Patent ID: 7924147

Claim:
A tyre pressure monitoring system for a vehicle comprising: at least two tyre pressure transducers, each transducer being associated with a tyre of the vehicle; and at least two initiators each of which is associated with a corresponding one of said transducers, each of said initiators being operable to transmit an initiation signal with said transducers responding to exposure from said initiation signals by transmitting a return signal indicating that it has been woken by one of said initiation signals, each initiator being located in a position on the vehicle that is close to said transducer associated with said initiator with said initiator detecting a response only from its associated transducer when said associated transducer is a favorable position and the other transducer is an unfavorable position, but with said initiator also receiving a response from said other transducer only when said other transducer is in a favorable position and not receiving the response from its associated transducer when said associated transducer is in a least favorable position, each of said initiators further arranged to vary the strength of said initiation signal emitted by said initiator across a number of values within a range until the signal strength is such that the response is received from only one of said transducers.