Abstract: A method for managing location of a user device in a passenger compartment of a vehicle, including in particular the steps of calculating the distance of the user device in relation to each of the transceivers from the received response signals, calculating, for each transceiver, the difference between the distance between the transceiver and the user device that has been calculated and the distance between the transceiver and the user device that was previously used to determine the position of the user device in the passenger compartment, and, when one of the differences calculated in relation to one of the transceivers is erroneous by being higher than a predetermined “inconsistency threshold”, calculating the positional variation of the user device from the received response signals by excluding the response signal received for the transceiver.

Abstract: A method for locating a user device in a sub-zone of a main zone defined with respect to a vehicle, especially including detecting the user device in a first sub-zone, locating the user device in the first sub-zone, keeping locating the user device in the first sub-zone for as long as the user device is detected in the first sub-zone, detecting the user device in a second sub-zone, and locating the user device in the second sub-zone when the user device is detected solely in the second sub-zone.

Abstract: A method for securely accessing a motor vehicle whose opening elements are locked and unlocked through wireless communication between a portable access device and an access control module on board the vehicle. The method includes authenticating the device with the access control module, unlocking the vehicle when the device has been authenticated, periodically transmitting, by way of the access control module, an interrogation signal into at least part of the passenger compartment of the vehicle intended for the device following unlocking of the vehicle, upon each reception by the device of said interrogation signal, triggering a first timeout the duration of which is greater than the transmission period of the interrogation signal, and deactivating the device when the first timeout has expired and the immobile state of the device is detected.

Abstract: A method for securely accessing a motor vehicle whose opening elements are locked and unlocked through wireless communication between a portable access device and an access control module on board the vehicle. The method includes authenticating the device with the access control module, unlocking the vehicle when the device has been authenticated, periodically transmitting, by way of the access control module, an interrogation signal into at least part of the passenger compartment of the vehicle intended for the device following unlocking of the vehicle, upon each reception by the device of said interrogation signal, triggering a first timeout the duration of which is greater than the transmission period of the interrogation signal, and deactivating the device when the first timeout has expired and the immobile state of the device is detected.

Abstract: A method for temporarily inhibiting remote activation of a function present in a motor vehicle, the activation taking place between an activation device 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 device and the activation module, the inhibition taking place after a predetermined number of activation attempts that are unsuccessful as they are considered to be located outside of a detection zone. The respective mathematical positions of the unsuccessful activation attempts are stored, and 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.

Abstract: A method for temporarily inhibiting remote activation of a function present in a motor vehicle, the activation taking place between an activation device 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 device and the activation module, the inhibition taking place after a predetermined number of activation attempts that are unsuccessful as they are considered to be located outside of a detection zone. The respective mathematical positions of the unsuccessful activation attempts are stored, and 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.

Abstract: A method of defense against an attack relay action on a remote activation of a function present in an automotive vehicle. The attack relay receives a frame of electromagnetic waves emitted by the activation module and retransmits it to the at least one activation device, nevertheless out of range of emission of the activation module, which dispatches a response frame of electromagnetic waves to the activation module. There is performed, out of range of emission of the activation module, an at least partial interception of a retransmitted frame of electromagnetic waves originating from the attack relay in the direction of the activation device. An at least partial destruction of the retransmitted frame at the activation device and/or of the response frame of the activation device toward the activation module rendering the activation of the function inoperative is performed.

Abstract: A method of defense against an attack relay action on a remote activation of a function present in an automotive vehicle. The attack relay receives a frame of electromagnetic waves emitted by the activation module and retransmits it to the at least one activation device, nevertheless out of range of emission of the activation module, which dispatches a response frame of electromagnetic waves to the activation module. There is performed, out of range of emission of the activation module, an at least partial interception of a retransmitted frame of electromagnetic waves originating from the attack relay in the direction of the activation device. An at least partial destruction of the retransmitted frame at the activation device and/or of the response frame of the activation device toward the activation module rendering the activation of the function inoperative is performed.

Abstract: Method for improving the security of communication between the electronic key and vehicle to prevent interception by a third-party item of electronic equipment by highlighting in such event, a time delay in acknowledgement of this signal by the key. This method includes, before authorizing the access to and/or starting of the vehicle, additional steps of adapting the amplitude of a coded identification request signal received by the key to reach the detection threshold of the key as soon as possible; measuring the sum of the duration of the emission of the coded interrogation signal and of the duration of the response signal of the electronic key; comparing the sum of the measured durations to a reference duration, and triggering an alarm relating to the conditions of access to and/or starting of the vehicle when the separation between this sum of durations and the reference duration is above a preset threshold.

Abstract: Method for improving the security of communication between the electronic key and vehicle to prevent interception by a third-party item of electronic equipment by highlighting in such event, a time delay in acknowledgement of this signal by the key. This method includes, before authorizing the access to and/or starting of the vehicle, additional steps of adapting the amplitude of a coded identification request signal received by the key to reach the detection threshold of the key as soon as possible; measuring the sum of the duration of the emission of the coded interrogation signal and of the duration of the response signal of the electronic key; comparing the sum of the measured durations to a reference duration, and triggering an alarm relating to the conditions of access to and/or starting of the vehicle when the separation between this sum of durations and the reference duration is above a preset threshold.

Abstract: A device for hands-free locking/unlocking of doors/windows of a vehicle implements at least two modes of operation: an approach-detection mode D and a tracking mode P. At least two antennas 14a, 14b are respectively coupled to amplifiers 12a, 12b that are active in tracking mode P. In approach-detection mode D the antennas are decoupled from the amplifiers used in mode P and coupled to an additional amplifier 12c that is active in mode D. Preferably, elements are provided to reduce the consumption of the amplifiers when the device is in a mode of operation where they are inactive.

Abstract: In a method for protecting a motor vehicle, the vehicle is equipped with antennas such that each zone of the cabin is covered by at least two antennas, and with an electronic tag furnished with a device measuring three-dimensional orientation of the magnetic fields received by the electronic tag. A sequence of emissions that consists of a succession of magnetic fields emitted in succession in a given random order from the antennas of the vehicle is randomly determined. After the tag receives this magnetic field succession, a check is carried out to verify that the random emission order has indeed been complied with and that the orientation of the fields that is received by the tag conforms to the expected random orientation. Additionally, the amplitude of the fields can be randomly varied. Authorization to start the vehicle is granted if this random variation is actually received by the tag.

Abstract: A device for hands-free locking/unlocking of doors/windows of a vehicle implements at least two modes of operation: an approach-detection mode D and a tracking mode P. At least two antennas 14a, 14b are respectively coupled to amplifiers 12a, 12b that are active in tracking mode P. In approach-detection mode D the antennas are decoupled from the amplifiers used in mode P and coupled to an additional amplifier 12c that is active in mode D. Preferably, elements are provided to reduce the consumption of the amplifiers when the device is in a mode of operation where they are inactive.

Abstract: A method for temporarily inhibiting, when it is detected inside a locked vehicle, a portable remote control unit, known as a tag, of a keyless entry device designed to implement access authorization procedures to allow access to the vehicle, these including an initial identification procedure which includes causing a central processing unit to periodically transmit a data frame incorporating a preamble consisting of a predefined wake-up code that can be identified by the tag. The inhibition method include defining a first wake-up code at least intended for the procedure of temporarily inhibiting the tags, and a second wake-up code specifically intended for the procedure of identifying the tags, and in setting up temporary inhibition procedures which consist in causing a specific data frame incorporating, in its preamble, the first wake-up code and designed to deactivate the recognition, by each target tag, of the second wake-up code, to be transmitted.

Abstract: A device for hands-free access to a vehicle (V) includes a portable remote control unit (1) and a central processing unit (2) installed in the vehicle, each integrating transmission element (1a, 3) making it possible to implement procedures for authorizing access to the vehicle (V), and a switch (8-11) integrated into the handle (P) of at least one door and designed to switch from a passive to an active state when a user makes access to the handle. The central processing unit (2) is programmed to control the supply of an actuator (13) for unlocking the door immediately after validation of an access authorization procedure, and the switch (8-11) is electrically integrated into the circuit (6) for supplying this actuator (13) so as to keep this supply circuit open in the passive state of the switch.

Abstract: To avoid the untimely locking of the exits of a vehicle 1 using a hands-free locking/unlocking device by detecting the proximity to the vehicle of an identifying device 2, the method comprises measurement of the radio frequency noise level present on the antenna of the identifying device in the frequency range of the request signals transmitted by the system on board the vehicle 1. When the noise level is sufficiently high and the request signal is not received by the identifying device 2, the transmission of the locking signal, which is normally transmitted when the request signal stops being received because of the distance of the identifying device 2 from the vehicle 1, is inhibited.

Abstract: A process and circuit for the connection of electrical loads to the terminals of an amplifier, and for detection of a possible connection defect of said electrical loads. An electrical load is connected to two terminals of the amplifier according to a complete-bridge mounting. At least one second electrical load is connected according to a half-bridge mounting. In a preliminary phase, reference values representative of the currents flowing in each of the connection branches are memorized and measured and there are detected from these measurements and memorized, the reference values of the currents flowing through each of the terminals. During operation of the amplifier, the current passing through each of the two terminals is measured and compared to the corresponding memorized reference value, so as to detect therefrom the connection branch or branches which suffer a connection defect of an electrical load.

Abstract: A method for locating a badge for a motor vehicle handsfree system includes transmission in the form of an inquiry of a signal by a first group of antennas of the vehicle to the tag, response of the tag to this first inquiry, transmission in the form of an inquiry of a signal by a second group of antennas of the vehicle to the tag, and response of the tag to this second inquiry. In responding to the first inquiry, the tag stores for a predetermined time span the fact that it has responded to a signal transmitted by an antenna of the first group of antennas. The response made to the second inquiry may include a cue indicating that a response has already been transmitted following an inquiry originating from the first group of antennas.

Abstract: In this process for controlling at least two groups of antennas, a coded signal (26) is emitted by a first group of antennas, whilst the antennas of a second group emit a residual signal (28) similar to the coded signal but of lesser amplitude. The coding used in this case is such that the coded signal (26) has dead time. A parasitic signal (34) is sent to the second group of antennas (6) during dead time of the coded signal (26) sent to the first group of antennas.

Abstract: In a method for protecting a motor vehicle, the vehicle is equipped with antennas such that each zone of the cabin is covered by at least two antennas, and with an electronic tag furnished with a device measuring three-dimensional orientation of the magnetic fields received by the electronic tag. A sequence of emissions that consists of a succession of magnetic fields emitted in succession in a given random order from the antennas of the vehicle is randomly determined. After the tag receives this magnetic field succession, a check is carried out to verify that the random emission order has indeed been complied with and that the orientation of the fields that is received by the tag conforms to the expected random orientation. Additionally, the amplitude of the fields can be randomly varied. Authorization to start the vehicle is granted if this random variation is actually received by the tag.