Enhanced sensitivity gesture detection system for a motor vehicle

Abstract

A gesture detection device (1) intended to be mounted on a motor vehicle, comprising: - a radar module (2), with at least one radio frequency antenna (21) for emitting a radio frequency signal and receiving a return radio frequency signal resulting from the reflection of the emitted radio frequency signal onto a target (50); and - a signal processing module (3), for receiving data relating to the return signal and deducing information relating to the detection of a gesture. The radio frequency antenna (21) is configured to emit a linearly polarized signal, along a polarization axis (201) oriented substantially vertically in use.The system (1) comprises at least one housing (4) receiving the radar module (2), with a distance (d1) greater than or equal to: dlim = 2*D² / λ + d0 between the antenna (21) and an external surface (41) of the housing (4) forming, in use, a part of the external surface of the vehicle, with D a diameter of the antenna (21), λ the central wavelength of the emitted signal, and d0 a positive or zero constant. Figure 1 for the abbreviation.

Description

Title of the invention: Gesture detection system with improved sensitivity, for a motor vehicle Technical field

[0001] The invention relates to the automotive field and more particularly to a gesture detection system intended to be installed on a motor vehicle, to detect a predetermined gesture performed by a user located outside the vehicle.

[0002] Upon detection of the predetermined gesture, the gesture detection system generates a command allowing, for example, direct or indirect control of the opening and / or unlocking of an opening such as a side door or a trunk door of the vehicle. State of the art

[0003] Such gesture detection systems are known in the prior art, based on radiofrequency detection. In particular, a radar module is configured to emit a radiofrequency signal, called the transmitted signal, and to receive a radiofrequency signal, called the return signal, originating from the reflection of the transmitted signal on a target.

[0004] Analysis of the return signal makes it possible to obtain information relating to a movement made by the target, and thus to identify a predetermined gesture, in particular by comparison with threshold values.

[0005] In practice, the return signal is advantageously mixed with a signal at the frequency of the transmitted signal, to obtain data relating to an in-phase component I(t) and a quadrature phase component Q(t) of the return signal. The analysis of these components makes it possible to extract, in particular, phase values ​​describing the movement carried out by the target.

[0006] In use, the target is formed by a part of a user's body, generally the hand or the foot. For example, it is known to implement the detection of a foot movement made by the user under the rear bumper of the vehicle, to control the opening of the trunk or tailgate. Another application consists of detecting a hand movement made by the user near a lateral intermediate pillar of the vehicle (for example the "B-pillar"), to control the opening of a side door (for example a sliding door).

[0007] The detection of a predetermined gesture may however be affected by parasitic movements in the external environment, in particular parasitic movements generated by rain droplets.

[0008] Indeed, when it rains, the rain droplets falling all around the vehicle form moving targets for the gesture detection system. These taste- droplets then generate significant detection noise. What is more, this noise is located in the same frequency band as a useful signal associated with the gesture made by the user, because the falling speed of the droplets is of the same order of magnitude as the speed of movement of the target in the predetermined gesture.

[0009] Solutions exist to overcome this noise. They are based on complex digital signal processing, which shows limitations for heavy rain and extreme weather conditions.

[0010] An objective of the present invention is to propose a gesture detection system intended to be embedded in a motor vehicle to detect a predetermined gesture made by a user located outside the vehicle, and which is robust to noise generated by rain, even in the event of heavy rain.

[0011] Another object of the present invention is to propose a solution which does not involve extremely complex signal processing. Statement of the invention

[0012] This objective is achieved with a gesture detection system intended to be installed on a motor vehicle, to detect a predetermined gesture made by a user located outside the vehicle, the system comprising: - a radar module comprising a printed circuit board provided with at least one radiofrequency antenna, the at least one radiofrequency antenna being configured to emit a radiofrequency signal, called the emitted signal, and to receive a radiofrequency signal, called the return signal, originating from the reflection on a target of the emitted signal; and - a signal processing module in communication connection with the radar module, configured to receive data relating to the return signal and to deduce therefrom information relating to the detection of a predetermined gesture.

[0013] According to the invention: - the at least one radiofrequency antenna is configured for the emission of a linearly polarized transmitted signal along a predetermined polarization axis, the predetermined polarization axis being intended to be oriented substantially vertically in use; and - the system includes at least one housing receiving the radar module, with a distance dl greater than or equal to: diim=2*D2 / X+d0 between the at least one radiofrequency antenna and an external surface of the housing, with From a diameter of said radiofrequency antenna, X the central wavelength of the emitted signal, and d0 a positive or zero constant, i.e. greater than or equal to the zero value, where said external surface of the housing is intended to form part of the external surface of the vehicle, in use.

[0014] The invention is therefore based on an advantageous combination of two characteristics.

[0015] On the one hand, for gesture detection, an emitted radar signal is used which is linearly polarized. The gesture detection system is configured so that, in use within a motor vehicle and when the vehicle has its four wheels in contact with horizontal ground, the polarization axis is oriented substantially vertically. By "substantially vertically" is meant "parallel to the axis of gravity, at plus or minus 10° angle, or even plus or minus 5° angle, or even plus or minus 1° angle (where 180° angle is equal to ir radians). The predetermined polarization axis is therefore, in use, substantially parallel to the axis of movement of the rain droplets.

[0016] On the other hand, a distance dl greater than or equal to diim=2*D2 / X+d0 is guaranteed, between the at least one radiofrequency antenna, and an external surface of the housing forming, in use, a part of the external surface of the vehicle. When there are several radiofrequency antennas for emitting the emitted signal and / or receiving the return signal, each of them satisfies this condition, dl is the smallest distance between the antenna considered and said external surface of the housing forming, in use, a part of the external surface of the vehicle.

[0017] D corresponds to a diameter of the radiofrequency antenna, defined in the plane of the printed circuit board and corresponding to the largest rectilinear dimension of the antenna in this plane. Preferably, D is the diameter of the smallest square or rectangle in which the radiofrequency antenna in question is inscribed. The ground plane is not considered to be part of the antenna.

[0018] X corresponds to a central wavelength of the emitted signal, with X=C / f, where C is the speed of light in vacuum and f the central frequency of the emitted signal.

[0019] 2*D2 / X defines the limiting distance between the far field, and the near field and the Fresnel region of the antenna considered.

[0020] The constant d0 defines a safety margin to ensure work in the far field, taking into account in particular the mechanical tolerance values ​​of the system according to the invention.

[0021] The constant d0 can take the value zero, but it is advantageously between 2 mm and 7 mm, for example equal to 5 mm.

[0022] By this distance dl greater than or equal to diim, it is ensured that the external environment likely to generate noise, and more particularly any raindrops, is in the far field of the at least one radio antenna. frequency.

[0023] By this combination of far-field detection only, and vertical polarization on transmission, it is ensured that the return signal reaching the radar module is not or only slightly affected by the movement of the rain droplets.

[0024] In particular, the arrangement according to the invention avoids any near-field detection associated with rain droplets. In the far field, rain droplets could be detected with a circularly polarized emitted signal. Thanks to the vertical linear polarization of the emitted signal, substantially parallel to the axis of movement of the rain droplets, the detection of droplets in the far field is also minimized.

[0025] The invention thus proposes a clever solution for minimizing the effect of rain on the return signal, in a gesture detection system intended to be embedded in a motor vehicle to detect a predetermined gesture made by a user located outside the vehicle. Instead of optimizing the processing of received signals, as the person skilled in the art was encouraged to do, the invention proposes to optimize the physical characteristics of the detection system instead. This solution makes it possible to avoid complex processing that is costly in terms of computing resources and energy. In addition, this solution has optimal robustness, even with regard to heavy rain and extreme weather conditions.

[0026] By reducing the effect of rain on the return signal, a signal-to-noise ratio is increased between the useful signal associated with a gesture performed by the user and the noise linked in particular to rain. This makes it possible in particular to reduce a false detection rate of the predetermined gesture (erroneous detection of the predetermined gesture, or conversely, absence of detection of the predetermined gesture despite the appropriate action of the user).

[0027] In practice, the distance between the at least one radiofrequency antenna and said external surface of the housing is advantageously greater than or equal to 5 mm, or even greater than or equal to 8 mm, or even greater than or equal to 10 mm.

[0028] In an advantageous embodiment, a single antenna is configured to transmit the transmitted signal and receive the return signal.

[0029] Alternatively, one antenna is configured to transmit the transmitted signal and another separate antenna is configured to receive the return signal. The two antennas are advantageously integrated on the same printed circuit board. According to the invention, they both satisfy the condition that the distance to the external surface of the housing is greater than or equal to 2*D;2 / X, with D; the diameter of the antenna considered and X the central wavelength of the signal transmitted by the transmitting antenna.

[0030] In an advantageous embodiment, the radar module comprises at least two radiofrequency antennas, with a linearly polarized antenna, for transmitting the transmitted signal, and a circularly polarized antenna, for receiving the return signal.

[0031] The transmitted signal is advantageously a radiofrequency signal with a central frequency between 5 GHz and 10 GHz.

[0032] In addition or as a variant, the emitted signal is advantageously a radiofrequency signal with a spectral width greater than 500 MHz.

[0033] The housing advantageously comprises a trim part or a vehicle structural part provided with a recess for receiving the radar module, as well as an ornamental plate covering the recess and forming said external surface of the housing.

[0034] The radar module may be fixed to the bottom of the housing, on the side opposite said external surface of the housing.

[0035] In addition or as a variant, the radar module is provided with at least one shim, on the side of said external surface of the housing.

[0036] The invention also covers a motor vehicle equipped with a system according to the invention.

[0037] Said system is advantageously located at the level of a structural pillar of the vehicle, with the polarization axis of the linearly polarized radiofrequency antenna substantially parallel to an elongation axis of said pillar, at a plus or minus 10° angle. Description of the figures

[0038] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This is purely illustrative and must be read in conjunction with the appended drawings in which:

[0039] [Fig.l] [Fig.l] schematically illustrates a gesture detection system according to the invention, in use in a rainy environment;

[0040] [Fig.2] [Fig.2] schematically illustrates, in a top view, a printed circuit board of the radar module, in the system of [Fig.l];

[0041] [Fig.3] [Fig.3] schematically illustrates a gesture detection system according to a first variant of the invention; and

[0042] [Fig.4] [Fig.4] schematically illustrates a gesture detection system according to a second variant of the invention.

[0043] Detailed description of at least one embodiment

[0044] We first describe a first embodiment of a detection system of gesture 1 according to the invention, shown in [Fig.l] in use in a rainy environment.

[0045] The gesture detection system 1 is intended to be installed on a motor vehicle, not shown, to detect a predetermined gesture made by a user located outside the vehicle.

[0046] Advantageously, the detection of the predetermined gesture generates, directly or indirectly, a command to open and / or unlock an opening such as a side door or a trunk door of the vehicle.

[0047] For example, in use, the gesture detection system 1 is integrated at the level of a rear bumper of the vehicle, to detect a predetermined gesture made by the foot of a user in order to control the opening of a trunk door or tailgate.

[0048] Alternatively, the gesture detection system 1 is integrated at the level of a lateral intermediate pillar of the vehicle, preferably the “B-pillar”, to detect a predetermined gesture made by the hand of a user in order to control the opening of a side door. The invention is obviously not limited to these two examples.

[0049] The system 1 comprises a radar module 2, a signal processing module 3, and a housing 4 receiving at least the radar module 2.

[0050] The radar module 2 is illustrated in more detail and in a top view in [Fig.2].

[0051] The radar module 2 comprises in particular a printed circuit board 20, [Fig.2] being a plan view of said printed circuit board.

[0052] The printed circuit board 20 is provided with at least one radiofrequency antenna 21, shown schematically in Figures 1 and 2.

[0053] Throughout the text, the term “radio frequency” refers to a signal whose carrier frequency is between 3 kHz and 300 GHz. Preferably, the carrier frequency is, in the invention, between 5 GHz and 30 GHz. For example, the carrier frequency is between 5 GHz and 10 GHz, more preferably between 7 GHz and 9 GHz, more preferably between 6.5 GHz and 8 GHz inclusive, for example equal to 8 GHz. Alternatively, the carrier frequency is between 20 GHz and 30 GHz, for example equal to 24 GHz.

[0054] The at least one radiofrequency antenna 21 is configured to emit a radiofrequency signal, called the emitted signal, and to receive a radiofrequency signal, called the return signal, originating from the reflection on a target of the emitted signal.

[0055] The transmitted signal is advantageously a pulsed signal, in which the pulses are carried by a carrier at a radio frequency as defined above. The frequency of the carrier may vary as a function of time within each pulse.

[0056] Preferably, the emitted signal then has a ratio greater than or equal to 20% between its spectral width and its central frequency, and / or its spectral width is greater than 500 MHz. In other words, the emitted signal is an ultra-wideband signal, or UWB, for the English “ultra-wideband”.

[0057] Alternatively, the transmitted signal is a frequency modulated continuous wave, or FMCW. This is a continuous signal whose frequency varies over time, in order to be able to sweep a wide frequency range.

[0058] In any event, it is advantageous for the transmitted signal to have a wide spectral band, for the implementation of gesture detection. However, the invention is not limited to this characteristic and also covers the case of a continuous transmitted signal.

[0059] In use, the transmitted signal is reflected on at least one target present in the environment of the radar module 2 and returns to the radar module in the form of a return signal. The return signal has physical characteristics, in particular in terms of phase, beat frequency and amplitude, which make it possible to describe a movement of the target. This return signal is received by the at least one radiofrequency antenna 21.

[0060] In the example illustrated in [Fig.2], a single radiofrequency antenna 21 carries out both the transmission of the transmitted signal and the reception of the return signal. In variants, two separate antennas carry out respectively the transmission of the transmitted signal and the reception of the return signal. According to still other variants, several antennas carry out a transmission of the transmitted signal and / or several antennas carry out a reception of the return signal. Each antenna can then be dedicated to a specific detection zone.

[0061] Here, and advantageously, the printed circuit board 21 also comprises a pre-processing unit 22, connected to the at least one antenna 21.

[0062] The pre-processing unit 22 is configured to: - generate a suitable electrical signal and bring this signal to the input of the at least one antenna 21, for the transmission of the transmitted signal; - receive an electrical signal coming from the at least one antenna 21 and corresponding to the return signal; - carry out at least one mixing between an electrical signal corresponding to the return signal and an electrical signal at the frequency of the emitted signal, preferably an in-phase signal and a phase quadrature signal so as to generate a signal I(t), respectively Q(t).

[0063] For this, the pre-processing unit 22 advantageously comprises elements such as an electrical oscillator, to generate an electrical signal capable of being converted into a radiofrequency signal, at least one mixer, as well as at least one analog-digital converter to carry out time sampling and convert an analog signal into a digital signal.

[0064] The radar module 2 is connected to the signal processing module 3. The signal processing module comprises at least one processor and at least one memory storing a data analysis computer program.

[0065] The signal processing module 3 is configured to receive as input data relating to the return signal, for example the signals I(t) and Q(t) mentioned above. high (for example in the form of so-called CIR matrices, grouping these signals into packets transmitted at regular intervals). It is configured to carry out an analysis of this data relating to the return signal, so as to recognize when a target has made a predetermined gesture with regard to the antenna 21.

[0066] Gesture recognition is based on an extraction of characteristics such as a phase shift between the transmitted signal and the return signal, and / or a Doppler frequency, and / or an amplitude variation between the transmitted signal and the return signal, etc. The extracted data are analyzed, for example compared to predetermined threshold values ​​defining the predetermined gesture. Advantageously, the transmitted signal is a broadband signal as described above, and the signal processing module 3 first performs an extraction of the data relating to a desired distance interval between the target and the antenna 21.

[0067] The signal processing module 3 is configured to provide as output, when it has detected the predetermined gesture, information relating to said detection. This information is sent as input to a control unit such as a unit for controlling an unlocking and / or an opening of an opening of the vehicle, where an unlocking and / or opening command is then generated. In variants, said control unit is an integral part of the signal processing module 3.

[0068] The gesture detection system 1 aims to recognize that a predetermined gesture has been performed by a target 50, located outside the vehicle, and formed by a part of the body of a user (generally the hand or the foot). It is understood, however, that any moving object in the field of vision of the radiofrequency antenna 21 can reflect at least part of the emitted signal and thus generate a parasitic signal. This parasitic signal jams the detection of the signal reflected by the target 50. This jamming is all the more difficult to limit, as it is generated by objects moving at a speed comparable to that of the target 50. This is the case in particular when these objects are formed by rain droplets 60.

[0069] According to the invention, the at least one radiofrequency antenna 21 is configured for the emission of a linearly polarized transmitted signal along a predetermined polarization axis. In other words: - when a single radiofrequency antenna 21 carries out both the transmission of the transmitted signal and the reception of the return signal, the latter is linearly polarized; and - when two separate antennas carry out respectively the transmission of the transmitted signal and the reception of the return signal, the transmission antenna, at least, is linearly polarized. The antenna for receiving the return signal may have a non-linear polarization, for example a circular polarization.

[0070] In [Fig.l], the polarization axis of the linearly polarized emitted signal is schematically represented by an arrow 201.

[0071] In use, when the system 1 according to the invention is installed on a vehicle having its wheels resting on a horizontal plane ground, the polarization axis 201 is oriented substantially vertically, that is to say substantially parallel to the axis of gravity.

[0072] By "substantially parallel" is meant an angular difference less than or equal to 10° of angle in absolute value, or even less than or equal to 5° of angle in absolute value, less than or equal to 1° of angle in absolute value (where 180° of angle is equal to ir radians).

[0073] In an advantageous but non-limiting example, the system 1 according to the invention is configured to be housed at a lateral intermediate pillar of the vehicle, for example the “B-pillar”, with said polarization axis 201 substantially parallel to an elongation axis of said pillar. Here again, by “substantially parallel”, we understand an angular difference less than or equal to 10° angle in absolute value, or even less than or equal to 5° angle in absolute value, less than or equal to 1° angle in absolute value (where 180° angle is equal to ir radians). The lateral intermediate pillar generally extending along the vertical axis, this arrangement of the polarization axis 201 relative to the elongation axis of said pillar easily achieves the desired orientation relative to the vertical axis.

[0074] A person skilled in the art will easily find in the literature and his general knowledge, examples of linearly polarized radiofrequency antennas, preferably capable of being integrated directly onto a printed circuit board. Examples include monopole antennas integrated onto printed circuits.

[0075] According to the invention also, the system 1 comprises the housing 4, inside which the radar module 2 is located. Here, but in a non-limiting manner, the signal processing module 3 is arranged offset outside the housing 4. In practice, the housing 4 is configured to allow electrical connection wires to emerge, extending from the radar module 2 towards the outside.

[0076] The radar module 2 is fixedly arranged in the housing 4, and ensures that a distance dl between the at least one radiofrequency antenna 21, and an external surface 41 of the housing, verifies: dl>dUm, with diim=2*D2 / X+d0.

[0077] D is the diameter of the radiofrequency antenna 21 considered. The diameter D of the antenna 21 is its largest transverse rectilinear dimension in the plane of the printed circuit board 20. In practice, it is advantageously the diameter of the smallest rectangle (or square) in which the antenna is inscribed, according to a top view in the plane of the printed circuit board 20. In [Fig. 2], this smallest rectangle 29 is shown in dotted lines. The latter delimits the path of the antenna 21 in the plane of the printed circuit board 20. Here, this path includes a rectangular emission region, as well as an adaptation zone between the rectangular emission region and a track for the circulation of an electrical signal. On the other hand, the path of the antenna excludes a plane of mass. D is for example between 1 cm and 3 cm, for example equal to 2 cm.

[0078] X is the central wavelength of the transmitted signal (substantially equal to the wavelength of the return signal).

[0079] d0 is a positive or zero constant, advantageously between 2 mm and 20 mm, or even between 2 mm and 5 mm, for example equal to 5 mm.

[0080] Said external surface 41 of the housing is an external surface of the housing intended to form a part of the exterior surface of the vehicle, in use.

[0081] The external surface 41 of the housing is thus, in use, opposite the detection zone of the gesture detection system 1.

[0082] The value 2*D2 / X delimits a region RI of the detection zone corresponding to the far field of the radiofrequency antenna 21 (distances greater than or equal to 2*D2 / X), a region R2 of the detection zone corresponding to the near field and the Fresnel region (distances less than 2*D2 / X).

[0083] Thus, thanks to the housing 4 and the arrangement of the radar module 2 in the housing 4, it is ensured that only objects in the far field are detected.

[0084] However, in the far field, the detection is sensitive to polarization. In other words, in the far field, the return signal is not or only slightly affected by objects whose movement is parallel to the polarization axis of the emitted signal. By orienting the polarization axis of the emitted signal along an axis parallel to the axis of movement of the raindrops, we ensure, by construction, great robustness with regard to noise generated by rain.

[0085] The invention thus makes it possible, by combining a linearly polarized signal emission and a far-field detection only, to minimize a parasitic signal generated by the movement of rain droplets with respect to the radar module 2.

[0086] According to an advantageous embodiment, the emitted signal has a central frequency f equal to 8 GHz (where X=C / f, with C the speed of light in a vacuum. This corresponds to 2*D2 / X« 5.3 mm. Advantageously, dUm is then chosen to be between 8 mm and 20 mm, for example dUm= 8 mm, or dUm=10 mm.

[0087] [Fig. 3] schematically illustrates a gesture detection system 1' according to a first variant of the invention. [Fig. 3] will only be described for its differences relative to the embodiment of [Fig. 1].

[0088] In this variant, the housing 4 is formed by a recess 43 in a trim part 44 or a structural part of a motor vehicle, and by at least part of an ornamental plate 45 covering said recess 43.

[0089] The recess 43 is formed for example at the level of a pillar B as defined above, directly in the pillar, or otherwise in a covering of said pillar.

[0090] The decorative plate 45 is for example made of glass or plastic. The external face of the decorative plate 45, located on the side opposite the recess 43 and the radar module 2, forms the external surface 41 of the housing 4 as mentioned above.

[0091] In the embodiment of [Fig.3], the radar module 2 is fixed against the bottom of the housing 4, on the side opposite the external surface 41.

[0092] [Fig.4] schematically illustrates a 1” gesture detection system according to a second variant of the invention. [Fig.4] will only be described for its differences relative to the embodiment of [Fig.3].

[0093] Here, the radar module 2 is provided with shims 25, located between the printed circuit board 20 of the radar module 2 and the external surface 41 of the housing 4, and making it possible to ensure that a desired distance is maintained between these two elements.

[0094] In variants not shown, the wall of the housing 4 located on the side of the detection zone of the radar module 2 has a large thickness, for example greater than or equal to 5 mm, making it possible to ensure the desired distance between the printed circuit board 20 of the radar module 2 and the external surface 41 of the housing 4.

Claims

Claims

1. Gesture detection system (1; 1'; 1”) intended to be mounted on a motor vehicle, to detect a predetermined gesture made by a user located outside the vehicle, the system comprising: - a radar module (2) comprising a printed circuit board (20) provided with at least one radiofrequency antenna (21), the at least one radiofrequency antenna (21) being configured to emit a radiofrequency signal, called the emitted signal, and to receive a radiofrequency signal, called the return signal, originating from the reflection on a target (50) of the emitted signal; and - a signal processing module (3) connected to the radar module (2), configured to receive data relating to the return signal and to deduce therefrom information relating to the detection of a predetermined gesture;characterized in that: - the at least one radiofrequency antenna (21) is configured for the emission of a linearly polarized transmitted signal along a predetermined polarization axis (201), the predetermined polarization axis being intended to be oriented substantially vertically in use; and - the system (1; 1'; 1”) comprises at least one housing (4) receiving the radar module (2), with a distance (dl) greater than or equal to: diim=2*D2 / X+d0 between the at least one radiofrequency antenna (21) and an external surface (41) of the housing (4), with D a diameter of said radiofrequency antenna (21), X the central wavelength of the transmitted signal, and d0 a constant greater than or equal to the zero value, where said external surface (41) of the housing (4) is intended to form a part of the external surface of the vehicle, in use.;

2. System (1; 1'; 1”) according to claim 1, characterized in that the distance (dl) between the at least one radiofrequency antenna (21) and said external surface (41) of the housing (4) is greater than or equal to 8 mm.

3. System (1; 1'; 1”) according to claim 1 or 2, characterized in that the radar module (2) comprises at least two radiofrequency antennas (21), with a linearly polarized antenna, for the emission of the transmitted signal, and a circularly polarized antenna, for the reception of the return signal.

4. System (1; 1'; 1”) according to any one of claims 1 to 3, characterized in that the emitted signal is a radiofrequency signal with a central frequency between 5 GHz and 10 GHz.

5. System (1; 1'; 1”) according to any one of claims 1 to 4, characterized in that the emitted signal is a radiofrequency signal with a spectral width greater than 500 MHz.

6. System (1; 1'; 1”) according to any one of claims 1 to 5, characterized in that the housing (4) comprises a vehicle trim part or structural part (44) provided with a recess (43) for receiving the radar module (2), as well as an ornamental plate (45) covering the recess (43) and forming said external surface (41) of the housing (4).

7. System (1') according to any one of claims 1 to 6, characterized in that the radar module (2) is fixed to the bottom of the housing (4), on the side opposite said external surface (41) of the housing.

8. System (1”) according to any one of claims 1 to 7, characterized in that the radar module is provided with at least one wedge (25), on the side of said external surface (41) of the housing.

9. Motor vehicle equipped with a system (1; 1'; 1”) according to any one of claims 1 to 8.

10. Motor vehicle according to claim 9, wherein said system (1; 1'; 1”) is located at a structural pillar of the vehicle, with the polarization axis (201) of the linearly polarized radiofrequency antenna (21) substantially parallel to an elongation axis of said pillar, at a plus or minus 10° angle.

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