Use of Artificial Magnetic Anomalies in Indoor Pedestrian Navigation

Pedestrian dead reckoning (PDR) based on inertial sensing alone does not provide absolute user location relative to the environment. Moreover, accuracy of the PDR position estimates degrades as a function of time due to the inaccuracies in the raw sensor data. Therefore, a key for successful and cost-effective indoor positioning is to find a way to provide occasional location fixes to assist the PDR. We present a novel way to use a magnetometer to detect and identify artificially created magnetic anomalies that can be interpreted as location fixes. Since inertial measurement units (IMUs) commonly include a built-in magnetometer for heading estimation, the proposed method does not require any additional hardware to be carried by the user. The objective of the paper is to introduce the aforementioned approach in more detail and to evaluate it with a prototype and a positioning trial.