Indoor positioning system using geo-magnetic field

In this paper we address the problem of non-adversarial co-operative localization using the Earth's ambient magnetic field. We demonstrate the feasibility of using magnetic field to perform localization and tracking. A three-axis magnetic field sensor is employed to locate and track a target. The algorithm estimates the position using the magnitude of the current magnetic field readings. Our technique depends on the local distortions in the Earth's magnetic field created by presence of various magnetic or metallic objects in the local workspace. These objects may be manmade or naturally occurring. The magnetic field data corresponding to known locations is stored in a database. A reverse lookup is used to estimate the position of the target. The localization techniques described in this paper have demonstrated successful target tracking with the average error radius of 2.5 feet.