Multipath-assisted indoor positioning enabled by directional UWB sector antennas

High-accuracy indoor radio positioning can be achieved by using high signal bandwidths to increase the time resolution. Multiple fixed anchor nodes are needed to compute the position or alternatively, reflected multipath components can be exploited with a single anchor. In this work, we propose a method that explores the time and angular domains with a single anchor. This is enabled by switching between multiple directional ultra-wideband (UWB) antennas. The UWB transmission allows to perform multipath resolved indoor positioning, while the directionality increases the robustness to undesired, interfering multipath propagation with the benefit that the required bandwidth is drastically reduced. The positioning accuracy and performance bounds of the switched antenna are compared to an omni-directional antenna. Two positioning algorithms are presented based on different prior knowledge available, one using floorplan information only and the other using additionally the beampatterns of the antennas. We show that the accuracy of the position estimate is significantly improved, especially in tangential direction to the anchor.