Anchor-based localization adopting UWB technology. An enhancement proposal to be effective in harsh environments

Localization in indoor environments is a hard task due to several constraints, both in terms of multiple reflections due to wall and people moving around the localization domain. This is mainly due to the adopted communication technologies to perform both ranging and positioning. Furthermore, there are some applications where the work environment is even more difficult. For example, in underground and underwater scenarios or in special environments where the risk of explosions is very high. In these applications, the object to localize is covered by a metallic shield, e.g. robots, and the localization sensor must be embedded inside the object. This is a special case of Non–Line–of–Sight condition. In our research activity [1], the UltraWide Band (UWB) technology [2] is adopted to perform localization task in indoor environment, considering a square domain, by means of three fixed anchors and one mobile node. In this scenario, we tried to solve three problems: evaluate the nominal performance of UWB localization technology, find a way to approach it in harsh conditions, as the one above specified, and a further investigation on optimal anchors’ positions in the localization domain to verify sensitivity to specific set-up arrangement. Two analyses were carried out to highlight the system susceptibility to nonnominal conditions: presence of an aluminum shield around the mobile node and anchor’s placement in different points along the localization domain boundary.