Method for activating a vehicle function and associated activation device

A method for activating a function of a motor vehicle by means of an activation device, from a portable “hands-free” access device carried by a user, the activation of the function being triggered by detection of the presence of the user in a predetermined zone with respect to the vehicle, and depending on a result of authentication of the “hands-free” access device by the vehicle, the activation device comprising at least two ultra-wideband transceiver modules which are able to communicate with said device in the ultra-wideband in the predetermined zone, of which an internal module is situated in a passenger compartment of the vehicle, the method comprising:

• a) Detecting the closure of the opening elements of the vehicle,
• b) Transmitting ultra-wideband waves into the predetermined zone,
• c) Receiving the waves from the access device and, for each module:
• i) Calculating a time-of-flight value for the waves thus received and comparing it with predetermined time-of-flight values,
• ii) Determining the presence of the portable device in the predetermined zone depending on the result of the comparison,
• iii) If the portable device is situated in said zone, then
• 1) Activating the vehicle function, and
• 2) Measuring and comparing a received power value for the waves with predetermined received power values,
• 3) Determining the presence of the portable device in the zone depending on the result of the comparison:
• a. If the portable device is not detected in the zone, then calculating a correction value between the received power and the predetermined received power,
• b. The activation device storing said correction value associated with an identifier of the device for subsequent detection of the presence of the device in said zone,
• c. Applying said correction value to all the received power values from said device,
• d. Locating said device in the passenger compartment depending on the received power thus corrected,
• wherein the predetermined received power values and the predetermined time-of-flight values are measured during a prior phase of calibration with a reference portable device situated in the predetermined zone.

A device for activating a function of a motor vehicle from a portable “hands-free” access device carried by a user, the activation of the function being triggered by detection of the presence of the user in a predetermined zone with respect to the vehicle, and depending on a result of authentication of the “hands-free” access device by the vehicle, the activation device comprising at least two ultra-wideband transceiver modules which are able to communicate with said device in the ultra-wideband in said zone, of which an internal module is situated in a passenger compartment of the vehicle, wherein the device further comprises

• a) Means for detecting closure of the opening elements,
• b) Means for transmitting waves in the ultra-wideband into said zone and for receiving the waves from the device,
• c) Means for calculating a time-of-flight value for the waves and for comparing it with predetermined time-of-flight values,
• d) Means for determining the presence of the portable device in the zone depending on the result of the comparison with predetermined time-of-flight values,
• e) Means for activating the vehicle function depending on detection of the device in the zone,
• f) Means for measuring and for comparing a received power value for the waves with predetermined received power values,
• g) Means for determining the presence of the portable device in the zone depending on the result of the comparison with predetermined received power values,
• h) Means for calculating a correction value between the received power and the predetermined received power,
• i) Means for storing said correction value associated with the identifier of the device.

A device for activating a function of a motor vehicle from a portable “hands-free” access device carried by a user, the activation of the function being triggered by detection of the presence of the user in a predetermined zone with respect to the vehicle, and depending on a result of authentication of the “hands-free” access device by the vehicle, the activation device comprising at least two ultra-wideband transceiver modules which are able to communicate with said device in the ultra-wideband in said zone, of which an internal module is situated in a passenger compartment of the vehicle, wherein the device further comprises

• a) Means for detecting closure of the opening elements,
• b) Means for transmitting waves in the ultra-wideband into said zone and for receiving the waves from the device,
• c) Means for calculating a time-of-flight value for the waves and for comparing it with predetermined time-of-flight values,
• d) Means for determining the presence of the portable device in the zone depending on the result of the comparison with predetermined time-of-flight values,
• e) Means for activating the vehicle function depending on detection of the device in the zone,
• f) Means for measuring and for comparing a received power value for the waves with predetermined received power values,
• g) Means for determining the presence of the portable device in the zone depending on the result of the comparison with predetermined received power values,
• h) Means for calculating a correction value between the received power and the predetermined received power,
• i) Means for storing said correction value associated with the identifier of the device,
• wherein the activation device further comprises received power values and time-of-flight values which were predetermined during a prior phase of calibration with a reference portable device situated in the zone.