Radar localisation system for accessing a motor vehicle

Abstract

The invention relates to a radar system (100) for a motor vehicle (10), the system comprising a plurality of radar modules (110) connected to a localisation unit (120), wherein: - each radar module (110) comprises a localisation antenna and a signal processing unit for emitting a pulse-modulated radiofrequency signal, referred to as an interrogation signal (101), and receiving, in return, a response signal (102) emitted by a badge (200) carried, when in use, by a human operator (300); - the localisation unit (120) is configured to receive data from each of the radar modules and to deduce therefrom data relating to the location of the badge; - the at least one radar module forms an enhanced module (130), which is also capable of emitting a gesture detection signal (103) and receiving, in return, a reflected signal (104) corresponding to the reflection, off a target, of the gesture detection signal; and - a gesture detection unit (140) is configured to receive data related to the reflected signal (104) and to deduce therefrom an item of information related to the detection of a predetermined gesture performed by the human operator (300), the detection of the predetermined gesture being intended to control the opening or closing of at least one door of the motor vehicle.

Description

Description Radar location system for access to a motor vehicle Technical field

[0001] The invention relates to the automotive field and more particularly to a radar system dedicated to locating a user located outside the vehicle, by two-way communication with a badge worn in use by the latter.

[0002] User location by two-way communication with a badge is used, in a manner known per se, in the context of a vehicle access control system, for example to trigger requests to authenticate the user via his badge. State of the art

[0003] Radar systems for a motor vehicle are known in the prior art, comprising a plurality of radar modules arranged in different locations on the vehicle.

[0004] For example, there are four radar modules located at the four corners of the vehicle.

[0005] Each of these radar modules comprises at least one radiofrequency antenna, for emitting a pulsed radiofrequency signal called an interrogation signal, and receiving in return at least one pulsed radiofrequency signal called a response signal, emitted by a badge worn in use by a human operator. Throughout the text, the expression "pulsed signal" designates a pulse-modulated signal, in other words a signal consisting of a carrier modulated in amplitude according to a pulse modulation.

[0006] At the level of each radar module, and in a manner known per se, the measurement of time shifts between an interrogation signal transmission and a response signal reception, and the exploitation of data encoded in the return signal relating to the time shift between an interrogation signal reception by the badge and a response transmission, by the badge, of a response signal, makes it possible to determine a distance between the badge and said module.

[0007] By combining the distance values ​​associated with each of the radar modules, and knowing the relative positions of the radar modules between them, we can then, by simple triangulation calculation, precisely locate the badge relative to the radar modules.

[0008] An objective of the present invention is to optimize the size of such a radar system. Statement of the invention

[0009] This objective is achieved with a radar system for a motor vehicle, comprising a plurality of radar modules connected to a location unit, and in which: - each radar module comprises at least one radiofrequency antenna and a signal processing unit, configured together for the emission of at least one pulse-modulated radiofrequency signal called an interrogation signal, and the receiving in return at least one pulse-modulated radiofrequency signal called a response signal, emitted by a badge worn in use by a human operator; and - the location unit is configured to receive data from each of the radar modules, and to deduce location data from said badge.

[0010] According to the invention: - at least one radar module forms an improved module, configured to further emit a radiofrequency signal called gesture detection signal, and to receive, in return, a reflected signal corresponding to the reflection, on a target, of the gesture detection signal, the gesture detection signal (103) being able to be distinct from or confused with the interrogation signal; and - the radar system further comprises a gesture detection unit, configured to receive as input data from the improved module, relating to the reflected signal, and to deduce therefrom information relating to the detection of a predetermined gesture performed by the human operator, the detection of the predetermined gesture being intended to control the opening or closing of at least one opening of the motor vehicle.

[0011] Gesture detection systems for motor vehicles are known in the prior art, intended to detect a predetermined gesture in order to control the opening or closing of an opening of the vehicle.

[0012] The predetermined gesture is performed by a human operator located outside the vehicle. This could be, for example, a foot gesture or a hand gesture.

[0013] The opening is, for example, a rear trunk door, or a front trunk door, or a side door of the motor vehicle.

[0014] The gesture detection system may implement radar detection, based on the detection of a radiofrequency signal reflected on a target formed by a part of the user's body, in particular the hand or the foot.

[0015] The gesture detection system then comprises at least one radiofrequency antenna, capable of emitting a so-called gesture detection radiofrequency signal, and of receiving a so-called reflected radiofrequency signal, corresponding to the reflection on a target of the gesture detection signal.

[0016] A gesture detection unit receives as input data relating to said reflected signal, and implements a gesture recognition method to detect when a predetermined gesture is performed by the target.

[0017] The detection of said predetermined gesture then controls the opening (or even closing) of an opening in the vehicle.

[0018] The invention thus proposes to pool radar means dedicated to the location of a user badge, with radar means dedicated to gesture detection. In other words, one of the radar modules is modified, so as to be able to offer, in addition to its initial function of locating a user badge, an additional function of gesture detection. The size of the radar system is thus optimized, since for the same size an additional function is filled.

[0019] Preferably, the system further comprises at least one collision alert unit, configured to receive as input data from the gesture detection unit and data from the location unit, to store information relating to a trajectory of the opening when it is open or closed in response to the detection of the predetermined gesture, and to deduce therefrom information relating to a risk of collision between the opening and the user.

[0020] Advantageously, the system further comprises a light and / or sound alert means, and the collision alert unit is configured to issue a command to actuation of said light and / or sound alert means, when a risk of collision is determined to be greater than a predetermined threshold.

[0021] The improved module advantageously has at least two operating modes, including: - a location mode, in which it is configured to receive at least one response signal from the badge; and - a gesture detection mode, in which it is configured to receive the reflected signal.

[0022] The system may include an enhanced module driver unit configured to: - maintaining the enhanced module in the location mode, as long as a distance between the badge and the enhanced module is greater than a predetermined threshold, said distance being determined using the location unit; and - switch the enhanced module into gesture detection mode, when said distance between the badge and the enhanced module reaches and / or becomes lower than said predetermined threshold.

[0023] The interrogation signal advantageously has a ratio of the bandwidth divided by the central frequency which is greater than or equal to 20%, and / or has a spectral width which is greater than 500 MHz.

[0024] Each radar module has a transmitting and receiving antenna called a location antenna, omnidirectional, for transmitting the interrogation signal and receiving the response signal.

[0025] The location antenna of the enhanced module may be further configured to transmit the gesture detection signal, separate from or confused with the interrogation signal, and to receive the reflected signal.

[0026] Alternatively, the location antenna of the enhanced module may be further configured to transmit the gesture detection signal, separate from or confused with the interrogation signal, and the enhanced module further comprises a directional receiving gesture detection antenna configured to receive the reflected signal.

[0027] According to yet another variant, the improved module further comprises a directional transmitting and receiving gesture detection antenna, configured to transmit the gesture detection signal distinct from the interrogation signal, and to receive the reflected signal.

[0028] Advantageously, the gesture detection signal and the reflected signal are pulse-modulated signals, and the system comprises extraction means, configured to extract, from data relating to the reflected signal, data relating only to a predetermined detection zone.

[0029] Said extraction advantageously uses a temporal sampling of the reflected signal, and an extraction of sampled data relating to portions of said reflected signal, for which the temporal difference between the reception of said portions and the emission of a corresponding pulse of the gesture detection signal is less than a predetermined threshold.

[0030] The gesture detection unit is advantageously configured to issue a command to open or close an opening of the motor vehicle, when the predetermined gesture has been detected.

[0031] The invention also covers a vehicle comprising a system according to the invention, in which one improved module is located at the rear of the vehicle, offset laterally relative to a longitudinal central axis of the vehicle.

[0032] The invention also covers a vehicle comprising a system according to the invention, in which one improved module is located in a central region of the rear of the vehicle. Description of figures

[0033] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and must be read in conjunction with the appended drawings in which:

[0034] [Fig. 1] Figure 1 schematically illustrates a radar system according to a first embodiment of the invention, installed on a motor vehicle, and in a top view;

[0035] [Fig. 2] Figure 2 corresponds to Figure 1, which also shows the various radiofrequency signals leaving and arriving from the radar system;

[0036] [Fig. 3] Figure 3 schematically illustrates sampled data relating to a reflected signal detected using the improved module in the system of Figures 1 and 2;

[0037] [Fig. 4] Figure 4 schematically illustrates the improved module of a radar system according to a second embodiment of the invention, in use in a motor vehicle; and

[0038] [Fig. 5] Figure 5 schematically illustrates a radar system according to a third embodiment of the invention. Detailed description of at least one embodiment

[0039] Firstly, with reference to Figures 1 and 2, a radar system 100 according to a first embodiment of the invention, installed on a motor vehicle 10, and according to a top view, is described. Figure 2 differs from Figure 1 only in that it also schematically represents the radiofrequency signals transmitted and received by the radar system 100.

[0040] The radar system 100 comprises a plurality of radar modules 110, here four radar modules distributed at the four corners of the vehicle 10. The invention is of course not limited to this arrangement of radar modules, and covers variants with three, five or more radar modules, which can be distributed at the corners of the vehicle and / or on vertical side pillars of the vehicle and / or in an upper central region of the vehicle, etc.

[0041] Each radar module 110 comprises at least one radiofrequency antenna 111 called a location antenna, and a signal processing unit 112.

[0042] 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, more preferably between 5 GHz and 10 GHz or between 20 GHz and 25 GHz.

[0043] The locating antenna 111 is configured to transform an electrical signal into an electromagnetic signal forming a radiofrequency wave, and vice versa.

[0044] Here, and advantageously, the location antenna 111 is an omnidirectional antenna. Throughout the text, an omnidirectional antenna designates an antenna emitting substantially equal power in all directions orthogonal to a line of sight. Unlike an isotropic antenna whose radiation pattern is perfectly spherical, but which is only a theoretical concept that cannot be realized in practice, the omnidirectional antenna has a rotationally symmetrical radiation pattern but a minimum of emission in the line of sight.

[0045] In each radar module 110, the location antenna 111 and the signal processing unit 112 are configured together to (see Figure 2): - the emission, by the location antenna 111, of at least one pulsed radiofrequency signal, called interrogation signal 101, and - reception, by the location antenna 111, of at least one radiofrequency pulse signal, called response signal 102, and emitted by a badge 200 in response to the reception of an interrogation signal 101.

[0046] In the example illustrated here, the location antenna 111 is a transmitting and receiving antenna. Alternatively, two antennas are used respectively for transmitting the interrogation signal 101 and for receiving the response signal 102.

[0047] The signal processing unit 112 comprises in particular: - an electrical oscillator, for generating an electrical signal capable of being converted into a radiofrequency signal by the location antenna 111; and - a clock, to time-stamp the times of transmission and reception of radiofrequency signals; and - a calculation unit, making it possible to manage the exchanges of location frames constituting respectively the interrogation signal 101 and the response signal 102.

[0048] The interrogation signal 101 is a pulse-modulated radio frequency signal. Preferably, but not limited to, it is a signal in which a ratio of the bandwidth divided by the center frequency is greater than or equal to 20%, and / or a signal which has a spectral width greater than 250 MHz, preferably greater than 500 MHz. In other words, it is of a signal called UWB, for Ultra-Wide Band, or ultra-large band in French.

[0049] The badge 200 designates a device capable of establishing two-way radio frequency communication with each of the radar modules 110. The badge 200 can form a dedicated device, usually called a “keyfob” in English. Alternatively, the badge 200 can be formed by a smartphone equipped with a dedicated application. In use, the badge 200 is worn by a human operator, or user 300. In FIG. 2, the user 300 is symbolized by a star. Advantageously, the badge 200 comprises a memory, storing an authentication number capable of being communicated to at least one of the radar modules 110, to authenticate the user 300 and authorize access to functions such as unlocking the openings.

[0050] The radar modules 110 are all connected to a location unit 120. In Figures 1 and 2, this connection is symbolized by simple arrows 121. It is preferably a wired connection.

[0051] The location unit 120 comprises calculation means, preferably at least one processor and at least one memory. The location unit 120 is configured to receive as input data from each of the radar modules 110, and to deduce location data from the badge 200.

[0052] In use, each radar module 110 emits a succession of interrogation signals 101, received by the badge 200. In response to each interrogation signal 101 that it receives, the badge emits a response signal 102 each time. The time delay between the reception of an interrogation signal 101 and the emission of a response signal 102, at the badge 200, takes a value known by the location unit 120 (preferably communicated to it via an encoding in the response signal 102). Thus, by measuring: - a time of transmission of the interrogation signal 101 at the radar module 110, and - a time of reception of the response signal 102 at the same radar module 110, it is possible to determine the time taken by the radiofrequency wave to travel from the radar module 110 to the badge 200, and thus to deduce a distance between these two elements. This distance calculation can be carried out directly at the radar module 110, or at the location unit 120, from time stamp data.

[0053] In any event, the location unit 120 is configured to combine the distance values ​​to the badge 200 of at least three of the radar modules 110, and to deduce therefrom a position of the badge in the reference system of the radar modules 110 (and of the vehicle), this position forming said location data of the badge 200.

[0054] According to the invention, the radar system 100 not only has a function of locating a user by bidirectional communication with his badge 200, but also a function of detecting a predetermined gesture, said gesture being intended to control an opening or a closing of an opening of the motor vehicle 10. Advantageously, this localization is said to be “secure”, because the frame of a signal exchanged between the badge 200 and the radar module 110 incorporates a identification parameter, which makes it possible to verify in particular the identity of the sender of the message received by the module 110.

[0055] Preferably, said opening is a tailgate or rear trunk door. Alternatively, it may be an opening providing access to a front trunk. According to still other variants, the opening is a side door of the motor vehicle 10.

[0056] For this, at least one of the radar modules 110 forms an improved module 130.

[0057] For this, the improved module 130 is also capable of (see figure 2): - emit a radiofrequency signal, forming a gesture detection signal 103; and - to receive, in return, a reflected signal 104 corresponding to the reflection, on a target, of the gesture detection signal 103.

[0058] In use, said target is advantageously formed by a part of the user's body, in particular a hand or a foot.

[0059] Advantageously, the gesture detection signal 103 is also a pulse-modulated radiofrequency signal. It is advantageously formed by a frame of pulses, like the interrogation signal 101. Its other characteristics may or may not be identical to those of the interrogation signal 101. Preferably, but in a non-limiting manner, it is a signal in which a ratio of the bandwidth divided by the central frequency is greater than or equal to 20%, and / or a signal which has a spectral width greater than 250 MHz, preferably greater than 500 MHz. In other words, it is a so-called UWB signal, for Ultra-Wide Band, or ultra-large band, in French.

[0060] The reflected signal 104 is also a radio frequency signal, preferably pulse-modulated like the gesture detection signal 103.

[0061] In variants, the gesture detection signal 103 (and therefore the reflected signal 104 as well) is a continuously modulated radio frequency signal.

[0062] According to the invention also, the radar system 100 further comprises a gesture detection unit 140. The gesture detection unit 140 comprises calculation means, preferably at least one processor and at least one memory. These latter may in practice be distinct from or combined with a processor and a memory forming the location unit 120.

[0063] The gesture detection unit 140 comprises at least one processor and at least one memory. It is configured to receive as input data from the at least one improved module 130, relating to the reflected signal, and to deduce therefrom information relating to the detection of a predetermined gesture performed by the user 200. An example of a gesture detection algorithm is described in more detail below.

[0064] The detection of the predetermined gesture is intended to control the opening or closing of at least one opening of the motor vehicle, preferably the opening of a trunk located at the rear or at the front of the motor vehicle 10.

[0065] If necessary, the gesture detection unit 140 can be configured to directly issue a command to open or close an opening of the vehicle. automobile, when the predetermined gesture has been detected. Alternatively, this command is generated by an ancillary unit, in response to the reception of information relating to the detection of the predetermined gesture, provided by said gesture detection unit 140.

[0066] In a first embodiment: - the gesture detection signal 103 is emitted by the location antenna 111, advantageously omnidirectional, also emitting the interrogation signal 101; and - the reflected signal 104 is received by the same advantageously omnidirectional location antenna 111, also receiving the response signal 102.

[0067] The gesture detection signal 103 can then be made up of frames identical to those of the interrogation signal 101. The gesture detection signal 103 and the reflected signal 104 are then advantageously pulse-modulated radiofrequency signals.

[0068] In a second embodiment (not specifically shown, but close to the embodiment of Figure 4): - the gesture detection signal 103 is emitted by the location antenna 111', advantageously omnidirectional, also emitting the interrogation signal 101; and - the reflected signal 104 is received by an antenna, called the gesture detection antenna in reception, distinct from the location antenna 111' which receives the response signal 102.

[0069] The gesture detection signal 103 and the reflected signal 104 are then advantageously pulse-modulated radiofrequency signals.

[0070] The receiving gesture detection antenna is advantageously a directional antenna, the line of sight of which is oriented towards a predetermined gesture detection zone.

[0071] In a third embodiment, illustrated in Figure 4: - the gesture detection signal 103 is emitted by an antenna, called the gesture detection antenna 113' for transmission and reception, distinct from the location antenna 111' which receives the response signal 103; and - the reflected signal 104 is received by said gesture detection antenna 113' for transmission and reception.

[0072] The 113' transmitting and receiving gesture detection antenna is advantageously a directional antenna, the line of sight of which is oriented towards a predetermined gesture detection zone.

[0073] The gesture detection signal 103 and the reflected signal 104 are then advantageously pulse-modulated radiofrequency signals. In variants, the gesture detection signal 103 and the reflected signal 104 may be continuously modulated radiofrequency signals.

[0074] According to still other variants, the gesture detection antenna 113' for transmission and reception can be replaced by two directional antennas, respectively for transmission and reception.

[0075] Advantageously, the improved module 130 has at least two operating modes, including: - a location mode, in which it is configured to transmit the at least one interrogation signal 101 and receive the at least one response signal 102 from the badge 200; and - a gesture detection mode, in which it is configured to transmit the gesture detection signal 103 and to receive the reflected signal.

[0076] Advantageously, the system 100 comprises a control unit 150, receiving as input data supplied by the location unit 120 and the gesture detection unit 140 (link not shown in the figures, so as not to overload the figure), and providing as output instructions for switching the improved module 130 to the location mode or the gesture detection mode.

[0077] In particular, the control unit 150 is configured to: - maintaining the enhanced module 130 in the location mode, as long as a distance between the badge 200 and the enhanced module 130 is greater than a predetermined threshold, said distance being determined using the location unit 120; - switching the improved module 130 into gesture detection mode, when said distance between the badge 200 and the improved module 130 reaches and / or becomes lower than said predetermined threshold; then - switching the enhanced module 130 back into the localization mode after the predetermined gesture has been detected by the gesture detection unit 140, or after a predetermined duration (to avoid any blocking in the gesture detection mode).

[0078] The control unit 150 comprises calculation means, preferably at least one processor and at least one memory. These may be separate or combined with a processor and a memory forming the location unit 120 and / or a processor and a memory forming the gesture detection unit 140.

[0079] According to still other variants, the improved module is capable of operating simultaneously in gesture detection mode and in location mode, the location mode being a background task controlled by an external computer while the gesture detection mode is activated by the approach of the badge 200.

[0080] Advantageously, the improved module 130 is located, in use, at the rear of the motor vehicle 100, offset laterally relative to a longitudinal central axis of said vehicle, and in particular at a rear corner of the vehicle. Preferably, the improved module 130 then makes it possible to detect a gesture for controlling an opening or closing of the tailgate or rear trunk door. The user 300 must then perform the gesture with regard to this corner of the vehicle, which reduces a risk of collision when opening, respectively closing, said opening.

[0081] Alternatively, the improved module 130 is located, in use, in a rear central region of the motor vehicle 100.

[0082] In a variant not shown, the improved module 130 is located, in use, at the front of the motor vehicle 100, offset laterally relative to a longitudinal central axis of said vehicle, and in particular at a front corner of the vehicle. Preferably, the improved module 130 then makes it possible to detect a gesture of control of opening or closing of the tailgate or front trunk door.

[0083] In still other variants, the opening is a side door and / or the improved module is located in use in a central side area of ​​the vehicle.

[0084] According to still other variants, the system comprises a plurality of radar modules each forming an improved module.

[0085] The system may comprise at least three radar modules, each forming an enhanced module, located respectively in a central area at the rear of the vehicle, at a right side door (in a door handle or a side structural pillar between the front and rear doors, for example), at a left side door (in a door handle or a side structural pillar between the front and rear doors, for example), and where appropriate in a front central area of ​​the vehicle.

[0086] The gesture detection implemented by the gesture detection unit 140 is now described in more detail. This gesture detection can be based on implementing Doppler frequency calculations, based for example on the use of a fast Fourier transform (or FFT) applied to the demodulated signals (I and Q). The FFT makes it possible to obtain the frequencies of the return signal. If a difference exists between the frequency of the transmitted carrier f, and the received frequency, this is due to the Doppler effect. From this difference, a speed of the target is deduced. By integrating this speed over time, a measurement of the displacement of said target is deduced.

[0087] In an advantageous variant, the gesture detection is based instead on the extraction and tracking of phase values. For this, the steps described below are implemented. Some of said steps can be implemented upstream of the gesture detection unit 140, at the level of the signal processing unit 112 of the improved module 130.

[0088] Generation of the signals l(t) and Qft): This step is advantageously implemented within the signal processing unit 112 of the improved module 130. It involves carrying out, using at least one mixer, an in-phase mixing and a quadrature-phase mixing between the reflected signal 104 and a signal at the frequency of the gesture detection signal 103, so as to generate a signal l(t) relating to an in-phase component of the reflected signal 104 and a signal Q(t) relating to a quadrature-phase component of the reflected signal 104. In other words, it involves implementing a demodulation of the reflected signal 104.

[0089] Time sampling: This step is advantageously implemented within the signal processing unit 112 of the improved module 130, using an analog-to-digital converter. It consists of performing a time sampling of data relating to the reflected signal 104. The time sampling can be implemented downstream of the generation of the signals l(t) and Q(t), or upstream of the generation of the signals l(t) and Q(t), for example directly at the level of the reflected signal 104. In any event, this step results in sampled data l(t) and Q(t), corresponding to a time sampling of the signals l(t) and Q(t). The sampling step is advantageously between 0.8 ns and 2 ns, for example equal to 1 ns.

[0090] Optional matrix construction step: Advantageously, the sampled data l(ti) and Q(ti) are each arranged in the form of matrices. In Figure 3, data l(ti), respectively Q(ti) are illustrated as an example in the form of such a matrix. One axis of the matrix, called "CIR index", corresponds to a pulse index of the gesture detection signal 103 (pulse-modulated radiofrequency signal). One axis of the matrix corresponds to a "tap num" index of a sampling instant. The value of the index is reset to zero at each new pulse of the gesture detection signal 103. In other words, this involves implementing a time folding of a signal formed by the data considered. A final axis of the matrix corresponds to the value S taken by each sampled data.

[0091] Extraction of data associated with a predetermined detection zone: This step consists of extracting, from the sampled data l(ti) and Q(ti), the data relating only to portions of the reflected signal 104, for which a time difference AT between the reception of said portion of signal and the emission of a corresponding pulse of the gesture detection signal 103, is less than or equal to a threshold T1.

[0092] In other words, it is a matter of extracting, for each pulse of the gesture detection signal 103, data relating to a portion of the corresponding pulse of the reflected signal 104, a portion for which the difference between: - the time of emission, by the improved module 130, of the pulse of the gesture detection signal 103; and - the time of reception, by the improved module 130, of said portion of the corresponding pulse of the reflected signal 104; is lower than the threshold T 1 .

[0093] The threshold T1 defines a predetermined detection zone which extends, from the improved module 130, up to a maximum distance D1 from the latter, with D1 = c / T1, with c the speed of light in a vacuum.

[0094] This extraction step is easily visualized when the sampled data l(ti) and Q(t) are represented in the form of matrices, as illustrated in Figure 3.

[0095] If necessary, data relating only to portions of the reflected signal 104 can be extracted, for which a time difference AT between the reception of said portion of signal and the emission of a corresponding pulse of the gesture detection signal 103, is both lower than the threshold T1 and higher than a second threshold T2 lower than T1. The predetermined detection zone then extends between two concentric discs of radius D1=c / T1 and D2=c / T2 respectively. T2 can be chosen = 1 “tap num” unit, to overcome the effect of internal reflections within the improved module 130.

[0096] In any event, this extraction step makes it possible to consider only portions of the signal associated with a reflection on a target located in said predetermined detection zone, and to avoid the effect of reflection on targets that are not relevant because they are located outside said detection zone.

[0097] Here, the predetermined detection zone corresponds to an area in which the movement intended to control the opening of the opening generally takes place. This predetermined detection zone does not extend beyond a distance D1 = 60 cm, which corresponds to T1 = 4 ns, i.e. a “tap num” index equal to 4 on the matrix of figure 4.

[0098] The extraction step is implemented at the level of at least one processor forming extraction means, and belonging for example to the gesture detection unit 140 or to the improved module 130.

[0099] The gesture detection unit 140 is then configured to monitor the temporal evolution, on said extracted data, of the phase of the signal reflected on a target, and to deduce therefrom the movement of said target.

[0100] In particular, the following steps are advantageously implemented within the gesture detection unit 140:

[0101] Calculation of the modulus of the data l(tj) and Q(tj): For each sampling time t i; we calculate a module of the data l(ti) and Q(ti) noted |CIR(ti)|, corresponding to the amplitude of the demodulated reflected signal 104, and of value equal to the square root of l 2 (ti)+Q 2 (ti).

[0102] Identification of an amplitude peak of the first demodulated reflected signal 104: This step consists of searching, on the data |CIR(ti)| and successively for each pulse of the gesture detection signal 103, for the presence of a peak of amplitude greater than or equal to a predetermined threshold. When such a peak is identified, this corresponds to the identification of the start of a gesture. The instant tj associated with this peak is recorded. This peak is associated with a pulse of index k of the first gesture detection signal 103.

[0103] Phase calculation: Once this peak has been identified, we calculate the phase 4>(k) of the demodulated reflected signal 104. To do this, we use the values ​​I and Q associated with the instant tj. In particular, we have: If l(tj) >0, then 4>(k)=arctan (Q(tj) / I(tj)) If l(tj) <0 and if Q(tj) <0, then 4>(k)=arctan (Q(tj) / I(tj)) - n If l(tj) <0 and if Q(tj) >0, then 4>(k)=arctan (Q(tj) / I(tj)) + n

[0104] Monitoring phase values: The evolution of the phase value is then calculated for the following k+n pulses of the gesture detection signal 103. The phase being representative of a position of the target, the evolution of the phase indicates a variation in the position of the target, and therefore a movement of the target. Thus, the evolution of this phase value makes it possible to characterize a movement made by the target, and thus to recognize whether this movement corresponds or not to a predetermined gesture associated with an opening or closing command for an opening.

[0105] Tracking phase values ​​takes into account that every time the distance traveled by the radio frequency wave varies by X (where X is the center wavelength of the radio frequency signal carrier), this phase value varies by 2n.

[0106] This monitoring also takes into account a possible change in time difference between the peak considered on the reflected signal 104 and the instant of emission of the pulse corresponding to the gesture detection signal 103 (in other words, a change in the “tap num” index of the peak considered).

[0107] Figure 4 schematically illustrates the improved module 130' of a radar system according to a second embodiment of the invention, in use in a motor vehicle 10'. This second embodiment will only be described for its differences relative to the embodiment of Figures 1 and 2.

[0108] In this embodiment, the improved module 130' comprises, in addition to the location antenna 111', a gesture detection antenna 113' for transmission and reception as mentioned above, configured for the transmission of the gesture detection signal 103 and the reception of the reflected signal 104.

[0109] The 113' transmitting and receiving gesture detection antenna is a radiofrequency antenna, configured to transform an electrical signal into an electromagnetic signal forming a radiofrequency wave, and vice versa.

[0110] The gesture detection antenna 113' is a directional antenna, emitting power distributed mainly in an emission cone oriented along a line of sight A1. In other words, its radiation pattern has a main lobe, receiving the majority of the emitted power.

[0111] Here, the sight axis A1 is oriented in use along an axis oriented towards the rear of the vehicle.

[0112] In a variant not shown, the gesture detection signal 103 is emitted by the location antenna, while the reflected signal is received by a directional gesture detection antenna in reception.

[0113] According to yet another variant, not shown, gesture detection uses both: - a first gesture detection signal and a first reflected signal, such as those described above, with pulse modulation, and - a second gesture detection signal and a second reflected signal, with continuous modulation, transmitted and received by a dedicated, directional radiofrequency antenna, having a line of sight inclined by at least 30° relative to a line of sight in reception of the antenna receiving the first reflected signal.

[0114] The gesture detection unit is then configured to implement: - a first gesture detection, using data from the first reflected signal; - a second gesture detection, using data from the second reflected signal; and - a fusion of the data from the first gesture detection and the second gesture detection.

[0115] The second gesture detection may be based on known techniques, for example extracting and tracking frequency values ​​from the second reflected signal, using a so-called Fast Fourier Transform (or FFT) function.

[0116] In an advantageous variant, the second gesture detection is based instead on the extraction and tracking of phase values, as described with reference to Figures 1 to 3 (except for the extraction of a portion of the second reflected signal).

[0117] Finally, with reference to Figure 5, a 100” radar system according to a third embodiment of the invention is described. The 100” radar system will only be described for its differences relative to the system of Figures 1 and 2.

[0118] In this embodiment, the radar system 100” further comprises a collision warning unit 160”.

[0119] The 160” collision alert unit is configured to - receive as input data provided by the location unit 120” (badge location data) and by the gesture detection unit 140” (information relating to the detection of the predetermined gesture), - store information relating to a trajectory of the opening when it is opened or closed in response to the detection of the predetermined gesture, and - deduce 16” information relating to a risk of collision between the opening and the user.

[0120] Said information 16” relates to a level of risk of collision, in the event of imminent movement of opening or closing of the opening (linked to the detection of the predetermined gesture by the gesture detection unit 140”), taking into account a current position of the user (location data of the badge, provided by the location unit 120”), and taking into account a known trajectory of the opening. The information 16” can be of binary type (risk level equal to 0 or 1). Alternatively, the information 16” can be a percentage, or any other non-binary value.

[0121] Advantageously, the system 100” further comprises a light and / or sound alert means, not shown, for example a lighting device of the LED or other type and / or a loudspeaker, connected to the collision alert unit 160”. The collision alert unit 160” is then configured to emit a command to actuation of said light and / or sound alert means, when a risk of collision is determined to be greater than a predetermined threshold.

[0122] It is obviously understood that the 100” radar system of Figure 3 can be combined with the improved module described with reference to Figure 4.

[0123] The invention is not limited to the examples described above, and also covers variants with other radio frequency signal frequencies, other locations of the radar modules on the vehicle, etc.

Claims

Claims

1. Radar system (100”) for a motor vehicle (10; 10'), comprising a plurality of radar modules (110) connected to a location unit (120; 120”), and in which: - each radar module (110) comprises at least one radiofrequency antenna (111; 111'; 113') and a signal processing unit (112; 112'), configured together for the transmission of at least one pulse-modulated radiofrequency signal, called an interrogation signal (101), and the reception in return of at least one pulse-modulated radiofrequency signal, called a response signal (102), transmitted by a badge (200) worn in use by a human operator (300); and - the location unit (120; 120”) is configured to receive data from each of the radar modules, and to deduce location data from said badge; in which: - at least one radar module (110) forms an improved module (130; 130'), configured to further emit a radiofrequency signal called gesture detection signal (103), and to receive, in return, a reflected signal (104) corresponding to the reflection on a target of the gesture detection signal, the gesture detection signal (103) being able to be distinct from or confused with the interrogation signal (101); and - the radar system (100; 100”) further comprises a gesture detection unit (140), configured to receive as input data from the improved module (130; 130'), relating to the reflected signal (104), and to deduce therefrom information relating to the detection of a predetermined gesture performed by the human operator (300), the detection of the predetermined gesture being intended to control the opening or closing of at least one opening of the motor vehicle; the system (100”) further comprising at least one collision warning unit (160”), configured to receive as input data from the gesture detection unit (140”) and data from the location unit (120”), to store information relating to a trajectory of the opening when it is open or closed in response to the detection of the predetermined gesture, and to deduce therefrom information (16”) relating to a risk of collision between the opening and the user.

2. System (100”) according to claim 1, characterized in that it further comprises a light and / or sound alert means, and in that the collision alert unit (160”) is configured to issue a command to actuation of said light and / or sound alert means, when a risk of collision is determined to be greater than a predetermined threshold.

3. System (100”) according to claim 1 or 2, characterized in that the improved module (130; 130') has at least two operating modes, including: - a location mode, in which it is configured to receive the at least one response signal (102) from the badge; and - a gesture detection mode, in which it is configured to receive the reflected signal (104).

4. System (100”) according to claim 3, comprising a control unit (150) of the improved module configured to: - keep the enhanced module (130; 130') in location mode, as long as a distance between the badge (200) and the enhanced module is greater than a threshold predetermined, said distance being determined using the location unit (120; 120”); and - switching the enhanced module (130; 130”) into gesture detection mode, when said distance between the badge (200) and the enhanced module (130; 130') reaches and / or becomes lower than said predetermined threshold.

5. System (100”) according to any one of claims 1 to 4, characterized in that the interrogation signal (101) has a ratio of the bandwidth divided by the central frequency which is greater than or equal to 20%, and / or has a spectral width which is greater than 500 MHz.

6. System (100”) according to any one of claims 1 to 5, characterized in that each radar module (110; 130; 130') comprises a transmitting and receiving antenna called a location antenna (111; 111'), omnidirectional, for transmitting the interrogation signal (101) and receiving the response signal (102).

7. System (100”) according to claim 6, wherein the location antenna (111; 111') of the improved module (130; 130') is further configured to transmit the gesture detection signal (103), distinct from or merged with the interrogation signal (101), and to receive the reflected signal (104).

8. System (100”) according to claim 6, wherein the location antenna (111; 111') of the improved module (130; 130') is further configured to transmit the gesture detection signal (103), distinct from or merged with the interrogation signal (101), and the improved module (130; 130') further comprises a directional receiving gesture detection antenna, configured to receive the reflected signal (104).

9. System (100”) according to claim 6, wherein the improved module (130; 130') further comprises a directional transmitting and receiving gesture detection antenna (113”), configured to transmit the gesture detection signal (103), distinct from the interrogation signal (101), and to receive the reflected signal (104).

10. System (100”) according to any one of claims 1 to 9, characterized in that the gesture detection signal (103) and the reflected signal (104) are pulse-modulated signals, and the system (100; 100”) comprises extraction means, configured to extract, from data relating to the reflected signal, data relating only to a predetermined detection zone.

11. System (100”) according to claim 10, characterized in that said extraction uses a time sampling of the reflected signal, and an extraction of sampled data relating to portions of said reflected signal, for which the time difference (AT) between the reception of said portions and the emission of a corresponding pulse of the gesture detection signal (103) is less than a predetermined threshold (T1).

12. System (100”) according to any one of claims 1 to 11, characterized in that the gesture detection unit (140; 140”) is configured to issue a command to open or close an opening of the motor vehicle, when the predetermined gesture has been detected.

13. Vehicle (10; 10') comprising a system (100”) according to any one of claims 1 to 12, wherein the one improved module (130; 130') is located at the rear of the vehicle, laterally offset relative to a longitudinal central axis of the vehicle.

14. Vehicle (10; 10') comprising a system (100”) according to any one of claims 1 to 12, wherein the one improved module (130; 130') is located in a central region of the rear of the vehicle.

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