METHOD FOR ULTRA HIGH FREQUENCY CONTINUOUS COMMUNICATION WITH AND LOCATION OF A PORTABLE DEVICE FOR "HANDS-FREE" ACCESS TO A MOTOR VEHICLE

A method and a system for ultra high frequency communication with and location of a portable device for “hands-free” access to a motor vehicle, the motor vehicle having an on-board communication device comprising an ultra high frequency transceiver, an electrical power supply source and at least one antenna, the motor vehicle including a first arrangement, in which the transceiver is connected to the antenna, and a second arrangement, in which the transceiver is disconnected from the antenna. The transceiver is connected to an attenuation module located at a predetermined distance from the transceiver. The attenuation module includes an impedance of predetermined value connected to ground. The predetermined distance between the transceiver and the attenuation module, as well as the predetermined value of the impedance, defining a locating area of the portable device in and around the motor vehicle.