FR3108732A1 - Process for locating a product in an industrial building - Google Patents

Abstract

A method for locating at least one product (L1, L2) in an industrial building (B) comprising a plurality of unitary zones (Z1-Z6) comprising: a step of transmitting (E1) an interrogation signal according to a first interrogation radiation (I1), a step of reception (E2), by an RFID reader (3), of a response signal (REP) by each zone beacon (11-16), the response (REP) comprising the zone identifier (ID11-ID16), a step of reception (E3), by the RFID reader (3), of a response signal (REP) by each product tag (ID21, ID22 ), the response signal (REP) comprising the product identifier (ID21, ID22), a step E4 of associating the product identifier(s) (ID21, ID22) with the zone identifier(s) (ID11-ID16) in a database for the first interrogation radiation (I1), the association being free of power measurement of a response signal, a step of renewing steps E1 to E4 for at least ns a second interrogation radiation and a step E5 for determining the unit area (Z1-Z6) in which each product (L1, L2) is located by statistical analysis of the database. Figure of the abstract: Figure 7

Description

Process for locating a product in an industrial building

The present invention relates to the field of product location and more particularly the geolocation of spare parts in an industrial building by radio frequency identification.

In an industrial building, for example an aeronautical turbine engine assembly workshop, it is necessary to know at all times the stock of spare parts available as well as the location of each part in the building.

In practice, an assembly workshop comprises a plurality of zones in which different operations are carried out. The workshop includes, for example, a storage area for spare parts, an assembly area for parts for assembling turbine engines for sale or even a development area, allowing tests to be carried out on the assembled turbine engine.

In other words, in such a workshop, a spare part can either be stored in the storage area when it is not in use, or mounted on a turbine engine intended for sale, or mounted on a turbine engine in development.

When the part is mounted on a turbine engine intended for sale, it must be removed from stock. On a turbine engine under development, the spare part is regularly assembled and disassembled to allow operators to perform various tests. In addition, when the spare part has been used and then dismantled, it is known to check its condition on a checkpoint before storing it in the storage area.

In summary, each spare part is regularly moved to different workstations and must be regularly identified to know its location in the workshop. Indeed, it is necessary for each operator to have an exhaustive view of the available stock and the geolocation of each part at all times, in order to limit the loss of time related to the search for a specific part, for example.

In a known solution, each spare part is equipped with an RFID tag, meaning "radio frequency identification" in English, configured to be detected remotely by an RFID reader. The RFID reader is configured to emit a radio frequency (RF) electromagnetic wave signal received by the RFID tag. For the sake of brevity, such a signal will be referred to below as an RF signal.

A so-called "passive" RFID tag, that is to say one without a power supply device, is known. When an RF interrogation signal is emitted by the RFID reader, the emitted wave activates the RFID tag which sends back an RF response signal including, for example, an identifier of the tagged part. The RFID reader then detects the presence of the part nearby, but without precise information on its location, which presents a major drawback since it requires the operator to manually search for the spare part. Such a manual search is time-consuming and inconvenient.

Also, document US 20190235069 discloses a method for detecting a product to be located equipped with an RFID tag, by means of an RFID reader and several RFID tags placed at fixed positions. The RFID reader emits an RF interrogation signal, received both by the product to be located and by the fixed RFID tags. The reader then measures the distance that separates it from the product to be located and from each fixed RFID tag based on the strength of the RF response signal it receives from each. The position of the reader is then determined from the known position of each fixed RFID tag and the measured distance of each with the RFID reader. The operation is repeated for at least three positions of the RFID reader, which makes it possible to deduce the position of the product to be located by triangulating the distances between the product to be located and the different positions of the determined RFID reader.

However, such a method has the disadvantage of being long and complex to implement since it requires at least three measurements from three different positions. In addition, the method described in document US 20190235069 is not very precise since the method determines the position of the RFID reader from the power of the RF response signals received from the fixed RFID tags. An industrial building comprising many metal parts, these can be in the path of the transmitted waves, which can alter the response signals and falsify the power measurements. The location is therefore imprecise.

The invention aims to eliminate at least some of these drawbacks by proposing a method for locating a product to be located in a reliable and practical building, making it possible to ensure the presence of the product in a geographical area and its precise position. in the geographical area.

PRESENTATION OF THE INVENTION

• une étape d’émission E1 dans le bâtiment industriel, par un lecteur RFID, d’un signal d’interrogation selon un premier rayonnement d’interrogation,
• une étape de réception E2, par le lecteur RFID, d’un signal de réponse audit signal d’interrogation par chaque balise de zone positionnée dans le premier rayonnement d’interrogation et dont le lecteur RFID est positionné dans leur rayonnement de zone, le signal de réponse comprenant l’identifiant de zone de ladite balise de zone,
• une étape de réception E3, par le lecteur RFID, d’un signal de réponse audit signal d’interrogation par chaque balise de produit positionnée dans le premier rayonnement d’interrogation et dont le lecteur RFID est positionné dans leur rayonnement de produit, le signal de réponse comprenant l’identifiant de produit de ladite balise de produit,
• une étape d’association E4 de l’identifiant/des identifiants de produit à l’identifiant/aux identifiants de zone dans une base de données pour le premier rayonnement d’interrogation, l’association étant exempte de mesure de puissance d’un signal de réponse,
• une étape de renouvellement des étapes E1 à E4 pour au moins un deuxième rayonnement d’interrogation de manière à ce que la base de données comporte une pluralité d’associations obtenues pour une pluralité de rayonnements d’interrogation et
• une étape de détermination E5 de la zone unitaire dans laquelle chaque produit est situé par analyse statistique de la base de données.

The invention relates to a method for locating at least one product in an industrial building comprising a plurality of unitary zones, each unitary zone of the industrial building comprising at least one zone tag of the RFID type which is fixed in the unitary zone and which defines a zone radiation which at least partially covers said unitary zone, the zone tag comprising a zone identifier, the product to be located comprising at least one product tag of the RFID type which defines a product radiation, the product tag comprising a product identifier, the location method comprising:

• a step E1 of emission in the industrial building, by an RFID reader, of an interrogation signal according to a first interrogation radiation,
• a step of reception E2, by the RFID reader, of a response signal to said interrogation signal by each zone beacon positioned in the first interrogation radiation and whose RFID reader is positioned in their zone radiation, the signal response comprising the zone identifier of said zone beacon,
• a step of reception E3, by the RFID reader, of a response signal to said interrogation signal by each product tag positioned in the first interrogation radiation and whose RFID reader is positioned in their product radiation, the signal response comprising the product identifier of said product tag,
• a step E4 of associating the product identifier(s) with the zone identifier(s) in a database for the first interrogation radiation, the association being free of signal power measurement Answer,
• a step of renewing steps E1 to E4 for at least one second interrogation radiation so that the database includes a plurality of associations obtained for a plurality of interrogation radiations and
• a step E5 of determining the unit area in which each product is located by statistical analysis of the database.

Thanks to the invention, the distance between the RFID reader and the product tags or the zone tags, nor the power received, is advantageously not taken into account. As explained previously, in an industrial environment comprising a large number of structural elements, storage, metal or plastic tools, the distance measurement by an RFID reader, carried out from the power of the radiofrequency signals received, is a imprecise measurement: metallic or plastic materials modify the propagation of electromagnetic fields around the antennas, affecting their reception pattern. In addition, power measurement requires significant hardware resources which increase the cost of an RFID reader. According to the present invention, a database is advantageously formed by multiplying the associations between the product identifier(s) to the zone identifier(s) in a database for several interrogation radiations. Such a database is relevant given that the products are not very mobile in the building between several emission stages for different interrogation radiation. As a result, by statistical analysis of associations, it is easy to determine the most probable location of a product. A statistical localization is more precise than a deterministic analysis based on very imprecise and time-consuming distance measurements.

Preferably, the zone radiations of at least two adjacent zone beacons have an overlapping portion in order to avoid the formation of white zones not covered by a zone beacon.

Preferably, the overlap portion represents a maximum of 10% of each zone radiation in order to avoid the simultaneous transmission of very many zone identifiers following the transmission of an interrogation signal. This advantageously makes it possible to refine the geographical detection zone.

According to one aspect, the step of emitting an interrogation signal according to a first interrogation radiation and the step of emitting an interrogation signal according to a second interrogation radiation are carried out sequentially . This advantageously makes it possible to use a single RFID reader, for example, every second, to acquire associations.

Preferably, the RFID reader is moved to carry out emission steps according to the different interrogation radiations, in particular, by an automaton.

According to another aspect, the step of emitting an interrogation signal according to a first interrogation radiation and the step of emitting an interrogation signal according to a second interrogation radiation are carried out simultaneous. Preferably, several RFID readers are used simultaneously. Preferably again, RFID readers are positioned in different places. This advantageously makes it possible to simultaneously obtain a plurality of associations and therefore to immediately determine the location of the product.

Preferably each product tag is a passive tag. Preferably again, each zone beacon is a passive beacon. A passive beacon makes it possible to limit the detection zone, which improves the precision of the associations and, consequently, the localization.

Preferably, the method includes a step of generating a map of the industrial building including the location of the product(s). Thus, an operator can visually determine the position of the products in the building. He can thus ensure that their locations are in line with the industrialization process.

• au moins une première balise de zone dont le rayonnement de zone est configuré pour s’étendre uniquement dans la première sous-zone et
• au moins une deuxième balise de zone dont le rayonnement de zone est configuré pour s’étendre uniquement dans la deuxième sous-zone.

According to a preferred aspect, at least one unit area being partitioned into at least a first sub-area and a second sub-area, the unit area comprises:

• at least one first zone beacon whose zone radiation is configured to extend only into the first sub-zone and
• at least one second zone beacon whose zone radiation is configured to extend only into the second sub-zone.

A partition of the unit area makes it possible to increase the precision and thus to facilitate the localization of a product.

According to a preferred aspect, the building comprises at least one support post in the unitary zone at the interface between the first sub-zone and the second sub-zone, the post comprising at least a first face facing the first sub-zone on which the first beacon is mounted and a second face, opposite the first face, which is turned towards the second sub-zone on which the second beacon is mounted. Thus, the support post makes it possible to form a support in height for the beacons, which limits interference. In addition, a post also allows to constrain the radiation towards the sub-zone. Preferably, the post is metallic.

Preferably, the first beacon and the second area beacon are omnidirectional beacons, the face of the support post being configured to reduce the area radiation of a first/second area beacon. Thus, advantage is taken of the configuration of the building to use omnidirectional beacons, which are inexpensive, to obtain zone radiations which are directional and only in a given sub-zone.

PRESENTATION OF FIGURES

The invention will be better understood on reading the following description, given solely by way of example, and referring to the accompanying drawings given by way of non-limiting examples, in which identical references are given to similar objects. and on which:

Figure 1 is a schematic representation of an industrial building comprising a plurality of unit areas and two products to be located;

Figure 2 is a schematic representation of area radiation from a plurality of area beacons of Figure 1;

Figure 3 is a schematic representation of product radiation from a plurality of product beacons of Figure 1;

FIG. 4 is a schematic representation of the interrogation radiation from an RFID reader during a step of transmitting an interrogation signal in a building of FIG. 1;

FIG. 5 is a schematic representation of a step for sending an interrogation signal and steps for receiving a response signal according to one embodiment of the invention;

Figures 6A to 6D are schematic representations of a plurality of interrogation stages for different interrogation radiations in the industrial building of Figure 1;

FIG. 7 is a detailed representation of FIG. 6A during an interrogation step according to a first interrogation radiation;

FIG. 8 is a schematic representation of the association and determination steps according to an example implementation of the invention;

Figure 9 is a schematic representation of a unit area comprising two sub-areas according to one embodiment of the invention.

It should be noted that the figures expose the invention in detail to implement the invention, said figures can of course be used to better define the invention if necessary.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a method for locating a product in an industrial building.

Referring to Figure 1, the industrial building B, for example an aeronautical assembly plant, comprises a plurality of unitary zones Z1-Z6, forming a partition of the industrial building B. In this example, the industrial building B comprises six zones units Z1-Z6, presenting equivalent surfaces. It goes without saying that the number of unitary zones Z1-Z6 and/or that their surfaces could be different.

The location method is implemented by means of a location system S. Referring to Figure 1, the location system S comprises a plurality of RFID type zone tags 11-16 and a plurality of product tags of the RFID type 21, 22 and an RFID reader 3 (FIG. 5).

According to the invention, each unit zone Z1-Z6 of the industrial building B comprises at least one zone tag of the RFID type 11-16 which is fixed in the unit zone Z1-Z6 and which defines a zone radiation which covers at least partially said unitary zone Z1-Z6, the zone tag 11-16 comprising a zone identifier ID11-ID16. According to the invention, each product to be located L1-L2 comprises at least one product tag of the RFID type 21, 22 which defines product radiation, the product tag 21, 22 comprising a product identifier ID21, ID22.

Area tags 11-16 and product tags 21, 22 will now be presented in detail.

According to the invention, each unitary zone Z1-Z6 comprises an RFID-type zone beacon, subsequently designated zone beacon 11-16. Each zone beacon 11-16 is fixed in the unitary zone Z1-Z6, on a predetermined and known location.

• recevoir un signal d’onde électromagnétique radiofréquence désigné par la suite signal d’interrogation INT, issu du lecteur RFID 3 et
• émettre un signal d’onde électromagnétique radiofréquence comprenant l’identifiant ID11-ID16, désigné par la suite signal de réponse REP.

In known manner, each zone beacon 11-16 comprises a memory storing an identifier ID11-ID16 of the zone beacon 11-16. Referring to Figure 5, each area beacon 11-16 further comprises an antenna capable of:

• receive a radio frequency electromagnetic wave signal subsequently designated INT interrogation signal, coming from the RFID reader 3 and
• emitting a radiofrequency electromagnetic wave signal comprising the identifier ID11-ID16, hereinafter referred to as response signal REP.

Each zone tag 11-16 is preferably a so-called passive RFID tag. “Passive” means that the 11-16 zone beacon does not include a power supply device (e.g. a battery). A passive RFID tag has a limited cost and eliminates the need for maintenance operations such as, for example, replacing a used battery.

In this example, still with reference to FIG. 1, each unit zone Z1-Z6 comprises a structural post A1-A6, the position of which is known in the industrial building B. As such, each structural post A1-A6 defines an identifier geographical area of each unit zone Z1-Z6. The zone beacon 11-16 of each unit zone Z1-Z6 is preferably positioned on the structural post A1-A6 of the unit zone Z1-Z6 concerned. Alternatively, it goes without saying that each zone beacon 11-16 could be fixed to a different support, in particular, on a wall of the unit zone Z1-Z6.

Preferably, each zone beacon 11-16 is fixed in the unit zone Z1-Z6 in height (see figure 5), so as to limit the disturbances during the propagation of RF signals received and transmitted by the zone beacon 11- 16 due to the presence of obstacles. For example, the presence of metallic objects can alter the wave propagation of an RF signal.

In a known manner, with reference to FIG. 2, each antenna of a zone beacon 11-16 defines a zone radiation Q1-Q6 in which a response signal REP is emitted following reception of an interrogation signal INT by zone beacon 11-16. Thus, when the RFID reader 3 emits an INT interrogation signal and is located in its zone radiation Q1-Q6, the RFID reader 3 can know the identifier ID11-ID16 of a zone beacon 11-16.

The Q1-Q6 zone radiation advantageously extends over a limited perimeter, due to the use of zone beacons 11-16 which are passive and whose transmission distance is low. Preferably, with reference to FIG. 1, each zone radiation Q1-Q6 is configured to extend over a coverage radius R comprised between 1 and 20m, more preferably comprised between 5 and 10m around its zone beacon 11 -16. This advantageously makes it possible to limit the movement of the RFID reader 3, in particular, by means of an automaton.

Preferably, as illustrated in FIG. 2, two zone beacons 11-16 of two adjacent unit zones Z1-Z6 are spaced apart by a distance of between 1.8 and 2 times the coverage radius of the zone radiation Q1- Q6. This advantageously makes it possible to limit their overlap while ensuring coverage without a white zone. The probability of detecting two zone beacons 11-16 during the same instance of interrogation is thus low.

Similarly, with reference to FIG. 2, two adjacent zone radiations Q1-Q6 (for example the unit zones Z1 and Z2 or Z1 and Z6) preferably comprise a portion of overlap QR, at most equal to 10% of each zone radiation Q1-Q6. Such a maximum overlap advantageously makes it possible to limit the simultaneous detection of too many unitary zones Z1-Z6 by the RFID reader 3 as will be presented later.

Each zone radiation Q1-Q6 extends substantially according to one or more radiation cones comprised between 1° and 360° around the zone beacon 11-16. Preferably, the 11-16 area beacons are omnidirectional, that is to say, their antennas are omnidirectional. For an omnidirectional 11-16 zone beacon, the radiation cone is then substantially 360° as illustrated schematically in Figure 2.

Referring to Figure 2, each unit zone Z1-Z6 comprises only a single zone beacon 11-16. The zone radiation Q1-Q6 of each unit zone Z1-Z6 is configured to cover the majority of the unit zone Z1-Z6 concerned. Preferably, each zone beacon 11-16 is omnidirectional and positioned centrally in its zone Z1-Z6.

Preferably, each zone beacon 11-16 is configured to transmit on a frequency comprised between 100 kHz and 10 GHz, preferably between 860 and 900 MHz, more preferably between 865 MHz and 868 MHz.

Furthermore, in this example, each zone beacon 11-16 is configured to be updated electronically remotely by an external electronic device, for example a computer. By updating the zone beacon 11-16 is meant the updating of the information included in the electronic chip of the zone beacon 11-16, in particular, its identifier ID11-ID16.

The location system S according to the invention is configured to locate a product L1-L2, a spare part for example, in the industrial building B.

• recevoir un signal d’onde électromagnétique radiofréquence désigné par la suite signal d’interrogation INT, issu du lecteur RFID 3 et
• émettre un signal d’onde électromagnétique radiofréquence comprenant l’identifiant produit ID21, ID22, désigné par la suite signal de réponse REP.

For this, with reference to Figure 1, each product to be located L1, L2 comprises an RFID tag, designated product tag 21, 22. Analogously to zone tags 11-16, a product tag 21, 22 comprises a memory storing a product identifier ID21, ID22 of the product tag 21, 22. Referring to Figure 5, each product tag 21, 22 further comprises an antenna capable of:

• receive a radio frequency electromagnetic wave signal subsequently designated INT interrogation signal, coming from the RFID reader 3 and
• emitting a radiofrequency electromagnetic wave signal comprising the product identifier ID21, ID22, hereinafter designated response signal REP.

The product tag 21, 22 is preferably a so-called passive RFID tag, having the advantages mentioned above. Similarly, the product beacon 21, 22 defines a radiation called "product radiation" P1, P2 (Figure 3) corresponding to the transmission and reception distance of RF signals by the antenna of the product beacon 21 , 22 in a perimeter around the product tag 21, 22. The operation of an area tag 11-16 and that of a product tag 21, 22 are similar.

Preferably, the product radiation P1, P2 has a radius between 1 and 20 m, preferably between 5 and 10 m. Preferably, the product beacon 21, 22 is configured to emit the product radiation P1, P2 360° (omnidirectional) around the product beacon 21, 22.

As described above, the location system S according to the invention further comprises an interrogation device by radio frequency identification, commonly referred to as RFID reader 3. At each instance of interrogation, the RFID reader 3 is configured to emit a signal of interrogation INT defining an interrogation radiation I (FIG. 4) whose range is predetermined and known. Each instance of RFID reader 3 interrogation is activated manually (trigger) or automatically (PLC).

When an area beacon 11-16 is reached by the interrogation radiation I and the RFID reader 3 is located within the area radiation Q1-Q6 of the area beacon 11-16, this area beacon 11-16 emits a response signal REP comprising its zone identifier ID11-ID16. Similarly, when a product tag 21, 21 is reached by the interrogation radiation I and the RFID reader 3 is located in the product radiation P1-P2 of the product tag 21-22, this tag of product 21-22 sends a response signal REP comprising its product identifier ID21-ID22.

In a simplified manner, and as schematically illustrated in FIG. 5, the principle of the method of the invention is as follows: when a zone tag 11-16 is reached by an interrogation radiation I from the RFID reader 3, this tag zone 11-16 sends a response signal REP comprising its zone identifier ID11-ID16. Similarly, if a product tag 21, 22 is reached by this same interrogation radiation I from the RFID reader 3, this product tag 21, 22 emits a response signal REP comprising its product identifier ID21, ID22. If the RFID reader 3 is indeed in the zone radiation Q1-Q6 of the zone beacon 11-16 and in the product radiation P1, P2 of the product beacon 21, 22, it receives their respective response signals REP , which allows an association in a database DB (FIG. 8), of the zone identifiers ID11-ID16 and of the product identifiers ID21, ID22 for this query I. (instance activation time), it is thus possible to associate one or more zone tags 11-16 with none, one or more product tags ID21, ID22.

Preferably, the interrogation radiation I has a radius comprised between 0m and 30m allowing precise detection of the product to be located, and a radiation cone comprised between 1° and 360° around the RFID reader 3. In this example, the radiation interrogation I has a radiation cone of the order of 90-150° and interrogation radiation I has a ring sector shape but it goes without saying that it could be diverse. Preferably, the range of the interrogation radiation I of the RFID reader 3 can be adapted to reduce the interconnections of the radiation zones and improve the precision of the location.

In a preferred embodiment, the RFID reader 3 is in the form of a shower-type RFID reader, which can be carried and moved by an operator. Alternatively, the RFID reader 3 belongs to a mobile system in the building B, for example, a robot on the ground capable of carrying out a programmable route, a drone or a robot on rails or the like.

The RFID reader 3 is configured to be activated manually by an operator or automatically, in particular periodically, for a predefined period. For example, the RFID reader 3 is configured to emit between 2 and 400 INT interrogation signals per second, preferably around 10. Such an interrogation frequency is relevant since it is higher than the movement frequency d a product L1-L2 in a building B. Thus, it can be validly assumed that the product L1-L2 has remained immobile between several successive interrogations.

Preferably, the RFID reader 3 comprises a display screen in order to display, for example, the location of the products L1, L2 in the building B which has been determined from the location method according to the invention.

Preferably, the RFID reader 3 is free of means for measuring the power of the response signals REP. In other words, the RFID reader 3 has a hardware and software structure that is not very complex and inexpensive. The absence of such power measurement means makes it possible to reduce the cost. As indicated previously, a power measurement is not relevant in an aeronautical context in which the propagation of the REP response signals is strongly impacted by the environment, in particular, by the presence of metallic equipment.

• associer l’identifiant/les identifiants de produit ID21, ID22 à l’identifiant/aux identifiants de zone ID11-ID16, obtenus par le lecteur RFID 3, dans une base de données DB pour chaque rayonnement d’interrogation I, l’association étant exempte de mesure de puissance, et
• déterminer la zone unitaire Z1-Z6 dans laquelle chaque produit L1, L2 est situé, par analyse statistique de la base de données DB.

Still with reference to FIG. 5, the location system S according to the invention further comprises a computer 4 configured for:

• associate the product identifier(s) ID21, ID22 with the zone identifier(s) ID11-ID16, obtained by the RFID reader 3, in a database DB for each interrogation radiation I, the association being exempt from power measurement, and
• determining the unit zone Z1-Z6 in which each product L1, L2 is located, by statistical analysis of the database DB.

In other words, the computer 4 is configured to determine an association, at each instance of interrogation, without measuring a power of the response signal REP, the value of which may be erroneous due to the environment. In other words, the computer 4 determines the location of the product to be located L without performing any distance measurement between the RFID reader 3 and one of the RFID tags 11-16, 21, 22.

Advantageously, such a determination free of a power measurement of a response signal REP allows a significant time saving and also makes it possible to overcome measurement errors which would be due for example to the presence of metallic objects in the perimeter of the interrogation radiation I and/or of the product radiation P1, P2. Preferably, each association comprises a time stamp. This facilitates the interpretation of the DB database as will be presented later.

In this example, with reference to FIG. 5, the computer 4 is directly integrated into the RFID reader 3, which is then configured to receive and analyze the information directly received by the RFID reader 3. The location of the product L1, L2 can be displayed on the display screen of the RFID reader 3.

According to one aspect, the location system S comprises a central server hosting the database DB and configured to carry out the determination of the unitary zone Z1-Z6 in which each product L1, L2 is located. Alternatively, the computer 4 is directly integrated into the central server.

There will now be described a location method according to an embodiment of the invention with reference to Figures 5, 6A-6D and 7.

In this example, the location method is carried out for two products to be located L1, L2 in an industrial building B comprising six unitary zones Z1-Z6, each comprising a single zone beacon 11-16. In the example implementation presented, only an RFID reader 3 was used. Nevertheless, it goes without saying that the location system S could also comprise a plurality of RFID readers 3 used in a pooled manner to allow faster determination of the unitary zone Z1-Z6 in which the product L1, L2 is located.

This example of implementation will be presented in relation to FIGS. 6A to 6D showing the displacement of the RFID reader 3 by an operator in the building B in order to locate a product L1, L2. In this example, four successive interrogation steps will be presented in the industrial building B at four successive times t1, t2, t3, t4 for four interrogation radiations I1-I4 which are different.

• une étape d’émission E1 dans le bâtiment industriel B (figure 5), par un lecteur RFID 3, d’un signal d’interrogation INT selon un premier rayonnement d’interrogation I1.
  Dans l'exemple illustré sur les figures 6A et 7, le premier rayonnement d’interrogation I1 couvre partiellement les zones unitaires Z1, Z6 et atteint les balises de zone associées 11 et 16.
• une étape de réception E2, par le lecteur RFID 3, d’un signal de réponse REP audit signal d’interrogation INT par chacune des balises de zone atteintes par ce premier rayonnement d’interrogation I1. Le lecteur RFID 3 reçoit le signal de réponse REP d'une de ces balises de zone, 11, 16 s’il se trouve lui-même dans le rayonnement de zone Q1, Q6 de cette balise de zone 11, 16. Dans le cas présent, en référence aux figures 6A et 7, le premier rayonnement d’interrogation I1 a atteint les balises de zone 11, 16 et le lecteur RFID 3 est uniquement dans le rayonnement de zone Q1 de la balise de zone 11. Le lecteur RFID 3 reçoit ainsi un unique message de réponse REP comprenant l’identifiant de zone ID11 de la balise de zone 11.
• une étape de réception E3, par le lecteur RFID 3, d’un signal de réponse REP audit signal d’interrogation INT par chacune des balises de produit 21, 22 atteintes par le premier rayonnement d’interrogation I1. Dans le cas présent, en référence aux figures 6A et 7, le premier rayonnement d’interrogation I1 a atteint la balise de produit 21 du produit L1 et le lecteur RFID 3 se trouve dans son rayonnement produit P1 : le lecteur RFID 3 reçoit un message de réponse REP provenant de cette balise de produit 21, qui comprend l’identifiant de produit ID21 du produit L1.
• une étape d’association E4 (figure 8) de l’identifiant de produit ID21 à l’identifiant de zone ID11 pour le premier rayonnement d’interrogation I1, dans la base de données DB, l’association étant exempte de mesure de puissance.

The location process includes:

• a step of emission E1 in the industrial building B (FIG. 5), by an RFID reader 3, of an interrogation signal INT according to a first interrogation radiation I1.
  In the example illustrated in FIGS. 6A and 7, the first interrogation radiation I1 partially covers the unitary zones Z1, Z6 and reaches the associated zone beacons 11 and 16.
• a step of reception E2, by the RFID reader 3, of a response signal REP to said interrogation signal INT by each of the zone beacons reached by this first interrogation radiation I1. The RFID reader 3 receives the response signal REP from one of these zone beacons, 11, 16 if it is itself in the zone radiation Q1, Q6 of this zone beacon 11, 16. In the case Now, with reference to Figures 6A and 7, the first interrogating radiation I1 has reached the area beacons 11, 16 and the RFID reader 3 is only within the area radiation Q1 of the area beacon 11. The RFID reader 3 thus receives a single response message REP comprising the zone identifier ID11 of the zone beacon 11.
• a step E3 of reception, by the RFID reader 3, of a response signal REP to said interrogation signal INT by each of the product tags 21, 22 reached by the first interrogation radiation I1. In the present case, with reference to FIGS. 6A and 7, the first interrogation radiation I1 has reached the product beacon 21 of the product L1 and the RFID reader 3 is in its product radiation P1: the RFID reader 3 receives a message response REP from this product tag 21, which includes the product identifier ID21 of the product L1.
• a step E4 of association (FIG. 8) of the product identifier ID21 with the zone identifier ID11 for the first interrogation radiation I1, in the database DB, the association being free of power measurement.

Steps E1-E4 are repeated for a second interrogation radiation I2 which is different from the first interrogation radiation I1. In the example of FIG. 6B, the second interrogation radiation I2 partially covers the unit zones Z1, Z2, Z5 and reaches the zone tags 11, 12 and the product tags 21, 22. The RFID reader 3 is in position to receive the signals transmitted in response by the beacons 11, 21, 22. A new association can thus be formed in the database DB with the product identifiers ID21, ID22 and the zone identifier ID11 for this second radiation of query I2.

In the example, steps E1-E4 are repeated four times (FIGS. 6A-6D) to obtain a DB database comprising 4 associations as illustrated in FIG. 8.

The method comprises a step E4 of determining the unit zone Z1-Z6 in which each product L1, L2 is located by statistical analysis of the database DB. Such a statistical analysis is based on a logical analysis of the different associations. In the present case, it is determined that the first product L1 is located in the unit area Z1 while the second product L2 is located in the unit area Z5. The result of the determination can advantageously be displayed on the RFID reader 3.

In this implementation example, the RFID reader 3 transmits an INT interrogation signal successively at different times t1-t4, corresponding to as many interrogation instances, and each association refers to the corresponding instance.

The existence of an interrogation instance according to the invention is advantageous given that it also makes it possible to determine the position of product tags 21, 22 even in the absence of detection of zone tags 11-16. Indeed, a query instance defines a "dated" association which allows, if necessary, by analysis of the database DB, an additional association step, in which one can "retrospectively" associate, by analysis of the database of DB data, at least one zone tag 11-16 to a product tag 21-22 in the event that a product tag 11-16 has been detected in a query instance and for which no zone tag 11-16 will not have been detected.

In other words, the query instance is not associated with any zone tag 11-16 but only with one or more product tags 21-22. Such a situation arises in particular when this or these product beacon(s) 21-22 would be found outside an area covered by a zone beacon 11-16. Since the query instances are performed frequently, in a short period of time, the product tags 21, 22 located in uncovered areas can still be located by association of the area tags previously identified during the a few previous or next query instances. In other words, the location of product tags can be estimated from the temporally close associations.

In one mode of implementation, with reference to FIG. 8, the method includes a generation step E5 of a map 6 of the industrial building B comprising the location of the product(s) L1, L2. Such a map 6 can for example be displayed on a computer interface, in particular on the RFID reader 3.

The method can also comprise a step of determining the absence of a product to be located L1, L2 when no product tag 21, 22 has been detected in a unitary zone Z1-Z6.

In another embodiment, represented in FIG. 9, a unitary area Z1 is partitioned into a first sub-area Z1-1 and a second sub-area Z1-2. The unitary zone Z1 comprises a first zone beacon 11-1 whose zone radiation Q1-1 is configured to extend only into the first sub-zone Z1-1 and a second zone beacon 11-2 whose radiation from zone Q1-2 is configured to extend only into the second subzone Z1-2. Such an embodiment advantageously makes it possible to improve the precision of detection of a geographical location by limiting the cone of zone radiation Q11, Q12 of each zone beacon 1, in other words by refining the geographical mesh of the industrial building B.

Preferably, the building B comprises at least one support post A1 in the unit zone Z1 at the interface between the first sub-zone Z1-1 and the second sub-zone Z1-2. As illustrated in Figure 9, the support post A1 comprises a first face facing the first sub-zone Z1-1 on which is mounted the first zone beacon 11-1 and a second face, opposite the first face, which faces the second sub-zone Z1-2 on which the second zone beacon 11-2 is mounted.

Such a partition can be obtained with zone beacons 11-1, 11-2 which are directional with a radiation cone angle of the order of 180°. Preferably, this partition is obtained with zone beacons 11-1, 11-2 which are omnidirectional with a cone of the order of 360°. The metal face of an A1 retaining post forms an obstacle which reduces the radiation cone Q1-1, Q1-2 in the manner of a directional beacon but at a reduced cost with improved ease of assembly.

Such a location method advantageously makes it possible to locate a product L1, L2, such as a spare part for example, in an industrial building, for example an aeronautical assembly plant, in a simple and rapid manner, without requiring any power measurement of REP or distance response signal. Thus, the method can be carried out simply at low cost by means of passive RFID tags and an RFID reader free of power measurement or measurement means.

Claims (10)

Method for locating at least one product (L1, L2) in an industrial building (B) comprising a plurality of unitary zones (Z1-Z6), each unitary zone (Z1-Z6) of the industrial building (B) comprising at least a zone beacon (11-16) of the RFID type which is fixed in the unit zone (Z1-Z6) and which defines a zone radiation (Q1-Q6) which at least partially covers said unit zone (Z1-Z6), the zone tag (11-16) comprising a zone identifier (ID11-ID16), the product (L1, L2) to be located comprising at least one product tag (21, 22) of the RFID type which defines product radiation (P1, P2), the product tag (21, 22) comprising a product identifier (ID21, ID22), the location method comprising:

• a step of emission (E1) in the industrial building (B), by an RFID reader (3), of an interrogation signal (INT) according to a first interrogation radiation (I1),
• a step of reception (E2), by the RFID reader (3), of a response signal (REP) to said interrogation signal (INT) by each zone beacon (11-16) positioned in the first radiation of interrogation (I1) and whose RFID reader (3) is positioned in their area radiation (Q1-Q6), the response signal (REP) comprising the area identifier (ID11-ID16) of said area beacon (11 , 16);
• a step of reception (E3), by the RFID reader (3), of a response signal (REP) to said interrogation signal (INT) by each product tag (ID21, ID22) positioned in the first radiation of interrogation (I1) and whose RFID reader (3) is positioned in their product radiation (P1, P2), the response signal (REP) comprising the product identifier (ID21, ID22) of said product tag (21 , 22);
• a step of associating (E4) the product identifier(s) (ID21, ID22) with the zone identifier(s) (ID11-ID16) in a database (DB) for the first radiation of interrogation (I1), the association being exempt from power measurement of a response signal (REP),
• a step of renewing steps E1 to E4 for at least one second interrogation radiation (I2) so that the database (DB) comprises a plurality of associations obtained for a plurality of interrogation radiations (I1 -I4), and
• a step E5 of determining the unit area (Z1-Z6) in which each product (L1, L2) is located by statistical analysis of the database (DB).

Locating method according to Claim 1, in which the area radiations (Q1-Q6) of at least two adjacent area beacons (11-16) have an overlap portion (QR). Locating method according to Claim 2, in which the overlap portion (QR) represents at most 10% of each zone radiation (Q1-Q6). Locating method according to one of Claims 1 to 3, in which the step of transmitting an interrogation signal (INT) according to a first interrogation radiation (I1) and the step of transmitting an interrogation signal (INT) according to a second interrogation radiation (I2) are carried out sequentially. Locating method according to one of Claims 1 to 3, in which the step of transmitting an interrogation signal (INT) according to a first interrogation radiation (I1) and the step of transmitting an interrogation signal (INT) according to a second interrogation radiation (I2) are carried out simultaneously. Locating method according to one of Claims 1 to 5, in which each product tag (21, 22) is a passive tag and in which each area tag (11-16) is a passive tag. Method according to one of Claims 1 to 6, comprising a step of generating a map (6) of the industrial building (B) comprising the location of the product(s) (L1, L2). Location method according to one of Claims 1 to 7, in which at least one unitary zone (Z1) being partitioned into at least a first sub-zone (Z1-1) and a second sub-zone (Z1-2), the unit area (Z1) comprising at least one first area beacon (11-1) whose area radiation (Q1-1) is configured to extend only in the first sub-area (Z1-1) and at least a second zone beacon (11-2) whose zone radiation (Q1-2) is configured to extend only into the second sub-zone (Z1-2). Locating method according to claim 8, in which the building (B) comprising at least one support post (A1) in the unit zone (Z1) at the interface between the first sub-zone (Z1-1) and the second sub-zone (Z1-2), the support post (A1) comprising at least a first face facing the first sub-zone (Z1-1) on which the first zone beacon (11-1) is mounted and a second face, opposite the first face, which faces the second sub-zone (Z1-2) on which the second zone beacon (11-2) is mounted. Locating method according to claim 9, wherein the first beacon and the second area beacon (11-1, 11-2) are omnidirectional beacons, the face of the supporting post (A1) being configured to reduce the area radiation (Q1-1, Q1-2) of a first/second zone beacon (11-1, 11-2).