Indoor Passive Localization With Channel State Information Using a Single Access Point

With the development of multi-antenna technology, the localization technology based on Wi-Fi has made progress. However, the single station passive localization is still confronted with the problem of low accuracy. Towards this end, this paper proposes an indoor localization system with a single Access Point (AP). Firstly, we present a novel Channel State Information (CSI) phase error correction method to eliminate the phase error that caused by the Symbol Time Offset (STO) and the Sample Frequency Offset (SFO) due to the lack of rigid time synchronization between Wi-Fi transceivers. Then, the Time of Flight (ToF) of the reflected signal is obtained by the discrete correlation estimation algorithm. On this basis, we propose a Regionalized Orthogonal Matching Pursuit (R-OMP) algorithm to estimate the Angle of Arrival (AoA) of the reflected signal. The proposed R-OMP algorithm reduces the complexity of the traditional Orthogonal Matching Pursuit (OMP) algorithm via reducing the search area. Finally, we get the location of the target by building a single station localization model. Experiments show that the median localization error of the system can reach 0.75 meters in a typical indoor environment, which is significantly improved compared with the previous single station localization system.