Magnetic Mapping for Robot Navigation in Indoor Environments

Magnetic disturbances of the Earth’s magnetic field (magnetic anomalies) occur normally in indoor environments due to the presence of ferromagnetic artefacts, such as reinforced concrete or steel infrastructures and other local metallic objects. In conventional robot navigation, which uses the direction of the Earth’s magnetic field to determine orientation, these anomalies are seen as undesirable. However, if the environment is rich in anomalies with sufficient local variability, these can be mapped and used as features for localization purposes. The work presented here aims at exploiting these magnetic features optimally for navigation of mobile robots, by employing advanced interpolation techniques that permit precise mapping of magnetic fields in indoor environments that cannot be surveyed according to a regular grid during map acquisition and may suffer from large gaps in the magnetic coverage. First, the issues addressed to create a magnetic map are depicted, namely data acquisition, methods of interpolation employed, and map validation processes. Subsequently, the results of multiple localization experiments are presented and discussed.