Patent ID: 8031065

Claim:
A tire monitor device for a vehicle comprising: a first antenna and a second antenna; a sensor unit attached to each of a front left tire, a front right tire, a back left tire, and a back right tire; and a determining unit, wherein the tire monitor device is operable to transmit a response request signal from the first and second antennas with respect to at least one of the sensor units, and to monitor information of at least one of the tires based on a response signal returned from the at least one sensor unit in response to the response request signal; wherein the first antenna is arranged at a position shifted by a predetermined amount in a left or right direction from an intermediate position between the front left and the front right tires; wherein the second antenna is arranged at a position shifted by a predetermined amount in a left or right direction from an intermediate position between the back left and the back right tires; wherein the sensor unit measures a reception level of the response request signal, and returns a measurement result in the response signal; and wherein the determining unit is operable to determine a position of each sensor unit based on information of the reception level of the response request signal contained in the response signal returned from each of the sensor units.