Patent ID: 11914020
Assignee: VITESCO TECHNOLOGIES GMBH
Field: Measurement (Instruments)
Classification: CPC G  B | IPC B  G

Claim 18:
19. A method for detecting the presence of a user close to a motor vehicle based on a device (1) as claimed in claim 1, said method comprising the following steps:
a) during what is called an “awake” time interval (R), the control unit (210) activates the piezoelectric element (230), in order to stabilize said piezoelectric element (230),
b) once the piezoelectric element (230) has stabilized, the microcontroller (20) controls the supply of voltage to the oscillator (120) and supplies the oscillator with the reference electrical signal associated with said current reference, so that the transceiver circuit (10) transmits a signal during a transmission time interval (E),
c) during said transmission time interval (E):
the microcontroller (20) measures the frequency of the Doppler signal resulting from said reflected signal, and
the microcontroller (20) measures the frequency of the transmission signal supplied at the output of the oscillator (120),

d) using a comparison between the value of a target frequency and the measurement of the frequency of the transmission signal, the microcontroller (20) determines a corrected value of the reference, the corrected value of the reference making it possible to reduce a difference between the value of the target frequency and the measurement of the frequency of the transmission signal, when the oscillator (120) is supplied with a voltage and receives said corrected reference.