Feasibility of Smartphone-Attached UWB Tag for Daily life Indoor Pedestrian Tracking

Features like high bandwidth, low-cost, and low power consumption make ultra-wideband (UWB) technology a preferable candidate for indoor pedestrian tracking at centimeter-level accuracy. For that reason, the latest smartphones are embedded with UWB chips. However, the daily life wearable locations of smartphone can severely degrade the UWB tracking accuracy due to the signal blocking between the pedestrian-worn UWB sensor (UWB tag) and infrastructure UWB sensors (UWB anchors). And each wearable location of the UWB tag can lead up to meter-level error depending on the degree of signal blocking. This paper describes the feasibility of a smartphone-attached UWB tag for daily life indoor pedestrian tracking application. We evaluated the UWB tracking performance in daily life smartphone wearing locations, such as texting, calling, swinging, and pocketing, by performing a real-time indoor pedestrian walking experiment. For experimental validation, ground truth pedestrian trajectory is measured using state-of-the-art Hokuyo Lidar. The experimental results demonstrated that the mean absolute error of the UWB tracking can rise up to 0.37 m, 1.12m, 0.74m, and 0.46 m for the texting, calling, swinging, and pocketing, respectively, compared to the 0.14 m of head-placed UWB tag.