An Inter Smart Phones Relative Positioning Method Based On Inertial Sensors

As the technology and people’s living standard develops, location-based services for people’s daily lives are becoming more and more important. Applications such as navigation system are based on location-based services. However, most location-based services are based on the absolute position, which are not intuitive under some scenarios. For example, in a shopping mall, and you would like to confirm the location of your companion as soon as possible, the absolute position is not particularly intuitive. Imagine if you can get the relative position, you can easily and quickly find your companion. Actually there has been many applications request relative position between two mobile devices, such as monitoring and tour guiding. However, the existing positioning methods have many problems. For example, some of them need complex deployments which makes the positioning systems lack of flexibility. Based on the considerations mentioned above, we propose a relative positioning method based on inertial sensors in smart phones.Using geometrical method, this positioning method calculates the relative position between two devices through measuring the distance and position change of the two devices in the moving process with the inertial sensors and wireless chips. In the process, acceleration sensors in smart phones can be used to measure the acceleration of the phones in order to take gait detection. And geomagnetic sensors can be used to judge the heading direction of the phones. Compared to many other existing positioning methods, the method mentioned in this thesis has many advantages. First, the method only requires the basic wireless chips and inertial sensors equipped into the mobile device instead of any external infrastructures. It greatly reduces the cost and enhances the flexibility of the positioning system. Furthermore, the device can move casually during the positioning process without limitations, making the positioning process very flexible. Totally, relative positioning method based on inertial sensors in smart phones will have a good development prospect.