Location of RFID tags within the monitoring area

Abstract

To provide a method for identifying a position of an RFID tag in a monitored zone.SOLUTION: The method comprises the steps of: emitting a reference signal including reference information from a reference RFID tag at a predetermined reference position within a monitored zone; at a plurality of receivers, receiving the reference signal as a plurality of received reference signals; calculating a position of the reference RFID tag according to the received reference signals; comparing the calculated position of the reference RFID tag with the predetermined reference position for obtaining a test result; emitting an operation signal including operation information associated with the RFID tag from the RFID tag; at the plurality of receivers, receiving the operation signal as a plurality of received operation signals; comparing the received operation information with predetermined validation information associated with the RFID tag for obtaining a validation result; according to the test result and / or the validation result, calculating a position of the RFID tag on the basis of or in accordance with the received operation signals, and / or emitting a position signal indicating the position of the RFID tag on the basis of or in accordance with the received operation signals.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005] , ,

[0001] The present invention relates to a method for localizing the position of RFID tags within a monitoring area and a localization system for localizing the position of RFID tags within a monitoring area.

Background Art

[0002] Technologies based on radio frequency (RF) emissions can be used to enhance the safety of a monitoring area, such as an area within an industrial plant, so that the monitoring area is considered safe. The monitoring area can be considered "safe" if the positions of location tags, particularly RFID tags, can be known in a reliable manner, especially in accordance with established and accepted safety criteria. Location tags can be attached to objects or people entering the monitoring area so that the positions of the objects or people can be transmitted to the monitoring system. Such positions can be used, in particular, as feedback variables when defining the safety-related operations of potentially dangerous devices, such as machinery present in an industrial plant.

[0003] It is desirable for the position to be known in real time. This is referred to as a so-called "real-time localization system" (RTLS) solution.

[0004] The main disadvantage of the above-described systems is that they are not inherently safe, i.e., the safety function is not fully realized by the RF system itself, and other devices are required, particularly in accordance with the necessary safety criteria, to achieve the desired level of safety. An example is provided in U.S. Patent Application Publication No. 2021 / 0232102, where two different technologies verify each other.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Therefore, an object of the present invention is to provide an improved method and system for locating RFID tags within a surveillance area that can overcome such disadvantages. [Means for solving the problem]

[0006] According to the first embodiment, a method is provided for identifying the location of an RFID tag within a monitoring area. This method is The steps include: emitting a reference signal containing reference information from a reference RFID tag at a predetermined reference location within the monitoring area; The steps include receiving a reference signal as multiple received reference signals in multiple receivers, A step of calculating the position of the reference RFID tag according to the received reference signal, To obtain the test results, the steps include comparing the calculated position of the reference RFID tag with a predetermined reference position, The steps include: emitting an operation signal from the RFID tag that includes operation information associated with the RFID tag; The steps include receiving the operation signal as multiple receiving operation signals in multiple receivers, To obtain the verification result, the received operational information is compared with predetermined verification information associated with the RFID tag. The steps include: calculating the position of the RFID tag based on or in accordance with the received operation signal, and / or emitting a position signal indicating the position of the RFID tag based on or in accordance with the received operation signal; Includes.

[0007] According to the second aspect, a location identification system is provided for identifying the location of an RFID tag within a monitoring area. This location identification system is A reference RFID tag that emits a reference signal containing reference information, At least one RFID tag that emits an operation signal containing operation information associated with the RFID tag, Multiple receivers that receive the aforementioned reference signal as multiple received reference signals and the aforementioned operation signal as multiple received operation signals, Equipped with a safety unit, The aforementioned safety unit is The position of the reference RFID tag is calculated according to the received reference signal. To obtain the test results, the calculated position of the reference RFID tag is compared with a predetermined reference position. In order to obtain the verification result, the received operational information is compared with predetermined verification information associated with the RFID tag. Based on the test results and / or verification results, the position of the RFID tag is calculated based on or in accordance with the received operation signal, and / or a position signal indicating the position of the RFID tag is emitted based on or in accordance with the received operation signal. It is structured in this way.

[0008] A “monitoring area” refers to any area where the location of an RFID tag needs to be identified. Location identification may be required for safety reasons. A monitoring area is, for example, a work area within a workshop that contains one or more hazardous machines, whether fixed or movable. RFID tags are attached to people, such as workers operating and moving within a monitoring area, or to objects, such as vehicles or machines operating and moving within a monitoring area. The location of an RFID tag within a monitoring area is identified by defining its coordinates relative to a Cartesian coordinate system. The Cartesian coordinate system may be a spatial 3D system requiring the definition of three coordinates to identify the RFID tag's location, a planar 2D system requiring the definition of two coordinates, or a 1D system such as a horizontal or vertical track requiring the definition of one coordinate.

[0009] A "receiver" is a device, such as an antenna, used to receive the radio signals emitted by RFID tags. Multiple receivers may be installed in any number inside or near the monitoring area. The number of receivers depends on the dimensions of the monitoring area; generally, larger areas require more receivers. A large number of receivers provides the desired level of redundancy.

[0010] The RFID tag and the reference RFID tag may be active or passive RFID tags. The RFID tag and the reference RFID may be active tags comprising one emitter and one memory chip. Alternatively, the RFID tag and the reference RFID tag may each be active RFID tags comprising two emitters, each emitting at a different frequency, and each equipped with one memory chip. The reference RFID tag is positioned at a predetermined reference location within the monitoring area. This predetermined reference location is compared to a calculated location of the reference RFID tag to obtain test results. The test results provide an indicator of the capability of the method or system for calculating the predetermined reference location. The verification results provide an indicator of the capability of the method or system for extracting operational information from signals received from the RFID tag. The operational information must conform to predetermined verification information associated with the RFID tag.

[0011] "Safety unit" means any software or hardware unit configured to perform steps specified by reference to the first or second aspect of the present invention. The safety unit may be, for example, a computer client or server located in or near the monitoring area. Alternatively, the safety unit may be located remotely from the monitoring area. The safety unit may be connected to the receiver by any means of communication, whether wired or non-wired. According to embodiments of the present invention, the safety unit may be provided in at least partially one or more receivers.

[0012] Depending on the test results and / or verification results, it may be determined whether or not the RFID tag's position is calculated. For example, if the test results indicate that the method or system can calculate a predetermined reference position and the verification results indicate that the operational information conforms to the predetermined verification information, the RFID tag's position is calculated based on or in accordance with the received operational signal. Here, the expression "based on or in accordance with" means that the received operational signal can be treated as a mathematical entity in order to calculate the coordinates of the RFID tag relative to the coordinate system associated with the monitoring area. Alternatively or additionally to the calculation of the RFID tag's position, a position signal indicating the RFID tag's position may be generated. The position signal may be used, for example, as input for multiple operations performed within the monitoring area. For example, the position signal may be used as input for operating one or more machines within the monitoring area. For example, if the test results and / or verification results indicate that the method or system cannot calculate a predetermined reference position and / or the operational information does not conform to the predetermined verification information, the RFID tag is not calculated. As a result, the system may be locked out.

[0013] Furthermore, the present invention provides rated positions for RFID tags, particularly rated positions with respect to safety standards. This is provided in a single-technology (RF) based system. Therefore, this system can be considered inherently safe, that is, it complies with safety standards and does not require any additional system to verify compliance.

[0014] According to one embodiment, the method according to the first embodiment further includes the steps of sequentially stopping at least one receiver and calculating the position of a reference RFID tag according to reference information received by the remaining receivers.

[0015] The word "sequentially" here can be understood as "one after another." Specifically, all receivers are activated at the same first time. The position of the reference RFID tag is calculated according to the received reference signal, and the calculated position of the reference RFID tag is compared to a predetermined reference position to obtain a test result. Then, at a second time later than the first time, one receiver is activated, and the position of the reference RFID tag is calculated again according to the received reference signal, and the calculated position of the reference RFID tag is compared to a predetermined reference position, or the reference position calculated at the first time, to obtain a test result. This series of steps is repeated for all receivers. This embodiment can determine whether one or more receivers are not functioning correctly.

[0016] According to one embodiment, the test result shows the positional deviation between the calculated position of a reference RFID tag and a predetermined reference position and / or a previously calculated position. The step of comparing the calculated position of the reference RFID tag with the predetermined reference position may include determining whether the positional deviation is less than or equal to a predetermined threshold. The predetermined reference position is fixed and known, i.e., the coordinates of the predetermined reference position relative to the Cartesian coordinates associated with the monitoring area are known. The positional deviation may be calculated as the distance between the predetermined reference position and the calculated position. Such a difference may be compared to a predetermined threshold to obtain the test result.

[0017] According to one embodiment, the operation information and / or verification information includes an encryption key, identification information, or a timestamp. The operation information and / or verification information may be encrypted. The encryption key may be a shared key or a periodic list of keys. The test results and / or verification results may depend on a comparison between the encryption key and the verification key. The identification information may include the ID code of the RFID tag. The test results and / or verification results may depend on a comparison between the ID code and an expected ID code. The timestamp is information, in particular encoded information, that identifies when an event occurred. The test results and / or verification results may depend on a comparison between the timestamp and an expected timestamp.

[0018] According to one embodiment, the test result and / or verification result indicates compliance with a predetermined communication standard. Specifically, the verification result indicates that the communication between the RFID tag and the receiver complies with safety standards regarding the functional safety of an electrical / electronic / programmable electronic safety-related system, such as IEC13849 and / or IEC61508-2 regarding the safety of machinery, particularly the safety standards according to Annex A.

[0019] According to one embodiment, the method according to the first aspect includes a step of comparing the received operation information with predetermined verification information associated with the RFID tag in each receiver. According to the same or another embodiment, the method according to the first aspect includes a step of calculating the position of the RFID tag based on or in response to the received operation signal in each receiver, or a step of emitting a position signal. According to such an embodiment, each receiver can function independently of other receivers.

[0020] According to one embodiment, the method according to the first aspect includes a step of executing an RTLS algorithm and determining a position with respect to a coordinate system within a monitored area. The RTLS algorithm may be a multilateration algorithm.

[0021] In a plurality of embodiments, the step of calculating the position of the RFID tag is executed only when the test result and / or verification result indicates the normal or effective state of a positioning system, such as the RFID tag and / or the receiver. The test result and verification result may indicate abnormalities such as misalignment of the reference tag, interfering signals, and unwanted interference signals. The normal state is a state in which the device functions without being obstructed.

[0022] In a plurality of embodiments, when the test result and / or verification result indicates an abnormality, a safety signal is emitted to instruct a machine associated with the monitored area to be put into a safety mode. The safety mode may include stopping parts and devices of the machine to make the monitored area safe. In the safety mode, preferably, no dangerous events occur.

[0023] According to one embodiment, the emitted reference signal has a first frequency, and the method according to the first aspect further includes simultaneously emitting the combined reference signal at the first frequency and a second frequency, receiving the combined reference signal as a plurality of combined received reference signals, and calculating the position of the reference RFID tag according to the combined received reference signals.

[0024] According to one embodiment, the emitted operation signal has a first frequency, and the method according to the first aspect further includes simultaneously emitting the combined operation signal at the first frequency and a second frequency, receiving the combined operation signal as a plurality of combined received operation signals, and comparing the received operation information with predetermined verification information associated with the combined received operation signals to obtain a verification result.

[0025] Embodiments in which signals are emitted at two different frequencies provide a more detailed comparison to obtain verification results and test results.

[0026] According to an embodiment of the method according to the first aspect, at least one subset of the steps of the method is periodically executed according to a period, specifically a period of 100 to 500 ms. Preferably, the period is preset based on safety requirements defined by safety criteria for monitoring the movement of people or objects in a safety area. The above-mentioned or below-mentioned safety criteria may be relevant. Specifically, the verification results and test results may be periodically updated according to the period.

[0027] According to one embodiment, the location tracking system according to the second embodiment comprises a wearable worn by a worker entering a monitored area, the wearable comprising an RFID tag. The wearable may be, for example, a wristband or other type of clothing. The wearable may also comprise sensors, such as a heart rate sensor and / or a stress sensor, to provide further information about the worker. Safety actions may be further conditioned by the information provided by such sensors. For example, a warning may be provided if the worker's stress level exceeds a predetermined stress threshold. The sensors may also be used to recognize the worker's ID, for example, for comparison with access rights. For example, a warning may be issued if the worker does not have the specific authority required to enter the monitored area. This prevents unauthorized workers from borrowing RFID tags from authorized workers.

[0028] It should be understood that location systems and / or devices provided in location systems for locating RFID tags are provided to cooperate in carrying out the methods of disclosure and / or requests.

[0029] In a further embodiment, the present invention relates to a computer program product that includes program code for locating the location of an RFID tag within a monitoring area according to the first embodiment, when executed on at least one computer.

[0030] Computer program products, such as computer program means, may be embodied as memory cards, USB sticks, CD-ROMs, DVDs, or as files that can be downloaded from a server on a network. For example, such files may be provided by transferring the files constituting the computer program product over a wireless communication network.

[0031] Further possible embodiments or alternative solutions of the present invention include combinations of features described or described above (not expressly mentioned herein) with respect to embodiments. Furthermore, those skilled in the art may add individual or isolated aspects and features to the most basic form of the present invention. It should be understood that any regulations, norms, or standards referred to in this disclosure refer to their respective versions as of the filing date or priority date of this application. [Brief explanation of the drawing]

[0032] Further embodiments, features, and advantages of the present invention will become apparent from the following description and dependent claims, with reference to the accompanying drawings.

[0033] [Figure 1] This figure shows a monitoring area equipped with a location identification system according to a second aspect of the present invention. [Figure 2] This figure shows a first embodiment of the RFID tag according to the present invention. [Figure 3] This figure shows a second embodiment of the RFID tag according to the present invention. [Figure 4] This is a block diagram of a method according to the first aspect of the present invention. [Figure 5] This figure shows the first modified example of the block diagram in Figure 4. [Figure 6] This figure shows a second modified example of the block diagram in Figure 4. [Modes for carrying out the invention]

[0034] In drawings, similar reference figures indicate similar or functionally equivalent elements unless otherwise specified.

[0035] Figures 1 to 3 show a location system 20 for locating an RFID tag 10 within a monitoring area S. The monitoring area may be a work area within a workshop equipped with one or more hazardous machines (either stationary or mobile, not shown in Figure 1). The monitoring area S is associated with a Cartesian coordinate system XYZ, and each point within the monitoring area S is defined by three coordinates X, Y, and Z of the Cartesian coordinate system XYZ. In the representation in Figure 1, the third coordinate Z of the Cartesian coordinate system XYZ is oriented perpendicular to the plane of the figure and faces the observer. According to other embodiments of the present invention (not shown), the Cartesian coordinate system may be a 2D planar system requiring two defined coordinates, or a 1D system requiring one defined coordinate, such as a horizontal or vertical track.

[0036] The location identification system 20 identifies the location of the RFID tag 10 within the monitoring area S by calculating the coordinates X, Y, and Z of the RFID tag 10 relative to the Cartesian coordinate system XYZ, in accordance with predetermined communication and safety standards, as will be more clearly defined below.

[0037] The RFID tag 10 can be attached to a person, such as a worker operating and moving within the monitoring area S, or to an object, such as a vehicle or machine operating and moving within the monitoring area S. The RFID tag 10 is an active RFID configured to emit operation signals S1 and S2 at frequencies F1 and F2, respectively. The operation signals S1 and S2 contain operation information associated with the RFID tag 10.

[0038] Figure 2 shows a first embodiment of the active RFID tag 10 or reference RFID tag 11 according to the first embodiment of the present invention. The active RFID tag 10 and reference RFID tag 11 of the first embodiment each include emitters 10a, 11a and memory chips 10c, 11c. The emitters 10a, 11a emit an operation signal S1 and a reference signal ST1 at a frequency F1 in the range of 3.1 to 10.6 MHz. The memory chips 10c, 11c each contain identification information relating to the active RFID tag 10 and reference RFID tag 11. Figure 3 shows a second embodiment of the active RFID tag 10 or reference RFID tag 11 according to the second embodiment of the present invention. The active RFID tag 10 and reference RFID tag 11 of the second embodiment each include first emitters 10a, 11a and second emitters 10a, 11a and memory chips 10c, 11c. The first emitters 10a and 11a emit a first operating signal S1 and a first reference signal ST1 at a frequency F1 in the range of 3.1 to 10.6 MHz. The second emitters 10b and 11b emit a second operating signal S2 and a second reference signal ST2 at a frequency F2 in the range of 3.1 to 10.6 MHz. Ultra-wideband frequencies may be considered, for example, for use as CEVE-RivieraWaves®. Tags may conform to IEEE 802.15.4z HPR.

[0039] The location identification system 20 further comprises a reference RFID tag 11. The RFID tag 11 is an active RFID tag configured to emit reference signals ST1 and ST2 at frequencies F1 and F2, respectively. The reference signals ST1 and ST2 contain reference information. The RFID tag 11 is assumed to be positioned at a predetermined reference position P. The coordinates of the predetermined reference position P with respect to the Cartesian coordinate system XYZ are known.

[0040] The location identification system 20 further comprises multiple receivers (four receivers 21, 22, 23, 24 in the embodiment of Figure 1) that receive reference signals ST1, ST2 as multiple received reference signals ST1'-ST1'''',ST2'-ST2'''' and operation signals S1, S2 as multiple received operation signals S1'-S1''',S2'-S2''''. The multiple receivers 21, 22, 23, 24 may be provided as multiple antennas capable of receiving radio signals emitted by RFID tags. According to different embodiments of the present invention, any number of the multiple receivers are provided inside or near the monitoring area. The signals ST1'-ST1'''',ST2'-ST2'''',S1'-S1'''',S2'-S2'''' received by the receivers 21, 22, 23, 24 are used to calculate the positions of RFID tags 10, 11 with respect to the Cartesian coordinate system XYZ. Therefore, if three coordinates must be defined, as in the exemplary embodiment of Figure 1, at least three receivers are required. Since some surplus is desirable, a preferred embodiment includes four or more receivers.

[0041] The location identification system 20 further comprises a safety unit 15. The safety unit may be, for example, a computer client or server located in or near the monitoring area S. According to another embodiment of the present invention, the safety unit may be located remotely from the monitoring area. The safety unit 15 is connected to the receiver by any means of communication, which may be wired or not. According to an embodiment of the present invention, the safety unit may be at least partially provided in any of the receivers 21, 22, 23, or 24.

[0042] The security unit 15 is configured to perform a method 100 for locating the RFID tag 10 within the monitoring area S, as shown in Figure 4.

[0043] Method 100 includes step 110, in which a reference RFID tag 11 is placed at a known reference location P within the monitoring area S, that is, at a location P to which coordinates X, Y, Z are assigned with respect to the Cartesian coordinate system XYZ.

[0044] In step 120 of method 100, a reference signal ST1 is emitted from a reference RFID tag 11. The reference signal ST1 includes reference information for re-protecting the reference RFID tag 11. The reference information includes an encryption key (or a periodic list of keys) and / or identification (ID) information and / or a timestamp. After step 120, in step 130 of method 100, the reference signal ST1 is received by a plurality of receivers 21, 22, 23, 24 as a plurality of received reference signals ST1', ST1'', ST1'''', ST1''''. After step 130, in step 140 of method 100, the position of the reference RFID tag 11 is calculated according to the received reference signals ST1'-ST1''''. The position may be calculated by an RTLS algorithm, such as a multilateration algorithm. The position of the reference RFID tag 11 may be defined through three coordinates X1, Y1, Z1 in a Cartesian coordinate system XYZ. Following step 140, in step 150 of method 100, the calculated position of the reference RFID tag 11 is compared with a predetermined reference position P, and the received reference information is compared with predetermined reference information associated with the reference RFID tag to obtain a test result. The test result may indicate the positional deviation between the calculated position X1,Y1,Z1 of the reference RFID and the predetermined reference position P. In embodiments of the present invention, step 150 of method 100 includes calculating the positional deviation between the coordinates X1,Y1,Z1 of the calculated position and the coordinates X,Y,Z of the reference position P, and determining whether the positional deviation is below a predetermined threshold. The positional deviation may be calculated as the geometric distance between the coordinates X1,Y1,Z1 and the coordinates X,Y,Z. Thus, the test result is an indicator of how accurately the known reference position P can be calculated based on or in accordance with the received reference signals ST1'-ST1''''. The predetermined threshold determines the acceptable precision of such calculation. If the test results are positive, it can be assumed that the location system 20 and / or method 100 can provide a reliable measurement of the location of the RFID tag 10. The test results may further depend on a comparison between the received reference information and predetermined reference information associated with a reference RFID tag. The test results may also indicate compliance with a predetermined communication standard.The reference information may be encrypted, for example. Dynamic decryption of the reference information message confirms that the reference RFID tag 11 is functioning correctly in accordance with a predetermined standard, such as IEC 13849 and / or IEC 61508-2. If the test result is positive, it can be assumed that the location system 20 and / or method 100 can communicate securely in accordance with the predetermined standard, and / or that the reference RFID tag 11 is functioning correctly.

[0045] Steps 120, 130, 140, 150, or in parallel therewith, Method 100 includes step 111 of attaching an RFID tag 10 to a person or object before the person or object enters a monitored area S, for example, to perform one or more actions inside the area. Step 111 may be performed by a worker entering the monitored area S wearing a wearable equipped with the RFID tag 10. The wearable may be, for example, a wristband or any other type of clothing.

[0046] Further safety devices (not shown in the attached diagram) may be provided in the monitoring area S to detect whether a person or object has entered the monitoring area S. Such safety devices may be, for example, a light curtain, a photoelectric sensor equipped with a laser scanner or light grid, or other similar devices. Such safety devices operate in conjunction with receivers 21, 22, 23, and 24 and can detect whether a person or object has entered the monitoring area S without an attached RFID tag. In this case, a warning signal may be generated.

[0047] In step 160 of Method 100, an operation signal S1 is emitted from the RFID tag 10. The operation signal S1 includes operation information associated with the RFID tag 10. The operation information includes an encryption key (or a periodic list of keys) and / or identification (ID) information and / or a timestamp. After step 160, in step 170 of Method 100, the operation signal S1 is received by a plurality of receivers 21, 22, 23, 24 as a plurality of received operation signals S1', S1'', S1''', S1''''. After step 170, in step 180 of Method 100, the received operation information is compared with predetermined verification information associated with the RFID tag 10 to obtain a verification result. The verification result may indicate compliance with a predetermined communication standard. The operation information may be encrypted, for example. Dynamic decryption of the reference information message confirms that the RFID tag 10 is operating correctly according to a predetermined standard, such as IEC 13849 and / or IEC 61508-2. If the verification result is positive, it can be assumed that the location system 20 and / or method 100 can communicate securely in accordance with the specified standards, and / or that the RFID tag 10 is functioning correctly.

[0048] Steps 160, 170, and 180 of Method 100 may be performed after or in parallel with steps 120, 130, 140, and 150.

[0049] In step 190 of method 100, the location of the RFID tag 10 is calculated based on the test results and / or verification results. If the test results or verification results indicate that the location system 20 and / or method 100 cannot provide a reliable measurement of the location of the RFID tag 10 and / or do not conform to a given communication standard, the location of the RFID tag 10 is not calculated. In this case, a warning is generated and / or the system may be locked out. The location of the RFID tag 10 is calculated based on or in accordance with the received operation signals S1'~S1'''' by an RTLS algorithm, such as a multilateration algorithm. Alternatively or additionally to step 190, method 100 may include step 191, which generates a location signal indicating the location of the RFID tag 10 based on or in accordance with the received operation signals S1'~S1''''. The location signal may be used, for example, as input for multiple operations performed within a monitoring area. For example, the location signal may be used as input for operating one or more machines within a monitoring area.

[0050] At least some or a subset of the steps of method 100, for example, the sequence of steps 120, 130, 140, 150, 160, 170, 180, 190 / 191, may be performed periodically according to a period consisting of 100 to 500 ms.

[0051] Figure 5 shows a first modification of method 100 of Figure 4. In the modification according to Figure 5, method 100 differs from the above in that it includes a step 115 of stopping one receiver 21,22,23,24, and a step 140 of calculating the location of the reference RFID tag 11 according to the reference information received by the remaining receivers 21,22,23,24. The stopping of one receiver 21,22,23,24 is performed iteratively and sequentially, with one of the receivers 21,22,23,24 being stopped in each iteration. Thus, in the embodiment of the appended figures having four receivers 21,22,23,24, the stopping of one receiver 21,22,23,24 is performed four times. According to another embodiment of the present invention, in each iteration, multiple receivers are stopped simultaneously.

[0052] According to the method in Figure 5, after step 150 is performed, step 151 is performed to check whether all receivers 21, 22, 23, and 24 have been sequentially stopped. If all receivers 21, 22, 23, and 24 have not been sequentially stopped, the method continues with step 115, in which one receiver 21, 22, 23, or 24 is stopped. Subsequently, steps 120, 130, 140, and 150 are repeated for the other driven receivers (three driven receivers in the embodiment shown in the attached figure). After all receivers 21, 22, 23, and 24 have been sequentially stopped, the iteration of sequentially stopping receivers 21, 22, 23, and 24 is terminated. In each execution of step 150, the calculated position of the reference RFID tag 11 is updated and compared with a predetermined reference position P to obtain a test result. Also in each execution of step 150, the calculated position of the reference RFID tag 11 is updated and compared with the position calculated in the previous iteration. Repeated test results may indicate that in each instance, one or more receivers are not functioning correctly with one stopped receiver 21, 22, 23, 24.

[0053] Figure 6 shows a second modification of method 100 in Figure 4. In the modification according to Figure 6, the emitted reference signal ST1 and the emitted operating signal S1 have a first frequency F1, and the method further... Step 122 involves simultaneously emitting combined reference signals ST1 and ST2 at a first frequency F1 and a second frequency F2. Step 132 involves receiving the combined reference signal ST1 as a plurality of combined received reference signals ST1'-ST1'''';ST2'-ST2'''', Step 142 calculates the position of the reference RFID tag 11 according to the combined received reference signals ST1'-ST1'''', Step 162 involves simultaneously emitting coupled operating signals S1 and S2 at a first frequency F1 and a second frequency F2. Step 172 involves receiving the operation signals S1 and S2 as multiple combined received operation signals S1'-S'''';S2'-S2'''', Step 182 involves comparing the received operation information with predetermined verification information associated with the combined received operation signals S1'-S1'''';S2'-S2'''' to obtain a verification result. Includes.

[0054] The sequence of steps for the modified example of Method 100 shown in Figure 6 is described in detail below. The RFID tag 10 and the reference RFID tag 11 follow the embodiment shown in Figure 3.

[0055] Following step 110, in step 117 of method 100, it is checked that both emitters 11a and 11b of the reference RFID tag 11 are deactivated and no signal is received by receivers 21, 22, 23, and 24. Subsequently, only the first emitter 11a is driven at a first frequency F1 to emit the reference signal ST1.

[0056] After step 117, the sequence of steps 120, 130, 140, and 150 is performed as described with reference to Figure 4. After step 150, step 153 is performed to check whether the test result calculated in the previous step 150 indicates that the reference RFID tag 11 is operating correctly at the first frequency F1 for calculating the reference position P. If the check in step 153 is positive, the sequence of steps 122, 132, and 142 described above is performed. After step 142, in step 152 of method 100, the position calculated in step 142 is compared with a predetermined reference position P to update the test result. If the system is operating correctly, the test results from both steps 150 and 152 are expected to be the same or similar.

[0057] In steps 117, 120, 130, 140, 150, 153, 122, 132, 142, 152 or in parallel therewith, method 100 includes step 111 of attaching an RFID tag 10 to a person or object before the person or object enters a monitoring area S, for example, to perform one or more actions inside it.

[0058] Following step 111, in step 118 of method 100, it is checked that both emitters 10a and 10b of the reference RFID tag 10 are deactivated and no signals are received by receivers 21, 22, 23, and 24. Subsequently, only the first emitter 10a is driven at a first frequency F1 to emit an operation signal S1.

[0059] After step 118, the sequence of steps 160, 170, 170, and 180 is performed as described with reference to Figure 4. After step 180, step 183 is performed to check whether the test result calculated in the previous step 180 indicates that the RFID tag 10 is operating correctly at the first frequency F1. If the check in step 183 is positive, the sequence of steps 162, 172, and 182 described above is performed. If the system is operating correctly, the verification results from both steps 180 and 182 are expected to be the same or similar. When both emitters 10a and 10b emit simultaneously, a pulse wave is generated with a theoretically known beat frequency (|F1-F2|) and a predetermined amplitude and phase. If such a wave does not correspond to the theoretical superposition of signals emitted by the two emitters 10a and 10b, a negative verification result is issued in step 182.

[0060] Steps 118, 160, 170, 180, 183, 162, 172, and 182 may be performed after or in parallel with steps 117, 120, 130, 140, 150, 153, 122, 132, 142, and 152. For example, the sequence of steps 118, 160, 170, 180, 183, 162, 172, and 182 may be performed only after the positive test results have been obtained in steps 150 and 152.

[0061] After steps 152 and 182, steps 190 and 191 are performed as described with reference to Figure 4.

[0062] According to a first aspect of the present invention, A method (100) for determining the location of an RFID tag (10) within a monitoring area (S), Step (120) of emitting a reference signal (ST1) containing reference information from a reference RFID tag (11) at a predetermined reference position (P) within the monitoring area (S), Step (130) of receiving the reference signal (ST1) as multiple received reference signals (ST1'-ST1'''') in multiple receivers (21, 22, 23, 24), A step (140) to calculate the position of the reference RFID tag (11) according to the received reference signal (ST1'-ST1''''), To obtain the test results, the steps include: (150) comparing the calculated position of the reference RFID tag (11) with the predetermined reference position (P); Step (160) of emitting an operation signal (S1) from the RFID tag (10) that includes operation information associated with the RFID tag, Step (170) of receiving the operation signal (S1) as multiple received operation signals (S1'~S1'''') in multiple receivers (21, 22, 23, 24), To obtain the verification result, the process involves comparing the received operational information with predetermined verification information associated with the RFID tag (10) (180), Step (190) to calculate the position of the RFID tag based on or in accordance with the received operation signals (S1'~S1'''') according to the test results and / or verification results, and / or step (191) to emit a position signal indicating the position of the RFID tag 10 based on or in accordance with the received operation signals (S1'~S1''''), This provides a method that includes [something].

[0063] According to a second aspect of the present invention, the steps include sequentially stopping at least one receiver (21, 22, 23, 24) (115), The steps include: (140) calculating the position of the reference RFID tag according to the reference information received by the remaining receivers (21, 22, 23, 24); The present invention provides a method according to the first embodiment, including the following:

[0064] According to a third aspect of the present invention, the method of the first or second aspect is provided, wherein the test result indicates a positional deviation between the calculated position of the reference RFID tag and the predetermined reference position (P) and / or a previously calculated position.

[0065] A fourth aspect of the present invention provides a method according to the third aspect, wherein the step (150) of comparing the calculated position of the reference RFID tag (11) with the predetermined reference position (P) includes determining whether the positional deviation is less than or equal to a predetermined threshold.

[0066] According to a fifth aspect of the present invention, the method according to any one of the first to fourth aspects is provided, wherein the operation information and / or reference information includes an encryption key, identification information, or a timestamp.

[0067] According to a sixth aspect of the present invention, the method according to any one of the first to fifth aspects is provided, wherein the test results and / or verification results indicate compliance with a predetermined communication standard.

[0068] According to a seventh aspect of the present invention, the method is provided as described in any one of the first to sixth aspects, wherein the steps of comparing the received operation information with predetermined verification information associated with the RFID tag (10) (180), and / or calculating the position of the RFID tag based on or in accordance with the received operation signal (S1'-S1'''') (190), or emitting the position signal (191), are performed at each receiver (21, 22, 23, 24).

[0069] According to an eighth aspect of the present invention, the method is provided as described in any one of the first to seventh aspects, comprising the step (150) of comparing the received reference information with predetermined reference information associated with the reference RFID tag (11).

[0070] According to the ninth aspect of the present invention, the method is provided which, if the test result and / or verification result indicates an abnormal state of the RFID tag and / or the receiver, the step (180) of calculating the position of the RFID tag (10) is blocked, and / or, if the test result and / or verification result indicates an abnormal state of the RFID tag and / or the receiver, a safety signal is emitted instructing the machine associated with the monitoring area to be placed in safety mode.

[0071] According to a tenth aspect of the present invention, the emitted reference signal (ST1) has a first frequency (F1), The method further includes a step (122) of simultaneously emitting coupled reference signals (ST1, ST2) at the first and second frequencies (F1, F2); a step (132) of receiving the coupled reference signal (ST1) as a plurality of coupled received reference signals (ST1'-ST1'''';ST2'-ST2''''); and a step (142) of calculating the position of the reference RFID tag (11) according to the coupled received reference signals (ST1'-ST1''''), wherein the method provides a method according to any one of the first to nine embodiments.

[0072] According to the eleventh aspect of the present invention, the emitted operating signal (S1) has a first frequency (F1), The method further includes the steps of: (162) simultaneously emitting coupled operation signals (S1, S2) at a first frequency and a second frequency (F1, F2); (172) receiving the coupled operation signals (S1, S2) as a plurality of coupled received operation signals (S1'-S1''''; S2'-S2''''); and (182) comparing the received operation information with predetermined verification information associated with the coupled received operation signals (S1'-S1''''; S2'-S2'''') in order to obtain the verification result.

[0073] According to a twelfth aspect of the present invention, the present invention provides a method according to any one of the first to eleventh aspects, wherein at least one subset of the steps of the method is performed periodically according to a predetermined period.

[0074] According to a thirteenth aspect of the present invention, a location identification system (20) for identifying the location of an RFID tag (10) within a monitoring area (S), A reference RFID tag (11) that emits a reference signal (ST1) containing reference information, At least one RFID tag (10) that emits an operation signal (S1) including operation information associated with the RFID tag, Multiple receivers (21, 22, 23, 24) receive the aforementioned reference signal (ST1) as multiple received reference signals (ST1'-ST1'''') and the aforementioned operation signal (S1) as multiple received operation signals (S1'-S1''''), Equipped with a safety unit (15), The aforementioned safety unit (15) The position of the reference RFID tag (11) is calculated (140) according to the received reference signal (ST1'-ST1''''), To obtain the test results, the calculated position of the reference RFID tag (11) is compared with a predetermined reference position (P) (150), In order to obtain the verification result, the received operation information is compared (180) with predetermined verification information associated with the RFID tag (10), Based on the test results and / or verification results, the position of the RFID tag is calculated (190) based on or in accordance with the received operation signal (S1'-S1''''), and / or a position signal (191) indicating the position of the RFID tag is emitted based on or in accordance with the received operation signal (S1'-S1''''). We provide a location-finding system configured in such a way.

[0075] According to a fourteenth aspect of the present invention, the safety unit (15) is provided as part of the location identification system according to the thirteenth aspect, wherein the safety unit (15) is at least partially configured in one of the receivers (21, 22, 23, 24).

[0076] According to a 15th aspect of the present invention, a location identification system according to the 13th or 14th aspect is provided, further comprising a wearable worn by an operator entering a monitoring area (S), wherein the wearable comprises the RFID tag (10).

[0077] Although the present invention has been described according to preferred embodiments, it will be apparent to those skilled in the art that modifications are possible in all embodiments. It should be understood that the presented technology is not limited to the numerical values ​​and ranges mentioned, such as frequency and / or duration. [Explanation of Symbols]

[0078] 10 RFID tags 11 Standard RFID tags 20 Location tracking systems 21, 22, 23, 24 Receivers 100 ways 110, 111, 115, 117, 118, 120, 130 Method Steps 132, 140, 142, 150, 151, 152, 153 Method Steps 160, 162, 170, 172, 180, 182, 183 Method Steps 190,191 Method Steps F1, F2 frequencies S monitoring area ST1, ST2 Reference Signals ST1'-ST1'''';ST2'-ST2'''' Received reference signal S1,S2 operating signal S1'-S1''''; S2'-S2'''' Receive operation signal X,X1,Y,Y1,Z,Z1 coordinates XYZ coordinate system

Claims

1. A method (100) for identifying the location of an RFID tag (10) within a monitoring area (S), Step (120) of emitting a reference signal (ST1) containing reference information from a reference RFID tag (11) at a predetermined reference position (P) within the monitoring area (S), Step (130) of receiving the reference signal (ST1) as a plurality of received reference signals (ST1'-ST1'''') in multiple receivers (21, 22, 23, 24), The steps include: (140) calculating the position of the reference RFID tag (11) according to the received reference signal (ST1'-ST1''''), To obtain the test results, the steps include: comparing the calculated position of the reference RFID tag (11) with the predetermined reference position (P) (150); Step (160) of the RFID tag (10) to emit an operation signal (S1) which includes operation information associated with the RFID tag, which includes an encryption key, identification information, or a timestamp, Step (170) of receiving the operation signal (S1) as a plurality of received operation signals (S1' to S1'''') in multiple receivers (21, 22, 23, 24), To obtain the verification result, the steps include: comparing the received operation information associated with the RFID tag (10) with predetermined verification information associated with the RFID tag (10) (180); Includes, (a) stopping one of the plurality of receivers (21, 22, 23, 24) (115), (b) calculating the position of the reference RFID tag (11) according to the reference information received by the remaining receivers (21, 22, 23, 24) (140), and (c) comparing the calculated position of the reference RFID tag (11) with the predetermined reference position in order to obtain a test result, these steps are repeated sequentially for all of the plurality of receivers (21, 22, 23, 24). A method comprising the steps of: calculating the position of the RFID tag (10) based on or in accordance with the received operation signals (S1' to S1'''') and / or emitting a position signal indicating the position of the RFID tag (10) based on or in accordance with the received operation signals (S1' to S1''''), only if the test results and verification results indicate that the RFID tag (10) and the receivers (21, 22, 23, 24) are in a normal state (190); and / or emitting a position signal indicating the position of the RFID tag (10) based on or in accordance with the received operation signals (S1' to S1'''') (191).

2. The method according to claim 1, wherein the test results indicate a positional deviation between the calculated position of the reference RFID tag and the predetermined reference position (P) and / or a previously calculated position.

3. The method according to claim 2, wherein the step (150) of comparing the calculated position of the reference RFID tag (11) with the predetermined reference position (P) includes determining whether the positional deviation is less than or equal to a predetermined threshold.

4. The method according to claim 1 or 2, wherein the reference information includes an encryption key, identification information, or a timestamp.

5. The method according to claim 1 or 2, wherein the test results and / or verification results indicate compliance with a predetermined communication standard.

6. The method according to claim 1 or 2, wherein the steps of comparing the received operation information with predetermined verification information associated with the RFID tag (10) (180), and / or calculating the position of the RFID tag based on or in accordance with the received operation signal (S1'-S1'''') (190), or emitting the position signal (191), are performed at each receiver (21, 22, 23, 24).

7. The method according to claim 1 or 2, further comprising the step (150) of comparing the received reference information with predetermined reference information associated with the reference RFID tag (11).

8. The method according to claim 1 or 2, wherein if the test result and / or verification result indicates an abnormal state of the RFID tag and / or the receiver, the step (180) of calculating the position of the RFID tag (10) is blocked, and / or if the test result and / or verification result indicates an abnormal state of the RFID tag and / or the receiver, a safety signal is emitted instructing the machine associated with the monitoring area to be placed in safety mode.

9. The emitted reference signal (ST1) has a first frequency (F1), The method according to claim 1 or 2, further comprising the steps of: (122) simultaneously emitting combined reference signals (ST1, ST2) at the first and second frequencies (F1, F2); (132) receiving the combined reference signal (ST1) as a plurality of combined received reference signals (ST1'-ST1''''; ST2'-ST2''''); and (142) calculating the position of the reference RFID tag (11) according to the combined received reference signals (ST1'-ST1'''').

10. The emitted operating signal (S1) has a first frequency (F1), The method according to claim 1 or 2, further comprising the steps of: (162) simultaneously emitting coupled operation signals (S1, S2) at a first frequency and a second frequency (F1, F2); (172) receiving the coupled operation signals (S1, S2) as a plurality of coupled received operation signals (S1'-S1''''; S2'-S2''''); and (182) comparing the received operation information with predetermined verification information associated with the coupled received operation signals (S1'-S1''''; S2'-S2'''') in order to obtain the verification result.

11. The method according to claim 1 or 2, wherein at least one subset of the steps of the method is performed periodically according to a predetermined period.

12. A location identification system (20) for identifying the location of an RFID tag (10) within a monitoring area (S), A reference RFID tag (11) that emits a reference signal (ST1) containing reference information, At least one RFID tag (10) that emits an operation signal (S1) which includes operation information associated with the RFID tag, which includes an encryption key, identification information, or a timestamp, Multiple receivers (21, 22, 23, 24) receive the aforementioned reference signal (ST1) as a plurality of received reference signals (ST1'-ST1'''') and the aforementioned operation signal (S1) as a plurality of received operation signals (S1'-S1''''), A safety unit (15) is provided, The safety unit (15) is The position of the reference RFID tag (11) is calculated (140) according to the received reference signal (ST1'-ST1''''), To obtain the test results, the calculated position of the reference RFID tag (11) is compared with a predetermined reference position (P) (150), In order to obtain the verification result, the received operation information associated with the RFID tag (10) is compared (180) with predetermined verification information associated with the RFID tag (10), (a) stopping one of the plurality of receivers (21, 22, 23, 24) (115), (b) calculating the position of the reference RFID tag (11) according to the reference information received by the remaining receivers (21, 22, 23, 24) (140), and (c) comparing the calculated position of the reference RFID tag (11) with the predetermined reference position in order to obtain a test result, these steps are repeated sequentially for all of the plurality of receivers (21, 22, 23, 24). Only if the test results and verification results indicate that the RFID tag (10) and the receivers (21, 22, 23, 24) are in a normal state, the position of the RFID tag is calculated (190) based on or in accordance with the received operation signal (S1'-S1''''), and / or a position signal (191) indicating the position of the RFID tag is emitted based on or in accordance with the received operation signal (S1'-S1''''). A location-finding system configured in such a way.

13. The location identification system according to claim 12, wherein the safety unit (15) is at least partially configured in any of the receivers (21, 22, 23, 24).

14. The location identification system according to claim 12 or 13, further comprising a wearable device worn by an operator entering a monitoring area (S), wherein the wearable device comprises the RFID tag (10).

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