Improved Indoor Localization With NLOS Signal Propagations

This paper considers the indoor localization problem with possible non-line-of-sight (NLOS) signal propagations. Although centimeter-level accuracy can be achieved using ultrawideband (UWB) signal sources, NLOS propagation due to reflection and refraction of signals as well as multipath effect may lead to significant errors in UWB-based localization systems. To mitigate this issue, a novel and simple NLOS error compensation method is proposed in this paper, which introduces a correction factor that takes into account the influence of NLOS conditions on the UWB distance measurements. The inertial measurement unit (IMU) information are then used to correct the UWB distance measurements before passing them through a Kalman filter for data fusion. The effectiveness of the proposed approach over the state-of-the-art one is illustrated by both simulation and experiment.