Magnetic Signature Sensor Model for Accurate Short-Distance Localization

Abstract

In the realm of indoor localization Bluetooth and Wi-Fi signal strength based ranging approaches are well established. Also, some methods based on signal propagation time are used to determine the distance between an access point and a device. These methods work well at medium to long distances and in line-of-sight, but the provided accuracy of a few meters is too inaccurate for short distances below two meters. In order to introduce a better localization method for short distances, that is only infinitesimally affected by non-ferrous materials, a novel magnetic signature sensor approach is presented. The static part of the system consists of at least two alternating current coils to excite an alternating magnetic field. The dynamic part leverages the magnetometer hardware, found in most smartphones, to measure the coil's magnetic field sampled at a fixed frequency. Further, an automatic set-up method of the system is described, where the measuring device only needs to be moved in between the coils.