8th INTERNATIONAL CONGRESS on NATURAL and ENGINEERING SCIENCES, Antalya, Turkey, 21 - 23 December 2023, pp.15
In this paper, the effect of line-of-sight (LOS) and non-LOS (NLOS) conditions in range measurements are investigated. For that purpose, an indoor ultra-wideband (UWB) positioning data set and a classical multi-lateration algorithm are used. In the data set, a tag (mobile device) is moved on a predefined path, and range measurements between the tag and 8 anchors (fixed devices) are collected at each position on the path. For each UWB channel (there are 6 of them, but only the first channel is used), 31 range measurements to each anchor are taken from the tag’s each position on the path. In this study, median of those 31 measurements is used to obtain positioning outputs. Although measurements are collected in 4 different indoor environments (house, apartment, office, industry), measurements of only one environment (industry) allow us to compare LOS and NLOS conditions because 57 samples out of 84 samples (~68%) of the chosen environment’s path can be used for LOS positioning and NLOS positioning at the same time while maximum of that percentage in other three environments’ path is ~26%. This study shows that if one uses only LOS measurements, root mean square of positioning error (RMSE) is 0.53 m. RMSE of only NLOS measurements is 3.11 m. If both LOS and NLOS measurements are used, RMSE is 1.55 m. As a result, use of LOS measurements is more preferrable.