Method and device for locating the position of wheels of a vehicle
Method of locating the position of wheels ( 2 - 5 ) of a vehicle ( 1 ) equipped with an electronic module ( 6 - 9 ) and with transmitting antennas ( 12 - 14 ) positioned in such a way as to present a coverage area in which at least one wheel ( 2 - 5 ) is located. Furthermore, n successive transmissions are ordered, by each transmitting antenna, of an identification request signal, and the number of identification request signals received by each electronic module ( 6 - 9 ) is counted. Furthermore, a ratio representative of the number of counted identification request signals received by each electronic module ( 6 - 9 ) is calculated, relative to the number of identification request signals actually transmitted by the transmitting antenna ( 12 - 14 ), and an indication of presence of the electronic module in the coverage area of the transmitting antenna is provided when the calculated ratio is greater than a predetermined threshold value.
1. Method of locating the position of wheels ( 2 - 5 ) of a vehicle ( 1 ) equipped with an electronic module ( 6 - 9 ) designed to transmit, to a central processing unit ( 11 ) mounted on the vehicle ( 1 ), signals representative of operating parameters of each wheel comprising, in addition, an identification code of the latter, said locating method consisting in equipping the vehicle ( 1 ) with transmitting antennas ( 12 - 14 ) each positioned in such a way as to present a coverage area in which at least one wheel ( 2 - 5 ) is located, and being characterized in that it consists in applying a locating procedure according to which, in succession for each of the transmitting antennas ( 12 - 14 ):
the central processing unit ( 11 ) orders n successive transmissions, by said transmitting antenna, of an identification request signal,
each electronic module ( 6 - 9 ) counts the number of identification request signals received by said electronic module, and, on an ad-hoc basis, orders the transmission of at least one counting signal incorporating the number m of said identification request signals received,
and the central processing unit ( 11 ) is programmed, for each electronic module ( 6 - 9 ), to:
calculate a ratio representative of the number of counted identification request signals received by said electronic module compared to the number of identification request signals actually transmitted by the transmitting antenna ( 12 - 14 ),
and providing an indication of presence of said electronic module in the coverage area of the transmitting antenna ( 12 - 14 ), when the calculated ratio is greater than a predetermined threshold value.
2. Locating method according to claim 1 , in which each electronic module ( 6 - 9 ) is programmed to transmit periodically, in a pre-running phase following a vehicle start-up, an identification signal incorporating the identification code of the wheel ( 2 - 5 ), characterized in that it consists in incorporating the counting data in each of said identification signals.
3. Locating method according to claim 1 , characterized in that the central processing unit ( 11 ) is programmed to order ad hoc transmissions of the counting signals by the electronic modules ( 6 - 9 ).
4. Locating method according to claim 2 , characterized in that, for each transmitting antenna ( 12 - 14 ), the central processing unit is programmed to calculate the ratio at the end of the n transmissions of the identification request signal.
5. Locating method according to claim 2 , characterized in that, for each transmitting antenna ( 12 - 14 ), the central processing unit ( 11 ) is programmed to perform at least one intermediate ratio calculation, and to order the interruption of the n transmissions of the identification request signal when said calculated intermediate ratio is greater than the predetermined threshold value.
6. Locating method according to claim 1 , characterized in that, on each switchover between two transmitting antennas ( 12 - 14 ), the central processing unit ( 11 ) is programmed to transmit a signal to reset the counting of the identification request signals received by the electronic modules ( 6 - 9 ).
7. Locating method according to claim 1 , characterized in that the antennas ( 12 - 14 ) of a hands-free access device fitted on the vehicle ( 1 ), designed to allow access to said vehicle and to start the latter, are used in the locating procedure.
8. Locating method according to claim 3 , characterized in that, for each transmitting antenna ( 12 - 14 ), the central processing unit is programmed to calculate the ratio at the end of the n transmissions of the identification request signal.
9. Locating method according to claim 3 , characterized in that, for each transmitting antenna ( 12 - 14 ), the central processing unit ( 11 ) is programmed to perform at least one intermediate ratio calculation, and to order the interruption of the n transmissions of the identification request signal when said calculated intermediate ratio is greater than the predetermined threshold value.
10. Locating method according to claim 3 , characterized in that, on each switchover between two transmitting antennas ( 12 - 14 ), the central processing unit ( 11 ) is programmed to transmit a signal to reset the counting of the identification request signals received by the electronic modules ( 6 - 9 ).
11. Locating method according to claim 3 , characterized in that the antennas ( 12 - 14 ) of a hands-free access device fitted on the vehicle ( 1 ), designed to allow access to said vehicle and to start the latter, are used in the locating procedure.