FR2929468A1 - Portable remote control case i.e. identifier, identifying method for hands-free access system for accessing cab interior of vehicle, involves identifying radiolabel in identification zone, and locating radiolabel in location zone - Google Patents

Abstract

The method involves identifying a radiolabel (7) in an identification zone (Z5) by controlling an emission of a radio frequency signal of identification data transmission. The radiolabel is located in a location zone (Z4) by controlling an emission of the radio frequency signal and a low frequency signal, and by conditioning the transmission and recognition of the identification data of the label only during reception of the low frequency signal whose level is higher than the predetermined threshold, by the radiolabel. An independent claim is also included for a hands-free access system comprising a portable remote control case.

Description

The invention relates to a method of identifying a portable remote control unit, said identifier, a hands-free access system to a vehicle. It extends to a hands-free access system implementing this identification method.

Hands-free access devices to a vehicle conventionally comprise a portable remote control unit, called identifier, a central unit embedded in the vehicle, and transmission means arranged on the one hand in the vehicle and integrated on the other hand in the identifier and adapted to allow to establish a dialogue for the implementation of identification procedures of said identifier. In addition, the transmission means disposed in the vehicle usually comprise: external antennas for transmitting identification signals to identifiers located outside the vehicle, enabling identification of said identifiers as soon as possible; introduction into a predetermined range identification area around the vehicle, and indoor antennas for issuing identification signals to identifiers located inside the vehicle. One of the drawbacks of such hands-free access devices lies in their high cost resulting from the design of the transmission means and in particular the number of antennas required in the vehicle with all the following subjections: connection cables, control amplifiers The present invention aims at overcoming this drawback and its main objective is to provide a method for identifying identifiers of hands-free access systems leading to a significant reduction in the cost price of such access systems for simplification. in particular on-vehicle transmission means and identifiers. For this purpose, the invention is directed to a method of identifying a portable remote control unit, called an identifier, of a hands-free access system to a vehicle interior, according to which: an identifier integrating a radio-tag comprising, on the one hand, identification data storage means of the identifier, and on the other hand, an antenna for low frequency signals, called LF signals, and an antenna for high frequency signals, said RF signals, 2 • the vehicle is equipped with a central unit comprising: • means for transmitting LF low frequency signals determining at least one zone, called the localization area, • and means for transmitting / receiving signals RF high frequency, able to provide the radio-tags with the energy necessary for their activation, in a zone, called the identification zone, and a procedure for identifying identifiers combining: • an identification step radio tags in the identification area, comprising controlling the transmission by the central unit of RF signals of request for transmission of identification data, and a step of locating the radio tags in each location area , consisting of: • controlling the transmission by the central unit, on the one hand of LF signals, and on the other hand of RF signals for the request for transmission of identification data, and conditioning the transmission or transmission taking into account identification data of a radio-tag only when the latter concomitantly receives LF signals of a level greater than a predetermined threshold.

It should be noted that, according to the invention, is meant: • by low frequency signals LF, signals whose frequency is in a range of frequencies ranging between values of the order of tens of KHz and values of the order of tens of MHz, • by RF high frequency signals, signals whose frequency falls within a frequency range extending between values of the order of tens of MHz and values of the order some GHz. It should also be noted that the limit values of these frequency ranges are functions of the legal provisions establishing the authorized transmission powers according to the transmission frequencies.

According to the invention, and firstly, the electronic unit of the identifier consists of a radio-label, that is to say a component whose cost is very low. It should be noted that according to the invention, it is intended to define, by means of radio tags, markers commonly comprising at least one antenna (two RF and LF antennas respectively according to the invention), a silicon chip and a substrate and / or encapsulation, intended for the implementation of a so-called radio-identification technique (a word derived from the English radio frequency identification, better known in abbreviated form as RFID), for: • storing data in the said radio- labels (data comprising, according to the invention, identification data); and recovering these data by using active radiofrequency transmitter RF devices, called readers, designed to supply the radio-tags which are in their radius. action, the energy necessary for the emission of a signal in which said data are introduced. In addition, according to the invention, the transmission means equipping the vehicle are limited to LF transmission means and RF transmission / reception means integrated in the central unit and designed so that: • the RF transmissions are adapted to activate the radio tags (when transmitting the RF signal of the vehicle to the radio label) and to convey the identification data (when transmitting, in return, the RF signal by the radio label to the vehicle), • the LF signals emitted by the central unit to the radio tags are used to enable precise location of the radio tags to ensure their presence in predetermined areas requiring precise location.

It should be noted that the radio-tags according to the invention do not need to transmit LF signals to the vehicle. It should be noted that the extent of the location areas (in which one seeks to locate the radio tags) and therefore the steps of locating the method according to the invention are a function of the overall identification procedure implemented.

Thus, as a first advantageous embodiment, the location area corresponds to the surface of the passenger compartment of the vehicle. Thus the search for an identifier in this location area makes it possible to check the presence of an identifier in the passenger compartment. Such a verification procedure can be advantageously used, according to the invention, to condition the authorization to start a vehicle to the presence of an identifier in the cockpit of the latter. This verification procedure can also be advantageously used, according to the invention, to prohibit the locking of a vehicle, after stopping the latter, during the presence of an identifier in the passenger compartment of said vehicle. In the usual way, moreover, such a prohibition may be signaled to the user by an audible signal. As a second advantageous embodiment, the location zone is constituted by a predetermined width of the surface around the passenger compartment of the vehicle, in order to control an automatic unlocking of the vehicle, as soon as the identifier is at near this one.

Whatever the extent of the location area, the identification procedure implemented, and generically according to the invention, the transmission means integrated in the vehicle therefore comprise only two antennas (an RF antenna and an antenna LF) and are gathered and centralized in the central unit. As a result, the cost price of these transmission means (antennas, afferent subjugations, etc.) is also minimized in an optimal manner. According to a first advantageous variant embodiment of the invention, during each location step, the transmission by the central unit of RF signals of request for transmission of identification data including a threshold value representative of an LF signal reception level below which each radio tag is programmed to block any RF signal transmission. At the same time the transmission by the central unit of the vehicle of a signal LF is controlled. According to this first variant, the radio-tag responds to the received RF signal only if it has received at the same time a LF signal of a given level. According to a second variant of advantageous implementation, during each location step: • the transmission by the central unit (3), on the one hand of LF signals, and on the other hand, of RF signals of request for the transmission of identification data, • data indicative of the reception level of the LF signals received concomitantly by said radio tags are incorporated in the RF signals of identification data transmitted by the radio tags; the central unit is programmed to take into account the identification data received from the radio tags only if the value of the reception level of the signals LF incorporated with said data has a value greater than a given threshold value. According to this second variant, the radio-tag always responds to the received RF signal and indicates in its response message the level of the signal LF that it has received at the same time as the RF signal. It is then the central unit of the vehicle that decides whether or not it processes the message received from the radio-tag, as a function of the level of the signal LF received by the tag. This makes it possible to process a signal received from a radio-label only when this radio-tag is in a determined localization zone (either in the vehicle or in a zone of determined width around this vehicle) by the signal level. LF received by the radio-label. Moreover, in order to guarantee precise three-dimensional detection of the identifiers during the transmission of the LF signals, the vehicle LF transmission means and / or the identifiers advantageously comprise a multidirectional LF antenna. According to the invention, during each locating step, the central unit sends signals LF consisting of pulses transmitted with a given periodicity.

The invention extends to a hands-free access system to a vehicle cabin comprising a portable remote control unit, called an identifier, a central unit embedded in the vehicle, and transmission means, on the one hand, arranged in the vehicle, and secondly, integrated in the identifier, and adapted to allow a dialogue between the central unit and the identifier for the implementation of a procedure for identifying said identifier. According to the invention, this hands-free access system is characterized in that: • the identifier integrates a radio-tag comprising means for storing identification data of said identifier, • the transmission means comprise: • incorporated in the radio-tag, an antenna for low frequency signals, called LF signals, and an antenna for high frequency signals, called RF signals, and incorporated in the central unit, means for transmitting LF low frequency signals determining at at least one zone, called the location zone, and means for transmitting / receiving RF high frequency signals, capable of supplying the radio-tags with the energy necessary for their activation, in a zone, called an identification zone, the radio label and the central unit being programmed so as to implement a procedure for identifying identifiers combining: a step of identification of the radio tags in the zone of ide ntification, consisting in controlling the transmission by the central unit of RF signals of request for transmission of identification data, and a step of locating the radio tags in each location zone, consisting in: - controlling the transmission by the central unit, on the one hand LF signals, and on the other hand, identification data transmission RF signals, and conditioning the transmission or the taking into account of identification data. of a radio-tag only when the latter concomitantly receives LF signals of a level greater than a predetermined threshold.

In addition, advantageously according to the invention, and for the purpose of transmitting the LF signals, the vehicle LF transmission means and / or the identifiers comprise a multidirectional antenna. Other features and advantages of the invention will become apparent from the detailed description which follows with reference to the accompanying drawings which represent by way of non-limiting example a preferred embodiment. In these drawings: FIG. 1 is a diagrammatic top view of a vehicle equipped with a hands-free access device according to the invention, FIG. 2 is a schematic partial view of a radio-label conforming to FIG. the invention, and FIG. 3 is a schematic representation of the transmission means of a central unit according to the invention. The invention shown by way of example in FIG. 1 consists of a hands-free access system adapted to allow access to the passenger compartment 2 of a vehicle 1 and to start it by means of the identification of a portable remote control unit or identifier 6. As represented in FIG. 1, this hands-free access system comprises, in the first place, a central unit 3 embedded in the vehicle 1 and positioned in a central position inside. of the passenger compartment 2, for example under the roof of said vehicle.

This central unit 3 integrates a connected computer (FIG. 3) with a low frequency transmitter LF connected to a multidirectional antenna 4 and an RF high frequency transmitter / receiver connected to a plane antenna 5.

In addition, the transmitter LF and its associated multidirectional antenna 4 are adapted to have a coverage area, called the location area Z4, corresponding, with a given tolerance, to the surface of the passenger compartment 2 of the vehicle 1, according to a first embodiment of the invention. The RF transmitter / receiver and its associated flat antenna 5, for their part, are adapted to have a coverage area, called Z5 identification zone, delimiting a strip of a width of a few meters around the vehicle 1. 7 The The hands-free access system also comprises, as mentioned above, an identifier 6. This identifier 6 integrates a radio-tag 7 comprising, on the one hand, a chip or ASIC 8 (FIG. 2) provided with a storage memory identification data of said identifier, and secondly, an antenna 9 for receiving low frequency signals LF, and an antenna 10 for receiving and transmitting RF high frequency signals. This radio-tag and equipped with two antennas is an electronic component of very low cost. According to a basic principle of the hands-free access system according to the invention described above, the power of the RF signals emitted by the central unit 3 is adapted so that said signals are able to provide the radio tags 7 located in the identification zone Z5, the energy necessary for their activation. This activation then causes a response of the radio-tag, in the form of an RF signal, incorporating the identification data contained in the radio-tag. By way of illustration, an example of an identification procedure implemented according to the principle of the invention is described below, this example aims at an identification procedure of combining an identification step in the area of identification Z5 for authorizing access to the vehicle 1, and a location step in the location zone Z4 for authorizing the start of said vehicle.

In the first place, the identification step intended to authorize access to the vehicle 1 consists in controlling the periodic transmission, by the plane antenna 5, of RF signals recognizable by specific radio-labels 7, in response to which said radio tags are adapted to transmit an identification signal to the RF transmitter / receiver of the central unit 3. In this identification step, the central unit of the vehicle is not obliged to transmit LF signals concomitantly with the RF signals sent. Indeed, it is desired in this identification step, only identify an identifier near the vehicle, but it is not yet necessary to locate it accurately. The purpose of this identification is simply to launch a bidirectional dialogue, in RF, between the vehicle and the identifier to ensure that it is an identifier associated with the vehicle in question. It should be noted that the radio tag finds the energy to respond to the RF signal sent by the vehicle in this received RF signal. The radio-tag does not need a source of clean energy to return to the vehicle, the data it contains. This is what makes its cost much lower than a conventional identifier with a battery.

This first identification step makes it possible to control the unlocking of the doors of the vehicle 1 and authorizes, as mentioned above, access to the cockpit 2 of the latter. The second step of the method according to the invention is a step of locating the radio tags 7 in the location zone Z4. Indeed when an identifier is located in this area, it allows the start of the vehicle 1 (for example). This locating step consists of: • controlling the transmission, by means of the multidirectional antenna 4, of signals LF consisting of pulses emitted with a given periodicity, and, to control the emission, via the planar antenna 5, identification data transmission RF signals, further comprising a threshold value representative of a signal reception level LF below which the radio tags 7 are programmed to block any RF signal transmission in response. These two emissions (LF and RF) can be concomitant. Such a location step thus makes it possible, not only to identify the radio tags 7, but also to guarantee that the radio tags 7 that triggered the start authorization are located in the location zone Z4, that is to say ie, inside the passenger compartment 2 of the vehicle 1. It should be noted that, alternatively, this second step may also consist of: • controlling the transmission, via the multidirectional antenna 4, of LF signals consisting of pulses emitted with a given periodicity, • to control the transmission, by means of the plane antenna 5, of RF signals of request for transmission of identification data, • to be incorporated in the signals RF identification data transmitted in response by the RFID tags 7, a data representative of the reception level of the RF signals received by said RFID tags, and programming the CPU 3 to take into account the identification data received from the radio tags 7 only if the value of the reception level of the signals LF incorporated with said data has a value greater than a given threshold value. The invention, of which an example of an identification procedure implemented is described above, thus makes it possible to provide a hands-free access system having an optimized cost price both with regard to the equipment integrated in the vehicle and that necessary for the realization of identifiers 6.

According to a second mode of implementation of the method, the location zone Z4 surrounds the vehicle. When an identifier is recognized as being in this zone, functions of welcome lighting and / or unlocking of the openings can be realized for example. The invention is not limited to the embodiments of the method described above. Thus the extent of zones Z4 and Z5 may be different from those shown without departing from the scope of the present invention.

Claims (11)

REVENDICATIONS1. A method of identifying a portable remote control unit (6), called an identifier, of a hands-free access system to a vehicle interior (2) (1), characterized in that: • one uses a identifier (6) integrating a radio-tag (7) comprising: • on the one hand, means (8) for storing identification data of the identifier (6), • and on the other hand, an antenna ( 9) for low frequency signals, called LF signals, and an antenna (10) for high frequency signals, called RF signals, • the vehicle (1) is equipped with a central unit (3) comprising: • transmission means (4) low-frequency signals LF determining at least one zone (Z4), called the location zone, and means (5) for transmitting / receiving RF high-frequency signals, capable of supplying the radio tags (7) the energy necessary for their activation, in a zone (Z5), called the identification zone, and a procedure for identifying the identi fiers (6) combining • a step of identification of the radio tags (7) in the identification area (Z5), of controlling the transmission by the central unit (3) of RF signals requesting transmission of identification data, and a step of locating the radio tags (7) in each location zone (Z4), consisting of: controlling the transmission by the central unit (3), on the one hand, of signals LF, and secondly, RF signals request for transmission of identification data, and conditioning the transmission or the taking into account of identification data of a radio-tag (7) only during the concomitant reception by the latter of LF signals of a level greater than a predetermined threshold. 2. Identification method according to claim 1 characterized in that the identification procedure comprises a location step in a surface location area (Z4) corresponding to the surface of the passenger compartment (2) of the vehicle (1). adapted to make it possible to check the presence of an identifier (6) in said cabin. 3. Identification method according to claim 2, characterized in that the locating step in the locating zone (Z4) corresponding to the surface of the passenger compartment (2) of the vehicle (1) is intended to authorize the starting. of the vehicle. 4. Identification method according to claim 2 characterized in that the locating step in the location zone (Z4) corresponding to the surface of the passenger compartment (2) of the vehicle (1) is intended to prohibit the locking of the vehicle (1), after stopping the latter, when detecting an identifier (6) in the passenger compartment (2) of said vehicle. 5. Identification method according to one of claims 1 to 4 characterized in that the identification procedure comprises a location step in a location zone incorporating a predetermined width of the surface band around the passenger compartment (2). vehicle (1) for controlling an automatic unlocking of said vehicle. 6. Identification method according to one of claims 1 to 5 characterized in that, during each locating step, it controls the transmission, by the central unit (3), of RF signals transmission request of identification data having a threshold value representative of an LF signal reception level below which each radio tag (7) is programmed to block any RF signal transmission. 7. Identification method according to one of claims 1 to 5 characterized in that, at each location step: • it controls the transmission by the central unit (3), on the one hand LF signals, and on the other hand, identification data transmission RF signals, RF data of identification data transmitted by the radio tags (7) are incorporated, data representative of the reception level of the data elements is transmitted. LF signals received concomitantly by said radio tags, • and the central unit (3) is programmed so as to take into account the identification data received from the radio tags (7) only if the value of the reception level of the radio-tags (7) embedded LF signals with said data has a value greater than a given threshold value. 8. Identification method according to one of the preceding claims characterized in that, for the transmission of the LF signals, the LF transmission means of the vehicle (1) and / or the identifiers (6) comprise a multidirectional antenna (4). 9. Identification method according to one of the preceding claims characterized in that, at each location step, it controls the transmission by the central unit (3) LF signals consisting of pulses issued with a given periodicity . 10. Hands-free access system to a vehicle interior (2) (1) comprising a portable remote control unit (6), said identifier, a central unit (3) embedded in the vehicle (1), and transmission means (4, 5, 9, 10), on the one hand, arranged in the vehicle (1), and on the other hand, integrated in the identifier (6), and adapted to allow a dialogue between the central unit (3) and the identifier (6) for the implementation of a procedure for identifying said identifier, said hands-free access system being characterized in that: • the identifier (6 ) integrates a radio-tag (7) comprising means (8) for storing identification data of said identifier, • the transmission means comprise: • incorporated in the radio-tag (7), an antenna (9) for low frequency signals, called LF signals, and an antenna (10) for high frequency signals, called RF signals, and incorporated in the unit hundred (3) means for transmitting (4) low frequency signals LF determining at least one zone (Z4), called localization area, and means for transmitting / receiving (5) RF high frequency signals, capable supplying the radio-labels (7) with the energy necessary for their activation, in a zone (Z5), called an identification zone, the radio-tag (7) and the central unit (3) being programmed so as to implementing an identifier identification procedure (6) combining: • a step of identifying the radio tags (7) in the identification zone (Z5), consisting of controlling the transmission by the central unit ( 3) identification data transmission RF signals, and • a location step of the radio tags (7) in each location area (Z4), consisting of: • controlling the transmission by the central unit (3), on the one hand LF signals, and on the other hand, RF signals for data transmission request of iden and conditioning the transmission or taking into account of identification data of a radio tag (7) only when concomitant reception by the latter of LF signals of a level greater than a predetermined threshold. 11. hands-free access system according to claim 10 characterized in that, for the transmission of the LF signals, the LF transmission means of the vehicle (1) and / or the identifiers (6) comprise a multidirectional antenna ( 4).