Real-time identification of NLOS range measurements for enhanced UWB localization

Despite of the ultra-wideband (UWB) system's robustness against multipath in cluttered environments, a number of challenges remain before UWB localization can be implemented. In particular, non-line-of-sight (NLOS) propagation is especially critical for high-resolution localization systems because non-negligibly positive biases will be introduced in distance measurements, thus degrading the localization performance. Here, based on received and first path powers obtainable from channel impulse response (CIR), we propose a simple but very efficient method to distinguish between NLOS and LOS conditions. Our method needs neither the training data nor the prior knowledge about the environments, thus enabling realtime NLOS identification. Despite the simplicity of our method, the experimental results verify its speediness and highly correct detection rate.