Method for temporarily inhibiting remote activation of a function present in a motor vehicle

1. A method for temporarily inhibiting remote activation of a function present in a motor vehicle, the remote activation taking place between an activation means carried by a person authorized to perform the remote activation and an activation module present in the vehicle through the transmission, reception and measurement of electromagnetic waves between the activation means and the activation module, the activation module being able to recognize the activation means, to determine a mathematical position in an electromagnetic field space of the activation means for a detection zone and to authorize the activation in this case, the activation being inhibited after a predetermined number of activation attempts that are unsuccessful as they are considered to be located outside of the detection zone, wherein the respective mathematical positions of the unsuccessful activation attempts are stored and that only activation attempts whose position differs by a certain threshold from at least one position of an already stored unsuccessful activation attempt are taken into account as unsuccessful activation attempts.

2. The method as claimed in claim 1 , wherein the activation module is associated with at least one antenna for transmitting and receiving electromagnetic waves and that is situated on or in the motor vehicle.

3. The method as claimed in claim 2 , wherein, when the activation module is associated with a plurality of antennas, the antennas are positioned at various locations of the vehicle, the antennas or groups of antennas transmitting electromagnetic waves alternately.

4. The method as claimed in claim 2 , wherein each mathematical position of the activation means is determined by at least one received signal strength indication, received by the antenna or each antenna, of an electromagnetic wave returning from the activation means.

5. The method as claimed in claim 4 , wherein each received signal strength indication, received from the electromagnetic wave returning from the activation means, undergoes processing so as to reduce amplitude dynamics on the basis of the distance from the activation means to the antenna or to each antenna.

6. The method as claimed claim 4 , wherein the stored unsuccessful attempts to remotely activate the vehicle are grouped into at least one software memory integrated into the activation module, the antenna or each antenna having a respective software memory.

7. The method as claimed in claim 6 , wherein, for a new unsuccessful activation attempt, the position of the new activation attempt is compared, in the activation module, with the positions of the unsuccessful activation attempts from the or from each memory per antenna, and if none of the positions of the unsuccessful activation attempts already in memory are identical to the position of the new activation attempt, with consideration to a predetermined margin of error, the position of the new activation attempt is deemed to be different, and this position is entered into the respective memory or memories.

8. The method as claimed in claim 7 , wherein the comparison is performed using a calculation of a mathematical distance between the position of the new unsuccessful activation attempt and the position of each stored unsuccessful activation attempt using the following equations, with, for a single antenna:

Distance= MES _memory 1 −MES _new 1

or, with, for n antennas, n being greater than or equal to 1:

Distance=(( MES _memory 1 −MES _new 1) 2 + . . . +( MES _memory n−MES _new n ) 2 ) 0.5

MES_memory 1 and MES_memory n being the received signal strength indications for the memory of the first antenna and of the nth antenna, MES_new 1 and MES_new n being the received signal strength indications for the new activation attempt for the memory of the first antenna and of the nth antenna, and if the distance is less than a predetermined threshold representative of a movement of the activation means in surroundings within the reach of a person carrying the activation means without the person moving, the position of the new activation attempt is deemed to be identical and is not counted in the list or lists, whereas, if none of the positions of the unsuccessful activation attempts already in memory are identical to the new position, the new position is deemed to be different, and this position is entered into the respective memory or memories.

9. The method as claimed in claim 8 , wherein, after a maximum number of unsuccessful activation attempts is reached, inhibition of the remote activation is performed and remains valid for a predetermined inhibition duration, and in that, after successful activation of a function of the motor vehicle, where applicable with consideration to a delay time and/or a distance covered by the vehicle after the successful activation, at least some of the stored positions of the unsuccessful activation attempts are deleted.

10. A method for remotely activating a function of a motor vehicle, the activation taking place between an activation means carried by a person authorized to perform this activation and an activation module present in the vehicle through the transmission, reception and measurement of electromagnetic waves between the activation means and the activation module, comprising a temporary inhibition method as claimed in claim 1 .

11. The method as claimed in claim 3 , wherein each mathematical position of the activation means is determined by at least one received signal strength indication, received by the antenna or each antenna, of an electromagnetic wave returning from the activation means.

12. The method as claimed in claim 5 , wherein the stored unsuccessful attempts to remotely activate the vehicle are grouped into at least one software memory integrated into the activation module, the antenna or each antenna having a respective software memory.

13. The method as claimed in claim 7 , wherein, after a maximum number of unsuccessful activation attempts is reached, inhibition of the remote activation is performed and remains valid for a predetermined inhibition duration, and in that, after successful activation of a function of the motor vehicle, where applicable with consideration to a delay time and/or a distance covered by the vehicle after the successful activation, at least some of the stored positions of the unsuccessful activation attempts are deleted.