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A. Ettlinger, G. Retscher:
"Positioning Using Ambient Magnetic Fields in Combination with Wi-Fi and RFID";
Talk: 7th International Conference Indoor Positioning and Indoor Navigation IPIN 2016, Alcalá de Henares (invited); 2016-10-04 - 2016-10-06; in: "7th International Conference Indoor Positioning and Indoor Navigation IPIN 2016", (2016), ISBN: 978-1-5090-2424-7; Paper ID 47, 8 pages.

The earth´s magnetic field needs no transmitter infrastructure and can be measured everywhere. Therefore its use in fingerprinting technology for indoor-positioning and navigation seems to be useful. In this work the magnetic field is used in combination with Wi-Fi and RFID in the fingerprinting approach. The idea is to first calculate an approximate solution with Wi-Fi and then refine it with the magnetic field. Additionally RFID can also be used in this approach to further refine the approximate solution from Wi-Fi. To analyze the achievable accuracies static and kinematic test measurements are done. In the static test measurements the positions are calculated by using different sensors (Smartphone and low-cost IMU), different distance criteria and different signal sources. The smallest positioning errors (about 2m) occur by using all signal sources (magnetic field, Wi-Fi, RFID) and the Mahalanobisdistance. At the kinematic test measurements a Kalman Filter is used. A motion model delivers values for the system equation and the observations are retrieved by using magnetic field- and Wi-Fi-Fingerprinting. The kinematic positioning errors do not exceed 6m.

fingerprinting, geomagnetic field, Wi-Fi, RFID, kinematic positioning