A robotic lawnmower system comprising a signal generator (240), a boundary cable, at least one guide cable (260) and a robotic lawnmower (100), said signal generator being configured to transmit a control signal through said boundary cable and a guide signal through said at least one guide cable, and wherein said robotic lawnmower comprises a controller (110) and at least one sensor (170), wherein the controller is configured for receiving said control signal through said at least one sensor (170') and determining a signal level for the control signal; and if the signal level for the control signal is below a threshold value, the controller (110) is configured to receive said guide signal and to synchronize on said guide signal.
