Indoor positioning based on tightly coupling of PDR and one single Wi-Fi FTM AP

Abstract

ABSTRACTThe indoor positioning system is now an important technique as part of the Internet-of-Things (IoT) ecosystem. Among indoor positioning techniques, multiple Wi-Fi Access Points (APs)-based positioning systems have been researched a lot. There is a lack of research focusing on the scene where only one Wi-Fi AP is available. This work proposes a hybrid indoor positioning system that takes advantage of the Fine-Timing Measurements (FTM) technique that is part of the IEEE 802.11mc standard, introduced back in 2016. The system uses one single Wi-Fi FTM AP and takes advantage of the built-in inertial sensors of the smartphone to estimate the device’s position. We explore both Loosely Coupled (LC) and Tightly Coupled (TC) integration schemes for the sensors’ data fusion. Experimental results show that the proposed methods can achieve an average positioning accuracy of about 1 m without knowing the initial position. Compared with the LC integration method, the median error accuracy of the proposed TC fusion algorithm has improved by more than 52% and 67%, respectively, in the two experiments we set up.

Keywords

• Indoor positioning
• Wi-Fi Fine Time Measurement (FTM)/Round Trip Time (RTT)
• Tightly Coupled (TC) integration
• Pedestrian Dead Reckoning (PDR)
• Extended Kalman Filter (EKF)