A robotic lawnmower system comprising a charging station (210) and a robotic wetfe-teellawnmower (100), the charging station comprising a signal generator (240) to which a navigation signal cable (260； 250) is to be connected, the signal generator (240) being configured to transmit a signal (265 ； 245) through the navigation signal cable (260； 250), and the roboticwerkiagTeollawnniower (100) comprising: a propulsion system (130, 150)； a sensor (170) configured to sense field values of magnetic fields generated by the signal (265； 245) in the navigation signal cable (260； 250)； and a controller (110) configured to determine that the robotic lawnmower (100) is in a docking position； record the field value(s) of the sensed signal； control the propulsion system (130, 150) to reverse out of said docking position； and to control the propulsion system (130, 150) to enter into said docking position by sensing a current field value； comparing the current field value to the stored field value(s)； and determining how to navigate the robotic lawnmower (100) based on the comparison and navigating accordingly.To be published with Figs. 6A and 6B.
