WO2003003290A1

WO2003003290A1 - System and method for detecting persons or objects in definite areas provided each with at least an entrance

Info

Publication number: WO2003003290A1
Application number: PCT/EP2002/005328
Authority: WO
Inventors: Olivier Desjeux
Original assignee: Em Microelectronic-Marin Sa
Priority date: 2001-05-14
Filing date: 2002-05-14
Publication date: 2003-01-09
Also published as: EP1258829A1; US20050102919A1

Abstract

The invention concerns a system and a method for detecting persons (8) or objects in a plurality of definite areas (10) each provided with at least an entrance (6). The detecting system comprises LF transmission means (4, 4*, 5, 5*), placed at the entrance, for transmitting a LF electromagnetic signal (A, B), HF means for transmitting/receiving (12, 13) a HF electromagnetic signal (C, ACK), portable electronic cards or units (36), equipping each person or object, for receiving the LF signal and for transmitting the HF signal, and a central processing unit (20) for recording data concerning entrance and exit of the portable electronic units. The system can operate in at least two different operating modes and the LF signal comprises a selection information (SELECT) indicating which of the two operating modes should be used by the electronic units when passing through the entrance. The system is preferably configured to shift, at least temporarily, in one of said definite areas, from one operating mode to another.

Description

SYSTEM AND METHOD FOR DETECTING INDIVIDUALS OR OBJECTS IN DELIMITED SPACES HAVING EACH AT LEAST ONE ENTRY

The invention relates to the detection of individuals or objects in delimited spaces each having at least one entrance. By entrance, it is necessary to understand in a broad way any door or passage way giving access to the delimited space in question. For example, it is planned to detect the presence of individuals during a journey in a public transport or during a sporting or cultural event taking place in a demarcated place.

Within the framework of the present invention, provision is made for detecting the presence of individuals or objects by means of portable electronic cards or units having means for receiving and transmitting data in the form of electromagnetic signals. It is planned to equip individuals or objects with such portable electronic units.

The international application WO 01/03057, incorporated here by reference, also in the name of the present Applicant, describes such a detection method as well as a system for detecting individuals or objects in a delimited space having an entrance.

An embodiment of the detection system described in this document is shown in FIG. 1. It is proposed to provide each delimited space, indicated by the reference 10, (for example defined by compartment 32 with a metro train, of a railway wagon, a bus, etc.) of low-frequency emission means 4, 4 ^* , 5, 5 ^* placed at entrance 6 (in this case at each entrance). These transmission means are arranged to transmit, when an individual (indicated by the reference numeral 8) or an object passes through input 6, low frequency electromagnetic signals carrying data to an electronic unit. portable (indicated by the reference numeral 36) with which the individual 8 or the object is equipped.

The low-frequency transmission means 4, 4 *, 5, 5 * are arranged to transmit at relatively low frequency (of the order of a hundred kHz) at least a first low-frequency electromagnetic signal in a communication region ( formed of the communication regions 60, 61, 62 and 63 in the illustration of FIG. 1) essentially covering the entrance 6 to the delimited space 10.

The detection system further comprises high-frequency transmission-reception means 12, 13 associated with the demarcated space 10 and making it possible to establish two-way communication at relatively high frequency (of the order of one hundred MHz or more) with portable electronic units 36. More precisely, these high frequency transceiver means 12, 13 comprise one or more high frequency receivers, here two in number, and one or more high frequency transmitters, also two in this example, placed in the delimited space 10 so that the communication regions, indicated by the reference numerals 70 and 71, defined by these transceivers 12, 13 cover essentially the entire surface of the delimited space 10 including the entrance 6. These communication regions 70, 71 are in particular arranged to encompass the communication regions 61, 62, 63, 64 of the low frequency transmitters 4, 4 ^* , 5, 5 ^* placed at the entrances.

In Figure 1, only a delimited space is illustrated. It will nevertheless be understood that all of the demarcated spaces, defined for example by all of the metro trainsets or compartments of the means of transport considered, are each equipped with similar transmission and reception means. FIG. 2 schematically shows the structure of a portable unit 36 of the detection system of FIG. 1. This portable electronic unit comprises a low frequency reception block 46 and an antenna 28 for receiving the data transmitted by means of the electromagnetic signal (s) low frequency emitted by the transmission means 4, 4 *, 5, 5 *, as well as a high frequency transceiver block 48 and an antenna 30 for exchanging data with the high frequency transceiver means 12, 13 associated with the delimited space 10 by means of a high frequency electromagnetic signal. In this case, as will be seen in detail below, a high frequency electromagnetic signal (designated by the reference C in the following description) is transmitted by the transmit-receive block 48, and a receipt receipt (designated by the reference ACK in the following description) is transmitted by the transmission-reception means 12,13 associated with the delimited space 10.

An electronic data processing unit 44 associated with a memory 45 is connected to the low-frequency reception 46 and high-frequency transmission-reception blocks 48. The electronic unit 36 is powered by a power supply source 24 such as a battery or other battery. Preferably, the data processing unit 44 can be put in standby mode in order to save energy. Similarly, the high frequency transceiver block 48 is capable of being deactivated or put on standby by the data processing unit 44 as shown diagrammatically by the interrupt means 50. Thus, only the low reception block frequency 46 is supplied permanently or almost permanently, the latter activating the data processing unit 44 as soon as a signal low frequency electromagnetic emitted by the low frequency transmitting means is received by this reception block 46.

According to a general operating mode described in the above-mentioned international application, the electronic units 36 are normally in standby mode. In standby mode, the data processing unit 44 as well as the high frequency transceiver block 48 are thus deactivated. As soon as an electronic unit 36 in standby mode passes through an input to the system, such as input 6 in FIG. 1, this electronic unit 36 is activated by the low frequency electromagnetic fields emitted by the transmission means 4, 4 ^* , 5, 5 ^* and receives, via the transmitted low-frequency electromagnetic signal (s), data relating to the demarcated space in question (for example an identification of the vehicle or of the place where the individual or object enters, the date and time, and, if applicable, other parameters relating to the delimited space 10). These data are stored in the memory 45 of the portable electronic unit 36. As soon as the electronic unit 36 has been activated and has passed through the input 6, the latter undertakes to communicate at high frequency by means of its block d 'high frequency transmission-reception 48 with the transmission-reception means 12, 13 associated with the defined space. During this high-frequency communication, an identification of the portable electronic unit 36 is notably transmitted to the transmission-reception means 12, 13 of the demarcated space 10 to be recorded by an on-board computer 20 associated with this demarcated space 10 and connected to the low-frequency transmission means 4, 4 *, 5, 5 * as well as to the high-frequency transmission-reception means 12, 13. In response, the transmission-reception means 12, 13 transmit a receipt from reception to the portable electronic unit 36. The on-board computer 20, or more generally the central processing unit, thus maintains a register containing the entry and exit information of each electronic unit having entered the delimited space 10. Similarly, each portable electronic unit 36 can keep a register of the latest entries and exits in delimited spaces, in particular the time, the date and an idea. ntification of each delimited space considered.

According to a particular mode of operation of the detection system described in the above-mentioned international application, each portable electronic unit, once activated by the low frequency electromagnetic fields, proceeds to the emission, at least once, of a high frequency electromagnetic signal intended for high frequency transceivers 12, 13 awaiting a receipt from these transceivers 12, 13. Typically, this high frequency electromagnetic signal, or presence interrogation signal, is transmitted periodically, and, as soon as the high frequency signal emitted by a portable electronic unit is no longer received by the high frequency transceiver means during a determined period of time, it is assumed that this portable electronic unit is no longer inside the delimited space 10 and the portable electronic unit 36 is then switched to standby mode.

For the sake of simplification, this first operating mode will be designated in the following description by the acronym "BIBO" (Be _ \ n Be Out) meaning that the presence or absence of an electronic unit 36 in the delimited space is determined on the basis of a reception, by the high-frequency transmission-reception means 12, 13 associated with the space 10, of a high-frequency electromagnetic signal coming from the portable electronic unit.

According to a particular variant of the detection system described in the aforementioned international application, the transmission means comprise first and second low frequency transmitters, designated respectively by the numerical references 4, 4 ^* and 5, 5 *, as illustrated specifically in the Figure 1. These first and second transmitters are arranged to respectively transmit first and second low frequency electromagnetic signals (designated respectively by the references A and B in the following description) in respectively first 60, 61 and second 62, 63 regions communication spatially separated from each other and partially overlapping. These first 60, 61 and second 62, 63 communication regions essentially cover the entrance 6 to the delimited space and are located respectively towards the outside and towards the inside of the delimited space 10, so that, when an individual or object enters the delimited space 10, this first meets the first A, then the second low frequency electromagnetic signal B.

In the illustration of FIG. 1, the first and second transmitters each comprise a pair of transmitters 4 and 4 *, respectively 5 and 5 ^* , placed on either side of the input 6. It will nevertheless be understood that these first and second transmitters may each comprise only one transmitter or possibly more than two, the main thing being that the communication regions defined by these low frequency transmitters cover the area of passage of individuals or objects via input 6 and make it possible to define a succession of spatially separate regions in which distinct signals are emitted.

This arrangement of the first and second low frequency transmitters 4, 4 * and 5, 5 * and their emission field aims to allow, in addition to awakening the portable electronic units 36, the detection of the direction of passage of individuals or objects through entry 6. This direction of passage detection is carried out in determining the order of reception of the first and second low frequency electromagnetic signals A, B transmitted respectively by the transmitters 4, 4 * in the communication regions 60, 61 and by the transmitters 5, 5 * in the communication regions 62, 63 An embodiment of a passage detection system is more particularly described in European patent application No. 00204758.8 of 12.29.2000 entitled "System for detecting the passage of an individual or object by an entry-exit to a defined space. »Also on behalf of this Applicant.

According to this request, the detection of the direction of passage through the input 6 is in particular carried out by the electronic unit 36 based on the order of reception of the first and second low frequency electromagnetic signals A, B emitted at the Entrance. The information concerning the direction of passage is for example determined by detecting at least which of the first and second low frequency electromagnetic signals A, B was received first and last during the passage of the individual or the object by entry 6. This passage direction information, namely entry, exit information or information that the electronic unit 36 has remained inside or outside the delimited space is transmitted by the electronic unit 36 in the form of a high frequency electromagnetic signal to the high frequency transceivers 12, 13. Once the passage direction information has been transmitted, the portable electronic unit 36 is then put on standby. In this operating mode, the ACK reception receipt transmitted by the transceivers 12, 13 may or may not be considered by the electronic unit 36. Preferably, this ACK reception receipt is considered by the electronic unit in order to confirm the reception of high frequency signal C.

For the sake of simplification, this second operating mode will be designated in the following description by the acronym "WIWO" (Walk in Walk Out) meaning that the presence or absence of an electronic unit 36 in the delimited space is determined on the basis of the direction of passage information through entry 6. In a typical application of the aforementioned detection system, such as automatic invoicing of journeys made by users by means of public transport, it will be desired to equip the various vehicles of the public transport network of a detection system operating as optimally as possible in order to detect with great reliability the presence or absence of individuals in these various vehicles.

Due to practical considerations notably related to the possibilities of mounting low frequency transmitters placed at the entrances to the demarcated spaces defined by the vehicle compartments, it is more or less easy to implement the aforementioned second operating mode called WIWO, that is to say the operating mode based on the detection of the direction of passage of the portable electronic units at the through entrances. However, if the possibilities of mounting low-frequency transmitters at the inputs are limited or not adequate to allow reliable detection of the direction of passage through these inputs, the detection system based on the above-mentioned first operating mode called BIBO is then preferably adopted.

It will be noted that the second above-mentioned WIWO operating mode is generally preferred and adopted as far as possible since it does not require, in order to establish the presence or absence of a portable electronic unit in the delimited space, than a short-term communication between these electronic units and the transceivers associated with the demarcated space. The first operating mode BIBO mentioned above typically requires periodic exchanges between the electronic units and the transceivers associated with the delimited space in order to establish the presence or absence of an electronic unit in this space, and is therefore, compared to the second WIWO operating mode, slightly less optimal from the consumption point of view.

Until now, since portable electronic units are not able to determine a priori whether the system operates on the basis of the first or second operating mode mentioned above, the BIBO operating mode or the WIWO operating mode is adopted by default for all the delimited spaces considered. A compromise, by definition not optimal, is thus achieved. A general aim of the present invention is therefore to propose a solution making it possible to adopt one or the other of the abovementioned operating modes, or even others, depending on the type or characteristics of each delimited space considered, and in particular to adopt the operating mode best suited to the defined space considered, this in order to increase the reliability of the detection of individuals or objects in these spaces and also optimize consumption as much as possible.

A particular object of the present invention is further to propose a solution having great flexibility of use allowing, if necessary, the application of several distinct operating modes for a defined space considered, this in particular in order to overcome deficiencies potential of one or other of the operating modes used.

The present invention thus relates to a system for detecting individuals or objects in a plurality of delimited spaces each having at least one entry, the characteristics of which are set out in independent claim 1. Advantageous embodiments of the present invention are the subject of the dependent claims. The present invention also relates to detection methods, the characteristics of which are set out in claims 8 to 10.

According to the invention, the detection system is thus configured to operate in at least two distinct operating modes, such as the above-mentioned WIWO and BIBO operating modes (or even others), and the low-frequency signal or signals transmitted by the means. low-frequency transmission signals placed at the input include for this purpose selection information indicating which of the operating modes must be used by the portable electronic units when passing through the input.

In this way, it is possible to make several separate operating modes coexist and thus adopt the most adequate and optimal operating mode for the delimited space considered. The reliability of the detection of individuals or objects is thereby improved.

According to a preferred embodiment of the invention, the system is further configured to switch, at least temporarily, from one operating mode to another for the same delimited space considered, for example switching from the second WIWO operating mode to first BIBO operating mode and vice versa. It is thus possible to overcome certain problems that could potentially arise with one or other of the operating modes used.

For example, a drawback of the WIWO operating mode based on the detection of the direction of passage lies in the fact that there is a low probability that the portable electronic unit cannot correctly detect the direction of passage through the 'Entrance. Indeed, taking into account the physical characteristics of emission and reception of electromagnetic signals in the environment, it may be that the sequence of signals received by the portable electronic unit is not coherent or sufficiently determining and does not allow reach a sure conclusion as to the direction of passage of this electronic unit through (or in the vicinity) of the entrance.

Although this probability of error is relatively low, it is desirable to make the system as robust as possible in order to avoid this type of error as much as possible. Switching from the second WIWO operating mode to the first BIBO operating mode makes it possible to remove such ambiguity.

Likewise, a disadvantage of the BIBO operating mode based on the reception of the high frequency electromagnetic signal lies in the fact that there is a low probability that the electromagnetic presence interrogation signal will not be correctly received by the high frequency transmission-reception means associated with the delimited space or that the receipt of reception transmitted by the high-frequency transmission-reception means associated with the demarcated space is not correctly received by the electronic unit, this may have the consequence of placing the portable electronic unit on standby unexpectedly then that this one is in reality still inside the delimited space.

Switching from the first BIBO operating mode to the second WIWO operating mode makes it possible to correct such an interpretation error.

Other characteristics and advantages of the present invention will appear more clearly on reading the detailed description which follows, given with reference to the appended drawings given by way of nonlimiting examples and in which:

- Figure 1, already presented, is a schematic illustration of a system for detecting individuals or objects;

- Figure 2, already presented, schematically shows an embodiment of a portable electronic unit of the system of Figure 1;

- Figures 3a and 3b illustrate the appearance, respectively, of low frequency and high frequency electromagnetic signals exchanged between a portable electronic unit and the transmitters and receivers associated with the defined space;

- Figure 4 is a flowchart illustrating the progress of the process of detecting the presence or absence of an electronic unit according to the present invention; and

- Figures 5a and 5b illustrate first and second advantageous alternative embodiments of the detection system according to the present invention.

FIG. 3a shows the shape and the content of the low frequency electromagnetic signals A, B transmitted to a portable electronic unit within the specific framework of an application to means of public transport. It will again be emphasized that the invention is in no way limited to this single application. By way of purely illustrative and nonlimiting example, the first and second low frequency electromagnetic signals A, B each include data relating to the defined space with which the low frequency transmitters placed at the input are associated. Thus, the first and second electromagnetic signals A, B each comprise a code sequence broken down, without limitation, into a plurality of code words WRDj, i = 1, 2, ..., and preferably and typically ending in a verification word or CRC as illustrated diagrammatically in FIG. 3a. The first electromagnetic signal A can thus comprise, as illustrated, first and second words respectively indicating the date and the time of passage by the entry to the delimited space where this signal is emitted. In addition, this first electromagnetic signal A can include, if necessary, other words defining various parameters for the transmission and / or reception of the high frequency electromagnetic signals to be transmitted and / or received by the electronic unit as will emerge. from the discussion in Figure 3b. In the nonlimiting example of FIG. 3a, the second low frequency electromagnetic signal B comprises one or more words indicating the identity of the delimited space considered (for example an identification of the vehicle, of the railway wagon or the metro train, etc.), as well as, in the context of the application considered here, one or more words indicating the identity of the station or stop at which the public transport vehicle is parked. question. According to the invention, at least one of the first and second low frequency electromagnetic signals A, B (preferably both) includes selection information, designated SELECT, which may include one or more information bits, indicating which of the modes of operation must be used by electronic units when passing through the entrance to the delimited space considered. By way of example, FIG. 5a illustrates a first advantageous variant of the system according to the present invention according to which the first and second low frequency electromagnetic signals A, B both comprise a determined selection information item, designated SELECT_WIWO, so that the presence or the absence of an electronic unit 36 in the delimited space 10 is detected according to the WIWO operating mode.

Thus, according to this variant, if the electronic unit 36 enters or leaves the space delimited as illustrated diagrammatically by the arrows 100 and 200, respectively, or if this electronic unit 36 enters the low frequency fields but remains outside or inside the delimited space 10 as illustrated respectively by the arrows 105 and 205, the portable electronic unit 36 receives unique selection information SELECT_WIWO according to which it must operate according to the second operating mode WIWO and thus transmit, following passage through the input 6, a high frequency electromagnetic signal C comprising the direction of passage information detected by the electronic unit 36. Following this transmission, the portable electronic unit is preferably put on standby as already mentioned. Still by way of example, FIG. 5b illustrates a second advantageous variant of the system according to the present invention according to which the first signal frequency electromagnetic A, emitted outside the delimited space 10, includes a determined selection information, designated SELECTJ3IBO, so that the presence or absence of an electronic unit 36 in the delimited space 10 is determined according to the first BIBO operating mode after entering the defined space. The second electromagnetic signal B emitted towards the interior of the delimited space 10 comprises, for its part, determined selection information, designated SELECT_WIWO, so that the portable electronic unit 36 operates, if the latter is in standby mode , according to the second WIWO operating mode. According to this second variant, a portable electronic unit 36 operates normally according to the first operating mode BIBO, that is to say proceeds to the transmission of the high frequency electromagnetic signal C awaiting an ACK reception receipt from the high frequency transmission-reception means (12, 13 in FIG. 1) associated with the demarcated space 10. According to this variant, the portable electronic unit 36 operates according to the second operating mode WIWO only if this- it entered standby mode when it is actually still inside the demarcated space 10 and subsequently crosses the fields of the low frequency transmitters placed at input 6.

It will be recalled that, according to the BIBO operating mode, a portable electronic unit is normally put on standby only if it is actually outside the field of emission and reception of the associated high-frequency transmission-reception means. to the delimited space and consequently no longer receives an ACK receipt receipt. Under normal conditions, when an active portable electronic unit leaves the delimited space 10 (in the direction of the arrow 200) or temporarily enters the low frequency fields but remains inside the delimited space 10 (in the direction of arrow 205), the selection information transmitted by the second electromagnetic signal B is thus not considered.

It will thus be understood that the variant embodiment of FIG. 5b makes it possible to carry out a possible correction of the input-output register kept by the on-board computer 20 and, if necessary, of the data stored by the portable electronic unit 36 , in the event that this electronic unit has been put on standby unexpectedly.

FIG. 3b shows the shape and the content of the high frequency electromagnetic signal C transmitted by a portable electronic unit as well as the ACK reception receipt transmitted by the high frequency transmission-reception means associated with the defined space.

For example, the high frequency electromagnetic signal C transmitted by the portable electronic unit 36 includes in particular an identification number ID of the electronic unit, information concerning the date and time of passage through the entry as well as, if necessary, the direction of detection information of passage, designated DIRECTION, if the system operates according to the WIWO operating mode. As illustrated in FIG. 3b, a sequence formed by N repetitions of the above-mentioned data is preferably transmitted several times (for example with a maximum M of repetitions) with a repetition period T1. The transmission of the high frequency signal C is preferably carried out in this way in order to ensure a certain redundancy. If the portable electronic unit 36 operates according to the operating mode

BIBO, the emission of the above-mentioned sequences is also repeated periodically with a T2 repetition period.

The aforementioned T1 and T2 repetition periods as well as, if necessary, the N and M repetition parameters are preferably transmitted by means of the low frequency electromagnetic signals A and / or B. It will be noted that these parameters are adapted according to the characteristics of the 'delimited space considered and can, if necessary, be adapted over time, for example as a function of the duration between two successive stops of the transport vehicle.

As illustrated in FIG. 3b, the high-frequency transmission-reception means associated with the demarcated space proceed to the transmission of an ACK reception receipt (both in the first and second operating modes BIBO and WIWO) once the high frequency electromagnetic signal C has been received correctly.

FIG. 4 shows a flowchart illustrating the progress of the process for detecting the presence or absence of an electronic unit according to the present invention.

The detection process begins in step S100 with an electronic unit in standby mode. As soon as the portable electronic unit picks up one of the two low frequency electromagnetic signals A, B (step S102), the data processing means 44 of the electronic unit are activated (step S104) and these proceed to the reading and identifying the SELECT selection information contained in the first received electromagnetic signal (step S106), namely the first A or the second low frequency electromagnetic signal B.

If this selection information SELECT corresponds to the determined selection information SELECT_WIWO indicating that the electronic unit must operate according to the operating mode WIWO, the electronic unit first of all detects the direction of passage DIRECTION (step S108 ), then upon activation of the block of high frequency reception 30, 48 (step S112) and finally to the transmission of the high frequency electromagnetic signal C containing the direction of passage direction information (step S114).

If the selection information SELECT corresponds to the determined selection information SELECTJ3IBO indicating that the electronic unit must operate according to the BIBO operating mode, the electronic unit first of all activates the high frequency reception block 30, 48 (step S109), then the transmission of the high frequency electromagnetic signal C (step S111), and the verification of the reception of the reception receipt ACK (step S113), this last step being repeated as long as this reception receipt ACK is received.

As soon as the high frequency electromagnetic signal C comprising the direction of passage information DIRECTION has been transmitted in step S114 (in the operating mode WIWO) or no receipt of ACK reception is received in step S113 (in the BIBO operating mode), the data processing means 44 as well as the high frequency transceiver block 30, 48 of the electronic unit are deactivated (step S116) and the latter then passes again in standby mode and the detection process can start again at step S100.

In the WIWO operating mode, the detection of the direction of passage is for example carried out by the portable electronic unit based on the order of reception of the first and second low frequency electromagnetic signals A, B emitted at the input, by example by detecting at least which of the first and second low frequency electromagnetic signals A, B was received first and last during the passage of the individual or the object by entry 6. By way of example only , it is possible to constitute a truth table comprising at least the identifications of the first and last low frequency signals received. The table below shows by way of example a truth table formed by the identifications of the first, penultimate and last low frequency signals received as well as the resulting interpretation of the direction of passage.

In the table above, it is admitted that states 3 and 6 do not allow to conclude on an entry, an exit, or on the fact that the portable electronic unit remained inside or outside the delimited space. On the other hand, it has been admitted that states 2 and 7 correspond respectively to an input and an output of an electronic unit. It will of course be understood that these states could also be considered as undefined states.

In the event that the direction of passage information is inconclusive and does not make it possible to confirm whether the portable electronic unit has entered, left, or remained inside or outside the space delimited (by way of example if the sequence of signals detected corresponds to states 3 and 6 indicated in the table above), switching the system to the BIBO operating mode will advantageously make it possible to remove this ambiguity. This process is illustrated in FIG. 4 by step S110 where, if such ambiguity in the direction of passage is detected, the process continues with step S109 of activation of the transceiver block 30, 48 followed by steps S111 and S113.

Referring again to the variant illustrated in FIG. 5b, it will be noted that if the electronic unit has unexpectedly gone into standby mode when it is actually still inside the delimited space 10 , this unit will successively undertake the stages of the detection process according to the WIWO operating mode already described, thus allowing the correction of the input-output registers.

In either of the aforementioned cases where the portable electronic unit is switched from one operating mode to another, it will be necessary to include, in the high frequency electromagnetic signal C transmitted by the electronic unit, information indicating that the latter has carried out this switching, i.e. a information analogous to the SELECT selection information transmitted by the low frequency input electromagnetic signal (s).

It will be understood that various modifications and / or improvements evident to those skilled in the art can be made to the various embodiments described in the present description without departing from the scope of the invention defined by the appended claims.

Thus, in Figure 1, the low frequency transmission means 4, 4 *, 5, 5 * are illustrated as being arranged in the compartment 32 of the vehicle. In general, it suffices that these low frequency transmission means are associated with the delimited space considered, that is to say that they transmit in particular information relating to this delimited space. It is for example conceivable that the transmitters of the first low frequency electromagnetic signal A which are located outside the defined space are not placed inside the vehicle compartment but are arranged in a fixed manner on the platform or the stop where passengers get on and off. Similarly, the high frequency transmission-reception means can also be arranged outside the vehicle compartment, for example in access corridors to the platforms or directly on these platforms.

Claims

1. A system for detecting individuals (8) or objects in a plurality of delimited spaces (10) each having at least one entrance (6), this detection system comprising, for each of said delimited spaces: means of low frequency emission (4, 4 ^* , 5, 5 *) associated with the delimited space (10) and placed at said input (6) to transmit at least one low frequency electromagnetic signal (A, B) in a region of communication (61, 62, 63, 64) essentially covering said entry (6); and high frequency transceiver means (12, 13) associated with the defined space (10) for receiving and transmitting at least one high frequency electromagnetic signal (C, ACK), this detection system further comprising: portable electronic cards or units (36) each equipping an individual (8) or object, each electronic unit (36) comprising a low frequency reception block (28, 46) for receiving said low frequency electromagnetic signal (A, B), and a high frequency transceiver block (30, 48) for transmitting and receiving said high frequency electromagnetic signal (C, ACK); and at least one central processing unit (20) associated with said delimited spaces (10) and connected to said low-frequency transmission means (4, 4 *, 5, 5 *) as well as to said transmission means - high frequency reception (12, 13) for recording data relating to the input and output of said portable electronic units (36), characterized in that the system is configured to operate in at least two distinct operating modes (BIBO, WIWO ) and in that said low frequency electromagnetic signal (A, B) includes selection information (SELECT, SELECT_BIBO, SELECT_WIWO) indicating which of said at least two operating modes (BIBO, WIWO) is to be used by said electronic units (36 ) when passing through an entrance (6) of any one of said plurality of delimited spaces (10).

2. System according to claim 1, characterized in that it is configured to switch, at least temporarily, from one operating mode to another in at least one delimited space selected (10) from said plurality of delimited spaces.

3. System according to claim 1 or 2, characterized in that said low frequency transmission means comprise first (4, 4 ^* ) and second (5, 5 ^* ) low frequency transmitters for transmitting first (A) and second (B) low frequency electromagnetic signals carrying data relating to the delimited space (10), these first and second low frequency electromagnetic signals (A, B) being respectively emitted in first (60, 61) and second (62, 63) ) communication regions spatially separated from each other and at least partially overlapping, said first and second communication regions (60, 61, 62, 63) being located respectively outside and inside said space delimited (10), in that each electronic unit (36) comprises detection means for determining the direction of passage (DIRECTION) of said electronic unit (36) through said input (6) according to the reception of said first and second low frequency electromagnetic signals (A, B), in that the system is configured to operate in a first mode of operation (BIBO) in which each electronic unit (36) proceeds e on the emission, at least once, of said high frequency electromagnetic signal (C), the presence or absence of an electronic unit (36) in the delimited space (10) being determined on the basis of a reception, by said high frequency transceiver means (12, 13), of the high frequency electromagnetic signal (C) coming from this electronic unit (36), and in that the system is configured to operate in a second mode of operation (WIWO) according to which each electronic unit (36) detects said direction of passage (DIRECTION) and transmits, by means of said high frequency electromagnetic signal (C), information relating to said direction of passage (DIRECTION), the presence or absence of an electronic unit (36) in said delimited space (10) being determined on the basis of said direction of passage information (DIRECTION).

4. The system as claimed in claim 3, configured to pass, at least temporarily, from one operating mode to another in at least one delimited space selected (10) from said plurality of delimited spaces, characterized in that said first and / or second low frequency electromagnetic signal (A, B) includes selection information (SELECT_WIWO) determined so that the presence or absence of an electronic unit (36) in this selected delimited space (10) is determined according to said second operating mode (WIWO), and in that the system is switched, at least temporarily, into this selected delimited space (10), into said first operating mode (BIBO) if the direction of travel information (DIRECTION) determined by the electronic unit (36) is not conclusive.

5. System according to claim 3 configured to pass, at least temporarily, from one operating mode to another in at least one delimited space selected (10) from said plurality of delimited spaces, characterized in that said first low frequency electromagnetic signal (A) includes selection information (SELECT_BIBO) determined so that, following entry of an electronic unit (36) into said selected delimited space (10), the presence or absence of this electronic unit (36) in said delimited space (10) is determined according to said first operating mode (BIBO), and in that said second low frequency electromagnetic signal (B) comprises selection information (SELECT VVIWO) determined so that, when leaving an electronic unit from the delimited space selected (10), the system is switched, at least temporarily, to said second operating mode (WIWO) in the event that the system has previously concluded that there is no electronic unit (36) while the latter is still in said selected delimited space (10).

6. System according to any one of the preceding claims, characterized in that said first and / or second low frequency electromagnetic signals (A, B) carry data comprising an indication making it possible to identify said delimited space (10) as well as an indication of the time and the date of passage of the electronic unit (36) through said input (6).

7. System according to any one of the preceding claims, characterized in that said delimited space (10) is defined by a compartment (32) of a transport vehicle, such as a bus, a railway wagon or a train metro, and in that said first and / or second low frequency electromagnetic signals (A, B) carry data comprising an indication of the station or stop where said transport vehicle is located.

8. A method of detecting an individual (8) or an object in a detection system according to any one of claims 3 to 5, characterized in that each electronic unit (36) further comprises: means for data processing (44) for processing data from said low frequency receive block (28, 46) and / or data from or to said high frequency transmit and receive block (30, 48); and a source of electrical energy supply (24) for supplying said processing means (44) as well as said low frequency reception block (28, 46) and said high frequency transceiver block (30, 48), in that said low frequency reception block (28, 46) is supplied permanently or almost permanently, and in that said data processing means (44) as well as said high frequency transceiver block (30, 48) are deactivated in a so-called standby mode of said electronic unit (36), said data processing means data (44) being activated by said low frequency reception block (28, 46) as soon as it detects one or the other of said first and second low frequency electromagnetic signals (A, B), said block of high frequency transmission-reception (30, 48) being activated as soon as the electronic unit (36) must transmit and / or receive said high-frequency electromagnetic signal (C, ACK), this method comprising the following steps: a) reception by an electronic card or unit (36) carried by said individual (8) or object, said first and / or second low frequency electromagnetic signals (A, B) by means of said low frequency reception unit (28, 46) of the unit electronic (36); b) activation of said data processing means (44) of the electronic unit (36); c) reading of said selection information (SELECT) contained in the first low frequency electromagnetic signal received, namely said first or second low frequency electromagnetic signal (A, B), and identification of the operating mode associated with the delimited space ( 10); d) if said operating mode corresponds to the second (WIWO) of said operating modes, detection, by said electronic unit (36), of said direction of passage (DIRECTION) through the input (6); e) activation of said high frequency transceiver block (30, 48) of the electronic unit (36); and f) if said operating mode corresponds to the second (WIWO) of said operating modes, transmission, after passage through said input (6), of said high frequency electromagnetic signal (C) comprising said direction of passage information (DIRECTION) to the by means of said high frequency transceiver block (30, 48), otherwise transmitting, at least a first time, said high frequency electromagnetic signal (C) by means of said high frequency transceiver block (30, 48) waiting for a reception receipt (ACK) from said high frequency transceiver means (12, 13); and g) if said operating mode corresponds to the second (WIWO) of said operating modes, returning the electronic unit (36) to its standby mode and deactivating said data processing means (44) and said block high frequency transmission-reception (30, 48), and if said operating mode corresponds to the first (BIBO) of said operating modes, return of the electronic unit (36) to its standby mode and deactivation of said processing means data (44) and said high frequency transceiver block (30, 48) if no receipt receipt (ACK) is received during a determined period of time, otherwise repetition of the transmission of said high frequency electromagnetic signal ( C) until no receipt receipt (ACK) is received during said determined period of time.

9. Detection method according to claim 8 in a detection system according to claim 4, characterized in that, if said direction of passage information (DIRECTION) determined by the electronic unit (36) in step d) n is not conclusive and does not make it possible to unequivocally determine whether the electronic unit (36) is inside or outside said delimited space (10), said electronic unit (36) is then switched at least temporarily in said first operating mode (BIBO).

10. Detection method according to claim 8, in a detection system according to claim 5, characterized in that, if said electronic unit (36) is in standby mode and if the first low frequency electromagnetic signal received by said block of low frequency reception (28, 46) in step c) corresponds to said second low frequency electromagnetic signal (B), said electronic unit (36) is then switched at least temporarily to said second operating mode (WIWO).