1. A robotic system for systematically moving about an area to be covered, the system comprising: at least one boundary marker located along the outer edge of the area to be covered; a robot for systematically moving about said area to be covered, the robot including a navigation system for navigating said robot in generally straight, parallel lines from an initial location and for turning said robot when said robot encounters one of said at least one boundary marker; and a sensor unit for sensing proximity to one of said at least one boundary marker.