A low complexity NLOS error mitigation method in UWB localization

Ultra wideband (UWB) technique is attractive in indoor localization due to its high accuracy measurement and robustness to obstacle penetrations. However, considerable ranging errors can still be introduced by the presence of obstacles since the line of sight (LOS) is blocked. Many techniques have been proposed to address this problem, but most of them require too much a priori information, and become impractical. In this paper, we present a non-parametric non-line of sight (NLOS) error mitigation method based on the k-nearest neighbor (k-NN) framework, which is able to effectively compensate the ranging biases introduced by the obstacles. Our work is carried out and validated by practical measurements using FCC-compliant UWB radios. The results show that the proposed method provides relative high performance improvements, and is less computational required than the existing non-parametric strategies.