EP1378864A1 - Method for controlling access to a determined space by a personalized portable object, and personalized portable object for carrying out the method - Google Patents

Abstract

The electronic control system uses wireless transmission of a coded identification signal to a processing unit (26) mounted within a protected space. The coded identification signal comprises a specific analogue signature, compared with a reference signature which is stored in memory (25). The access control procedure uses wireless transmission of a coded identification signal. The electronic control system is mounted within the protected area, and includes a processing unit (26) connected to both signal transmission units (22,28) and signal reception units (21,27). To gain access a coded signal is transmitted to the unit, and this is verified in order to permit access to the space. The coded identification signal comprises a specific analogue signature. This analogue signature is compared with a reference signature which is stored in memory (25) in a part of the processing circuit (26) within the protected area. The analogue signature may be derived by examination of the variation in amplitude of the envelope of the encoded signal.

Description

The invention relates to a method for controlling access to a portable object. personalized to a specific space, such as a vehicle, by wireless transmission of a coded identification signal. To do this, electronic means are provided in space. These electronic means include in particular management means access connected to reception means and / or signal transmission means. The portable object for access control comprises a processing unit connected to means for transmitting and / or means for receiving signals. The process of Access control to space consists first of all in transmitting a coded signal identification by the transmission means of the portable object or respectively by the transmission means provided in the determined space. This coded signal is then received by space receiving means or respectively by means of reception of the portable object, when the object is in a restricted area around reception means and / or transmission means provided in space. A verification of the received coded signal is carried out in the access management means or in the processing unit to authorize access to the space.

The invention also relates to a personalized portable object for accessing the determined space. This portable object notably includes a processing unit of connected signals and transmission means and / or reception means for signals so as to transmit or receive a coded identification signal for access to the determined space.

Using the access control process, it is possible to authorize access to a person with the personalized portable object in a space determined after verification of the coded signal identifying the object and the space to be accessed. The transmission of the coded signal can be started automatically as soon as the presence of the object in a restricted area around the emission means and / or the means reception in space has been detected. This transmission of the coded signal can also be launched manually by activating object control means or space. This transmission of the coded signal can therefore be carried out from the object to the receiving means provided in space or vice versa of the means in the space provided for the object. As soon as the received coded signal has been recognized in the space access management means or in the data processing unit the object, it is then possible to access the space.

The determined space can be a security enclosure, a safe, a secure room or building with access door controlled by the portable object, a vehicle, or any other space in which entry is only allowed to people authorized. Access authorization allows for example to open or close a door enclosure, safe, or secure building. Preferably, the space is defined by a road vehicle, such as a passenger car, whose doors and trunk can be locked or unlocked by remote control using a personalized portable object.

The personalized portable object can be an electronic key, a watch, a cell phone, smart card, badge or other portable device. Of preferably, this portable object is an electronic key for controlling access to a vehicle. This portable object can include its own source of energy for the power of its electronic components. In this case, the portable object is active type. The power supply of said electronic components can also come from a signal with a determined carrier frequency which is transmitted by transmission means provided in space and which is received in the portable object. In this case, the portable object is of passive type. However with a portable object of type passive, it is necessary to transmit a high frequency signal from the means emissions provided in space to provide sufficient power to the electronic components of the object. This is why in the field of remote control of parts or functions of a vehicle, the portable object, which is an electronic key is preferably of the active type.

The electronic key notably includes a microcontroller connected to storage means in which an encryption algorithm is stored and / or a vehicle access code. As soon as a button is pressed of the key is operated, the microcontroller calculates a coded identification signal to transmit by means of transmitting signals towards the vehicle. After recognition of the coded signal received by the vehicle, a locking command or unlocking parts or functions of the vehicle is performed.

To facilitate access to the vehicle without having to handle the electronic key, it has an electronic key has already been proposed, a response signal of which is transmitted automatically to the vehicle based on an interrogation signal received from the vehicle. For this, the key must be in a restricted area around the vehicle to receive this interrogation signal from the vehicle. In addition, the key does not transmit a signal response to the vehicle only if the interrogation signal has been recognized by the key. This response signal thus makes it possible to control the locking or unlocking of parts or functions of the vehicle.

With the use of such an electronic key controlled automatically by the interrogation signal coming from the vehicle, there is the risk of allowing the opening of the vehicle through intermediary relays without the knowledge of the key holder electronic. Therefore, it gives the possibility to malicious people to use these intermediary relays between the vehicle and the electronic key holder to open the vehicle and start it. Said relays are able to reproduce the signal for the key or the vehicle respectively of interrogation, respectively the response signal which each comprise a binary data sequence.

Figure 1 shows schematically the principle of attack by relay intermediate. The two relays are placed respectively near an object portable, such as an automatically controlled electronic key, and the vehicle associated.

In a normal situation without relays, the wearer of portable object 2 must be in a restricted area 5 around the vehicle 1 to order the opening of the closed vehicle, because the interrogation signal 6, 8 transmitted by a antenna 11 of the vehicle signal transmission means 14, cannot be detected only a short distance away. This interrogation signal has a low carrier frequency LF frequency, for example of the order of 125 kHz. A sequence of binary data in the interrogation signal is for example generated by amplitude modulation of the carrier. An antenna 21 of means for receiving the object 2 cannot detect this low frequency interrogation signal only in an area around the vehicle which does not exceed, for example, 2 m. Once the interrogation signal can be controlled by the portable object, an antenna 22 of the means for transmitting the object portable transmits a response signal 9, 10. This response signal has a frequency UHF high frequency carrier, for example of the order of 433 MHz. This signal response is picked up by an antenna 12 of vehicle reception means 15. of the access management means 13 connected to the transmission means and to the reception of the vehicle will order in particular the opening of the doors and the trunk of the vehicle upon receipt of the response signal.

FIG. 2 represents a flow diagram of the stages of the control process access to a portable object, such as an electronic key, personalized to the vehicle so as to control the locking or unlocking, in particular of the doors and the trunk of said vehicle.

First of all at step 50, the electronic key in the possession of the user of the vehicle is in standby position. Once the vehicle handle has been grabbed by the user in step 51, an LF interrogation signal is transmitted by the means transmission in step 52 under the control of the access management means of the vehicle. In step 53, the key, placed in the restricted area around the vehicle, receives the interrogation signal and verifies the identity of the vehicle by this received signal. If this signal interrogation code is not recognized by the key, the latter is placed again in the standby position at step 50. On the other hand, if this interrogation signal is recognized by the key, then a response signal is calculated by a key processing unit at step 54. This high frequency response signal is transmitted by the antenna of the means for transmitting the key in step 55. Finally, the means for receiving the vehicle receives this response signal in order to allow the access management means to control the opening or closing of the vehicle in step 56.

As shown in Figure 1, when the holder of the electronic key moves away of the vehicle beyond the restricted area, the key is no longer able to receive a interrogation signal from the vehicle. So, through relays intermediaries 3 and 4, it is possible to make a remote bridge between the carrier the portable object 2 and the vehicle 1 to be opened. These intermediate relays are used in generally by malicious people to easily steal the vehicle without the knowledge of the vehicle user. The opening of the vehicle can thus be performed without having to steal said key and without forcing the vehicle locks.

The first intermediate relay 3, placed in the restricted area 5 around the vehicle, is able to receive by an antenna 31 an interrogation signal 6 to low frequency. This first relay converts the low frequency LF signal to transmit an RF radio signal 7 by an antenna 32 to a second relay 4 near the carrier of the portable object 2. This second relay converts the radiofrequency signal RF received by the antenna 42 in a low frequency signal LF, which is the image of the interrogation signal transmitted by the vehicle. This low signal frequency 8 is transmitted by antenna 41 to portable object 2. This object portable receives by the antenna 21 the interrogation signal 8 supplied by the second relay 4. After reception of the interrogation signal, a high frequency UHF 9 response signal is transmitted by antenna 22, if the identity of the vehicle has been recognized. The second relay this high frequency signal is picked up by the antenna 43. Second relay converts signal high frequency received by the portable object in a radio frequency signal which is transmitted by antenna 42. The first relay receives the high frequency signal and converts it into a high frequency UHF signal, which is the image of the response signal calculated by the object portable. This high frequency response signal 10 is transmitted by the antenna 33 to destination of the vehicle so that the antenna 12 of the reception means 15 receives the signal response 10. Access management means 13 connected to the transmission means and to the vehicle reception means will in particular order the opening of doors and trunk of the vehicle upon receipt of the response signal.

FIG. 3 represents a flow diagram of the steps of the control method access of a portable object, such as an electronic key, to the vehicle by means of intermediate relays for locking or unlocking especially doors and the trunk of said vehicle. Note that the steps in this Figure 3, which correspond to that of FIG. 2, bear identical reference signs.

After the person, wearing the first intermediate relay, has entered the handle of the vehicle in step 51, the interrogation signal is transmitted by the vehicle in step 52. This interrogation signal is therefore picked up by the first relay in step 60 in order to convert it into a radio frequency signal. This conversion to a signal radio frequency is required for long distance transmission. The second relay picks up the radio frequency signal from the first relay in step 61 in order to convert it to a signal which is the image of the interrogation signal. This signal of interrogation is transmitted to the electronic key.

In step 53, the key near the second relay receives the interrogation signal and verifies the identity of the vehicle by this received signal. If this coded interrogation signal is not recognized by the key, the latter is again placed in the waiting position in step 50. On the other hand, if this interrogation signal is recognized by the key, then a response signal is calculated by a key processing unit in step 54. This signal high frequency response is transmitted by the antenna of the key transmission means in step 55. In step 62, the second relay picks up this response signal in order to convert it again into a radio frequency signal. This radio frequency signal is transmitted from the second relay to the first relay. In step 63, the first relay, having received the radio frequency signal, converts it into a high frequency signal which is the image of the response signal transmitted by the key. This high frequency signal is transmitted to the vehicle so that in step 56, the access management means control the opening or closing the vehicle.

We therefore understand the need to carry out an access control process which prohibits the use of such intermediate relays for controlling locking or unlocking parts or functions of the vehicle.

A solution to avoid the use of such intermediate relays is mentioned in document WO 01/25060. This document describes a detection system which prevents an intermediate relay attack to unlock a vehicle at without the knowledge of the user of said vehicle. To do this, a frequency comparison of signals transmitted and received by the car is operated in the car so as to estimate the remote response time of the key. The frequency of the signal received by the key is used to define the operations processed in the key and the signal frequency key response. The frequency of the response signal is for example more than 1000 times higher than the frequency of the received signal.

Once the car has transmitted the interrogation signal at a frequency determined, the frequency is varied in the car until the signal response from the key is received. The frequency of the response signal is divided for correspond to the frequency of the signal initially transmitted. So a comparison between the frequency of the response signal and the frequency changed over time in the car is operated. The greater the distance separating the key from the car, the greater the signal frequency in the car will have changed. We can therefore detect by this frequency change measurement, if intermediate relays were used for the unexpected opening of said car.

One drawback of the solution proposed in this document is notably the complexity of creating this frequency variation in the car in order to be able to accurately estimate the distance between the car key. It is necessary that give a distance value from which the electronic means estimate that intermediate relays could have been used to unlock the car.

The object of the invention is therefore to carry out a method for controlling the access of a personalized portable object in a determined space preventing the use of relays intermediaries and overcoming the drawbacks of the cited prior art.

This object, as well as others, are achieved by the process cited above which is characterized in that the coded identification signal transmitted and received comprises a analog signature specific either to the portable object or to electronic means provided in space, either to the couple constituted by the personalized portable object and the electronic means provided in space so as to allow access to space in the event of recognition of said signature.

An advantage of the method is that with the use of an analog signature in the coded signal, this prevents possible intermediate relays held by malicious people to act as a bridge between object and means electronics provided in the space to be accessed. These possible relays are not measure than reproducing digital signals, i.e. in which a sequence of binary data is transmitted. By adding to these signals a analog coding specific for example to the couple constituted by the portable object and the electronic means provided in the space to be accessed, the relays cannot no longer exactly reproduce the coded signals. The analog signature, which depends also characteristics of the transmission means and / or reception means, can be at least a variation in amplitude of the envelope of the coded signal. It could be of an over-modulation of the envelope of the coded signal. This analog signature can also be defined as a function of a growth time and / or a time of amplitude decrease of the envelope of the coded signal at the beginning or at the end of the signal coded. If the coded signal comprises a sequence of binary data, this signature can be defined according to a time of growth and / or decrease of amplitude between two binary elements of different value of the sequence of data. The variation in amplitude during the growth time and / or decay being linear or hyperbolic or random.

Preferably, the determined space is a vehicle and the portable object is a electronic key personalized to the vehicle to be ordered. The components electronics of the key are powered by power supply means which include a standard battery or accumulator or photovoltaic cells or an oscillating mass generator.

The analog signature is preferably inserted in the coded signal of interrogation transmitted by the vehicle to the electronic key. This signal of interrogation includes a sequence of data obtained by modulation amplitude of the signal at a determined carrier frequency. This carrier frequency can be around 125 kHz. Each bit in the sequence is set to a time period greater than the inverse of the carrier frequency. At the reception of the coded interrogation signal, when the key is in a restricted area around the vehicle emission means, an amplitude indicator of the means of reception of signals from the key provides dynamic amplitude values of the envelope of the coded signal. With these amplitude values of the signal envelope coded received, it is possible to check the analog signature of the coded signal. This verification is carried out in a microcontroller by comparison of the values amplitude digitized with stored reference values.

As the interrogation signal transmitted by the vehicle is low frequency, the major part of the calculation operations in the key microcontroller is also done at low frequency which reduces consumption compared to a high frequency treatment. In standby mode, operation is also at low frequency. However, once the analog signature has been recognized, a high frequency response signal must be transmitted to the vehicle for the control for locking or unlocking parts or functions of the vehicle. This high carrier frequency can be of the order of 433 MHz, which makes it possible to control the vehicle at a distance between 10 to 30 m. Like the electronics of the key generating this high frequency signal only works sporadically, the power consumption remains low. This electrical consumption can be around 10 mA during a period of 100 ms.

The invention also aims to provide a portable object for setting implementation of the access control process.

This goal, as well as others, are achieved thanks to the above-mentioned object which is characterized in that the processing unit is arranged to control the means transmission and / or reception means for transmitting and / or receiving a coded identification signal with an analog signature specific to either the object portable, either by electronic means provided in space, or by the couple consisting of the object and the space to be accessed, such as a vehicle.

la figure 1 déjà citée représente schématiquement des relais intermédiaires placés entre l'objet portable et le véhicule pour l'ouverture ou la fermeture non autorisée du véhicule,

la figure 2 déjà citée représente un organigramme des étapes du procédé de contrôle d'accès d'une clé électronique personnalisée au véhicule de l'art antérieur pour verrouiller ou déverrouiller des parties on fonctions du véhicule,

la figure 3 déjà citée représente un organigramme des étapes du procédé de contrôle d'accès d'une clé électronique personnalisée au véhicule de l'art antérieur par le biais de relais intermédiaires pour le verrouillage ou le déverrouillage des parties on fonctions du véhicule,

la figure 4 représente schématiquement les composants électroniques de l'objet portable pour la mise en oeuvre du procédé de contrôle d'accès selon l'invention,

la figure 5 représente un organigramme des étapes du procédé de contrôle d'accès d'un objet portable, tel qu'une clé électronique, à un espace, tel qu'un véhicule selon l'invention,

les figures 6a à 6c représentent des graphiques montrant plusieurs types de signature analogique par variation d'amplitude dans le temps de l'enveloppe du signal codé, qui comprend une séquence de données binaires pour le procédé de contrôle d'accès selon l'invention, et

la figure 7 représente un graphique montrant de manière plus détaillée la porteuse du signal codé se terminant par une signature analogique reflétée par décroissance d'amplitude de l'enveloppe du signal codé comme illustrée à la figure 6a.

The aims, advantages and characteristics of the access control method and of the portable object for its implementation will appear better in the following description of at least one embodiment illustrated by the drawings in which:

FIG. 1, already cited, schematically represents intermediate relays placed between the portable object and the vehicle for the unauthorized opening or closing of the vehicle,

FIG. 2, already cited, represents a flow diagram of the steps of the method for controlling access to a personalized electronic key to the vehicle of the prior art for locking or unlocking parts or functions of the vehicle,

FIG. 3, already cited, represents a flow diagram of the steps of the method for controlling access to a personalized electronic key to the vehicle of the prior art by means of intermediate relays for locking or unlocking the parts or functions of the vehicle,

FIG. 4 schematically represents the electronic components of the portable object for implementing the access control method according to the invention,

FIG. 5 represents a flow diagram of the steps of the method for controlling access of a portable object, such as an electronic key, to a space, such as a vehicle according to the invention,

FIGS. 6a to 6c represent graphs showing several types of analog signature by variation in amplitude over time of the envelope of the coded signal, which comprises a sequence of binary data for the access control method according to the invention, and

FIG. 7 represents a graph showing in more detail the carrier of the coded signal ending with an analog signature reflected by decrease in amplitude of the envelope of the coded signal as illustrated in FIG. 6a.

A preferred embodiment of the control method will be described below. access to a specific space, such as a vehicle with a portable object consisting of preferably by an active type electronic key. Of course, all electronic components of the vehicle and of the portable object, which are known to those skilled in the art in this technical field will not be described so Detailed.

As indicated above with reference to FIG. 1, the portable object 2 must be find in a restricted area 5 around the electronic means of the vehicle 1 for the implementation of the access control method according to the invention. These means electronics include transmission means 11, 14 and / or transmission means reception 12, 15 of signals.

The portable object 2 is preferably an active electronic key in which electrical supply means supply all the components the key. These supply means may include a battery, accumulator, photovoltaic cells, mass generator oscillating or other well known source of electrical energy.

The electronic components of the key are shown schematically in reference to figure 4. As explained above, it is necessary that the key has its own source of energy because it must be able to respond with a high frequency coded signal which may be of the order of 433 MHz. A diet electric by an interrogation signal received at low frequency of the order of 125 kHz for example, in the case of a passive key, is not sufficient to allow the generation of the high frequency coded signal transmitted by the key.

The electronic key 2 essentially comprises a processing unit for signals 26 connected to signal receiving means 21, 27, and to means transmitting signals 22, 28. The power consumption of the key is of the order of 5 µA in standby mode within 99% of the time, and of the order of 10 mA during one 100 ms period when transmitting the high frequency coded signal.

The reception means are composed of a receiving antenna 21 for receive a low frequency coded signal from the vehicle, and a receiver 27. The coded interrogation signal received by the reception means comprises a binary data sequence. The LF 27 receiver, receiving the coded signal, provides the binary data sequence to a microcontroller 24 of the processing unit 26. This LF 27 receiver also includes an amplitude indicator (RSSI, Received Signal Strength Indicator in English terminology) providing values analog dynamic amplitude of the envelope of the coded signal received at a analog to digital converter 23 of the processing unit 26. This converter analog digital 23 digitizes the amplitude values provided by the indicator clocked by a clock signal of the order of 125 kHz. Digitized values amplitude, partially defining the analog signature, are compared to amplitude reference values. These reference values are stored in the storage means 25 of the processing unit 26, which are connected to the microcontroller.

As the amplitude of the coded signal is dependent on the distance between the vehicle and the key, it is rather the derivatives of the envelope of the coded signal or the amplitude deviations, which are digitized and compared in microcontroller 24 with stored reference values. After sampling at a frequency determined in converter 23, it is possible to evaluate these derivatives or these deviations in order to identify the torque formed by the key and the vehicle.

The LF 27 receiver, which includes the amplitude indicator, can be the electronic component referenced EM4083 produced by the company EM Microelectronic-Marin SA located in Marin, Switzerland. The microcontroller 24, used especially for the comparison of amplitude values and for the calculation of a signal answer, maybe the electronic component referenced EM6640 also produces by the company EM Microelectronic-Marin SA located in Marin, Switzerland.

Once the analog signature has been verified in the microcontroller 24, a response signal is calculated in said microcontroller in order to control the transmission of this response signal to the transmission means 22, 28. These means are composed of a UHF 28 transmitter and an antenna 22. As the elements composing the transmitter are well known in this technical field, they do not will not be explained below. However for the transmission of the high response signal frequency, a voltage-controlled oscillator of the transmitter is in principle used, which consumes a lot of electrical energy. Thus, the UHF 28 transmitter is not continuously engaged in the electronic key so as to avoid discharging too quickly the source of energy that the key includes. This transmitter is not engaged only if the microcontroller 24 has recognized the analog signature of the signal question received. This analog signature specifically defines the couple consisting of the personalized key and the vehicle, because it depends on characteristics specific means of transmission and means of reception of the key and vehicle.

The coded interrogation signal transmitted by the vehicle comprises a carrier at a frequency of 125 kHz on which a sequence of binary data is obtained by amplitude modulation of the carrier envelope. Each element binary of the sequence is thus defined over a time period greater than the inverse of the carrier frequency. Each binary element takes the value 1, respectively 0, when the amplitude level of the envelope of the binary element of the coded signal is greater than, respectively less than a threshold amplitude level determined. At this low frequency, the coded interrogation signal is only received a distance of less than 2 m, which defines the restricted area around the vehicle.

Of course, the carrier frequency of the coded signal transmitted by the vehicle may be different from 125 kHz. It can be envisaged to fix this frequency carrier for example at 90 kHz.

The response signal transmitted by the key to the vehicle includes a carrier at a frequency of the order of 433 MHz. Normally at this frequency, the coding of the response signal is not obtained by amplitude modulation, because problems well-known multi-path would influence recognition of coding transmitted.

As with the low frequency coded signal, the carrier frequency of this response signal may be different from 433 MHz. The value of this frequency carrier of the response signal may be dependent on certain prescriptions of the country where the access control process is applied. With such a carrier frequency, it it is possible to control parts or functions of the vehicle up to a distance of 30 m.

FIG. 5 represents a flow diagram of the steps of the control method access to a personalized electronic key to the vehicle for locking or unlocking in particular of the doors and boot of said vehicle according to the invention. he it should be noted that the steps of this FIG. 5, which correspond to that of FIG. 2, bear identical reference signs.

In step 50, the electronic key carried by the vehicle user is in waiting position. Once the vehicle handle has been grasped by the hand of the user in step 51, an LF interrogation signal is transmitted by the means transmission in step 52 under the control of the access management means of the vehicle. The electronic key, placed in the restricted area around the vehicle, receives the coded interrogation signal in step 70. In this step 70, the amplitude indicator of the RF receiver provides analog amplitude values to the converter. The converter digitizes these amplitude values to allow control of these amplitude digitized values in the microcontroller, defining the signature analog of the received signal, with stored reference values. If the signature analog is not recognized, the electronic key goes to step 50 of setting waiting. On the other hand, if the analog signature is recognized, the vehicle is identified with step 53. If the vehicle is not recognized, the key is returned to the position waiting in step 50. In the event of recognition of the vehicle to be controlled, a signal response is calculated by a key processing unit in step 54. This signal high frequency response is transmitted by the antenna of the key transmission means in step 55. Finally, the vehicle reception means pick up this response signal in order to allow the access management means to control the opening or the closing of the vehicle in step 56. It can also be planned to order at this step 56, the vehicle start-up function. In the latter case, at instead of grabbing the handle as explained above, this is for example the knob speed which is touched by the user's hand.

Of course, it is not compulsory for example to grasp the handle of the vehicle for the access control process to be implemented. He can be considered any other means of detecting the presence of the key near the vehicle to order the vehicle to transmit a coded interrogation signal with an analog signature. Acoustic or optical means for example can be used to order the transmission of the coded vehicle interrogation signal.

As mentioned above, the analog signature of the coded signal is defined by at least one amplitude variation of the envelope of the coded signal. Several nonlimiting examples of analog signatures are shown on the Figures 6a to 6c. The signals shown in these figures 6a to 6c are for example those provided by the amplitude indicator.

In these figures 6a to 6c, a coded interrogation signal transmitted by the vehicle comprises a data sequence obtained by amplitude modulation of the envelope of the coded signal. This data sequence is defined by a succession of binary elements. A binary element represents the value 1 when the amplitude of the envelope is above the threshold amplitude level As, whereas this bit represents value 0 when the amplitude of the envelope is below of level As. Preferably, the amplitude of the envelope defining the element binary 0 is close to 0. In a simplified manner in these figures, the sequence of data includes a succession of binary elements of different value. The sequence 10101010 is shown in these figures 6a to 6c. Normally, this data sequence may represent a vehicle identification code.

In FIG. 6a, the analog signature transmitted and received in the coded signal identification is defined as a function of a growth time and / or a decrease Δt in amplitude of the envelope of the coded signal of the passage between two bits of different value from the data sequence. Variation amplitude during the growth and / or decrease time can be linear or hyperbolic or random so as to specifically represent the couple consisting of the vehicle and the personalized key. As previously described, the digitized values provided by the converter of the processing unit allow to define derivatives of the growth and / or decrease curve of the envelope of the coded signal to be compared with stored reference values.

It should be noted that this analog signature depends in particular on specific characteristics of the transmission means and the reception means of the key and vehicle. The increase or decrease in amplitude of the envelope defining the signature can be obtained by an RC type resonator.

In the case of a signal whose coding is not generated by modulation amplitude, the analog signature can be defined at the beginning or at the end of the signal coded, as a function of a time of increase and / or decrease in amplitude of the envelope of the coded signal.

In FIG. 6b, the analog signature transmitted and received in the coded signal identification is defined by an amplitude over-modulation of the signal envelope coded. This over-modulation is applied for example to binary elements representing the value 1 of the data sequence. Amplitude growth in binary elements worth 1 is shown in this figure. However, it is also possible to predict a decrease in amplitude of the envelope of the series of said bits worth 1 in the data sequence.

In FIG. 6c, the analog signature transmitted and received in the coded signal identification is defined by an over-modulation of each binary element. Of preferably, this amplitude over-modulation is only applied to binary elements equal to 1 of the data sequence. Thus, several variations in amplitude by binary element worth 1 is noted after passage through the converter and comparison in the microcontroller of the processing unit. This over-modulation of each binary element worth 1 can be a sinusoidal or pulse variation envelope amplitude rectangles.

As the data sequence is defined by amplitude modulation of a carrier of the coded signal, FIG. 7 shows more precisely the form of coded signal in the case of an analog signature shown in FIG. 6a.

From the description which has just been made, multiple variants of implementation of the access control process and the portable object can be designed by a person skilled in the art without departing from the scope of the invention. The principle of the signature analog on a coded signal transmitted by a transmitter to a receiver can also apply to a space, such as a safe or an access door to a place secret. In this case, the portable object can be a watch, a badge, a telephone. portable, a smart card with or without a power source. Likewise, the analog signature can also be transmitted in a response signal transmitted by the portable object.

Claims (14)

Method for controlling access of a personalized portable object (2) to a determined space (1) by wireless transmission of a coded identification signal, electronic means, which include access management means (13 ) connected to reception means (12, 14) and / or signal transmission means (11, 15), being provided in space, and the portable object comprising a processing unit (26) connected to transmission means (22, 28) and / or reception means (21, 27) of signals, the method comprising steps of: transmission of a coded identification signal by the transmission means of the portable object or respectively by the transmission means provided in the determined space, reception of the coded identification signal by the reception means provided in space or respectively by the reception means of the portable object, when the object is in a restricted area (5) around the electronic means provided in the space, and verification of the coded signal in the access management means (13) or respectively in the processing unit (26) to authorize access to the space, the method being characterized in that the coded identification signal transmitted and receipt includes an analog signature specific either to the electronic means provided in the space (1), or to the portable object (2), or to the pair constituted by the personalized portable object and the electronic means provided in the so as to authorize access to the space in case of recognition of said signature. Method according to claim 1, characterized in that the analog signature transmitted and received in the coded identification signal is defined by at least one variation of amplitude of the envelope of the coded signal specific to the couple constituted by the personalized object and the electronic means provided in the determined space. Method according to claim 2, characterized in that the amplitude variation defining the analog signature is obtained by over-modulation of the envelope of the coded signal. Method according to claim 2, characterized in that the coded identification signal is defined by a sequence of binary data obtained by amplitude modulation of the signal at a determined carrier frequency, each binary element of the sequence being defined over a greater time period unlike the carrier frequency, and in that each bit takes the value 1, respectively 0, when the amplitude level of the envelope of the bit of the coded signal is higher, respectively lower than a level threshold determined. Method according to Claim 4, characterized in that an amplitude over-modulation of the envelope of the coded signal is applied to the binary elements of the data sequence corresponding to the value 1 by increasing or decreasing the amplitude by l envelope of the series of said binary elements of the sequence, or by several variations in amplitude of the envelope of said binary elements equal to 1, and in that the amplitude level of the envelope of the coded signal for a corresponding binary element at the value 0 is close to 0. Method according to one of claims 2 or 4, characterized in that the analog signature transmitted and received in the coded identification signal is defined as a function of a growth time and / or an amplitude decrease time of l envelope of the coded signal at the beginning or at the end of the coded signal, or as a function of a time of increase and / or decrease in amplitude of the envelope of the coded signal of the passage between two binary elements of value different from the sequence of data, the variation in amplitude during the growth and / or decrease time being linear or hyperbolic or random. Method according to one of the preceding claims, for controlling access to a personalized portal object (2), such as an electronic key, to a vehicle (1) so as to control the locking or unlocking of parts or functions of the vehicle (1), the method being characterized in that it comprises steps of: transmission by transmission means (11, 15) of the vehicle of a first coded signal defined as an interrogation signal (6, 8) with an analog signature specific to the couple constituted by the personalized object and the vehicle, reception of the interrogation signal by means of reception (21, 27) of the object, when the object is in a restricted area (5) around the transmission means (11, 15) of the vehicle (1) , comparison of the analog signature received with a reference signature stored in the processing unit (26) of the object, calculation of a second coded signal defined as a response signal in the object processing unit in the event of recognition of the specific analog signature, and transmission of the response signal (9, 10) in order to control the locking or unlocking of parts or functions of the vehicle. Method according to claim 7, characterized in that an analog signature specific to the torque constituted by the vehicle and the personalized portable object is transmitted with the first and second coded signals. Method according to one of the preceding claims, characterized in that an amplitude indicator (27) of the envelope of the coded signal, provided in the reception means (21, 27) of the object, such as a electronic key, or space, such as a vehicle, provides dynamic amplitude values of the envelope of the coded signal to the management means (13) or to the processing unit (26) for comparing the signature analog received with a stored reference signature. Method according to Claim 9, in which the object processing unit and / or the space management means comprise an analog-digital converter (23), a microcontroller (24) for processing the signals and storage means. (25) which include in particular an encryption algorithm and a reference signature, characterized in that the amplitude values supplied by the indicator are digitized by the analog-digital converter (23), in that the converter clocked by a signal clock provides digitized amplitude values of the envelope of the coded signal received to the microcontroller (24), and in that the microcontroller performs a comparison between the digitized amplitude values with amplitude values of the signature of reference stored. Personalized portable object (2) for implementing the method according to one of the preceding claims, the object comprising a processing unit (26) connected to transmission means (22, 28) and / or means of reception (21, 27) of signals, characterized in that the processing unit is arranged to control the transmission means and / or the reception means for the transmission and / or reception of a coded signal of identification with a specific analog signature either to the electronic means provided in the space, or to the portable object (2), or to the couple constituted by the object and the electronic means provided in the space to be accessed, such as a vehicle. Object according to claim 11, characterized in that it comprises means for transmitting high frequency signals (22, 28) and means for receiving low frequency signals (21, 27), and in that the means for receiving include an amplitude indicator (21) of the envelope of the coded signal received to provide dynamic amplitude values of the envelope of the coded signal to the processing unit (26) for comparing the received analog signature with a signature reference stored in storage means (25) of the processing unit. Object according to claim 12, characterized in that the processing unit comprises an analog-digital converter (23) for digitizing the amplitude values supplied by the indicator, and a signal processing microcontroller (24) for comparing the values amplitude data supplied by the converter with amplitude values of the stored reference signature. Object according to claim 11, characterized in that the object is an electronic key having means for supplying electrical power to the integrated electronic components, the supply means comprising a battery or an accumulator or photovoltaic cells or an oscillating mass generator .

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