A TPMS that uses a unique signature, such as RSSI signal levels and statistics or Doppler shift information, to identify the location of where the TPMS signal is being transmitted from. The TPMS includes a separate transmitter unit provided in each tire, where each transmitter unit transmits TPMS signals including an ID code identifying the tire and the pressure in the tire. The TPMS also includes a receiver unit that receives the TPMS signals from each of the transmitter units, where the receiver unit stores an average or other classification of the signature over time to identify the location of the transmitter unit for a particular ID code. The receiver unit compares the new received TPMS signals to the classified signals to identify whether the ID code indicates that the position of the tire has changed.