Indoor Localization Using a Single Receiver in NLoS Environments

At present, most of the indoor localization methods are based on Line-of-Sight (LoS) propagation path. However, Non-Line-of-Sight (NLoS) propagation degrades those methods significantly, which happens frequently in indoor environments. In this paper, we present a multipath assisted indoor localization system with only a single receiver in NLoS environment. First, we use the 3D Recursively Applied and Projected-Multiple Signal Classification (RAP-MUSIC) to estimate the Angle of Arrival (AoA), Angle of Departure (AoD) and Time of Flight (ToF) of propagation path. Then, considering the non-synchronization between the target and receiver, we use the relative ToFs of the NLoS paths and then propose a novel localization model according to the geometric relationship between the NLoS paths and locations of the target and receiver. In addition, we derive the closed-form solution of the target location. Finally, Wireless Insite is used to simulate the real environment which is a ray-tracing based simulation software and the simulation results show that the proposed method can achieve good performance with only a single receiver.

I. Introduction

With the development of Internet of Things (IoTs), the demand for Location Based Services (LBS) is increasing. Indoor localization as the basis of those LBS becomes more and more important. Most of the indoor localization researches are based on Line-of-Sight (LoS) propagations [1]. In addition, these localization methods achieve high localization accuracy at the cost of using multiple receivers. However, the presence of obstacles in indoor environment such as wall will lead to Non-Line-of-Sight (NLoS) propagations. Therefore, those LoS path based methods fail to locate the target. Besides that, using only a single receiver is more practical. Can we locate the target in NLoS environment, even use a single receiver? To answer this question, in this paper we propose an indoor NLoS localization method with only a single receiver.