Underwater Data Harvesting From a Bottom Landing Observatory Using AUVs With Underwater Optical Wireless Communication

Abstract The seafloor landing probe (Lander) and the autonomous underwater vehicle (AUV) are widely used for environmental monitoring of the deep-sea floor. Landers are effective for long-term environmental monitoring of fixed points and obtaining continuous temporal changes, while AUVs are effective for observing a wide area and detecting spatial singularities through autonomous navigation. Therefore, the combination of multiple landers and AUVs can optimize the environmental monitoring regime of the deep seafloor. The “underwater data harvesting” is also possible by deploying landers and AUVs on the seafloor simultaneously. The observation period of a lander can extend over a year, during which time there is a risk that observation data may be lost in an accident; if observation data by the lander can be transferred to the AUV while the AUV is simultaneously deployed on the seafloor, the risk of missing data for seafloor environmental monitoring can be suppressed. In this study, field trials of seafloor observation and underwater data harvesting were conducted. The lander “EDOKKO Mark-I type T2” and two AUVs, “Hobalin” and “Hobalin 2” (hereafter AUV1 and AUV2), were deployed simultaneously at a depth of 100 m in Suruga Bay, Japan. Two AUVs approached the lander alternately and acquired seafloor observation data stored on the lander respectively through underwater optical wireless communication at a distance of around 7 m. The approximately 3 GB and 2 GB of seafloor observed data by the lander were transferred to two AUVs and delivered to the research vessel successfully.