A robotic mower boundary sensing system includes a boundary driving circuit on a charging station (105) transmitting an encoded signal on a boundary wire (103, 104); a boundary sensor (119) on a robotic mower (100) and including an inductor receiving the encoded signal; and a vehicle control unit (101) on the robotic mower (100) receiving the encoded signal from the boundary sensor (119) and decoding the signal and determining the distance of the boundary sensor (119) to the boundary wire (103, 104).