1. A method for locating an object that is at least one of metallic and magnetic with a sensor comprising at least two transmitting coils and one receiving coil which are inductively coupled to each other, the method comprising: supplying a first pair of predetermined AC voltages to the transmitting coils; sampling first currents flowing through the transmitting coils and a first voltage of the receiving coil; supplying a second pair of predetermined AC voltages to the transmitting coils; sampling second currents flowing through the transmitting coils and a second voltage of the receiving coil; determining coupling factors between the transmitting coils and the receiving coil based on the determined first and second currents and the determined first and second voltages; and determining the object based on the coupling factors.