Patent ID: 6917287

Claim:
A system for monitoring the tires of a vehicle having two axles, each axle having a tire-wheel assembly and the two tire-wheel assemblies defining an axis D 1 , said system comprising: a wheel unit disposed in each tire-wheel assembly comprising a radio transmitter capable of transmitting waves of a frequency F of more than 300 MHz in short pulses, a central unit for processing data transmitted by the radio transmitter a device for automatically locating the position on the vehicle of the radio transmitters, wherein the automatic locating device comprises: a first radio reception channel having a first aerial; a second radio reception channel having a second aerial, the first and second aerials defining an axis that is substantially parallel to D 1 , said first and second aerials being separated by a distance d, wherein d satisfies the following equation: (2 n +1)λ/4−λ/8 ≦d ≦(2 n+ 1)λ/4+λ/8, n being an integer greater than or equal to 0, wherein λ is the wavelength of the frequency F of the radio transmissions of the transmitters; a first means of comparison of the phases of a radio signal received by the first and second aerials in order to determine whether the radio signal received by the first aerial is ahead of phase, behind phase or has an identical phase relative to the radio signal received by the second aerial; and a means of processing the results transmitted by the first means of comparison to indicate the position of the radio transmitter relative to the said aerials.