VISAS - Augmented diving - acoustic location of the underwater tablet

Augmented Diving - How does it work VISAS' acoustic location system?
case study: Cala Minnola (Levanzo island, Sicily)
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VISAS is a collaborative research project aimed to improve the responsible and sustainable exploitation of underwater archaeological sites. This strategic goal is reached through the development of an integrated package of services.
One of them is the Augmented diving, which is intended for the divers who are going to visit an underwater site, allowing them to have a virtual guide that provides specific information about the artifacts and the area they are visiting. The service is based on a tablet properly equipped with a waterproof case and an integrated system for acoustic localization and inertial navigation.
The underwater positioning tools currently available on the market are based on very expensive acoustic communication systems. The goal of the VISAS project is to build a low-cost underwater positioning and orientation system composed by one or more fixed beacons placed on the seabed and an underwater tablet equipped with an acoustic modem (LBL technique). The tracking system on the tablet sends a query to the beacons and computes the distance from each of them. The data it receives from beacons are used by a data fusion algorithm to correct the estimate on the position, obtained through an inertial system and a pressure sensor. The navigation software receives this information and shows the location of the tablet on a 3D map of the underwater archaeological site. The map, shown on the user interface together with other useful information (system status, battery charge, water temperature, depth), guides the diver along the selected track, inside the archaeological site, and gives also the opportunity to shoot photos, automatically geolocated.
For more info, visit the official website: www.visas-project.eu