Method for tracking movement of a mobile robotic device

This invention describes a robotic device that can track its own location and movement very accurately. It uses various sensors, like those measuring wheel turns and the surface it's on, to estimate where it's going. To correct any errors, it also takes pictures of its surroundings and compares what it sees to a set of possible locations, picking the most likely one to update its position. The claims narrow this to a robot with a chassis, wheels, motors, and tools for performing work.