Inertial Sensor Based Indoor Positioning System

Abstract

An indoor navigation system that tracks the location of a person is useful for nding and rescuing re ghters or other emergency rst responders, or for nding a place inside a building, targeted advertisement in a shopping mall and for other mixed and augmented reality applications. While GPS or other radio navigation aids are commonly used for navigation in outdoor areas, accurate indoor navigation remains an unsolved problem. Inertial sensors have been considered as a promising indoor navigation aid and it has gained popularity for its potential application to track people in risky environments or in rescue missions. Studies have been done to integrate information from inertial sensors like accelerometers, gyroscopes and magnetometers to accurately track the location of subjects on indoor environments. These self-contained inertial sensors allow location-independent and an infrastructure-free navigation. In this research, an inertial sensor based pedestrian positioning system was designed and implemented to track the position of a person without the aid of wireless technologies. A commodity smart phone with accelerometer, gyroscope and magnetometer was used as the sensor unit. The phone was placed on the waist of the users. The inertial navigation based tracking was done using pedestrian dead reckoning approach where the tracking is done by continuously estimating the displacement from a known location. The traveled distance is determined by step detection and step length estimation. Experiments were conducted on straight line tracks and the results indicate that the error of step detection is less than 1% and the system can achieve a mean accuracy of 2.2 m for distances up to 26 meters. Issues and proposed improvements to the system are also discussed in this work.