Robust 2D indoor positioning algorithm in the presence of non-line-of-sight signals

The presence of non-line-of-sight (NLOS) signals in indoor positioning systems can severely degrade the positioning accuracy. This paper proposes a novel and computationally efficient algorithm to determine the line-of-sight (LOS) signals and the 2D position of a target in an indoor positioning system. The proposed algorithm was evaluated by simulating an indoor positioning system in 8 m × 8 m room under the presence of NLOS signals. When benchmarked with COFFEE and Triangle-Inequality methods, the proposed method shows significant improvement in computational time (151ms to 768ms) and marginal improvements over COFFEE in terms of F1-Score (at least 5% gain in F1-Score). The 2D position estimates are in less than 4.1 cm mean squared error. Moreover, the proposed algorithm was evaluated experimentally using a low-cost ultrasonic hardware.