Determination of the Existence of LoS Blockage and Its Application to UWB Localization

The presence of a line-of-sight (LoS) blockage is one of the major causes of error for ultra-wideband (UWB) localization. LoS blockage degrades the accuracy of the time of arrival (ToA) estimation of the direct path signal by making the multipath structure complex. Furthermore, propagation through the obstructing material introduces excess propagation delay, which causes ranging errors. In this paper, a hypothesis test approach to determine the existence of a LoS blockage in UWB propagation is proposed. Once the non-LoS is identified, the maximum likelihood estimation (MLE) is used for ToA-based positioning. This ML localization algorithm is applied to a set of indoor propagation measurements made in an office building.