Global and Local Localizations Using an Environmental Magnetic Field and a Scan Matching Method

Global and local localizations are critical for mobile robots to perform tasks without human support. In this study, we proposed a new method for global and local localizations that combines an environmental magnetic field with a scan matching method. In this method, we record the environmental magnetic field at each waypoint during the map-building process. To perform global localization, we rotate the mobile robot’s magnetic sensor-detected heading direction (current magnetic heading direction) to approximate the heading direction of the environmental magnetic field stored on the map. Subsequently, we use the scan matching method at positions around each waypoint. The mobile robot is currently in the position with the highest matching rate. The experimental results show that the mobile robot can successfully localize almost anywhere in the indoor environment, with the exception of a position where the magnetic sensor is affected by electric boards, and has a high success rate in an outdoor environment. For the local localization, we calculate the deviation between the mobile robot’s current magnetic heading direction and the one stored on the map, and then use this deviation to improve the localization using the scan matching method. The experimental results show that the mobile robot can perform much stronger localization during autonomous navigation.