DETECTION SYSTEM, DETECTION APPARATUS, DETECTION METHOD, AND PROGRAM

Abstract

A detection system 10 includes: a tag T; a radar device R that sends a transmission radio wave to the tag T and acquires a received radio wave which is the transmission wave reflected off the tag T; and a detection device 1 connected to the radar device R. The tag T includes a pattern formed from a plurality of materials that reflect or scatter radio waves received from the radar device R. The pattern includes a known pattern T1 that is known to the detection device 1, and an unknown pattern T2 that is unknown to the detection device 1. The detection device 1 includes: an identification unit 22 that can detect the known pattern T1 from the received radio wave, calculate a relative speed between the radar device R and the tag T, and identify, from the calculated relative speed, a condition under which the radar device R sends the transmission radio wave for estimating the unknown pattern T2; and a notification unit 23 that notifies the radar device R of the identified condition. The radar device R sends the transmission radio wave to the tag T under the notified condition.

Description

[Technical field]

[0001] The present invention relates to a detection system, a detection device, a detection method, and a program. [Background technology]

[0002] Chipless RFID has been attracting attention in recent years (Non-Patent Document 1). Chipless RFID is an RFID (Radio Frequency IDentifier) ​​that can be implemented without an IC (Integrated Circuit). Chipless RFID is expected to be an environmentally friendly technology that can sense using radio waves.

[0003] Chipless RFID sensing is achieved by applying SAR (Synthetic Aperture Radar) imaging technology, which is used in satellite microwave sensing technology, etc. Chipless RFID tags enable the identification of object shapes and radio wave reflection characteristics of tags with high resolution.

[0004] A pattern capable of identifying the ID of the tag is provided on the chipless RFID tag. The pattern is formed of a plurality of materials that reflect or scatter the transmitted radio waves emitted by the radar device. The pattern provided on the chipless RFID tag is estimated from the received radio waves obtained from the chipless RFID tag, and the ID of the chipless RFID tag is estimated from the estimated pattern. When estimating the pattern provided on the chipless RFID tag, the relative speed between the chipless RFID tag and the radar device is referenced. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] H, Cristian, et al., "Chipless-RFID: a review and recent developments." Sensors 2019, 19, 3385 Summary of the Invention [Problem to be solved by the invention]

[0006] However, if the relative speed between the chipless RFID tag and the radar device is unknown, there is a problem in that the pattern provided on the chipless RFID tag cannot be estimated using SAR imaging technology.

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a technique that can estimate a pattern provided on a chipless RFID tag even when the relative speed between the chipless RFID tag and a radar device is unknown. [Means for solving the problem]

[0008] A detection system of one embodiment of the present invention includes a tag, a radar device that transmits transmission radio waves to the tag and acquires received radio waves reflected by the tag, and a detection device connected to the radar device, wherein the tag has a pattern formed of a plurality of materials that reflect or scatter the radio waves received from the radar device, the pattern including a known pattern known to the detection device and an unknown pattern unknown to the detection device, and the detection device is capable of detecting the known pattern from the received radio waves, and includes an identification unit that calculates the relative speed between the radar device and the tag and identifies conditions under which the radar device transmits transmission radio waves to estimate the unknown pattern from the calculated relative speed, and a notification unit that notifies the radar device of the identified conditions, and the radar device transmits transmission radio waves to the tag under the conditions.

[0009] A detection device of one embodiment of the present invention is a tag having a pattern formed from a plurality of materials that reflect or scatter received radio waves, the tag having a known pattern in the detection device and an unknown pattern in the detection device, and the detection device is capable of detecting the known pattern from received radio waves that are reflected or scattered from a radar device.The detection device is equipped with an identification unit that calculates the relative speed between the radar device and the tag and, from the calculated relative speed, identifies the conditions under which the radar device transmits radio waves to estimate the unknown pattern, and a notification unit that notifies the radar device of the identified conditions.

[0010] A detection method of one embodiment of the present invention provides a detection system including a tag, a radar device that transmits transmission radio waves to the tag and acquires received radio waves reflected by the tag, and a detection device connected to the radar device, wherein the tag has a pattern formed of a plurality of materials that reflect or scatter the radio waves received from the radar device, the pattern including a known pattern known to the detection device and an unknown pattern unknown to the detection device, the detection device is capable of detecting the known pattern from the received radio waves, calculates a relative speed between the radar device and the tag, and identifies conditions under which the radar device transmits transmission radio waves to estimate the unknown pattern from the calculated relative speed, the detection device notifies the radar device of the identified conditions, and the radar device transmits transmission radio waves to the tag under the conditions.

[0011] One aspect of the present invention is a program for causing a computer to function as the above-mentioned detection device. Effect of the Invention

[0012] According to the present invention, it is possible to provide a technique that can estimate a pattern provided on a chipless RFID tag even when the relative speed between the chipless RFID tag and a radar device is unknown. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a system configuration of a detection system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating functional blocks of the detection device according to the embodiment of the present invention. [Diagram 3] FIG. 3 is a flowchart showing an example of the operation of the detection device. [Figure 4] FIG. 4 is a diagram for explaining an example of a process in which the radar device irradiates a transmission wave and calculates a speed. [Diagram 5] FIG. 5 is a diagram for explaining an example of detecting a tag floating on the sea surface. [Figure 6] FIG. 6 is a diagram for explaining an example in which a tag has a pattern in two dimensions. [Figure 7] FIG. 7 is a diagram for explaining an example of identifying the speed of a tag in three-dimensional directions. [Figure 8] FIG. 8 is a diagram illustrating the hardware configuration of a computer used in the detection device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same parts are given the same reference numerals and the description will be omitted.

[0015] (Detection System) The detection system 10 according to the embodiment of the present invention includes a tag T, a radar device R, and a detection device 1.

[0016] The tag T is a so-called chipless RFID tag. The detection system 10 may include a plurality of tags T. The tag T includes a pattern formed of a plurality of materials that reflect or scatter radio waves received from the radar device R. The characteristics of reflecting or scattering radio waves differ depending on the material. The pattern is formed depending on the positions at which the plurality of materials are provided on the surface of the tag T.

[0017] The pattern may be formed by providing a predetermined material on the substrate of the tag T. The predetermined material is formed on the substrate by any method such as printing or pasting. Both the material of the substrate and the material provided on the substrate are capable of reflecting or scattering radio waves. The material provided on the substrate has reflection or scattering characteristics different from those of the substrate. By providing a material having reflection or scattering characteristics different from those of the substrate on a part of the substrate of the tag T, the detection system 10 can estimate the position where the material different from the substrate is provided from the radio waves reflected or scattered by the tag T. The detection system 10 can estimate the pattern formed on the tag T from the position where the material is provided.

[0018] The pattern formed on the tag T can express various data depending on the position of the material applied to the substrate. For example, if the part where the material is applied is defined as "1" and the part where the material is not applied and the substrate is exposed is defined as "0", the pattern can express various data using the binary values ​​"1" and "0".

[0019] The radar device R transmits a transmission radio wave to the tag T and acquires a received radio wave that is the transmission radio wave reflected by the tag T. The radar device R irradiates radio waves from an antenna to the tag T. The tag T reflects or scatters the irradiated radio wave. The radar device R receives a received radio wave that is the transmission radio wave reflected or scattered by the tag T. From this received radio wave, a pattern provided on the tag T is estimated. SAR imaging technology is used to estimate the pattern.

[0020] The radar device R moves relatively around the tag T while maintaining a predetermined distance between the tag T and the radar device R. While moving, the radar device R irradiates the tag T with vertically polarized waves (transmitted radio waves) at predetermined distance intervals. The predetermined distance intervals are half the wavelength of the vertically polarized waves transmitted by the radar device R using SAR imaging technology. The radar device R irradiates the tag T with vertically polarized waves at predetermined distance intervals, taking into account the relative speed between the tag T and the radar device R.

[0021] The tag T reflects or scatters the vertically polarized waves and returns the horizontally polarized waves to the radar device R. The radar device R detects the horizontally polarized waves (received radio waves) returned from the tag T. The detected horizontally polarized waves are converted into signal data. The horizontally polarized signals are used to estimate the pattern provided on the tag T using SAR imaging technology.

[0022] The detection device 1 is connected to the radar device R. The detection device 1 processes a received signal that is a digitalized version of the radio waves received by the radar device R. The detection device 1 only needs to be able to refer to the received signal of the radio waves received by the radar device R, and the means for doing so is not important. In the embodiment of the present invention, a case will be described in which the detection device 1 acquires the received signal from the radar device R, but the detection device 1 may also generate the received signal by referring to the received radio waves.

[0023] In the embodiment of the present invention, the detection device 1 is mounted in a housing different from the radar device R, and transmits and receives data to and from the radar device R through communication, but the present invention is not limited to this. For example, the detection device 1 may be mounted inside the radar device R, and transmit and receive data to and from the radar device R via an internal bus or the like.

[0024] In the embodiment of the present invention, the pattern provided on the tag T includes a known pattern T1 known to the detection device 1 and an unknown pattern T2 unknown to the detection device 1.

[0025] The known pattern T1 is a pattern that the detection device 1 knows in advance as being provided on the tag T. The detection device 1 holds data that identifies the known pattern T1 of the tag T. The number of known patterns T1 used in the detection system 10 may be one or more.

[0026] The unknown pattern T2 is a pattern that the detection device 1 does not know in advance is provided on the tag T. The detection device 1 estimates the unknown pattern T2 from the radio waves received from the tag T. The unknown pattern T2 represents, for example, an identifier of the tag T. The unknown pattern T2 may be a pattern provided on a general chipless RFID tag.

[0027] (Detection device) A detection device 1 according to an embodiment of the present invention will be described with reference to Fig. 2. The detection device 1 identifies conditions under which the radar device R transmits radio waves to detect an unknown pattern T2 from a received signal 11 for detecting a known pattern T1, and notifies the radar device R. The detection device 1 estimates the unknown pattern T2 from a received signal 13 in response to the transmitted radio waves transmitted under the conditions notified to the radar device R, and outputs the estimated unknown pattern T2.

[0028] The detection device 1 includes received signals 11 and 13, condition data 12, and estimated data 14, and includes functions of an identifying unit 22, a notifying unit 23, and an estimating unit 24. Each piece of data is stored in a memory 902 or a storage 903. Each function is implemented in a CPU 901.

[0029] The received signals 11 and 13 are signals of radio waves received by the radar device R from the tag T when the radar device R irradiates the tag T with a transmitted radio wave. The received signals 11 and 13 have a data format that the detection device 1 can process.

[0030] The received signal 11 is a signal of a received radio wave in response to a transmission radio wave transmitted from the radar device R to detect the known pattern T1. In order to detect the known pattern T1, the radar device R irradiates the tag T with a predetermined frequency to obtain a received radio wave. The received signal 11 is a signal of the received radio wave obtained in this manner. The predetermined frequency is, for example, an arbitrary or default frequency designated by the radar device R or the detection device 1. Since the predetermined frequency is a distance interval of 1 / 2 or less of the wavelength of the transmission radio wave, analysis by SAR imaging technology becomes possible. Since the irradiation frequency for obtaining the known pattern T1 is higher than the irradiation frequency for obtaining the unknown pattern T2, the possibility of irradiating the known pattern T1 at a detectable position is increased, and the known pattern T1 can be efficiently detected.

[0031] The received signal 13 is a signal of a received radio wave in response to a transmission radio wave transmitted from the radar device R to detect the unknown pattern T2. ​​The detection device 1 notifies the radar device R of conditions for detecting the unknown pattern T2. ​​The radar device R irradiates the transmission radio wave to the tag T in accordance with the conditions notified by the detection device 1. The received signal 13 is a signal of a received radio wave in response to a transmission radio wave transmitted in accordance with the conditions notified by the detection device 1.

[0032] The condition data 12 is data that specifies a condition for the radar device R to transmit a transmission radio wave for estimating the unknown pattern T2. ​​The condition data 12 is specified by the specification unit 22 and notified to the radar device R by the notification unit .

[0033] The condition specified by the condition data 12 is a condition for the radar device R to irradiate the tag T with a transmission radio wave at a predetermined distance interval while maintaining a predetermined distance from the tag T in order to detect the unknown pattern T2. interval is 1 / 2 the wavelength of the transmission radio wave. The condition may be the position where the radar device R radiates the transmission radio wave, or the time when the radar device R radiates the transmission radio wave. The condition may also be expressed by multiple parameters such as the position and the time.

[0034] The estimated data 14 is data for identifying a pattern estimated from the received signal 13 for detecting the unknown pattern T2. ​​The estimated data 14 is generated by an estimation unit 24.

[0035] The acquisition unit 21 acquires the received signals 11 and 13 from the radar device R. The acquisition unit 21 may generate the received signals 11 and 13 by referring to the radio waves received by the radar device R.

[0036] The identification unit 22 calculates the relative speed between the radar device R and the tag T, at which the known pattern T1 can be detected from the received radio wave signal 11. The identification unit 22 identifies, from the calculated relative speed, the conditions under which the radar device R transmits a transmission radio wave for estimating the unknown pattern T2.

[0037] The identification unit 22 calculates the relative speed between the radar device R and the tag T at which the known pattern T1 can be detected in the received signal 11. The identification unit 22 reverse-calculates the relative speed between the radar device R and the tag T so that a pattern synthesized from the received signal 11 becomes the known pattern T1.

[0038] When the relative speed between the radar device R and the tag T is calculated, the identification unit 22 uses the calculated relative speed to identify the conditions under which the radar device R irradiates a transmission radio wave for estimating the unknown pattern T2. ​​Since the radar device R uses SAR imaging technology, Radar device R It is necessary to irradiate the tag T with vertically polarized waves at a distance interval that is half the wavelength of the vertically polarized waves irradiated by the radar device R. The identification unit 22 identifies conditions related to the irradiation timing, such as the position and time for irradiating the vertically polarized waves, from the relative speed between the radar device R and the tag T, so that the radar device R can irradiate the vertically polarized waves at a distance interval that is half the wavelength of the vertically polarized waves.

[0039] The specification unit 22 stores the specified condition as condition data 12.

[0040] The notification unit 23 notifies the radar device R of the conditions identified by the identification unit 22. The notification unit 23 inputs the condition data 12 to the radar device R. The radar device R irradiates the tag T with a transmission radio wave under the conditions identified by the condition data 12. This allows the radar device R to irradiate the tag T with vertically polarized waves at a distance interval of 1 / 2 the wavelength of the vertically polarized waves even if the relative distance between the radar device R and the tag T is unknown.

[0041] The estimation unit 24 estimates an unknown pattern T2 from a received signal 13 of a received radio wave corresponding to a transmitted radio wave transmitted under a condition specified by the condition data 12. The estimation unit 24 estimates the unknown pattern T2 by SAR imaging processing with reference to the received signal 13. The estimation unit 24 outputs the estimated pattern as estimated data 14.

[0042] A detection method according to an embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4. In Fig. 4, a "circle" indicates the position of the radar device R from which the radar device R transmits a transmission radio wave. A "square" indicates the position of the radar device R from which the radar device R transmits a transmission radio wave to detect an unknown pattern T2.

[0043] In step S1, the detection device 1 acquires a reception signal 11 for detecting a known pattern T1. The reception signal 11 is obtained by the radar device R irradiating the tag T with a transmission radio wave.

[0044] In step S2, the detection device 1 back-calculates the relative speed v that can reproduce the known pattern T1 from the received signal 11. As shown in Fig. 4, the radar device R performs high-frequency sensing to obtain received radio waves in order to detect the known pattern T1. The detection device 1 back-calculates the relative speed v so that the known pattern can be synthesized from the received signal 11 of the received radio waves.

[0045] In step S3, the detection device 1 uses the relative speed v obtained by the back calculation to identify the conditions for the radar device R to transmit a transmission radio wave to detect the unknown pattern T2. ​​Here, a case will be described in which the position of the "square mark" shown in FIG. 4 is identified as the condition for transmitting a transmission radio wave. In step S4, the detection device 1 notifies the radar device R of the conditions identified in step S3. In accordance with the notified conditions, the radar device R irradiates a transmission radio wave for sensing the unknown pattern T2 at the position of the "square mark" shown in FIG. 4 and obtains a received radio wave. The distance between the two "square marks" shown in FIG. 4 is λ / 2 (λ = wavelength of the transmission radio wave).

[0046] In step S5, the detection device 1 acquires a received signal 13 of a received radio wave corresponding to the transmitted radio wave irradiated under the conditions specified in step S3. In step S6, the detection device 1 estimates the unknown pattern T2 from the received signal 13 acquired in step S5 using SAR imaging technology, and outputs estimated data 14.

[0047] A detection system 10 according to an embodiment of the present invention estimates the relative speed between the tag T and the radar device R from the known pattern T1 prior to estimating an unknown pattern T2 of the tag T. The detection system 10 calculates a relative speed at which the known pattern T1 can be reproduced from received radio waves obtained by irradiating the tag T with a transmission radio wave at a predetermined frequency. The detection system 10 identifies conditions for transmitting a transmission radio wave to the unknown pattern T2 from the calculated relative speed. The radar device R irradiates the tag T with a transmission radio wave according to the identified conditions.

[0048] Such a detection system 10 can estimate an unknown pattern T2 provided on the tag T even if the relative speed between the tag T and the radar device R is unknown.

[0049] (First application example) In the embodiment of the present invention, the detection device 1 calculates the relative speed between the tag T and the radar device R. Here, when the tag T is fixed, the relative speed calculated by the identification unit 22 is the speed of the radar device R.

[0050] In the first application example, the tag T is fixed at a predetermined position and has a known pattern T1 and an unknown pattern T2. ​​The radar device R irradiates the tag T with a transmission radio wave while moving around the tag T and receives the radio wave. The detection system 10 calculates the relative speed at which the known pattern T1 can be obtained from the obtained received radio wave. Since the tag T is fixed, the calculated relative speed is the speed of the radar device R.

[0051] Furthermore, the detection system 10 refers to the speed of the radar device R to identify the conditions under which the radar device R irradiates the tag T. The detection system 10 identifies the conditions under which the radar device R can irradiate the tag T with vertically polarized waves at intervals of 1 / 2 the wavelength of the vertically polarized waves transmitted by the radar device R. From the horizontally polarized waves relative to the vertically polarized waves irradiated under such conditions, the detection system 10 can reproduce the unknown pattern T2 provided on the tag T by SAR imaging analysis.

[0052] As shown in the first application example, the detection system 10 can be applied to calculating the speed of a radar device R without using a speedometer or the like to calculate the speed of the radar device R by providing a known pattern T1 on the tag T in a situation where the tag T is fixed.

[0053] (Second application example) In the first application example, a case where the tag T is fixed is described. In the second application example, a case where the tag T is not fixed but moves is described.

[0054] When the tag T moves, the identification unit 22 may further acquire the speed of the radar device R, and calculate the speed of the tag T from the acquired speed of the radar device R and the relative speed.

[0055] In the second application example, the tag T moves without being fixed to a predetermined position, and has a known pattern T1 and an unknown pattern T2. ​​The radar device R irradiates the tag T with a transmitted radio wave while moving relatively around the tag T, and receives the received radio wave. The detection system 10 calculates the relative speed at which the known pattern T1 can be obtained from the received radio wave. When the speed of the radar device R is known, the moving speed of the tag T can be calculated from the relative speed calculated here.

[0056] The detection system 10 specifies the conditions under which the radar device R irradiates the tag T with light by referring to the relative speed at which the known pattern T1 can be reproduced. The detection system 10 specifies the conditions under which the tag T can be irradiated with vertically polarized waves at intervals of 1 / 2 the wavelength of the vertically polarized waves transmitted by the radar device R. From the horizontally polarized waves relative to the vertically polarized waves irradiated under such conditions, the detection system 10 can reproduce the unknown pattern T2 provided on the tag T by SAR imaging analysis.

[0057] The second application example can be applied to, for example, calculating the speed of an environment in which the tag T is installed. When the tag T floats in the environment, the speed of the tag T calculated in the second application example is the moving speed of the environment in which the tag T is located.

[0058] For example, as shown in Fig. 5, tags A and B float on the ocean surface. Tags A and B each have a known pattern T1 (not shown) and an unknown pattern T2 for identifying the tag. The unknown pattern T2 of tag A indicates "101". The unknown pattern T2 of tag B indicates "010".

[0059] By mounting a radar device R on a drone and having the radar device R irradiate each tag with a transmitted radio wave, the detection system 10 can calculate the relative speed between the radar device R and each tag T. Furthermore, when the speed of the radar device R is measured by another system, the detection system 10 can calculate the speed of each tag.

[0060] 5, the tag T floats and moves on the ocean surface. The speed of the tag T calculated by the detection system 10 is the speed of the ocean current.

[0061] Although the case of measuring the speed of the sea surface has been described with reference to Fig. 5, the present invention is not limited to this. By attaching the tag T to the water surface of a river, the detection system 10 can measure the speed of the river. Also, by attaching the tag T to drift ice, the detection system 10 can measure the flow speed of the drift ice.

[0062] In this way, installing the tag T having the known pattern T1 in the environment is preferable from multiple viewpoints such as low cost, low environmental load, and improved visibility. In the embodiment of the present invention, the tag T may have a pattern formed of multiple materials that reflect or scatter radio waves received from the radar device R. The tag T does not require a conductive material such as an antenna and can be realized at low cost. The tag T has a high degree of freedom in materials and can realize a low environmental load. Therefore, as shown in FIG. 5, by installing the tag T in an environment such as the sea, it is possible to measure the sea environment such as ocean currents at low cost and with low environmental load. In addition, the visibility of the tag T can be controlled by giving the tag T a color with high visibility or a color with low visibility depending on the environment in which the tag T is installed. In addition, by using the SAR imaging technology, it is possible to achieve a higher resolution and improved reading distance than conventional radar sensing, and therefore it is possible to measure the state of the environment with high accuracy.

[0063] (Third application example) In the above embodiments, the case where the pattern is one-dimensional has been described. However, with reference to FIG. 6, a case where the pattern is two-dimensional will be described in a third application example.

[0064] In the example shown in Figures 6(a) and (b), the x direction is the angular direction (the direction of movement of the radar-equipped drone), and the y direction is the ground range direction. The tag T is located diagonally below the radar-equipped drone and moves in two dimensions. The radar is, for example, a 77-81 GHz millimeter-wave FMCW (Frequency Modulated Continuous Wave) radar.

[0065] As shown in FIG. 6(a), the tag T has a known pattern T1 and an unknown pattern T2. ​​The known pattern T1 and the unknown pattern T2 form a predetermined pattern using a plurality of materials that reflect or scatter radio waves from the radar device R. In the example shown in FIG. 1, each material is provided in one direction, but in the example shown in FIG. 6(a), each material is provided in two-dimensional directions, the x direction and the y direction. One of the plurality of materials is a substrate of the tag T. The substrate is, for example, a radio wave absorbing sheet. One of the plurality of materials is a material provided on the substrate of the tag T, for example, carbon.

[0066] The size of the area in which the individual materials are provided depends on the resolution of the SAR imaging.

[0067] In the x direction, the pattern is measured by SAR imaging. The resolution in the x direction, Δx, is λ / 2 (where λ is the wavelength of the transmitted radio wave). In the y direction, the pattern is measured by a ranging FMCW (Frequency Modulated Continuous Wave) radar. The resolution in the y direction, Δy, is c / 2B (where c is the speed of light and B is the bandwidth used by the ranging FMCW radar).

[0068] Here, when Δx=2 mm and Δy=37.5 mm, 1 bit of information of unknown pattern T2 is 75 mm 2 Therefore, if the tag T is 10 cm square (1000 mm 2), 133 bits of data can be expressed. Even if a known pattern T1 is expressed by about 30 bits of the 133 bits, a tag T of 10 cm square can express an unknown pattern T2 of about 100 bits.

[0069] In the example shown in FIGS. 6(a) and (b), the detection system 10 can measure the movement speed of the tag T moving in two dimensional directions.

[0070] In the x direction, the pattern of the tag T is measured by SAR imaging, so the detection system 10 can determine the speed at which the known pattern T1 can be reproduced as the relative speed of the radar device R and the tag T in the x direction. Furthermore, by separately acquiring the speed of the radar device R in the x direction, the detection system 10 can calculate the speed of the tag T in the x direction. In the y direction, the detection system 10 can estimate the relative speed in the y direction by Doppler radar analysis. Furthermore, by separately acquiring the speed of the radar device R in the y direction, the detection system 10 can calculate the speed of the tag T in the y direction.

[0071] Furthermore, the detection system 10 can identify the location where the known pattern T1 is detected as the position of the tag T.

[0072] The radar device R irradiates a transmission radio wave to an area including the tag T. The radar device R receives the reception radio wave reflected from the irradiation area. The detection system 10 obtains the reflection intensity with respect to the distance in the x direction by analyzing the received radio wave with SAR imaging. The detection system 10 obtains the reflection intensity with respect to the distance in the y direction by performing frequency analysis of the received radio wave.

[0073] The radar device R emits transmitted radio waves while moving its position in the x direction in small increments, and acquires received radio waves from the tag T. This enables the detection system 10 to identify a pattern in the x direction from the change in the received radio waves in the x direction.

[0074] (Fourth Application Example) The radar device R uses the beamforming technique, so that the detection system 10 can efficiently detect a plurality of tags T from the radio waves received by a single radar device R.

[0075] For example, the direction in which the radar device R emits a transmitted radio wave is controlled by software or the like. The radar device R emits beams in various directions and receives radio waves from each direction. From the received radio waves, the detection system 10 can identify the relative speed at which the known pattern T1 can be detected and the position of the known pattern T1 when the known pattern T1 is detected.

[0076] (Fifth Application Example) In the third application example, it has been shown that the detection system 10 can measure the velocity in each of the angular direction and the ground range direction when the tag T moves in two dimensions. In contrast, in the fifth application example, a method will be described in which the detection system 10 determines a three-dimensional velocity vector when the tag T moves in three dimensions.

[0077] As shown in FIG. 7, a radar device R is mounted on each of three drones moving above a tag T. The three drones move to different positions. Each radar device R measures the velocity of the tag T in the ground range direction and the angular direction. The detection system 10 can obtain the three-dimensional velocity (Vx, Vy, Vz) of the tag T by vector-composing the measured velocities.

[0078] As described above, the detection system 10 according to the embodiment of the present invention can specify the relative speed at which the known pattern T1 can be reproduced from the received radio waves by providing the known pattern T1 on the tag T. Therefore, even if the relative speed between the radar device R and the tag T is unknown, the detection system 10 can estimate the unknown pattern T2 of the chipless RFID by using the SAR imaging technology.

[0079] Furthermore, when the speed of the radar device R is known, the detection system 10 can calculate the moving speed of the tag T. Conversely, when the moving speed of the tag T is known, the detection system 10 can calculate the speed of the radar device R.

[0080] The pattern provided on the tag T only needs to be made of a plurality of materials that reflect or scatter radio waves from the radar device R, and there are few restrictions on the material that forms the pattern. Since the material that forms the tag T can be selected according to the environment in which the tag T is installed, such tags T can be used for a wide range of applications. Furthermore, since there are few restrictions on the material of the tag T, the shape, design, color, and the like of the tag T can also be appropriately selected according to the environment. Furthermore, by forming the tag T from a material that returns to the environment, the cost of recovering the tag T can be reduced.

[0081] The detection device 1 of the present embodiment described above uses, for example, a general-purpose computer system including a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device 906. In this computer system, the CPU 901 executes a program loaded on the memory 902, thereby realizing each function of the detection device 1.

[0082] The detection device 1 may be implemented in one computer, or in multiple computers, or may be a virtual machine implemented in a computer.

[0083] The program for the detection device 1 can be stored in a computer-readable recording medium such as a HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or can be distributed via a network.

[0084] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the present invention. [Explanation of symbols]

[0085] 1. Detection device 10. Detection System 11, 13 Received signal 12 Condition Data 14 Estimated data 21 Acquisition Department 22 Specific section 23 Notification Department 24 Estimation part 901 CPU 902 Memory 903 Storage 904 Communication equipment 905 Input Device 906 Output Device T tag T1 Known Pattern T2 Unknown pattern R Radar equipment

Claims

1. Tags, a radar device that transmits a transmission radio wave to the tag and acquires a received radio wave that is the transmission radio wave reflected by the tag; a detection device connected to the radar device; The tag is a pattern formed of a plurality of materials that reflect or scatter radio waves received from the radar device, the pattern including a known pattern known to the detection device and an unknown pattern unknown to the detection device; The detection device includes: an identification unit that can detect the known pattern from the received radio waves, calculates a relative speed between the radar device and the tag, and identifies a condition for the radar device to transmit a transmission radio wave for estimating the unknown pattern based on the calculated relative speed; a notification unit that notifies the radar device of the specified condition; The radar device transmits a transmission radio wave to the tag under the condition. Detection system.

2. The detection device includes: an estimation unit that estimates the unknown pattern from a received radio wave corresponding to a transmission radio wave transmitted under the condition; The detection system of claim 1 further comprising:

3. If the tag is fixed, The relative speed calculated by the determination unit is the speed of the radar device. The detection system of claim 1 .

4. If the tag moves, The identification unit further acquires a speed of the radar device, and calculates a speed of the tag from the acquired speed of the radar device and the relative speed. The detection system of claim 1 .

5. If the tag is floating in the environment, the velocity of the tag is the moving velocity of the environment in which the tag is located. The detection system of claim 4.

6. a tag having a pattern formed of a plurality of materials that reflect or scatter received radio waves, the tag having a known pattern in a detection device and an unknown pattern in the detection device, the tag being capable of detecting the known pattern from received radio waves that are reflected or scattered from a radar device; a determination unit that calculates a relative speed between the radar device and the tag, and determines, from the calculated relative speed, a condition for the radar device to transmit a transmission radio wave for estimating the unknown pattern; A notification unit that notifies the radar device of the specified condition. A detection device comprising:

7. Tags, a radar device that transmits a transmission radio wave to the tag and acquires a received radio wave that is the transmission radio wave reflected by the tag; A detection system including a detection device connected to the radar device, The tag is a pattern formed of a plurality of materials that reflect or scatter radio waves received from the radar device, the pattern including a known pattern known to the detection device and an unknown pattern unknown to the detection device; the detection device calculates a relative speed between the radar device and the tag at which the known pattern can be detected from the received radio waves, and specifies, from the calculated relative speed, a condition under which the radar device transmits a transmission radio wave for estimating the unknown pattern; The detection device notifies the radar device of the identified condition; The radar device transmits a transmission radio wave to the tag under the condition. Detection methods.

8. A program for causing a computer to function as the detection device according to claim 6.

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