TPMS Tire Localization with RF Transceiver 2017-01-1638
Tire Pressure Monitoring System (TPMS) sensor measures air pressure and temperature in the tire and transmits tire information as wireless messages to TPMS central unit which consists of Radio Frequency (RF) receiver. TPMS central unit needs to determine the exact sensor locations (e.g. Front Left, Front Right, Rear Left or Rear Right) in order to correctly identify the location of the tire with pressure out of the desired range. The identified tire with abnormal pressure is highlighted on dash board in the car. Thus, determination of the location of a particular tire made automatically by the TPMS system itself or tire localization is required. TPMS tire localization is implemented currently in several methods. A new method is proposed in this paper. The proposed method uses at least two RF transceivers as repeaters. Each transceiver receives wireless messages (eg. Pressure, temperature, sensor ID) from the nearest TPMS sensor and re-transmits them with RF transceiver identity to TPMS central unit. RF transceiver is fixed near to each wheel in the car and its position is known to TPMS central unit. Based on its Received Signal Strength (RSSI), RF transceiver identifies sensor signal from the nearest TPMS sensor. To improve tire auto localization, an algorithm is developed by providing histogram distribution of wireless messages based on the signal strengths. The algorithm compares the histogram distribution to a predetermined histogram distribution to determine the position of the tire on the vehicle. The proposed method consumes less power and does not require additional wirings in the car as compared to using low frequency repeaters. Tire auto localization using hybrid method correlates sensor speed with wheel speed signal from anti braking system and so it involves access to other system. In practice, access to wheel speed signals is difficult.