Positioning system and positioning method

Abstract

The anchor device transmits the first and second search waves, while changing the height at which the augmented composite wave is generated, so that the first and second search waves interfere with each other around the height of the tag device (300) to generate an augmented composite wave. The tag device (300) detects the reception of the augmented composite wave and transmits a response signal containing the reception information. Based on the reception information contained in the response signal received from the tag device (300), the anchor device selects a height to match the height of the tag device (300).

Description

Technical Field

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[0001] The present disclosure relates to a positioning system and a positioning method using a search wave.

Background Art

[0002] As a technology used for positioning objects, people, etc., there is a Real Time Location System (RTLS) (see, for example, Patent Document 1). RTLS is a technology that can identify and track objects in real time or at a processing speed equivalent to real time within a specified area, and is used in environments where GPS signals cannot be used, such as warehouses, hospitals, factories, and airports.

[0003] In RTLS, within a specified area, a plurality of anchor devices having their own installation coordinates are installed in a fixed state on ceilings, walls, etc. Also, a tag device is attached to a moving object.

[0004] The principle of positioning is that signals such as radio waves and ultrasonic waves transmitted from a tag device are received by a plurality of spatially distributed anchor devices, and based on the time of reception (arrival time) of the signals by each anchor device and the difference thereof (TDoA: Time Difference of Arrival), etc., the three-dimensional position of the tag device is measured.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] <000003In conventional RTLS systems, anchor devices are installed at a higher elevation than tag devices. In particular, the accuracy of height measurement from the floor surface tends to be significantly reduced because it is susceptible to reflected waves generated by the floor and objects placed on the floor surface.

[0007] Therefore, countermeasures such as installing additional anchoring equipment or attaching external sensors to tagging equipment were necessary, leading to system complexity and increased costs. This disclosure was devised to solve the above problems. [Means for solving the problem]

[0009] The anchor device transmits a first search wave and a second search wave to generate a combined wave. The tag device detects the combined wave and transmits a response signal containing the received information. The anchor device sets the height of the tag device to the height of the combined wave corresponding to the received information contained in the response signal received from the tag device. [Effects of the Invention]

[0010] This disclosure describes a method for accurately measuring the height of tag devices using existing anchor and tag devices. in Yes, it does. Therefore, the accuracy of height measurement for tag devices is improved without the need to install additional correction equipment. [Brief explanation of the drawing]

[0011] [Figure 1] Block diagram showing an example of the main configuration of the main anchor device and tag device of the positioning system in Embodiment 1. [Figure 2] An explanatory diagram showing an example of the main configuration of the positioning system in Figure 1 of Embodiment 1. [Figure 3] An explanatory diagram showing an example of the positioning method used in this disclosure. [Figure 4] Block diagram showing an example of the main configuration of the main anchor device and sub-anchor device of the positioning system in Embodiment 1. [Figure 5]Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 4 of Embodiment 1 [Figure 6] Block diagram showing an example of the main configuration of the server and sub-anchor devices of the positioning system in Embodiment 1 [Figure 7] Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 6 of Embodiment 1 [Figure 8] Block diagram showing an example of the main configuration of the server and two sub-anchor devices of the positioning system in Embodiment 2 [Figure 9] Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 8 of Embodiment 2 [Figure 10] Block diagram showing an example of the main configuration of the main anchor device and two sub-anchor devices of the positioning system in Embodiment 2 [Figure 11] Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 10 of Embodiment 2 [Figure 12] Block diagram showing an example of the main configuration of two main anchor devices and sub-anchor devices of the positioning system in Embodiment 2 [Figure 13] Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 12 of Embodiment 2 [Figure 14] Block diagram showing an example of the main configuration of the server, sub-anchor device, and tag device of the positioning system in Embodiment 2 [Figure 15] Explanatory diagram showing an example of the main configuration of the positioning system in FIG. 14 of Embodiment 2

Mode for Carrying Out the Invention

[0012] Embodiment 1. The overall configuration of the positioning system in Embodiment 1 will be described with reference to FIG. 1.

[0013] The positioning system 100 is composed of a main anchor device 200 and a tag device 300, and the main anchor device 200 and the tag device 300 are time-synchronized.

[0014] The main anchor device 200 is composed of a second signal control unit 21, a second signal transmission unit 22, a second reception unit 23, a height determination unit 24, and a data storage unit 25.

[0015] A plurality of main anchor devices 200 are arranged at intervals, for example, arranged vertically and horizontally at an interval of 20 m. In Embodiment 1, one of them is taken out as a representative for explanation.

[0016] The tag device 300 is composed of a first reception unit 31, a first signal control unit 32, and a first signal transmission unit 33.

[0017] The second signal transmission unit 22 transmits a first search wave and a second search wave.

[0018] The emphasized composite wave in Embodiment 1 is a composite wave in which the first search wave and the second search wave have higher signal intensities than the first search wave and the second search wave due to the interference between the reflected wave of the first search wave reflected by the floor surface and the second search wave.

[0019] As the search wave, a UWB signal having a center frequency of about 7.9 GHz in channel 9 determined by IEEE 802.15.4 can be used.

[0020] Note that the main anchor device 200 may be calibrated during installation and configured to adjust information such as the installation position according to the installation environment.

[0021] The second signal control unit 21 determines the conditions of the search wave transmitted by the second signal transmission unit 22.

[0022] The second reception unit 23 receives a response signal transmitted from the tag device 300.

[0023] The height determination unit 24 determines the height of the tag device 300 based on the response signal received from the tag device 300.

[0024] The data storage unit 25 stores the position of the tag device 300 in the XYZ three-dimensional space obtained using RTLS, the estimated time when the enhanced composite wave calculated by the second signal control unit 21 is generated, and the ID information of each tag device 300.

[0025] The first receiving unit 31 receives the enhanced composite wave.

[0026] The first signal control unit 32 analyzes the received enhanced composite wave and transmits the result to the first signal transmission unit.

[0027] The first signal transmission unit 33 generates a response signal based on the analysis results of the first signal control unit 32 and transmits it to the outside of the tag device 300.

[0028] Furthermore, in transmitting and receiving signals, the second signal transmitting unit 22 and the second receiving unit 23 of the main anchor device 200, and the first receiving unit 31 and the first signal transmitting unit 33 of the tag device 300, can each use the same antennas as those used in conventional RTLS, and no additional hardware is required.

[0029] In Embodiment 1, the reception time at which the tagging device 300 received the enhanced composite wave is used as the reception information, and the estimated time at which the main anchoring device 200 estimated the time at which the enhanced composite wave was generated based on the conditions of the first search wave and the second search wave is used as the specific information.

[0030] The operation of the positioning system 100 configured as described above will now be explained.

[0031] The positioning system in this disclosure, like conventional RTLS, uses positioning technologies such as TDoA to measure the position of the tag device 300 in the XYZ three-dimensional space and stores it in the data storage unit 25.

[0032] In Embodiment 1, the first and second search waves are reflected at the reflection point 41 directly below the main anchor device 200 shown in Figure 2, and the reflected waves propagate from the reflection point 41 toward the main anchor device 200.

[0033] The tagging device 300 can receive the enhanced composite wave within the range of the cylindrical correction area 40 shown in Figure 2, and the radius of the correction area 40 is, for example, 7.5 cm. This is the range set for the tagging device 300 to receive the enhanced composite wave when using UWB as defined in the aforementioned standard, and it may vary depending on the installation environment of the main anchor device 200 and the conditions of the signal used as the search wave.

[0034] If the tag device 300 is outside the correction area 40, the main anchor device 200 constantly acquires and updates the coordinates (Xi, Yi, Zi) of the tag device 300 in the XYZ three-dimensional space obtained using RTLS.

[0035] The main anchor device 200 starts height correction if the location of the tag device 300 it is monitoring is within the correction area 40.

[0036] Figure 3 illustrates the positioning method in this disclosure. (a) shows the step of transmitting a first search wave and a second search wave, (b) shows the step of receiving a combined wave and transmitting a response signal, and (c) shows the step of receiving the response signal and correcting the height of the tag device 300.

[0037] In step S11, the second signal control unit 21 determines n heights L1, L2~Ln for generating the enhanced composite wave. The heights L1, L2~Ln are determined based on the height Zi of the tag device 300 acquired using RTLS.

[0038] In step S12, the second signal control unit 21 selects one of n heights L1, L2 to Ln for generating a reinforced composite wave, calculates the conditions for the first search wave, the conditions for the second search wave, and the elapsed time at the selected height Li, and generates a trigger command that includes the conditions for the first search wave and the conditions for the second search wave.

[0039] The conditions for the first and second search waves include waveform (single pulse waveform, biporous waveform, etc.), frequency, and phase.

[0040] The conditions for the second search wave also include a time difference between the transmission of the first search wave and the transmission of the second search wave.

[0041] The elapsed time is the time from when the first search wave is transmitted until the amplified composite wave is generated.

[0042] In step S13, the second signal control unit 21 transmits the trigger command generated in step S12 to the second signal transmission unit 22.

[0043] In step S14, the second signal transmission unit 22 generates and transmits the first search wave according to the conditions included in the trigger command received from the second signal control unit 21.

[0044] In step S15, the second signal transmission unit 22 transmits the transmission time, which is the time when the first search wave was transmitted, to the second signal control unit 21.

[0045] In step S16, the second signal control unit 21 calculates an estimated time at which a reinforced composite wave is estimated to be generated by adding the elapsed time to the transmission time received from the second signal transmission unit 22, and writes the pair of estimated time and height Li to the data storage unit 25.

[0046] In step S17, the second signal transmission unit 22 generates a second search wave according to the conditions included in the trigger command received from the second signal control unit 21 and transmits it after the difference time has elapsed.

[0047] In step S18, if the main anchor device 200 receives a response signal from the tag device 300, it terminates the transmission of the search wave; otherwise, it proceeds to step S19.

[0048] In step S19, the second signal control unit 21 determines whether it has transmitted search waves corresponding to all n heights L1, L2 to Ln determined in step S11. If it has transmitted for all heights, it terminates the transmission of search waves; otherwise, it returns to step S12.

[0049] Thus, the main anchor device 200 repeatedly performs the operations from step S12 to step S17, changing the height Li, until it receives a response signal from the tag device 300 or has finished transmitting search waves corresponding to all n heights L1, L2 to Ln.

[0050] After step S14, the first search wave is reflected from the floor, and the reflected wave propagates from the floor towards the main anchor equipment 200, interfering with the second search wave transmitted in step S16 at height Li within the correction area 40 to generate a combined wave.

[0051] In step S21, the first receiving unit 31 of the tagging device 300 receives a search wave, and the first signal control unit 32 measures the signal strength of the search wave and assigns a timestamp.

[0052] In step S22, if the signal intensity of the search wave is lower than the previous value, the first signal control unit 32 determines that a peak value has been detected and proceeds to step S23. If the signal intensity is higher than the previous value, it returns to step S21.

[0053] In step S23, the first signal control unit 32 determines whether the peak value measured in step S22 exceeds the reference value. If it does, the unit proceeds to step S24. The reference value is a value used to determine whether it is a composite wave and is determined in advance through experimentation or simulation.

[0054] If the peak value does not exceed the reference value, return to step S21.

[0055] In step S24, the first signal control unit 32 sets the timestamp attached to the signal intensity that it has determined to be a composite wave as the reception time when the composite wave was received.

[0056] In step S25, the first signal control unit 32 generates a trigger command including the reception time and ID information of the tag device 300 determined in step S24 and transmits it to the first signal transmission unit 33.

[0057] In step S26, the first signal transmission unit 33 generates and transmits a response signal that includes the reception time and ID information of the tag device 300, which are included in the trigger command.

[0058] In step S31, the second receiving unit 23 of the main anchor device 200 receives a response signal from the tag device 300 and transmits the reception time and the ID information of the tag device 300 included in the response signal to the height determination unit 24.

[0059] In step S32, the height determination unit 24 refers to the pairs of estimated time and height Li in the data storage unit 25 and selects the one that matches the reception time from among the estimated times. Here, the matching time is the time closest to the reception time among the estimated times. Other methods may also be used to determine the match.

[0060] In step S33, the height determination unit 24 writes the height Li corresponding to the selected estimated time to the data storage unit 25 as the height of the ID information tag device 300 received from the second receiving unit 23.

[0061] As described above, the positioning system 100, configured using the main anchor device 200 and the tag device 300, has the effect of improving the measurement accuracy of the tag device 300's height without installing additional equipment for height correction. This is achieved by having the main anchor device 200 repeatedly generate augmented composite waves while changing the height Li, and after the tag device 300 receives the augmented composite wave, it transmits the reception time to the main anchor device 200, and the main anchor device 200 select an estimated time that matches the reception time and stores the corresponding height Li as the corrected height of the tag device 300.

[0062] In Embodiment 1, an example was shown in which the main anchor device 200 includes a second signal control unit 21, a height determination unit 24, and a data storage unit 25. However, the main anchor device 200 does not necessarily have to include some or all of these functions.

[0063] For example, the positioning system 110 may consist of a main anchor device 210, a sub-anchor device 220, and a tag device 300, as shown in Figures 4 and 5.

[0064] The main anchor device 210 includes a second signal control unit 21, a second signal transmission unit 22, a second reception unit 23, a height determination unit 24, and a data storage unit 25, while the sub-anchor device 220 includes a second signal transmission unit 22A and a second reception unit 23A.

[0065] Furthermore, the main anchor device 210, the sub-anchor device 220, and the tag device 300 are assumed to be time-synchronized.

[0066] Below the main anchor device 210 is a correction area 40 similar to that of the main anchor device 200, and below the sub-anchor device 220 is another correction area 40A.

[0067] When the sub-anchor device 220 generates amplified composite waves in the correction area 40A, its operation is the same as that of the main anchor device 200, except that communication between the second signal control unit 21 and the second signal transmission unit 22A, and between the height determination unit 24 and the second receiving unit 23A, is conducted via the network 50.

[0068] When the main anchor device 210 generates amplified composite waves in the correction area 40, its operation will be the same as that of the main anchor device 200.

[0069] The positioning system 110 configured as described above integrates the functions of the second signal control unit 21 and the height determination unit 24 into a single main anchor device 210, and connects to multiple sub-anchor devices 220 via a network 50, thereby simplifying the configuration of most anchor devices.

[0070] For large-scale positioning systems, it may be possible to set up a separate server to manage the entire positioning system.

[0071] For example, the positioning system 120 consists of a server 400, a sub-anchor device 220, and a tag device 300, as shown in Figures 6 and 7.

[0072] Furthermore, it is assumed that server 400, sub-anchor device 220, and tag device 300 are time-synchronized.

[0073] The server 400 includes a second signal control unit 21, a height determination unit 24, and a data storage unit 25. The server 400 is connected to multiple sub-anchor devices 220 by a network 50.

[0074] By having the server 400 perform the same role as the main anchor device 210, it becomes possible to configure the system with simple anchor devices, even in the case of large-scale positioning systems.

[0075] Embodiment 2. The overall configuration of the positioning system 130 in Embodiment 2 will be explained with reference to Figures 8 and 9.

[0076] However, the same parts as in Embodiment 1 will not be described.

[0077] The positioning system 130 consists of a server 400, sub-anchor devices 220A, sub-anchor devices 220B, and tag devices 300.

[0078] Server 400, sub-anchor device 220A, sub-anchor device 220B, and tag device 300 are assumed to be time-synchronized.

[0079] Multiple sub-anchor devices are arranged, similar to the main anchor device 200 in Embodiment 1. In Embodiment 2, sub-anchor devices 220A and 220B will be selected as representative examples and described.

[0080] The server 400 consists of a second signal control unit 21, a height determination unit 24, and a data storage unit 25.

[0081] Sub-anchor device 220A consists of a second signal transmitting unit 22A and a second receiving unit 23A, and sub-anchor device 220B consists of a second signal transmitting unit 22B and a second receiving unit 23B, which have similar functions. The second signal transmitting units 22A and 22B have the same functions as the second signal transmitting unit 22 of the main anchor device 200, and the second receiving unit 23A and 23B have the same functions as the second receiving unit 23 of the main anchor device 200.

[0082] The tag device 300 has the same configuration as in Embodiment 1.

[0083] Server 400 and sub-anchor devices 220A and 220B are connected via network 50.

[0084] Server 400 constantly acquires and updates the coordinates (Xi, Yi, Zi) of the tag device 300 in the XYZ three-dimensional space, obtained using RTLS.

[0085] The server 400 can start height correction at any time, and height correction is possible even if the tag device 300 is outside the correction area 40.

[0086] When starting height correction, the server 400 selects sub-anchor devices 220A and 220B. The selected sub-anchor devices are two sub-anchor devices close to the tag device 300, determined from the XY coordinates (Xi, Yi) of the tag device 300. Other means may be used to select the sub-anchor devices.

[0087] The second signal transmitters 22A and 22B transmit either the first search wave or the second search wave. For example, the sub-anchor device closer to the tag device 300 transmits the first search wave, and the other sub-anchor device transmits the second search wave. Here, we will describe an example in which the second signal transmitter 22A transmits the first search wave and the second signal transmitter 22B transmits the second search wave.

[0088] In Embodiment 2, the enhanced composite wave is a composite wave in which the signal strength is higher than that of the first and second search waves due to interference between the direct waves of the first and second search waves.

[0089] The response signal only needs to be received by either sub-anchor device 220A or sub-anchor device 220B; in this explanation, we will assume that sub-anchor device 220A receives the signal.

[0090] In Embodiment 2, the received information is the reception time at which the tag device 300 received the enhanced composite wave, and the specific information is the estimated time at which the server 400 estimated the time at which the enhanced composite wave was generated based on the conditions of the first search wave and the second search wave.

[0091] The operation of the positioning system 130 configured as described above will now be explained.

[0092] In step S11, the second signal control unit 21 determines n heights L1, L2~Ln for generating the enhanced composite wave. The heights L1, L2~Ln are determined based on the approximate height of the tag device 300 acquired using RTLS.

[0093] Step S11 is the same as in Embodiment 1, except that a reinforced composite wave is generated at a position (Xi, Yi) not limited to the correction area 40. In Embodiment 1, the conditions for generating a reinforced composite wave by interference between the reflected waves of the first search wave and the second search wave were sought at a specified height Li within the correction area 40 below the main anchor device 200. In Embodiment 2, however, the conditions for generating a reinforced composite wave by interference between the direct waves of the first search wave and the second search wave are sought at a specified height Li at a position (Xi, Yi) not limited to the correction area 40.

[0094] In step S12, the second signal control unit 21 operates in the same manner as in Embodiment 1, but generates a first trigger command that includes the conditions for the first search wave and a second trigger command that includes the conditions for the second search wave.

[0095] Furthermore, the conditions for the first and second search waves include the same conditions as in Embodiment 1, plus the transmission time of the first search wave.

[0096] In step S13, the second signal control unit 21 transmits the first trigger command created in step S12 to the second signal transmission unit 22A via the network 50, and transmits the second trigger command to the second signal transmission unit 22B via the network 50.

[0097] In step S14, the second signal transmission unit 22A generates a first search wave according to the conditions included in the first trigger command received from the second signal control unit 21 and transmits it at the transmission time of the first search wave specified in the first trigger command.

[0098] In Embodiment 1, in step S15, the second signal transmission unit 22 transmits the transmission time of the first search wave to the second signal control unit 21. However, in Embodiment 2, step S15 is not performed. In step S16, the second signal control unit 21 adds the elapsed time to the transmission time of the first search wave to calculate the estimated time at which the enhanced composite wave is estimated to be generated, and writes the pair of the estimated time and height Li to the data storage unit 25.

[0099] In step S17, the second signal transmission unit 22B generates a second search wave according to the conditions included in the second trigger command received from the second signal control unit 21, and transmits it at a time after the elapsed time from the transmission time of the first search wave specified in the second trigger command.

[0100] In step S18, if the server 400 receives a response signal from the tag device 300 via the sub-anchor device 220A, it terminates the transmission of the search wave; otherwise, it proceeds to step S19.

[0101] In step S19, the second signal control unit 21 operates in the same manner as in step S19 in the first embodiment.

[0102] Thus, the server 400, sub-anchor devices 220A and 220B repeatedly perform the operations of steps S12, S13, S14, S16, and S17, changing the height Li, until they receive a response signal from the tag device 300 or have finished transmitting search waves corresponding to all n heights L1, L2~Ln.

[0103] After step S17, the first search wave and the second search wave interfere at height Li, generating a combined wave.

[0104] The steps from when the tag device 300 receives the enhanced composite wave to when it transmits the response signal are the same as steps S21 to S26 of Embodiment 1.

[0105] In step S31, the second receiving unit 23A receives a response signal from the tag device 300 and transmits the reception time and ID information of the tag device 300 included in the response signal to the height determination unit 24 of the server 400 via the network 50.

[0106] In step S32, the height determination unit 24 operates in the same manner as in Embodiment 1.

[0107] In step S33, the height determination unit 24 writes the height Li corresponding to the selected estimated time to the data storage unit 25 as the height of the ID information tag device 300 received from the second receiving unit 23.

[0108] As described above, the positioning system 130, configured using the server 400, sub-anchor device 220A, sub-anchor device 220B, and tag device 300, repeatedly generates augmented composite waves while changing the height Li through the operation of two different sub-anchor devices 220A and 220B. After the tag device 300 receives the augmented composite wave, it transmits the response time to the sub-anchor devices 220A and 220B, and the server 400 selects an estimated time that matches the reception time and stores the corresponding height Zi as the corrected height of the tag device 300. Therefore, it has the effect of improving the measurement accuracy of the height of the tag device 300 even outside the correction area 40 without installing any additional equipment.

[0109] In Embodiment 2, an example was shown in which the server 400 is equipped with a second signal control unit 21, a height determination unit 24, and a data storage unit 25. However, these functions may be provided by the main anchor device instead of the server 400.

[0110] For example, the positioning system 140 consists of a main anchor device 210, a sub-anchor device 220A, a sub-anchor device 220B, and a tag device 300, as shown in Figures 10 and 11.

[0111] The positioning system 140 consists of a single main anchor device and multiple sub-anchor devices, but here we will use the main anchor device 210 and two sub-anchor devices 220A and 220B as representative examples.

[0112] The main anchor device 210 has the same configuration and functions as the server 400 described above and is connected to the sub-anchor devices 220A and 220B via network 50.

[0113] Furthermore, as shown in Figures 12 and 13, the main anchor device may also perform the role of one of the sub-anchor devices. In this case, the second signal transmitter 22 and second receiver 23 of the main anchor device 210 can be used instead of the second signal transmitter 22A and second receiver 23A of the sub-anchor device 220A in Figures 10 and 11, and the device can operate similarly.

[0114] In the positioning system 140 configured as described above, the main anchor device 210 performs the same role as the server 400, eliminating the need for a separate server and thus reducing costs.

[0115] Furthermore, the positioning system of Embodiment 2 may be configured such that the main anchor device 200 of Embodiment 1 is connected via a network 50. In this case, it is equivalent to being composed of multiple main anchor devices, with one of the two main anchor devices having control rights, and the main anchor device that does not have control rights performing an operation equivalent to that of a sub-anchor device.

[0116] In this case, the configuration is similar to the example described above, which consists of a main anchor device and multiple sub-anchor devices, where one of the two sub-anchor devices is the main anchor device.

[0117] The positioning system 150 configured as described above can ensure redundancy by distributing the load on the system through the use of multiple main anchor devices.

[0118] The positioning system of Embodiment 2 may be configured by using a stopped tag device 300A in place of a sub-anchor device. For example, the positioning system 160 consists of a server 400, a sub-anchor device 220A, a tag device 300A, and a tag device 300, as shown in Figures 14 and 15.

[0119] The tag device 300A is connected to the server 400 via the network 50, and the first signal transmission unit 33A and the first receiver unit 31A of the tag device 300A are used instead of the second signal transmission unit 22B and the second receiver unit 23B of the sub-anchor device 220B shown in Figures 8 and 9, thereby enabling the tag device 300A to perform the operations of the sub-anchor device 220B.

[0120] It is also possible to use the main anchor device 210 instead of server 400.

[0121] The positioning system 160 configured as described above improves measurement accuracy because, compared to a configuration that uses only a main anchor device and a sub-anchor device for transmitting search waves, the arrangement of the devices transmitting search waves can be expanded from a two-dimensional arrangement in the XY plane to a three-dimensional arrangement in the XYZ space including the height direction.

[0122] In Embodiments 1 and 2, the second signal control unit 21 was shown to determine the conditions for the first search wave, the conditions for the second search wave, and the elapsed time for generating a reinforced composite wave at height Li by calculation each time. However, these conditions may be managed using a table.

[0123] In this case, the conditions for the first search wave, the conditions for the second search wave, and the elapsed time are stored in a table in the data storage unit 25, corresponding to each of the multiple expected heights.

[0124] The table may be created to reflect the calibration adjustment results during the calibration process.

[0125] When the second signal control unit 21 determines the height Li, it reads the search wave conditions and elapsed time corresponding to the height Li from the table stored in the data storage unit 25, sends a trigger command that includes the search wave conditions, and calculates the estimated time by adding the elapsed time to the transmission time.

[0126] In this way, by pre-determining the conditions for the first search wave, the conditions for the second search wave, and the elapsed time for generating augmented composite waves at multiple anticipated heights, and managing them in a table, the calculation time in the second signal control unit 21 can be shortened, enabling high-speed positioning.

[0127] In Embodiments 1 and 2, examples were shown in which the tagging device 300 determines that the received search wave is a composite wave based on its signal strength; however, other means may also be used.

[0128] For example, there is a method to determine a composite wave by analyzing its frequency components.

[0129] In this case, the tag device 300 samples the external signal and then calculates the frequency spectrum using the Fast Fourier Transform. It calculates the peak or integral value of the power spectral density in the frequency band to be measured, and determines that a composite wave has been received if it exceeds a predetermined threshold. The frequency band to be monitored and the threshold are determined in advance through experimentation or simulation and stored in the tag device 300.

[0130] By analyzing and evaluating the frequency components in this way, it becomes possible to determine the amplified composite wave with greater accuracy.

[0131] In determining whether a frequency band is an amplified composite wave, other means besides comparing the peak value or integral value with a threshold may be used.

[0132] In Embodiments 1 and 2, the height of the tag device 300 was determined by using the reception time as the reception information for the augmented composite wave and the estimated time as the identification information for the augmented composite wave. However, other information may also be used. For example, one method uses the reception frequency component as the reception information and the frequencies of the first and second search waves as the identification information.

[0133] In this case, the main anchor device, sub-anchor device, and the stopped tag device transmit a first search wave and a second search wave of different frequencies. The frequencies of the first and second search waves will be a different combination for each height L1, L2 to Ln.

[0134] The tagging device 300 uses the same method as in paragraph 0130 to determine multiple peak values ​​in the frequency band of the external signal. The tagging device 300 transmits the received frequency components, which are the frequency components corresponding to the multiple peak values, and ID information as received information.

[0135] The main anchor device and the server store multiple sets of frequencies for the first and second search waves and their corresponding heights Ln, and determine whether the received frequency component matches the frequencies of the first and second search waves. If they match, the height Li corresponding to the combination of frequencies for the first and second search waves is stored in the data storage unit 25 as the height of the tag device 300.

[0136] The condition for this to be met is that the frequencies of the first and second search waves and the frequencies of the peak values ​​included in the received frequency component are within a predetermined tolerance range. The tolerance range is determined in advance through experimentation or simulation.

[0137] By using the received frequency components, the first search wave, and the second search wave in this way, high-precision positioning becomes possible even when the main anchor device, sub-anchor device, server, or stopped tag device is not time-synchronized with the tag device 300.

[0138] Embodiments 1 and 2 show examples where specific information is used, but specific information is not required. For example, if the time it takes for the specified height to change is sufficiently long compared to the response time from the tag device 300, the height of the tag device 300 may be determined to be the latest specified height at the time the main anchor device and the server receive the response signal from the tag device 300.

[0139] The above embodiment is an example of the present disclosure, and it is possible to modify some of the components as appropriate without departing from the spirit of the present disclosure. [Explanation of Symbols]

[0140] 21 21A Second signal control unit, 22 22A 22B Second signal transmission unit, 23 23A 23B Second reception unit, 24 24A Height determination unit, 25 25A Data storage unit, 31 31A First receiving unit, 32 32A First signal control unit, 33 33A First signal transmitting unit, 40 40A correction area, 41 reflection points, 50 networks, 100 110 120 positioning system, 200 210 210A Main anchor equipment, 220 220A 220B Sub-anchor equipment, 300 300A tagging equipment, 400 servers

Claims

1. The first receiving unit, If the signal received by the first receiving unit is a composite wave generated by the interference of a first search wave and a second search wave, the first signal control unit transmits a trigger command including information on the reception of the composite wave. A first signal transmission unit receives the trigger command and transmits a response signal including the received information, A tag device having, A second signal control unit transmits a trigger command including conditions for the first search wave and the second search wave for generating the enhanced composite wave at a specified height, A second signal transmitting unit that transmits the first search wave and the second search wave in accordance with the above conditions, A second receiving unit that receives the aforementioned response signal, A height determination unit determines the specified height as the height of the tag device based on the received information contained in the response signal received by the second receiving unit, Main anchor equipment having, A positioning system equipped with [the following features].

2. The first receiving unit, If the signal received by the first receiving unit is a composite wave generated by the interference of a first search wave and a second search wave, the first signal control unit transmits a trigger command including information on the reception of the composite wave. A first signal transmission unit receives the trigger command and transmits a response signal including the received information, A tag device having, A second signal control unit transmits a trigger command including conditions for the first search wave and the second search wave for generating the enhanced composite wave at a specified height, Height determination unit, Main anchor equipment having, A second receiving unit that receives the aforementioned response signal, A second signal transmitting unit that transmits the first search wave and the second search wave, Sub-anchor equipment having, Equipped with, The height determination unit determines the specified height as the height of the tag device based on the received information included in the response signal received by the second receiving unit. Positioning system.

3. The first receiving unit, If the signal received by the first receiving unit is a composite wave generated by the interference of a first search wave and a second search wave, the first signal control unit transmits a trigger command including information on the reception of the composite wave. A first signal transmission unit receives the trigger command and transmits a response signal including the received information, A tag device having, A second signal control unit transmits a trigger command including conditions for the first search wave and the second search wave for generating the enhanced composite wave at a specified height, Height determination unit, A server having, A second receiving unit that receives the aforementioned response signal, A second signal transmitting unit that transmits the first search wave and the second search wave, Sub-anchor equipment having, Equipped with, The height determination unit determines the specified height as the height of the tag device based on the received information included in the response signal received by the second receiving unit. Positioning system.

4. The height determination unit determines the height to be the height of the tag device when the specific information corresponding to the specified height matches the received information. A positioning system according to any one of claims 1 to 3.

5. The first signal transmitting unit transmits the reception time of the enhanced composite wave as the reception information. The aforementioned specific information is the estimated time at which the enhanced composite wave occurs. When the height determination unit determines that the specified height is the height of the tag device, the estimated time, which is the specific information, matches the reception time. The positioning system according to claim 4.

6. It is equipped with another main anchor device having a second signal transmitting unit, The second search wave is transmitted by the other second signal transmitting unit instead of the second signal transmitting unit. The positioning system according to claim 1.

7. The aforementioned main anchor device has another second signal transmitting unit, The first search wave is transmitted by the other second signal transmitting unit instead of the second signal transmitting unit. The positioning system according to claim 2.

8. It is equipped with other sub-anchor equipment having a second signal transmitting unit, The second search wave is transmitted by the other second signal transmitting unit instead of the second signal transmitting unit. The positioning system according to claim 2 or 3.

9. Equipped with other tagging devices, The second search wave is transmitted by the first signal transmitting unit of the other tag device, instead of the other second signal transmitting unit. The positioning system according to any one of claims 6 to 7.

10. The conditions for the first search wave and the second search wave are determined by the second signal control unit by reading them from a table stored in the data storage unit. A positioning system according to any one of claims 1 to 3.

11. The first signal control unit determines whether the signal received by the first receiving unit is a composite wave by comparing the signal strength of the signal with a reference value. A positioning system according to any one of claims 1 to 3.

12. The first signal control unit determines whether the signal received by the first receiving unit is a composite wave by analyzing the frequency components of the signal and evaluating the results of the analysis. A positioning system according to any one of claims 1 to 3.

13. A condition determination step in which the second signal control unit determines the conditions for the first search wave and the second search wave so that a reinforced composite wave is generated by mutual interference at a specified height, A first transmission step in which a second signal transmission unit transmits the first search wave based on the conditions determined in the condition determination step, A second transmission step in which the second signal transmission unit transmits the second search wave based on the conditions determined in the condition determination step, The first receiving unit receives the enhanced combined wave in an enhanced combined wave receiving step, The first signal transmission unit transmits a response signal that includes reception information of the enhanced composite wave received in the enhanced composite wave reception step, A response signal receiving step in which a second receiving unit receives the response signal, A height determination step in which the height determination unit determines the specified height as the height of the tag device based on the received information received in the response signal reception step, A positioning method that includes [a specific feature / feature].

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