METHOD FOR ACTIVATING A VEHICLE FUNCTION AND ASSOCIATED ACTIVATION DEVICE

Abstract

Method for activating a vehicle function by an activation device (D) comprising at least two ultra-wideband transmitters and at least two ultra-high frequency transmitters and receivers, spatially offset from each other, the activation method comprising the following steps: a) Emission of ultra-high frequency signals, b) Reception of authenticated signals from the equipment and determination of a first distance between said equipment and the vehicle, c) If the first distance is less than a predetermined distance: i) emission of ultra-wideband waves, ii) reception of the reflected waves and calculation of a second distance and an angle of arrival, iii) determination of a correlation factor between the first and second distances,1) if the correlation factor is greater than a predetermined value: 2) activation of the vehicle function if a presence is detected from the second or first distance and angle of arrival. Figure for abstract: Fig. 1,

Description

Title of the invention: METHOD FOR ACTIVATING A VEHICLE FUNCTION AND ASSOCIATED ACTIVATION DEVICE Technical field

[0001] The invention relates to a method for activating a function of a motor vehicle and an associated activation device. The invention applies particularly but in no way limitingly to the hands-free access function of a motor vehicle, that is to say to the function of locking and unlocking the openings of a motor vehicle. Prior art

[0002] In a motor vehicle, it is known to use vehicle function activation devices capable of detecting the presence of a hand or a foot of a user of the vehicle and thus allowing the locking or unlocking of all or part of the openings of the vehicle, for example the doors or the trunk. For example, the detection of the presence of a user's hand on or in front of a door handle coupled with the recognition of an identifier of a "hands-free" access device worn by this user, allows the locking and unlocking of these openings.

[0003] A so-called "hands-free" access system for a motor vehicle allows an authorized user to lock and / or unlock the openings of his vehicle without having to physically press buttons on a key. To do this, the vehicle identifies portable equipment such as a badge or a remote control carried or even a key, by the user and if the badge or the remote control or the key is located in a predetermined area around the vehicle or in the vehicle and is identified as belonging to the vehicle, then the vehicle automatically locks / unlocks its openings according to the user's intention, without the user having to physically handle a key.

[0004] To do this, when the user approaches the vehicle, communication is established on a wireless communication link between the “hands-free” access equipment, for example an electronic badge or a smart mobile phone, and the vehicle function activation device in order to authenticate said access equipment using its identifier.

[0005] For this purpose, the activation device comprises at least one radiofrequency antenna allowing reception of the identifier sent by the “hands-free” access equipment. The activation device is connected to an electronic computer of the vehicle (“ECU”: English abbreviation for “Electronic Control Unit”) to which it transmits the identifier.

[0006] According to the state of the art, the access equipment is generally an electronic badge. The signal received by the antenna of the activation device, comprising the identifier of the access equipment, is transmitted via RF (Radiofrequency) or LF (Low Frequency) waves. The precise location of the portable equipment around the vehicle is achieved by measuring the intensity of the LF signal received by the portable equipment (via the antennas and the electronic control unit) from the vehicle, more commonly called RSSI measurements (Received Signal Strength Indication, or measurement of the power received by a signal received by an antenna).The measurement of the power of each signal received by the portable equipment from each antenna of the plurality of LF antennas located on the vehicle V, is received and analyzed by an activation device, on board the vehicle, which thus determines by triangularization, the position of the portable equipment relative to said LF antennas, that is to say relative to the vehicle.

[0007] Depending on the location of the portable equipment identified by the vehicle, in said location zones certain actions specific to said location zones are automatically carried out, unlocking / locking or prior switching on of the passenger compartment lighting (also called “welcome lighting” in English).

[0008] Nowadays, however, it is increasingly common to use a mobile phone to perform authentication functions, which makes it possible to avoid using a dedicated electronic badge and thus limit the number of devices. Most mobile phones do not have RF or LF communication means. It therefore becomes necessary to adapt the "hands-free" access and / or starting system to a vehicle so that it can also operate with a mobile phone equipped with other communication standards, such as, for example, "Ultra Wide Band" in English or Ultra Large Band, ULB in French, or by BLE ("Bluetooth Low Energy" ®), or by WIFI communication ("wireless fidelity" in English or wireless fidelity) and no longer only via radio waves and low frequencies (RF, LF).Ultra wideband (UWB) is a radio modulation technique based on the transmission of very short pulses, often less than a nanosecond. Thus, the bandwidth can reach very high values.

[0009] The approach of the access equipment close to the activation device (less than 2m) and the recognition of the identifier received by the computer, coupled with the detection of the presence of the user's hand, allows the door to be locked or unlocked.

[0010] The disadvantage of using ULB communication means lies in the location accuracy of the access equipment (mobile telephone or badge) which is degraded compared to the use of low-frequency communication means of the prior art at 125 kHz.

[0011] Ultra Wide Band is in fact more sensitive to reflections and interference. Thus, for precise location, the vehicle must be equipped with six to eight ULB transmitters / receivers (four to six outside the vehicle and two inside the vehicle), so that three ULB transmitters / receivers are always visible to the access equipment, whereas at low frequency, according to the prior art, a single visible transceiver can precisely locate the access equipment. This increase in the number of ULB transmitters / receivers on the vehicle results in an additional cost for the activation device, which is not desirable.

[0012] The solution of the prior art consists of using access equipment which is compatible with ultra wide band and which can thus communicate in ultra wide band and return information allowing their precise location. However, to date, only the iPhone ® from the Apple ® brand is compatible with ultra wide band. No other smart mobile phone currently available on the market is capable of communicating in ultra wide band.

[0013] The number of ULB transmitters / receivers on the vehicle cannot be reduced to three or four without running the risk that the activation device is often located in shadow areas, in particular when the user approaches the vehicle to unlock his vehicle and the device is only visible to a single transmitter / receiver. In this case, unlocking cannot be triggered.

[0014] The disadvantage for the user is major since certain functions will not be activated, for example the automatic “hands-free” unlocking or the automatic “hands-free” locking of the vehicle, when the user enters the unlocking or unlocking zone.

[0015] The disadvantage of using BLE communication means also lies in the lack of precision in the location of the access equipment. The use of the intensity of the signal received in BLE is too sensitive to obstacles, reflections, absorption by the human body to be reliable.

[0016] The invention therefore proposes a method for activating a vehicle function as well as an associated activation device overcoming the drawbacks of the prior art, more particularly allowing reliable and precise location of the access equipment. Presentation of the invention

[0017] The invention proposes a method for activating a vehicle function by an activation device intended to be mounted on a vehicle, comprising at least two ultra-wideband transceivers spatially offset from each other and at least two ultra-high frequency transceivers, spatially offset from each other, the vehicle function being triggered by detecting the presence of a user's portable equipment in a predetermined area around the vehicle and by authenticating said equipment, the activation method being remarkable in that it comprises the following steps: a. Transmitting ultra-high frequency signals on a plurality of channels, b. Receiving authenticated signals from the portable equipment and determining a first distance between the portable equipment and the vehicle, c. If the first distance is less than a predetermined distance, then i. emission of ultra-wideband waves, ii. reception of the reflected waves and calculation of a second distance between said equipment and the vehicle, and determination of an angle of arrival of the reflected waves, iii. determination of a correlation factor between the first distance and the second distance, 1. if the correlation factor is greater than a predetermined value, then, 2. activation of the vehicle function based on detection of the presence of the portable equipment in the predetermined area from the second or first distance and angle of arrival.

[0018] In a second embodiment, the method further comprises, if the first distance is less than a predetermined distance: a. The calculation of a first approach speed of the equipment, from the said first distance and a first flight time of the signals transmitted and received, b. Calculating a second approach speed of said equipment from the second distance and from a second time of flight of the waves, c. Determining a second correlation factor between the first speed and the second speed, d. The vehicle function is activated if in addition the second correlation factor is greater than a second predetermined value.

[0019] Preferably, the determination of the first distance between the portable equipment and the vehicle is carried out by calculating a phase shift for each channel between the transmitted signals and the received signals.

[0020] Judiciously, the calculation of the second distance between said equipment and the vehicle is carried out from a difference in frequencies between the emitted waves and the reflected waves.

[0021] The invention also relates to a device for activating a vehicle function, intended to be installed in a motor vehicle, comprising at least two ultra-wideband transmitters and receivers spatially offset from each other and at least two ultra-high frequency transmitters and receivers, spatially offset from each other, the vehicle function being triggered by detecting the presence of a user's portable equipment in a predetermined area around the vehicle and by authenticating said equipment, said device being remarkable in that it comprises: a. Means for determining a first distance between said portable equipment and the vehicle from authenticated ultra high frequency signals received from said equipment, b. Means for comparing said first distance with a predetermined distance, c. Means for calculating a second distance between said equipment and the vehicle and an angle of arrival of the waves from the reflected ultra-wideband waves, d. Means for calculating a correlation factor between the first distance and the second distance, e. Means of comparison between the correlation factor and a predetermined value, f. Means of activating the vehicle function according to: i. of the result of the said comparison, ii. detection of the presence of the portable equipment in the predetermined area from the second or first distance and angle of arrival.

[0022] In the second embodiment, the device further comprises: a. Means for calculating a first approach speed of the equipment, from said first distance and a first flight time of the signals transmitted and received, b. Means for calculating a second approach speed of said equipment from the second distance and from a second flight time of the waves, c. Means for determining a second correlation factor between the first speed and the second speed, d. Means of comparison between the second correlation factor and a second predetermined value, e. means for activating the vehicle function further triggering the function from the result of said comparison.

[0023] Preferably, the means for determining the first distance between the portable equipment and the vehicle are capable of calculating a phase shift for each channel between the transmitted signals and the received signals.

[0024] Judiciously, the means for calculating the second distance between said equipment and the vehicle determine the second distance from a difference in frequencies between the emitted waves and the reflected waves.

[0025] The invention relates to any computer program product comprising program code instructions for executing the steps of the method according to any one of the characteristics listed above, when said program is executed on a computer.

[0026] Finally, the invention applies to any motor vehicle comprising an activation device according to any one of the characteristics listed above. Brief description of the drawings

[0027] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and should be read in conjunction with the appended drawings in which:

[0028] [Fig.l]: [Fig.l] is a schematic representation of a vehicle equipped with an activation device according to the invention,

[0029] [Fig.2]: [Fig.2] is a schematic representation of an activation device according to the invention,

[0030] [Fig.3]: [Fig.3] is a flowchart illustrating the activation method according to the invention. Description of the embodiments

[0031] In [Fig.l] a motor vehicle V is shown comprising an activation device D for a vehicle function according to the invention. The activation device D according to the invention makes it possible to: a. detect the presence of a user U in a predetermined area around the vehicle V, b. to authenticate the SD portable access device carried by the user, in order to activate a vehicle function.

[0032] By vehicle function is meant the locking / unlocking of the openings of the vehicle V, such as the driver's door, or the rear trunk of the vehicle V, but also the switching on of the heated seats, the switching on of the light of the ceiling light ("welcome lighting"), or even the presetting of the seats or a radio station, even before the user U has entered the vehicle.

[0033] In [Fig.l] a motor vehicle V is shown equipped with the activation device D according to the invention. The activation device D comprises at least two ULB1, ULB2 transceivers in Ultra Wide Band ULB and two BLE1, BLE2 transceivers in ultra High Frequency, of the Bluetooth, BLE type, capable of communicating in ultra wide band and in BLE with portable access equipment SD, for example a smartphone or an electronic key carried by a user U.

[0034] The activation device D further comprises a central control unit 10 electronically connected to all the ULB1, ULB2, BLE1, BLE2, Bluetooth LE and Ultra Wide Band transceivers.

[0035] This central control unit 10 makes it possible to manage the transmission and reception of data in ULB, Bluetooth LE via the transceivers. This is known from the prior art and will not be detailed further here.

[0036] Ultra Wide Band (ULB) communication is understood to mean radiofrequency communication which is based on the transmission of very short pulses, often less than a nanosecond. Thus, the bandwidth can reach very high values ​​between 500 MHz and 1 GHz.

[0037] Bluetooth LE communication means communication in ultra high frequency around 2.4 GHz.

[0038] According to the invention, the transceivers of each pair of transceivers ULB1, ULB2 and BLE1, BLE2 are spatially offset from each other.

[0039] More precisely, the two transmitters ULB1 and ULB2 are spatially offset from each other on or in the vehicle V and the two transmitters BLE1, BL2 are spatially offset from each other on or in the vehicle V.

[0040] On the other hand, it is possible according to the invention to have an ultra wide band ULB2 transmitter receiver and an ultra high frequency BLE1 transmitter receiver located at the same location on the vehicle, as illustrated in [Fig.l].

[0041] The spatial shift makes it possible, according to the invention, to determine a distance separating the portable access equipment SD and the vehicle V reliably, whether by ultra-high frequency communication or by ultra-wideband communication.

[0042] According to the invention, the activation device also comprises (see [Fig.2]): a. Means for determining Ml a first distance dl between said portable equipment SD and the vehicle V from authenticated ultra high frequency BLE signals received from said equipment SD, b. Comparison means M2 between said first distance dl and a predetermined distance Dref, c. Means for calculating M3 a second distance d2 between said equipment SD and the vehicle V and for determining an angle of arrival 0 of the waves from the reflected ultra wide band ULB waves, a. Means for calculating M4 a correlation factor C between the first distance dl and the second distance d2, b. Means of comparison M5 between the correlation factor V and a predetermined value Cref, c. Means for activating M6 the vehicle function as a function of: i. the result of said comparison, ii. detection of the presence of the portable equipment in the predetermined zone ZI from the second d2 or the first distance dl and the angle of arrival 0.

[0043] The determination means M1, the comparison means M2, the calculation means M3, the calculation means M4, the comparison means M5 and the activation means M6 are preferably in the form of software and are located in a microprocessor of the central control unit 10.

[0044] The means for determining M1 a first distance d1 between the portable access equipment and the vehicle V are capable, from the ultra-high frequency signals received from said equipment, of authenticating it and determining the distance separating the vehicle from said equipment. For this purpose, an ultra-high frequency BLE communication is established beforehand between the access equipment SD and the vehicle V, during which a request is sent by the vehicle V to the equipment SD, and the equipment responds to the request by sending its identifier ID to the vehicle V. The vehicle V then verifies that the identifier ID is indeed that of the equipment paired with the vehicle and authenticates it. This is known from the prior art.

[0045] The determination of the first distance dl in ultra high frequency BLE is carried out by calculating a phase shift between the transmitted waves and the received waves for each communication channel used during the communication. This is the method called "Bluetooth channel sounding" in English, or channel sounding in Bluetooth, known from the Bluetooth protocol. This is known from the prior art and will not be detailed further here.

[0046] The comparison means M2 compare the value of the first distance dl with a predetermined distance value Dref. The purpose of this comparison is to ensure that the portable equipment is within the range of the ULB ultra wideband communication.

[0047] The means M3 for calculating a second distance d2 between said SD equipment and the vehicle V and for determining an angle of arrival 0 of the waves from the reflected ULB ultra-wideband waves, are capable, from the ultra-wideband waves received from the portable SD equipment, of determining the distance separating said SD equipment from the vehicle but also the angle of arrival of the received waves.

[0048] For this purpose, an emission of waves in ultra wide band ULB has been carried out beforehand (as will be described later in the activation method), and the waves received by the vehicle are the waves which have been reflected by the SD access equipment.

[0049] The determination of a second distance d2 is carried out from a calculation of a frequency difference between the emitted waves and the received waves, of the Doppler effect radar type. This is known to those skilled in the art and will not be detailed further here.

[0050] The determination of the arrival angle 0 is also known from the prior art.

[0051] The correlation means M4 calculate a correlation coefficient C between the value of the first distance d1 and the value of the second distance d2. Any correlation method known to those skilled in the art can be used here.

[0052] The comparison means M5 then compare the value of the correlation coefficient C with a predetermined value Cref. This value is for example equal to 90%. If the coefficient value C is greater than the predetermined value Cref, this means that the two distance values ​​dl, d2 are correlated.

[0053] The activation means M6 then trigger the activation of the vehicle function as a function of the value of the first d1 or second distance d2 and as a function of the value of the angle of arrival 0. Indeed, the combination of these two parameters makes it possible to reliably determine the position of the access equipment SD relative to the vehicle and to verify whether it is indeed located in a predetermined zone ZI around the vehicle where activation of the function is authorized.

[0054] In a second embodiment of the activation device D, said device further comprises: a. Means for calculating M7 a first approach speed vl of the SD equipment, from said first distance dl and a first flight time TOF1 of the transmitted and received signals, b. Means for calculating M8 a second approach speed v2 of said SD equipment from the second distance d2 and from a second time of flight of the TOF2 waves, c. Means for determining M9 a second correlation factor C2 between the first speed vl and the second speed v2, d. Comparison means M10 between the second correlation factor C2 and a second predetermined value C2ref, e. means of activating the vehicle function Mil, further triggering the function from the result of said comparison.

[0055] The calculation means M7, the calculation means M8, the determination means M9, the comparison means M10, the activation means Mil are preferably in the form of software and are located in a microprocessor of the central control unit 10.

[0056] The calculation means M7 calculate a first speed vl, from the first determined distance dl and from a first round-trip flight time TOF1 of the ultra high frequency BLE waves.

[0057] The calculation means calculate a second speed v2 from the second determined distance d2 and from a second round-trip flight time TOF2 of the ultra wide band ULB waves.

[0058] The determination means M9 calculate a second correlation factor C2 between the first speed vl and the second speed v2.

[0059] The comparison means M10 compare the value of the second correlation coefficient C2 with a second predetermined value C2ref.

[0060] The aim of this second embodiment which compares the approach speeds vl, v2, calculated in two different ways using the two ULB, BLE communication means is to ensure that the portable equipment SD which approaches the vehicle V is indeed the one authenticated beforehand and that there are not two authenticated access equipment located at the same distance from the vehicle V, even if the occurrence of this scenario may be very rare.

[0061] The central control unit 10 also comprises a processor 100 and a memory 101 (see [Fig.2]) in which instructions are recorded for configuring the processor to execute certain particular processes, in particular to implement the steps of the activation method, according to the embodiment as described below.

[0062] The activation method, illustrated in [Fig.3] will now be described.

[0063] In a prior step (step E0), an ultra high frequency BLE communication is established between the access equipment SD and the vehicle V on a plurality of BLE channels.

[0064] During this communication, the access equipment exchanges its identifier ID with the vehicle V (step E1) so that the latter can authenticate it (step E1). A first distance dl separating the access equipment SD from the vehicle V is also calculated (step E1) from the phase shift between the transmitted waves and the received waves for each channel.

[0065] During a second step E2, the first distance dl is compared (step E2) to a predetermined distance Dref, for example equal to a value between 15 m and 20 m. The predetermined distance Dref corresponds to the maximum distance of stable communication in ultra wideband by the vehicle V to obtain reliable localization of the SD access equipment.

[0066] If the first distance dl is greater than the predetermined distance Dref, then the portable equipment SD is not located in the stable communication zone in ultra wide band ULB and the method returns to the prior step of establishing communication in ultra high frequency BLE.

[0067] On the other hand, if the first distance dl is less than the predetermined distance Dref, then the portable equipment SD is located in the stable communication zone in ultra wide band ULB and the activation method passes to the third step E3.

[0068] During the third step E3, ultra wide band ULB waves are emitted by the vehicle V. It is important to note that this transmission does not contain data, it is therefore not a communication with the portable access equipment SD.

[0069] Then, during the fourth step, a second distance d2 is calculated from a frequency shift between the transmitted waves and the received waves which have been reflected by the SD access equipment.

[0070] The angle of arrival 0 of the reflected and received waves is also determined.

[0071] During a fifth step E5, a correlation coefficient C is calculated between the first distance dl and the second distance d2.

[0072] Then (step E6), the correlation coefficient C is compared to a predetermined value Cref equal to 90%.

[0073] If the correlation coefficient C is less than the predetermined value Cref, this means that the two distance values ​​d1, d2 are not correlated, and therefore that there is not one but two access equipments SD which are at a distance less than the predetermined distance or that the access equipment SD has not been located correctly. It is then not possible to know which of these two equipments wishes to activate the vehicle function, or else it is necessary to restart the location of said equipment, the method therefore returns to the previous step E0.

[0074] If, on the contrary, the correlation coefficient is greater than the predetermined value Cref, this means that the two distance values ​​dl, d2 are correlated and therefore that there is indeed a single authenticated access device around the vehicle V which wishes to activate the vehicle function.

[0075] In this case, the function is activated if, from the value of the first or second distance dl, d2 and from the value of the angle of arrival, it is found that the access equipment SD is indeed located in a predetermined zone ZI around the vehicle which allows and authorizes the activation of a function.

[0076] In a second embodiment, sequentially to the preceding steps (shown in [Fig.3]), or simultaneously with the steps previous (not shown in [Fig.3]), it is also verified that the two approach speeds of the SD access equipment which are calculated with parameters specific to the two means of communication BLE, ULB are well correlated.

[0077] For this purpose, in a subsequent step (step E7), a first approach speed vl of the access equipment SD is calculated using the first distance dl determined previously and a first round-trip flight time TOF1 of the waves exchanged between said equipment SD and the vehicle V in ultra high frequency BLE.

[0078] In a following step (step E8), a second approach speed v2 of the access equipment SD is calculated using the second distance determined previously and a second round-trip flight time TOF2 of the waves exchanged between said equipment SD and the vehicle V in ultra wide band ULB.

[0079] During a ninth step E9, a second correlation coefficient C2 between the first speed vl and the second speed v2 is calculated.

[0080] Then this second correlation coefficient C2 is compared to a second predetermined value C2ref (step E10) equal to 90%. Of course, this value is given only as an example.

[0081] If the value of the second correlation coefficient C2 is less than the second predetermined value C2ref, this means that the two speed values ​​vl, v2 are not correlated, and therefore that there is more than one portable access equipment SD around the vehicle V or that the access equipment has not been precisely located and the method returns to step E0.

[0082] If the value of the second correlation coefficient C2 is greater than the second predetermined value C2ref, this means that the two speed values ​​vl, v2 are correlated and therefore that there is indeed only one portable device SD around the vehicle V which requests the activation of the vehicle function.

[0083] In this case, the vehicle function is activated if, from the value of the first or second distance dl, d2 and from the value of the angle of arrival, it is found that the access equipment SD is indeed located in a predetermined zone ZI around the vehicle which allows and authorizes the activation of a function.

[0084] The invention is particularly ingenious because it makes it possible to overcome the drawbacks of the prior art inherent in the two BLE and ULB communication modes.

[0085] Thanks to the invention it is then possible to reliably and precisely determine the location of the access equipment relative to the vehicle V by using only four transmitters and by cleverly combining the advantages of each of the communication modes.

Claims

Claims

1. Method for activating a vehicle function by an activation device (D) intended to be on board a vehicle (V), the device comprising at least two ultra-wideband (ULB) transceivers (ULB1, ULB2) spatially offset from each other and at least two ultra-high frequency (BLE) transceivers (BLE1, BLE2), spatially offset from each other, the vehicle function being triggered by detecting the presence of a portable user equipment (SD) in a predetermined area around the vehicle (Zl) and by authenticating said equipment, the activation method being characterized in that it comprises the following steps: a. Transmission of ultra high frequency signals on a plurality of channels, b. Receiving authenticated signals from the portable equipment (SD) and determining a first distance (dl) between the portable equipment (SD) and the vehicle (V), c. If the first distance (dl) is less than a predetermined distance (Dref), then i. emission of ultra-wideband waves, ii. reception of the reflected waves and calculation of a second distance (d2) between said equipment (SD) and the vehicle (V), and determination of an angle of arrival (0) of the reflected waves, iii. determination of a correlation factor (C) between the first distance (dl) and the second distance (d2), 1. if the correlation factor (C) is greater than a predetermined value (Cref), then, 2. activation of the vehicle function based on detection of the presence of the portable equipment (SD) in the predetermined zone (Zl) from the second (d2) or first distance (dl) and the angle of arrival (0).

2. Activation method, according to the preceding claim, characterized in that it further comprises, if the first distance (dl) is less than the predetermined distance (Dref): a. The calculation of a first approach speed (vl) of the equipment (SD), from said first distance (dl) and a first flight time (TOF1) of the transmitted and received signals, b. The calculation of a second approach speed (v2) of said equipment (SD) from the second distance (d2) and from a second flight time of the waves (TOF2), c. The determination of a second correlation factor (C2) between the first speed (vl) and the second speed (v2), d. The vehicle function is activated if in addition the second correlation factor (C2) is greater than a second predetermined value (C2ref).

3. Activation method, according to claim 1 or 2, characterized in that the determination of the first distance (dl) between the portable equipment (SD) and the vehicle (V) is carried out by calculating a phase shift for each channel between the transmitted signals and the received signals.

4. Activation method according to any one of the preceding claims, characterized in that the calculation of the second distance (d2) between said equipment (SD) and the vehicle (V), is carried out from a difference in frequencies between the emitted waves and the reflected waves.

5. Device (D) for activating a vehicle function, intended to be embedded in a motor vehicle, the device (D) comprising at least two ultra-wideband (ULB) transceivers (ULB1, UBL2) spatially offset from each other and at least two ultra-high frequency (BLE) transceivers (BLE1, BLE2), spatially offset from each other, the vehicle function being triggered by detecting the presence of a user's portable equipment (SD) in a predetermined area (Zl) around the vehicle and by authenticating said equipment, said device (D) being characterized in that it comprises: a. Means (Ml) for determining a first distance (dl) between said portable equipment (SD) and the vehicle (V) from ultra-high frequency signals

6. (BLE) transmitted on a plurality of channels, authenticated received from said equipment, b. Comparison means (M2) between said first distance (dl) and a predetermined distance (Dref), c. depending on the result of the comparison between the first distance (dl) and the predetermined distance (Dref): i. Means for calculating (M3) a second distance (d2) between said equipment (SD) and the vehicle (V) and an angle of arrival (0) of the waves from the reflected ultra-wideband waves ii. Means for calculating (M4) a correlation factor (C) between the first distance (dl) and the second distance (d2), iii. Means of comparison (M5) between the correlation factor (C) and a predetermined value (Cref), iv. Means of activation (M6) of the vehicle function in operation:

1. the result of the said comparison between the correlation factor (C) and the predetermined value (Cref), 2. detection of the presence of the portable equipment (SD) in the predetermined zone (Zl) from the second (d2) or first distance (dl) and the angle of arrival (0). Activation device (D) according to the preceding claim, characterized in that it further comprises, as a function of a result of the comparison between the first distance (dl) and the predetermined distance (Dref): a. Means for calculating (M7) a first approach speed (vl) of the equipment (SD), from said first distance (dl) and a first time of flight (TOF1) of the signals transmitted and received, b. Means for calculating (M8) a second speed (v2) of approach to said equipment (SD) from the second distance (d2) and from a second time of flight of the waves (TOF2), c. Means for determining (M9) a second correlation factor (C2) between the first speed (vl) and the second speed (v2), d. Means for comparing (M10) the second correlation factor (C2) and a second predetermined value (C2ref), e. means for activating (Ml 1) the vehicle function further triggering the function if the second correlation factor (C2) is greater than the second predetermined value (C2ref).

7. Activation device (D) according to any one of claims 5 or 6, characterized in that the means (Ml) for determining the first distance between the portable equipment (SD) and the vehicle (V) are capable of calculating a phase shift for each channel between the transmitted signals and the received signals.

8. Activation device (D) according to any one of claims 5 to 7, characterized in that the means (M3) for calculating the second distance (d2) between said equipment (SD) and the vehicle (V), determine the second distance (d2) from a difference in frequencies between the emitted waves and the reflected waves.

9. A computer program product comprising program code instructions for executing the steps of the method according to any one of claims 1 to 4 when said program is executed on a computer.

10. Motor vehicle (V), characterized in that it comprises an activation device (D) according to any one of claims 5 to 8.

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