Magnetic map building for mobile robot localization purpose

Robotic mapping addresses the problem of modeling environments through mobile robots sensors. The resulting maps are commonly used for robot localization and navigation. Using a compass in mobile robotics is not frequently considered because it has a significant disadvantage: the data it provides can be easily contaminated by surrounding electromagnetic noise or by large ferrous structures. This makes the compass unreliable for heading determination in indoor environments. This paper addresses construction of an environmental magnetic map with a mobile robot, and how to use such map to determine the robots local heading. We present a novel approach that characterize indoor environments as a magnetic field function. A mobile robot gathers data from a low cost compass as it moves around. This method models the robots working area by means of a simple representation which is time persistent and does not require specialized sensors. Thus, we propose a methodology based on 2D interpolation aimed at determining the robots heading on the working area. Real test results showed the method is suitable for the partial correction of the robots position.