FR2814842A1 - Transmitter/receiver signal locking/unlocking cars having receiver detecting transmission intensity following relative position function and when comparison correct action commanded - Google Patents

Abstract

The signal transmission and reception has a mobile unit locking and unlocking a car. The mobile transmitter and receiver (4) has a receiver which detects the transmission intensity as a function of relative position between the two. An analysis unit compares the received values with set values. The action is commanded if the comparison is correct.

Description

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 The invention relates to a method for transmitting and receiving signals between at least a first transmitting and receiving device and at least one other transmitting and receiving device, in particular for unlocking and / or locking a vehicle, as well as transmitting and receiving devices and an arrangement consisting of such devices for such a method.

 Such transmitting and receiving methods and devices find, for example, an application in the automotive technique, in order to allow, in the most comfortable way possible for a user, the unlocking of the vehicle, more precisely of the vehicle doors, and / or the activation and deactivating the anti-theft device.

 Passive access devices are increasingly used in this case in which a user carries an identification generator, hereinafter also called an ID generator, which, unlike active devices, does not have to be operated by a button or the like, but communicates automatically with a corresponding base station in the vehicle.

 For such electronic key devices, operating most of the time by radio, of the active type and more particularly of the passive type, there are extensive imposed conditions relating to security against unauthorized access, such as for example fraudulent eavesdropping on an ID generator within or beyond the range of the base station located in the vehicle and illegal reproduction.

 Usually, to prevent unauthorized access, encryption algorithms and modifications to the access code are notably implemented to prevent unauthorized access.

 As the technique evolves, also making unauthorized access against such protective measures possible, there is in practice the need for additional sophisticated protection against unauthorized access or detection. fraud of an ID generator.

 This is why the present invention aims to provide a transmission and reception method comprising at least a first device transmitting and receiving an object and at least one other mobile transmitting and receiving device used to trigger at least one action. in the object, as well as providing a transmitter and receiver device and an arrangement

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 for the implementation of this method, which in a simple manner provide increased security against unauthorized interventions.

 To this end, the subject of the invention is a method of transmitting and receiving by means of at least one first transmitter and receiver device of an object and at least one second mobile transmitter and receiver device used to trigger at less action in the object, in particular for deactivation and / or activation of a line blocking or for unlocking and / or locking a vehicle, characterized in that, a) in the transmitter device and mobile receiver, both the intensity of the emission field and the direction of emission of the first transmitter and receiver device are detected as a function of the relative position between the two, b) in an analysis unit, it is proceeded to a comparison with set values and c) an action is commanded as a function of the result of the comparison.

 For the same purpose, the invention also relates to a transmitter and receiver device for the implementation of this method, characterized in that it comprises a transmitter and / or receiver unit having at least two field characteristics (field of 'transmission and / or reception) differing from each other.

 For the same purpose again, the invention also relates to an arrangement consisting of at least one first transmitter and receiver device and at least one other mobile transmitter and receiver device, making it possible to implement the above method, characterized in that the fixed transmitter and receiver device and the mobile transmitter and receiver device are each arranged respectively in accordance with the above device.

 By means of the detection of the intensity of the emission field and of the direction of emission of the first transmitting and receiving device, for example fixed with respect to the object, in the mobile transmitting and receiving device, additional parameters are transmitted and an action in the object is only triggered in the case of a positive result of the comparison with corresponding setpoints. Since, in such hitherto known transmission devices serving for the detection of a mobile transmitting and receiving device, these additional parameters are not hitherto used, security with regard to the methods currently used known to provide prohibited access is increased.

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 In addition, this method makes it possible to trigger an action in the object only when the mobile transmitter and receiver device, such as for example an ID generator, is within the range of the first transmitter and receiver device, for example of a station. base arranged in a vehicle. This advantageously makes it possible to successfully prevent unauthorized access by means of listening to an ID generator beyond the scope and of using the information thus obtained, since at a given instant, beyond the range, these parameters (emission field strength and emission direction) do not exist and therefore cannot be saved.

 The analysis unit for comparing the received values for the emission field strength and the direction of emission with corresponding set values may be located in the mobile transmitter and receiver device itself. However, it is also possible to imagine that these values are retransmitted by the mobile transmitter and receiver device to the fixed transmitter and receiver device and are only compared therein with corresponding reference values by means of a unit of analysis.

 In each case, it is only for a positive comparison result that an appropriate action can be triggered in the object, such as deactivation of the anti-theft device and / or unlocking of the vehicle, more precisely of the vehicle doors, since it has been correctly detected that the mobile transmitter and receiver device is within the range of the fixed transmitter and receiver device. Conversely, it is possible that, when the mobile transmitter and receiver device passes beyond the range of the fixed transmitter and receiver device, appropriate actions are triggered, such as activation of the anti-theft device and / or locking of a vehicle. .

 According to an advantageous embodiment of the invention, the fixed transmitter and receiver device transmits by means of two transmitting antennas, so that, during a transmission of data telegrams, which can for example take place at intervals or by pulses in digital blocks , switching between the transmitting antennas is possible, so that, due to the non-identical arrangement of these transmitting antennas, there are different emission fields. In this case, the switching times are also known to the mobile transmitting and receiving device, for example being fixedly predetermined

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 and possibly subject to modification by means of a fixed algorithm. However, it is also possible to imagine that the switching times are transmitted by means of the same transmission channel, or another, between the fixed transmitter and receiver device and the mobile transmitter and receiver device and are possibly stored temporarily. in memory and that in this way they can also be predetermined.

 According to another embodiment of the invention, it is also possible to vary the intensity of the emission field during a transmission, for example of a digital transmission block, the nature and the instants of the variations being able to be prefixed in the mobile transmitter and receiver device, as previously described for switching instants.

 Thanks to these other embodiments, security against an unauthorized access attempt advantageously increases, since other parameters are analyzed and compared with corresponding reference values and they do not trigger an appropriate action in the object only in the case of a positive result.

 The transmitter and receiver device for implementing such a device comprises at least two transmitting and / or receiving antennas. In this case, the fixed transmitter and receiver device can for example transmit by means of two antennas which are in non-identical locations and which can be arranged differently with regard to the position in space, at least two fields which can be received by a mobile transmitting and receiving device comprising at least two receiving antennas which are located in different locations, the magnitude of the emitting field, for example a magnetic field, as well as its direction being able to be calculated taking into account the position and the orientation of the mobile transmitter and receiver device, using known trigonometric methods. Instead of an arrangement consisting of two antennas (transmitting antenna and receiving antenna), it is also possible to imagine operating one and the same antenna (transmitting antenna or receiving antenna), for example in multiplex operation, with different parameters (transmit power), in order to also obtain different fields in this way.

 Of course, instead of what has been indicated, it is also possible that the mobile transmitter and receiver device transmits by means of

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 two transmitting antennas and that the fixed transmitting and receiving device receives in a corresponding manner by means of two receiving antennas.

 The transmission and reception method according to the invention may also have one or more of the following features: - the comparison takes place by means of an analysis unit provided in the mobile transmitter and receiver device, - the intensity of the emission field and the direction of emission detected by the mobile transmitter and receiver device are transmitted to the first transmitter and receiver device and the comparison takes place by means of an analysis unit provided in the first transmitter and receiver device, - the first transmitting and receiving device transmits by means of at least two transmitting antennas, - during a transmission between the transmitting antennas, switching is carried out at least once and the switching instant or instants can be prefixed in the device mobile transmitter and receiver as set values, - the intensity of the emission field is subject to at least one variation eg During a transmission and the variations can be prefixed in the mobile transmitter and receiver device as set values, - the instant or times of the switching and / or variation can be specified by means of a code changing between the first transmitter device and receiver and the mobile transmitter and receiver device.

 The transmitter and receiver device according to the invention can also have one or both of the following two particulars: - the transmitter and receiver device comprises at least two transmitter and / or receiver antennas, - the transmitter and receiver device comprises a unit analysis in which setpoints can be kept in memory.

 The invention is set out below in detail using an embodiment shown in the drawings. We see: in Figure 1, a schematic representation of a vehicle comprising a fixed transmitter and receiver device comprising two transmitting antennas,

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 in FIG. 2, a mobile transmitter and receiver device comprising three receiving antennas, in FIG. 3, a schematic representation of a vehicle comprising a fixed transmitter and receiver device comprising three transmitting antennas and, in FIG. 4, a schematic representation of 'a vehicle comprising a fixed transmitter and receiver device comprising four antennas.

 FIG. 1 represents a first embodiment of a surveillance of interior space of a vehicle which comprises a first transmitting antenna 1 and a second transmitting antenna 2 which are connected to a control device 3. The antennas 1 and 2, which are for example produced in the form of magnetic coils, can be supplied with low frequency alternating current by means of the control device 3, for data transmission. This alternating current oscillates with the carrier frequency, for example of the order of magnitude of 100 kHz, and is modulated by means of the control device 3 with a view to data transmission and the power variation.

 As shown in Figure 1, the transmitting antennas 1 and 2 are located in different locations, for example on the left and right side in the vehicle doors and they are operated with a power adjusted in an appropriate manner, d in such a way that, when it is in the detection space, therefore here in the interior space of the vehicle, a mobile transmitter and receiver device, for example an identification generator or ID generator 4, can detect the magnetic fields 1 ′, 2 ′ of the two antennas or coils 1 and 2 as a function of a peak value of field strength and field direction.

 To this end, as shown in FIG. 2, the generator ID 4 comprises three transmitter or detector coils 7,8 and 9 which are arranged perpendicularly to one another in spatial arrangement and which are each connected to the respective inputs (ADC) d a microprocessor 16 via a respective amplifier 10, 11, 12 and a respective peak value measurement unit 13, 14, 15. If such an ID 4 generator is located in a 1 ', 2' field, unequivocal information concerning the orientation of the field, more precisely field lines, taking into account the location of the ID 4 generator is

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 possible, using known trigonometric methods, by means of an evaluation of the different partial fields or field values received in the coils 7, 8, 9. The arrangement of the coils perpendicularly to each other is only an embodiment , presented by way of example, which is particularly advantageous with regard to the magnitude of the field strength, other angles of at least two antennas between them, with the exception of 0, therefore of a position identical in space, also make it possible to obtain appropriate information. In addition, it is also possible to determine in a simple manner the magnitude or the intensity of the magnetic field emitted at the location of the generator ID 4.

 If, as regards the microcontroller or the microprocessor 16, it is a relatively complex processor, the values determined in an appropriate manner already contained in the generator ID 4 are compared with corresponding reference values in the microprocessor 16 also playing the role of analysis unit and the result of the comparison can be transmitted by another radio channel, namely an HF transmitter stage 6 and a transmitter antenna, to a radio receiver 5 of the fixed transmitter and receiver device arranged in the vehicle.

 As a variant, it is also possible that only the measurement values received by means of the coils 7, 8 and 9 are transmitted, by means of a transmitter device 6, for example an HF transmitter, to the receiver device 5, for example a receiver HF of the fixed transmitter and receiver device placed in the vehicle and that they are only compared in this device, in an analysis unit which is, for example, additionally in the control device 3, with corresponding reference values which define the interior space of the vehicle or the space to be detected. If the comparison result is positive, a corresponding action can then be triggered in the vehicle, such as deactivating the driving lock.

 Data transmissions can take place with a changing code or by being encrypted, for a further increase in security against unauthorized intervention. In addition, in the case of a transmission by means of two antennas, a single or multiple switching can take place during a data transmission or a data telegram, the switching times being known beforehand to the generator ID 4 or being transmitted, so this is not

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 that with the suitable ID 4 generator a correct response (synchronization of switching times) can take place.

 A further improvement can take place by means of a power variation instead of a simple switching, the transmitting power being also set to intermediate values, so that the position and the orientation of the ID generator which can be detected are overdetermined and contribute to an increase in security by means of an analysis.

 FIG. 3 represents a fixed transmitter and receiver device, arranged in a vehicle, which comprises, in addition to the embodiment of FIG. 1, a third transmitter coil 17 which is itself located in a location other than the two other transmitting coils 1 and 2, for example in the central position, in the vehicle console or in the interior lining of the vehicle roof.

 By means of this third emission field 17 ′ which can also be determined on an ID generator 4, as previously described for the emission fields 1 ′, 2 ′, as a function of the field strength and of the direction at the location of this ID 4 generator, it is also possible to obtain, as previously described for a power variation, an overdetermination of the position of the ID 4 generator in the detectable space, in such a way that this overdetermination results in redundancy. By means of an appropriate analysis of this redundancy, more precisely of the values, the security of surveillance against unauthorized intervention can be further increased.

 Instead of monitoring an interior space, as shown in FIG. 1 and in FIG. 3, the example represented in FIG. 4 illustrates the monitoring of an exterior space of determined dimensions, for example of the exterior space from the wing to the rear of the left door and the right door of the vehicle. In addition to the transmitting antennas 1 and 2 which, in FIG. 4, however represent at least in addition a transmitting field in the external space 1 ′, 2 ′, there is provided, on each of the two sides, an additional antenna respectively 18 ( left side) and 19 (right side) which is arranged in a different location from the transmitting antennas 1 and 2. Therefore, here again, as already described in FIG. 1 for an interior space, the detection of an ID generator is possible given its precise position (for example when approaching the left as shown), as described below in detail.

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 If, during data transmission, a first transmitting antenna 1 produces an electromagnetic field 1 ′, with a power fixed beforehand, this field widens in the detection space with a characteristic very specific to the object, the field strength decreasing more than proportional to the distance from the transmitting antenna 1. If an ID 4 generator detects the amplitude of the field strength in the detection space during data transmission, it is possible to deduce from this measurement value on which equipotential surface (curved surface in space with the same field strength) the generator ID 4 is located. If the latter further detects the field direction, its orientation is thus defined taking account of the field gradient, to within a possible rotation.

 If then this generator ID 4 detects the amplitude of the field intensity in the detection space during the transmission of data by means of a second transmitting antenna 18, it is then possible to deduce from this measurement value over which second equipotential surface the generator ID 4 is located. In common with the first field strength measurement, the position of the generator ID 4 is restricted to the line of intersection of the two equipotential surfaces. By means of additional field direction detection in the context of the operation of the second transmitting antenna, the last degree of freedom is also fixed, since, in accordance with the invention, the two transmitting antennas are operated d 'in an alternating manner, for example by means of multiplexing during a data transmission, therefore at a short time interval one behind the other, so that the position and orientation of the generator ID 4 in the space do not vary in this time interval. The position thus determined can be compared, in an analysis unit, with reference values which define beforehand the possible positions in the detection space and thus also provide reliable information on the question of whether the generator ID 4 is or is not actually in the detection space or if this must be simulated by means of an unauthorized intervention.

d'espace intérieur (figure 1) à deux antennes","surveillance d'espace intérieur (figure 3) à trois antennes" et "surveillance d'espace extérieur (figure 4)"peuvent être combinés entre eux à volonté, d'une manière telle que par exemple le déverrouillage ou le verrouillage de la porte peut avoir Of course, the embodiments shown "monitoring

of indoor space (Figure 1) with two antennas "," indoor space monitoring (Figure 3) with three antennas "and" outdoor space monitoring (Figure 4) "can be combined as desired, so that for example unlocking or locking the door can have

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 place by means of a single ID 4 generator which is also used for deactivation or activation of a line blocking, so that, when a user who is carrying an ID 4 generator near him a door, this or the central locking unlocks and, when the user takes place in the driver's seat, the driving lock is automatically deactivated, while, when he gets up and leaves the vehicle, the locking line is activated and the door lock is locked automatically after the user has closed the door and left the relatively narrow monitored detection space, for example 1-5 m. Of course, the principle according to the invention can also be used on arrangements comprising several ID generators and several base stations.

 Although the example of embodiment presented presents the method according to the invention using a passive access device for a motor vehicle, this method can of course also be applied to an active access device, therefore detecting the position of at least one ID 4 generator only when actuating, for example, a button or the like located in this ID 4 generator. In addition, the method according to the invention and an arrangement of the devices transmitters and receivers according to the invention used for the implementation of such a method are not limited to automotive technology, but are applicable to many fields, such as data processing devices, domestic technique, technical monitoring, counting devices, etc.

 For example, such access controls can also be provided for data processing devices, residential doors, garage doors, etc. Furthermore, instead of being used for access control , the invention can also be used for the safe detection of a transmitting and receiving device (mobile) used to ensure the monitoring of mobile objects, such as for example of positions where such a mobile object is located, or the number of once it passes certain positions (counting systems).

Claims (11)

 CLAIMS 1. Method of transmitting and receiving by means of at least a first device transmitting and receiving an object and at least a second mobile transmitting and receiving device used to trigger at least one action in the object, in particular for deactivation and / or activation of a line blocking or for unlocking and / or locking a vehicle, characterized in that, a) in the mobile transmitter and receiver device (4), at the once the intensity of the emission field and the direction of emission of the first transmitting and receiving device are detected as a function of the relative position between the two, b) in an analysis unit, a comparison is made with setpoints and c) an action is commanded according to the result of the comparison.  2. Method according to claim 1, characterized in that the comparison takes place by means of an analysis unit provided in the mobile transmitter and receiver device.  3. Method according to claim 1, characterized in that the emission field strength and the direction of emission detected by the mobile transmitter and receiver device (4) are transmitted to the first transmitter and receiver device and the comparison takes place by means of an analysis unit provided in the first transmitter and receiver device.  4. Method according to any one of claims 1 to 3, characterized in that the first transmitter and receiver device transmits by means of at least two transmitting antennas (1,2, 17,18, 19).  5. Method according to claim 4, characterized in that, during a transmission between the transmitting antennas (1,2, 17,18, 19), switching is carried out at least once and the switching instant or instants can be prefixed in the mobile transmitter and receiver device (4) as setpoints.  6. Method according to any one of claims 1 to 5, characterized in that the intensity of the emission field is subject at least once to a variation during a transmission and the variations can <Desc / Clms Page number 12>  be prefixed in the mobile transmitter and receiver device (4) as set values.  7. Method according to any one of claims 5 and 6, characterized in that the instant or instants of the switching and / or variation can be specified by means of a code changing between the first transmitter and receiver device and the transmitter device and mobile receiver (4).  8. Transmitter and receiver device for implementing a method according to any one of Claims 1 to 7, characterized in that the transmitter and receiver device comprises a transmitter and / or receiver unit having at least two field characteristics (field of emission and / or reception) (1 ', 2', 17 ', 18', 19 ') differing from the other.  9. Transmitter and receiver device according to claim 8, characterized in that the transmitter and receiver device comprises at least two transmitting and / or receiving antennas (1,2, 17,18, 19; 7,8, 9).  10. Transmitter and receiver device according to any one of claims 8 and 9, characterized in that the transmitter and receiver device comprises an analysis unit in which reference values can be kept in memory.  11. Arrangement consisting of at least a first transmitter and receiver device and at least one other mobile transmitter and receiver device (4), making it possible to implement a method according to any one of claims 1 to 7, characterized in that the fixed transmitter and receiver device and the mobile transmitter and receiver device (4) are each arranged respectively according to any one of claims 8 to 10.