An indoor positioning scheme exploiting geomagnetic sensor of smartphones

Abstract

In this paper, an indoor positioning scheme using geomagnetic sensor of smart devices is proposed. The proposed scheme is based on a fingerprint technique that can estimate the position of the user by comparing the sensed values of geomagnetic sensor with a pre-collected database. To investigate the characteristics of geomagnetic sensor, we have conducted experiments by using only geomagnetic sensors among the built-in inertial sensors of smartphones. Three different experiments were conducted, and firstly we collected the measurements of geomagnetic sensor at the fixed points throughout a day to identify changes in values and patterns. Secondly, 9 points were selected and measured where feature of the geomagnetic value has, and thirdly geomagnetism data was collected while moving a specific route. With the results of experiments, we analyzed the collected data and proposed a positioning scheme to estimate the location by using the geomagnetic values. According to the results, the data measured throughout a day and the data collected at a specific point have a problem that can cause errors, because the measured values change with time. Meanwhile, it is shown that the measured data has a unique pattern while it moves a specific route and there is hardly changes in geomagnetism patterns as time is passed. Therefore, it is concluded that this feature can be utilized in indoor positioning scheme exploiting geomagnetic sensor, rather than the simple fingerprint scheme based on a static database of specific points.