An UWB-based System for Localization inside Merchant Vessels

Vessels are nowadays widely used for goods transportation. To ensure their physical integrity, they must be periodically surveyed, searching for defects, e.g. cracks and corrosion. The inspection process is carried out at a great cost due to the arrangements required to allow the surveyors to reach any point of the structure, while guaranteeing their safety. In recent years, the idea of introducing robots in the inspection of ships is being investigated. In this line, we propose two contributions for the estimation of 3D position inside vessels, making use of UWB technology. Since this technology is typically affected by the presence of metallic elements, we firstly propose a filtering method to improve the tag-anchor distance estimates. The second contribution consists in a novel method based on ICP to estimate the position of the UWB tag making use of point-to-sphere correspondence. Both contributions have been evaluated using several datasets taken inside a real vessel. The results show that our methods are able to provide satisfactory position estimates inside that environment.