Seamless outdoor/indoor navigation with WIFI/GPS aided low cost Inertial Navigation System

This paper describes an integrated navigation system that can be used for pedestrian navigation in both outdoor and indoor environments. With the aid of Global Positioning System (GPS) positioning solutions, an Inertial Navigation System (INS) can provide stable and continuous outdoor navigation. When moving indoors, WIFI positioning can replace the GPS in order to maintain the integrated system’s long-term reliability and stability. On the other hand, the position from an INS can also provide a priori information to aid WIFI positioning. Signal strength-based WIFI positioning is widely used for indoor navigation. A new fingerprinting method is proposed so as to improve the performance of WIFI stand-alone positioning. For pedestrian navigation applications, a step detection method is implemented to constrain the growth of the INS error using an Extended Kalman Filter (EKF). Experiments have been conducted to test this system and the results have demonstrated the feasibility of this seamless outdoor/indoor navigation system.