Improved UWB TDoA-Based Positioning Using a Single Hotspot for Industrial IoT Applications

The goal of this article is to investigate ultra wideband localization with time difference of arrival processing at the anchors. We consider scenarios where the anchors are placed very close to each other and the target to be localized is around the group of anchors. All target-anchor communications are assumed to be in line-of-sight. Since our analysis shows that symmetries in anchors' placement, with respect to the target position, degrade the positioning accuracy of standard algorithms, we propose to use a subset selection strategy, where position estimates obtained with properly selected subsets of asymmetric anchors are fused together to get the final localization output. Our results show improved localization accuracy with respect to the use of all anchors, especially in estimating the angle of arrival. Finally, we analyze the impact of an inaccurate time synchronization among the anchors, deriving guidelines for hardware implementation.