Navigation of Ground Vehicles Using Magnetic Field Variations

Abstract

Inexpensive three-axis magnetometers can sense not just heading, but also variations in Earth's magnetic field. Combined with a magnetic field map, this information can be used for positioning. Pairing the three-axis magnetometer measurements with position information from a ground vehicle creates a magnetic field map containing the variation and localized perturbations in Earth's magnetic field as a function of position. A magnetometer and the magnetic field map can then be used for navigation. This paper describes how magnetometer measurements can be used to calculate a position update using three different likelihood functions, and it also demonstrates direct incorporation of magnetic field measurements into a map-matching particle filter. These algorithms were tested in three different vehicles under a variety of road conditions and demonstrated meter-level positioning when local magnetic field features are available. Overall the information is sufficient for road level navigation when used as the sole source of navigation information. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.