Carrier Phase-based Wi-Fi Indoor Localization Method

Abstract

Channel State Information (CSI)-based indoor Angle of Arrival (AoA) localization has gradually become a hot research direction. However, due to the lack of the method toward improving angle resolution of AOA, AOA-based indoor localization method is difficult to achieve sub-meter accuracy. In this paper, a novel method for carrier phase-based Wi-Fi indoor localization using finer-grained and more diverse carrier phase information of CSI is proposed to improve the localization accuracy. According to the center frequency carrier phase of CSI and Time of Flight (ToF) in Line of Sight (LoS) path, the distance from the target to multiple receivers can be estimated. Secondly, a carrier phase localization model is constructed to get the initial target location. Then, combining the Least-squares Ambiguity Decorrelated Adjustment (LAMBDA) algorithm, we eliminate the integer ambiguity of carrier phase localization model. Finally, the initial location is updated to obtain the precise location of target. The experimental results show that the localization error reaches 0.25 m when there are 7 receivers in the environment.