2D UWB Localization in Indoor Multipath Environment Using a Joint ToA/DoA Technique

A 2D UWB localization technique based on joint ToA/DoA in indoor dense multipath environment is proposed. In this method, direction of arrival (DoA) is estimated from time of arrival (ToA). The joint usage of ToA and DoA results in an accurate localization of the mobile node (MN). Unlike conventional methods, the proposed localization technique needs only one access point (AP) with an array structure. This consequently eases the synchronization requirement of the proposed localization scheme when compared to the classical ToA-based technique requiring 3 of more synchronized APs. To verify the proposed method real time UWB measurements in dense indoor multipath environment covering 2-6 GHz band were carried out. The results show that accurate 2D localization can be achieved using the proposed scheme. Furthermore, the accuracy performance of the proposed technique is compared to the classical ToA localization technique using more than 3 APs. The results, in terms of average range error, show that the ToA method slightly outperforms the proposed scheme for the LOS. However, for the NLOS the proposed scheme always provides a better position estimation (i.e. less average range error). For instance, the proposed technique provides an average range error of less than 2.3 cm for LOS and 12.3 cm for NLOS situations. The angular error is less than 0.5 degrees and 1.48 degrees for LOS and NLOS scenarios, respectively.