Indoor NLOS Localization Using Customized Active Reflectors

To solve the problem of indoor non-line-of-sight (NLOS) localization using a single access point (AP), the customized active reflector is proposed, which can be used as virtual APs. Firstly, the parameters of the received paths are resolved using channel state information (CSI) and then the desired paths are extracted using the K-means clustering algorithm combined with the prior information of the reflector. Secondly, the relative time of flight (rTOF) is used to establish the localization model, and the rough estimation of target location is obtained from semi-definite programming (SDP). Then the least squares (LS) is used to solve the target location. Finally, we implement the proposed system in the real indoor environment, and the experimental result shows that the proposed system can achieve a localization accuracy of 1.3 m in the NLOS environment.