Indoor Real-Time Localization by Mitigating Multipath Signals

Indoor localization using WiFi signal has received great attentions since it is ubiquitous. So, in this paper we propose the design, implementation and evaluation of a real-time indoor localization system using commodity WiFi signal. The proposed system can localize the target by using Angle of Arrival (AOA) without any hardware modification and large localization latency. The contributions of this paper are follows. Firstly, an Angle estimation algorithm based on WiFi signals is proposed, which can quickly estimate AOA of Line of Sight (LOS) path in the case of fewer antennas and packets, ensuring real-time localization. Secondly, the influence of multipath signals on the energy spectrum of direct signals is analyzed by using the IEEE 802.11 Saleh-Valenzuela (S-V) channel model. Then, in order to improve localization accuracy, we propose a method of antenna selection. Finally, to deliver a real-time localization system we realize the proposed system by developing a software framework including a localization sever and a web-based location displayer. We have implemented the system on the commodity WiFi APs and the experimental results show that it can achieve accurate localization and has less the time cost.