystems and geophysical processes. In conclusion, this innovative methodology for deploying and retrieving autonomous deep ocean DAS landers, coupled with customizable submarine cable layouts, has the potential to revolutionize underwater sensing and monitoring capabilities across a wide range of scientific and industrial applications.