Method for scanning for presence inside a locked vehicle, associated device and scanning system

A method for scanning for presence inside a vehicle, using a scanning device comprising at least one internal ultra-wideband transceiver module capable of transmitting toward the inside of the vehicle and at least one external ultra-wideband transceiver module capable of transmitting toward the outside of the vehicle, and capable of locating portable “hands-free” access equipment carried by a user, said method being characterized in that the scanning device is previously equipped with Ultra High Frequency communication means for communicating with said equipment and in that the method comprising:

• a) detecting locking of the vehicle;
• b) for a predetermined duration:
• i) scanning for presence inside the vehicle using the internal ultra-wideband transceiver module, and comparing a profile of waves reflected and received by said internal module with at least one predetermined wave profile;
• ii) simultaneously transmitting, via Ultra High Frequency, a request to the portable equipment for detecting a U-turn by the user;
• iii) if a U-turn signal is received, stopping scanning and determining a position of the user using the internal module and the external module;
• and
• iv) if presence is detected inside the vehicle, then stopping scanning and transmitting a warning to the user;
• and
• c) otherwise, at the end of the predetermined duration, if no U-turn signal is received and if no presence is detected inside the vehicle, then determining the position of the user using the internal module and the external module.