Low-cost localisation considering LOS/NLOS impacts in challenging indoor environments

One popular indoor localisation method in wireless sensor networks (WSN) and wireless local area networks (WLAN) is fingerprinting technique. However, the training stage of fingerprinting and constructing the radio map is time-consuming and labour-intensive. Here, we propose a novel method to decrease the training cost by building a simulated radio map using an improved path-loss model in which the impacts of line of sight (LOS) and non-light-of-sight (NLOS) propagations are considered. Including LOS/NLOS effects also improves distance estimation. Furthermore, the simulated radio map helps assess and improve the fingerprinting area and network parameters prior to the actual positioning. For performance evaluation, three different radio maps are created using simulation and a test field experiment and then compared based on deterministic and probabilistic algorithms. The results indicate that the improved model outperforms the typical path-loss model and the localisation error gets closer to the actual error of the fingerprinting network.