Acoustic data analysis for underwater archaeological sites detection and mapping by means of autonomous underwater vehicles

In the framework of the ARROWS project (FP7 Environment 308724, September 2012 - August 2015), venture funded by the European Commission, modular Autonomous Underwater Vehicles (AUVs) have been developed to the main purposes of mapping, diagnosing, cleaning, and securing of underwater and coastal archaeological sites. These AUVs consist of modular mobile robots, designed and manufactured according to specific directions formulated by a group of expert archaeologists, the Archaeological Advisory Group (AAG). A preliminary fleet of mobile robots, with supplied functionalities that can be adjusted on the mission purpose, has been put together. The vehicles are typically equipped with acoustic modems to communicate during the dive and with different payload devices to sense the environment: a pair of synchronized digital cameras operating in the visible light range, a structured light source (blue laser) plus led illuminators and, depending on the mission requirement, a multibeam forward looking echo-sounder or a side looking sonar. These sensors represent appealing choices to the oceanographic engineer since they provide complementary information about the surrounding environment. Generally speaking acoustic sensors are exploited to create large scale maps of the environment while cameras provide more detailed images of the targets. The main goal of the ARROWS missions is to perform a systematic mapping of the marine seafloors and to process the output maps to detect and classify potential archaeological targets.