Radar location system for access to a motor vehicle

Abstract

Radar system (100) for a motor vehicle (10), comprising a plurality of radar modules (110) connected to a location unit (120), and in which: - each radar module (110) comprises a location antenna and a signal processing unit, for the transmission of a pulse-modulated radio frequency signal called an interrogation signal (101), and the return reception of a response signal (102) emitted by a badge (200) worn in use by a human operator (300); - the location unit (120) is configured to receive data from each of the radar modules, and to deduce location data from said badge; - at least one radar module forms an enhanced module (130), also capable of emitting a gesture detection signal (103), and of receiving in return a reflected signal (104) corresponding to the reflection, on a target, of the gesture detection signal;and - a gesture detection unit (140) is configured to receive data relating to the reflected signal (104), and to deduce from it information relating to the detection of a predetermined gesture made 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. Figure for abbreviation: Figure 2.;

Description

Title of the invention: Radar location system for accessing 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 bidirectional communication with a badge worn in use by the latter.

[0002] User location by bidirectional communication with a badge is used, in a way known per se, within the framework of vehicle access control systems, for example to trigger requests aimed at authenticating the user via his badge. State of the art

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

[0004] For example, we have four radar modules arranged at the four corners of the vehicle.

[0005] Each of these radar modules includes at least one radio frequency antenna for transmitting a pulsed radio frequency interrogation signal and receiving in return at least one pulsed radio frequency reply signal emitted by a badge worn during operation by a human operator. Throughout this text, the expression "pulsed signal" refers to a pulse-modulated signal, in other words, a signal consisting of a carrier wave modulated in amplitude using pulse modulation.

[0006] At the level of each radar module, and in a manner known per se, the measurement of time offsets between an emission of an interrogation signal and a reception of a response signal, and the exploitation of data encoded in the return signal relating to the time offset between a reception of an interrogation signal by the badge and an emission in response, 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 with each other, it is then possible, by simple triangulation calculation, to precisely locate the badge relative to the radar modules.

[0008] One objective of the present invention is to optimize the size of such a radar system. Description 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 radio frequency antenna and one signal processing unit, configured together to transmit at least one pulsed-modulated radio frequency signal called an interrogation signal, and to receive in return at least one pulsed-modulated radio frequency signal called a reply signal, transmitted 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 for said badge.

[0010] According to the invention: - at least one radar module forms an enhanced module, configured to further emit a radio frequency signal called a 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 distinct from or indistinguishable from the interrogation signal; and - the radar system also includes a gesture detection unit, configured to receive input data from the enhanced module relating to the reflected signal, and to deduce information relating to the detection of a predetermined gesture made 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, designed to detect a predetermined gesture in order to control the opening or closing of a vehicle opening.

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

[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 can implement radar detection, based on the detection of a radio frequency signal reflected on a target formed by a part of the user's body, in particular the hand or foot.

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

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

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

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

[0019] Preferably, the system further comprises at least one collision warning unit, configured to receive 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 opened or closed in response to the detection of the predetermined gesture, and to deduce information relating to a risk of collision between the opening and the user.

[0020] Advantageously, the system further includes a means of visual and / or audible warning, and the collision warning unit is configured to issue an actuation command for said visual and / or audible warning means, when a risk of collision is determined to be greater than a predetermined threshold.

[0021] The improved module advantageously offers at least two modes of operation, among which: - 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 control unit configured to: - maintain the enhanced module in location mode as long as the distance between the badge and the enhanced module exceeds a predetermined threshold, said distance being determined using the location unit; and - switch the enhanced module into gesture detection mode when the distance between the badge and the enhanced module reaches and / or falls below the predetermined threshold.

[0023] The interrogation signal advantageously has a ratio of the bandwidth divided by the center 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 includes a transmitting and receiving antenna named omnidirectional location antenna for transmitting the interrogation signal and receiving the reply signal.

[0025] The location antenna of the improved module can be further configured to emit the gesture detection signal, distinct from or confused with the interrogation signal, and to receive the reflected signal.

[0026] Alternatively, the location antenna of the improved module can be further configured to emit the gesture detection signal, distinct from or confused with the interrogation signal, and the improved module further includes 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 transmit and receive 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 includes 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 time sampling of the reflected signal, and extraction of sampled data relating to portions of said reflected signal, for which the time gap 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 an improved module is located at the rear of the vehicle, laterally offset 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 an improved module is located in a central region of the rear of the vehicle. Description of the figures

[0033] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

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

[0035] [Fig.2] The [Fig.2] corresponds to the [Fig.1], on which are also represented the different radio frequency signals leaving and arriving from the radar system;

[0036] [Fig.3] Fig.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, for use in a motor vehicle; and

[0038] [Fig.5] Fig.5 schematically illustrates a radar system according to a third embodiment of the invention.

[0039] Detailed description of at least one embodiment

[0040] A radar system 100 according to a first embodiment of the invention, installed on a motor vehicle 10, is described first with reference to Figures 1 and 2, and shown in a top view. Figure 2 differs from Figure 1 only in that it also schematically represents the radio frequency signals emitted and received by the radar system 100.

[0041] 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 a central upper region of the vehicle, etc.

[0042] Each radar module 110 includes at least one radio frequency antenna 111 called a location antenna, and a signal processing unit 112.

[0043] Throughout the text, the term "radio frequency" refers to a signal whose carrier frequency is between 3 kHz and 300 GHz. Preferably, in the invention, the carrier frequency is between 5 GHz and 30 GHz, more preferably between 5 GHz and 10 GHz or between 20 GHz and 25 GHz.

[0044] The location antenna 111 is configured to transform an electrical signal into an electromagnetic signal forming a radio frequency wave, and vice versa.

[0045] Here, and advantageously, the localization antenna 111 is an omnidirectional antenna. Throughout this text, an omnidirectional antenna refers to 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 not feasible in practice, the omnidirectional antenna exhibits a rotationally symmetric radiation pattern but a minimum emission along the line of sight.

[0046] In each radar module 110, the positioning antenna 111 and the processing unit signal 112 are configured together for (see [Fig.2]): - the emission, by the location antenna 111, of at least one pulsed radio frequency signal, called interrogation signal 101, and - the reception, by the location antenna 111, of at least one radio frequency pulse signal, called response signal 102, and emitted by a badge 200 in response to the reception of an interrogation signal 101.

[0047] 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 reply signal 102.

[0048] The signal processing unit 112 includes, in particular: - an electrical oscillator, to generate an electrical signal suitable for conversion into a radio frequency signal by the positioning antenna 111; and - a clock, to time-stamp the moments of transmission and reception of radio frequency signals; and - a computing unit, allowing the management of the exchange of location frames constituting respectively the interrogation signal 101 and the response signal 102.

[0049] The interrogation signal 101 is a pulse-modulated radio frequency signal. Preferably, but not limited to, it is a signal in which the ratio of the bandwidth to the center frequency is greater than or equal to 20%, and / or a signal with a spectral bandwidth greater than 250 MHz, preferably greater than 500 MHz. In other words, it is a so-called UWB signal, for Ultra-Wide Band.

[0050] Badge 200 designates a device capable of establishing bidirectional radio frequency communication with each of the radar modules 110. Badge 200 can form a dedicated device, commonly called a "keyfob." Alternatively, badge 200 can be formed by a smartphone equipped with a dedicated application. In use, badge 200 is worn by a human operator, or user 300. In [Fig. 2], user 300 is symbolized by a star. Advantageously, badge 200 includes memory, storing an authentication number capable of being communicated to at least one of the radar modules 110, to authenticate user 300 and authorize access to functions such as unlocking doors and windows.

[0051] 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.

[0052] The location unit 120 includes computing means, preferably at least one processor and at least one memory. The location unit 120 is configured to receive input data from each of the radar modules 110, and to deduce location data from the badge 200.

[0053] In operation, each radar module 110 emits a succession of interrogation signals 101, received by the badge 200. In response to each interrogation signal 101 it receives, the badge emits a response signal 102. 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 encoding in the response signal 102). Thus, by measuring: - a moment of transmission of the interrogation signal 101 at the level of the radar module 110, and - a moment of reception of the response signal 102 at the same radar module 110, It is possible to determine the time taken by the radio frequency device to travel from radar module 110 to badge 200, and thus deduce the distance between these two elements. This distance calculation can be performed directly at radar module 110, or at location unit 120, using timestamp data.

[0054] In any event, the location unit 120 is configured to combine the distance values ​​to the badge 200 from at least three of the radar modules 110, and to deduce a position of the badge in the reference frame of the radar modules 110 (and of the vehicle), this position forming said location data of the badge 200.

[0055] According to the invention, the radar system 100 not only has a function for locating a user by bidirectional communication with their badge 200, but also a function for detecting a predetermined gesture, said gesture being intended to control an opening or closing of a door of the motor vehicle 10. Advantageously, this location is said to be "secure", because the frame of a signal exchanged between the badge 200 and a radar module 110 incorporates an identification parameter, which makes it possible to verify in particular the identity of the sender of the message received by the module 110.

[0056] Preferably, said opening is a tailgate or rear trunk lid. Alternatively, it may be an access opening to a front trunk. According to still other variants, the opening is a side door of the motor vehicle 10.

[0057] For this purpose, at least one of the radar modules 110 forms an improved module 130.

[0058] For this purpose, the improved module 130 is also suitable for (see [Fig.2]): - to emit a radio frequency 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.

[0059] In use, said target is advantageously formed by a part of the user's body, in particular a hand or a foot.

[0060] Advantageously, the gesture detection signal 103 is also a signal Pulse-modulated radio frequency. 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 not exclusively, it is a signal in which the ratio of the bandwidth to the center frequency is greater than or equal to 20%, and / or a signal with a spectral bandwidth greater than 250 MHz, preferably greater than 500 MHz. In other words, it is a so-called UWB signal, for Ultra-Wide Band.

[0061] The reflected signal 104 is also a radio frequency signal, preferably with pulse modulation like the gesture detection signal 103.

[0062] In variants, the gesture detection signal 103 (and therefore the reflected signal 104 as well) is a continuously modulated radio frequency signal.

[0063] According to the invention, the radar system 100 further comprises a gesture detection unit 140. The gesture detection unit 140 includes computing means, preferably at least one processor and at least one memory. These can, in practice, be separate from or combined with a processor and memory forming the localization unit 120.

[0064] The gesture detection unit 140 comprises at least one processor and at least one memory. It is configured to receive input data from at least one enhanced module 130, relating to the reflected signal, and to deduce from this data 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.

[0065] 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 front of the motor vehicle 10.

[0066] If necessary, the gesture detection unit 140 can be configured to directly issue a command to open or close a door of the motor vehicle when the predetermined gesture has been detected. Alternatively, this command is generated by an auxiliary unit in response to receiving information relating to the detection of the predetermined gesture, provided by said gesture detection unit 140.

[0067] In a first embodiment: - the gesture detection signal 103 is emitted by the location antenna 111, advantageously omnidirectional, which also emits the interrogation signal 101; and - the reflected signal 104 is received by the same advantageously omnidirectional localization antenna 111, also receiving the response signal 102.

[0068] The gesture detection signal 103 can then consist of frames identical to those of the interrogation signal 101. The gesture detection signal 103 and the signal reflected 104 are then advantageously pulse-modulated radio frequency signals.

[0069] In a second embodiment (not specifically shown, but close to the embodiment of [Fig.4]): - the gesture detection signal 103 is emitted by the location antenna 111', advantageously omnidirectional, which also emits the interrogation signal 101; and - the reflected signal 104 is received by an antenna, called the gesture detection antenna in reception, distinct from the localization antenna 111' which receives the response signal 102.

[0070] The gesture detection signal 103 and the reflected signal 104 are then advantageously pulse-modulated radio frequency signals.

[0071] The gesture detection antenna in reception is advantageously a directional antenna, whose aiming axis is oriented towards a predetermined gesture detection zone.

[0072] In a third embodiment, illustrated in [Fig.4]: - the gesture detection signal 103 is emitted by an antenna, called the gesture detection antenna 113', which is separate from the localization antenna 111' that receives the response signal 103; and - the reflected signal 104 is received by said gesture detection antenna 113' of transmission and reception.

[0073] The gesture detection antenna 113' for transmission and reception is advantageously a directional antenna, whose aiming axis is oriented towards a predetermined gesture detection zone.

[0074] The gesture detection signal 103 and the reflected signal 104 are then advantageously pulse-modulated radio frequency signals. In alternative embodiments, the gesture detection signal 103 and the reflected signal 104 can be continuously modulated radio frequency signals.

[0075] According to other variants, the gesture detection antenna 113' for transmission and reception can be replaced by two directional antennas, respectively for transmission and reception.

[0076] Advantageously, the improved module 130 has at least two modes of operation, among which: - a location mode, in which it is configured to transmit at least one interrogation signal 101 and receive at least one response signal 102 from badge 200; and - a gesture detection mode, in which it is configured to emit the gesture detection signal 103 and to receive the reflected signal.

[0077] Advantageously, the system 100 comprises a control unit 150, receiving input data provided by the localization unit 120 and the gesture detection unit 140 (link not shown in the figures, so as not to overload the figure), and providing output instructions to switch the improved module 130 to localization mode or gesture detection mode.

[0078] In particular, the control unit 150 is configured to: - maintain the enhanced module 130 in 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; - switch the enhanced module 130 into gesture detection mode when the distance between the badge 200 and the enhanced module 130 reaches and / or falls below the predetermined threshold; then - switch the enhanced module 130 back into location mode after the predetermined gesture has been detected by the gesture detection unit 140, or after a predetermined time (to avoid any blocking in gesture detection mode).

[0079] The control unit 150 includes computing 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 localization unit 120 and / or a processor and a memory forming the gesture detection unit 140.

[0080] According to 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.

[0081] Advantageously, the improved module 130 is located, in operation, 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 enables the detection of a piloting action to open or close the tailgate or rear trunk lid. The user 300 must then perform the action with regard to this corner of the vehicle, which reduces the risk of collision when opening or closing said opening.

[0082] Alternatively, the improved module 130 is located, in use, in a central rear region of the motor vehicle 100.

[0083] In an alternative embodiment not shown, the improved module 130 is located, in operation, 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 enables the detection of a control gesture for opening or closing the tailgate or front trunk lid.

[0084] According to 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.

[0085] According to other variants, the system comprises a plurality of radar modules, each forming an enhanced module.

[0086] The system may include 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 lateral structural pillar between the front and rear doors, for example), at a left-side door (in a door handle or a lateral structural pillar between the front and rear doors, for example), and where appropriate in a central front area of ​​the vehicle.

[0087] The gesture detection implemented by the gesture detection unit 140 is now described in more detail. This gesture detection can be based on Doppler frequency calculations, for example, using a Fast Fourier Transform (FFT) applied to the demodulated signals (I and Q). The FFT allows the frequencies of the return signal to be obtained. 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 velocity of the target is deduced. By integrating this velocity over time, a measurement of the target's displacement is obtained.

[0088] In an advantageous embodiment, gesture detection is based instead on the extraction and tracking of phase values. For this purpose, the steps described below are implemented. Some of these 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.

[0089] Generation of the signals I(t) and O(t): This step is advantageously implemented within the signal processing unit 112 of the improved module 130. It involves performing, using at least one mixer, in-phase mixing and 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 I(t) relative to an in-phase component of the reflected signal 104 and a signal Q(t) relative to a quadrature phase component of the reflected signal 104. In other words, it involves demodulating the reflected signal 104.

[0090] 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 time sampling of data relating to the reflected signal 104. The time sampling can be implemented downstream of the generation of the signals I(t) and Q(t), or upstream of the generation of the signals I(t) and Q(t), for example directly at the level of the reflected signal 104. In any case, this This step results in sampled data I(f) and Q(t), corresponding to a time sampling of the signals I(t) and Q(t). The sampling step is advantageously between 0.8 ns and 2 ns, for example equal to 1 ns.

[0091] Optional step in matrix construction: Advantageously, the sampled data I(h) and Q(h) are each arranged in matrix form. In [Fig. 3], data I(L) and Q(t) are illustrated as examples in such a matrix. One axis of the matrix, called the "CIR index," corresponds to a pulse index of the gesture detection signal 103 (a pulse-modulated radio frequency signal). Another axis of the matrix corresponds to a "tap num" index of a sampling instant. The index value is reset to zero with each new pulse of the gesture detection signal 103. In other words, this involves implementing time folding of a signal formed by the data under consideration. A final axis of the matrix corresponds to the value S taken by each sampled data point.

[0092] Extraction of data associated with a predetermined detection zone: This step consists of extracting, from the sampled data 1(6) and Q(f), the data relating only to portions of the reflected signal 104, for which a time gap AT between the reception of said signal portion and the emission of a corresponding pulse of the gesture detection signal 103, is less than or equal to a threshold TL

[0093] In other words, it involves 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 moment of emission, by the improved module 130, of the pulse of the gesture detection signal 103; and - the moment of reception, by the improved module 130, of said portion of the corresponding pulse of the reflected signal 104; is below the TL threshold

[0094] The threshold Tl defines a predetermined detection zone which extends, from the improved module 130, up to a maximum distance DI from the latter, with Dl=c / Tl, with c the speed of light in a vacuum.

[0095] This extraction step is easily visualized when the sampled data 1(0 and Q(ti) are represented in the form of matrices, as illustrated in [Fig.3].

[0096] Where appropriate, data can be extracted relating solely to portions of the reflected signal 104, for which a time gap AT between the reception of said signal portion and the emission of a corresponding pulse of the gesture detection signal 103 is both lower than the threshold T1 and greater than a second threshold T2 lower than TL. The predetermined detection zone then extends between two disks concentric with radii respectively Dl=c / Tl and D2=c / T2. We can choose T2= 1 unit of "tap num", to eliminate the effect of internal reflections within the improved module 130.

[0097] 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 eliminate the effect of reflection on irrelevant targets because they are located outside said detection zone.

[0098] 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 Dl=60 cm, which corresponds to Tl=4 ns, i.e., a "tap num" index equal to 4 on the matrix of [Fig.4].

[0099] 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.

[0100] 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 the movement of said target.

[0101] In particular, the following steps are advantageously implemented within the gesture detection unit 140:

[0102] Calculation of the modulus of the data ht; ) and Oit): For each sampling instant h, we calculate a modulus of the data I(t;) and Q(ti) denoted ICIR(ti)l, corresponding to the amplitude of the reflected signal 104 demodulated, and of value equal to the square root of I^t0+Q2^).

[0103] Identification of an amplitude peak of the first reflected demodulated signal 104: This step involves searching the ICIR(t;)l data, successively for each pulse of the gesture detection signal 103, for the presence of a peak with an amplitude greater than or equal to a predetermined threshold. When such a peak is detected, it corresponds to the detection of the beginning of a gesture. The time tj associated with this peak is recorded. This peak is associated with a pulse of index k of the first gesture detection signal 103.

[0104] Phase calculation: Once this peak is identified, the phase is calculated. <p(k) du signal réfléchi 104 démodulé. To do this, we use the values ​​I and Q associated with time tj. In particular, we have: If I(tj) > 0, then <p(k)=arctan (Q(tj) / I(tj)) If I(tj) < 0 and if Q(tj) < 0, then <p(k)=arctan (Q(tj) / I(tj)) - ir If I(tj) < 0 and if Q(tj) > 0, then <p(k)=arctan (q(tj) i(tj)) + ir

[0105] suivi des valeurs de la phase : The evolution of the phase value is then calculated for the following k+n pulses of the gesture detection signal 103. Since the phase represents the target's position, the phase evolution indicates a change in the target's position, and therefore a movement of the target. Thus, the evolution of this phase value allows us to characterize a movement performed by the target, and thereby determine whether this movement corresponds to a predetermined gesture associated with an opening or closing command.

[0106] The monitoring of phase values ​​takes into account the fact that, each time the distance traveled by the radio frequency wave varies by X (where / is the central wavelength of the radio frequency signal carrier), this phase value varies by 2ir.

[0107] This monitoring also takes into account a possible change in the time gap between the peak considered on the reflected signal 104 and the emission time of the corresponding pulse of the gesture detection signal 103 (in other words, a change in the index "tap num" of the peak considered).

[0108] 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.

[0109] In this embodiment, the improved module 130' includes, 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.

[0110] The 113' transmit and receive gesture detection antenna is a radio frequency antenna, configured to transform an electrical signal into an electromagnetic signal forming a radio frequency wave, and vice versa.

[0111] The gesture detection antenna 113' is a directional antenna, emitting power distributed mainly in a cone of emission oriented along a line of sight AL. In other words, its radiation pattern has a main lobe, receiving most of the emitted power.

[0112] Here, the sighting axis Al is oriented in use along an axis oriented towards the rear of the vehicle.

[0113] In an unshown variant, the gesture detection signal 103 is emitted by the localization antenna, while the reflected signal is received by a directional, receiving gesture detection antenna.

[0114] 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 impulse modulation, and - a second gesture detection signal and a second reflected signal, continuously modulated, emitted and received by a dedicated, directional radio frequency antenna, having a sighting axis inclined at least 30° relative to a receiving sighting axis of the antenna receiving the first reflected signal.

[0115] The gesture detection unit is then configured to implement: - an initial gesture detection, using data from the first reflected signal; - a second gesture detection, using data from the second reflected signal; and - a fusion of data from the first gesture detection and the second gesture detection.

[0116] The second gesture detection can be based on known techniques, for example extraction and tracking of frequency values ​​of the second reflected signal, using a function called Fast Fourier Transform (or FFT).

[0117] In an advantageous embodiment, the second gesture detection is based rather 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).

[0118] Finally, with reference to [Fig. 5], a 100" radar system is described according to a third embodiment of the invention. The 100" radar system will only be described in terms of its differences from the system in Figures 1 and 2.

[0119] In this embodiment, the 100” radar system further comprises a 160” collision warning unit.

[0120] The 160” collision warning unit is configured for - receive as input data provided by the 120” location unit (badge location data) and by the 140” gesture detection unit (information relating to the detection of the predetermined gesture), - to store information relating to the trajectory of the opening when it is opened or closed in response to the detection of the predetermined gesture, and - deduce from this information 16” relating to a risk of collision between the opening and the user.

[0121] Said information 16” relates to a collision risk level in the event of imminent opening or closing of the door (linked to the detection of the predetermined gesture by the gesture detection unit 140”), taking into account the user's current position (badge location data, provided by the location unit 120”), and a known trajectory of the door. Information 16” can be binary (risk level equal to 0 or 1). Alternatively, information 16” can be a percentage, or any other non-binary value.

[0122] Advantageously, the 100” system further comprises a visual and / or audible warning means, not shown, for example an LED or other type lighting device and / or a loudspeaker, connected to the 160” collision warning unit. The 160” collision warning unit is then configured to issue an actuation command for said visual and / or audible warning means, when a risk of collision is determined to be greater than a predetermined threshold.

[0123] It is obviously understood that the 100” radar system of [Fig.3] can be combined with the improved module described with reference to [Fig.4].

[0124] The invention is not limited to the examples described above, and also covers variants with other radio frequency signal frequencies, other locations of radar modules on the vehicle, etc.

Claims

Claims

1. Radar system (100; 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 emission 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), emitted 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 for said badge therefrom; the radar system (100; 100”) being characterized in that: - 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.;

2. System (100”) according to claim 1, characterized in that it further comprises at least one collision alert 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.

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

4. System (100; 100”) according to any one of claims 1 to 3, 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).

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

6. System (100; 100”) according to any one of claims 1 to 5, 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.

7. System (100; 100”) according to any one of claims 1 to 6, 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).

8. System (100; 100”) according to claim 7, 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).

9. System (100; 100”) according to claim 7, wherein the location antenna (111; 111') of the improved module (130; 130') is configured furthermore 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).

10. System (100; 100”) according to claim 7, 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).

11. System (100; 100”) according to any one of claims 1 to 10, 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.

12. System (100; 100”) according to claim 11, 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 (Tl).

13. System (100; 100”) according to any one of claims 1 to 12, 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.

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

15. A vehicle (10; 10') comprising a system (100; 100”) according to any one of claims 1 to 13, wherein the one improved module (130; 130') is located in a central region of the rear of the vehicle.

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