The need for indoor pedestrian navigators is quickly increasing in various applications over the last few years. However, indoor navigation still faces many challenges and practical issues, such as the need for special hardware designs and complicated infrastructure requirements. This paper originally proposes a pedestrian navigator based on tightly-coupled (TC) integration of low-cost MEMS (micro-electromechanical systems) sensors and WiFi for handheld devices. Two other approaches are proposed in this paper to enhance the navigation performance: 1)
The use of MEMS solution based on PDR/INS (pedestrian dead reckoning / inertial navigation system) integration; 2) The use of motion constraints, such as non-holonomic constraints (NHC), zero velocity update (ZUPT), and zero angular rate update (ZARU) for the MEMS solution. There are two main contributions in this paper: (1) TC fusion of WiFi, INS, and PDR for pedestrian navigation using an EKF (Extended Kalman Filter); and (2) Better heading estimation using PDR and INS integration to remove the gyro noise which occurs when only vertical gyroscope is used. The performance of the proposed navigation algorithms has been extensively verified through field tests in indoor environments.Experiment results showed that the average RMS position error of the proposed TC integration solution was 3.47m in three trajectories, which is 0.01% of INS, 10.38% of PDR, 32.11% of the developed MEMS solution, and 64.58% of the loosely-coupled (LC) integration. The proposed TC integrated navigation system can work well in the environment with sparse deployment of WiFi access points (APs).