Sensing system, transmitting device, receiving device, control circuit, storage medium, sensing method, transmitting method, and receiving method

Abstract

A sensing system (30) is provided with: a transmission device (10) which has a plurality of transmission antenna elements (18), controls the generation of a radar signal, the generation of a code, and the timing of the generation of a carrier signal for dividing an available frequency band into a plurality of sub-bands and periodically switching the sub-bands, multiplies the radar signal by the code for each of the plurality of transmission antenna elements (18), and generates a carrier signal for each of the plurality of transmission antenna elements (18); generating a high-frequency signal having a bandwidth of a sub-band using the radar signal and the carrier signal multiplied by the code, and transmitting the high-frequency signal from a plurality of transmission antenna elements (18); and a reception device (20) that has a plurality of reception antenna elements (22), receives the high-frequency signal transmitted from the transmission device (10) and reflected or scattered by the object to be measured, generates transmission path information between the transmission device (10) and the reception device (20) using a carrier signal, a radar signal, and a code, and specifies the position of the object to be measured using the transmission path information. Focus correction is performed to generate an image of a measurement object.

Description

Technical Field

[0001] The present disclosure relates to a sensing system, a transmitting device, a receiving device, a control circuit, a storage medium, a sensing method, a transmitting method, and a receiving method for measuring a measurement object using electromagnetic waves. Background Art

[0002] In recent years, the demand for environmental sensing technology has increased, driven by the advancement of automated control of devices known as digital twin systems or cyber-physical systems, as well as the realization of a safe and secure society, as the workforce shrinks. For example, on-board radars for forward and side monitoring, essential for autonomous driving, are one example. Furthermore, new applications based on sensing technology are emerging, such as non-stop safety gates for quality control and safety assurance in production lines.

[0003] Conventionally, radar devices that utilize electromagnetic waves have been used to collect information about the surrounding environment from a remote location. For example, Patent Document 1 discloses technology for a MIMO (Multiple Input Multiple Output) radar device that improves the detection performance of moving objects. The radar device described in Patent Document 1 acquires information about a MIMO transmission path formed between multiple transmitting elements and multiple receiving elements and measures reflection points.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2021-81282 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Previous radar technology was developed primarily for the detection of aircraft, vehicles, and other objects, focusing primarily on detecting the position and relative speed of reflection points at a certain distance. On the other hand, new applications such as non-destructive inspection, such as detecting and determining the shape of metal objects held by pedestrians, determining their type and hazard level, and detecting cracks and voids within plastic resins, require high resolution close to the sensor and multi-layer spatial resolution in the depth direction.

[0009] To improve radar resolution, using shorter wavelengths, or higher frequencies, and increasing the antenna aperture diameter are effective. However, for short-range sensing applications, device miniaturization is crucial, making it difficult to increase antenna size. The antenna aperture diameter can be reduced in proportion to the wavelength, making it an effective solution for efficiently utilizing high-frequency bands.

[0010] In applications such as non-destructive inspection, resolution in the depth direction, that is, in the distance direction, is required. The so-called distance resolution depends on the bandwidth that can be used as a radar signal. However, since the low-frequency band is already used by other systems, in order to ensure a wide bandwidth, the high-frequency band must also be effectively utilized. In addition, in sensing at close distances where the opening diameter cannot be ignored relative to the measurement distance, that is, the opening diameter cannot be regarded as a point, a function equivalent to focus adjustment corresponding to the measurement distance is required. In addition, in order to perform tomography such as CT (Computed Tomography) scanning of the measurement object using X-rays, focus adjustment corresponding to the position of each layer becomes important.

[0011] Thus, achieving high-resolution three-dimensional sensing systems requires efficient utilization of broadband signals, and therefore, high-frequency bands are highly effective. However, the design and manufacture of high-frequency circuits capable of processing broadband signals exceeding 10 GHz in these bands is extremely difficult, leading to increased costs.

[0012] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a sensing system capable of improving the resolution when measuring a measurement object at a close distance using a high-frequency signal at low cost.

[0013] Means for solving problems

[0014] To solve the aforementioned problems and achieve the objectives, the presently disclosed sensing system comprises: a transmitting device having a plurality of transmitting antenna elements, the transmitting device controlling the generation of a radar signal, the generation of a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements into high-frequency signals transmitted from each transmitting antenna element at a receiving device, and the timing of generating a carrier signal for dividing a usable frequency band into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements so as to use the entire frequency band; multiplying the radar signal by the code for each of the plurality of transmitting antenna elements, generating a high-frequency signal having a bandwidth of the sub-band using the code-multiplied radar signal and the carrier signal, and transmitting the signal from the plurality of transmitting antenna elements; and a receiving device having a plurality of receiving antenna elements, receiving the high-frequency signal transmitted from the transmitting device and reflected or scattered by a measurement object, generating transmission path information indicating the state of a transmission path between the transmitting device and the receiving device using the carrier signal, the radar signal, and the code; determining the position of the measurement object using the transmission path information, performing focus correction on the measurement object, and generating an image of the measurement object.

[0015] Effects of the Invention

[0016] The sensing system disclosed herein has the effect of being able to improve the resolution when measuring a measurement target at a short distance using a high-frequency signal at low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram showing an overview of measurements assumed in the sensing system according to the first embodiment.

[0018] Figure 2 This is a diagram showing a configuration example of a sensing system according to the first embodiment.

[0019] Figure 3 This is a diagram showing an example of a high-frequency signal transmitted from the transmitting device according to Embodiment 1.

[0020] Figure 4 This is a flowchart showing the operation of the sensing system according to the first embodiment.

[0021] Figure 5 This is a flowchart showing the operation of the transmitting device according to the first embodiment.

[0022] Figure 6 This is a flowchart showing the operation of the receiving device according to the first embodiment.

[0023] Figure 7 This diagram shows a configuration example of a processing circuit in the case where the processing circuit realizing the transmission device according to Embodiment 1 is realized using a processor and a memory.

[0024] Figure 8This is a diagram showing an example of a processing circuit in the case where the processing circuit of the transmission device according to Embodiment 1 is configured by dedicated hardware.

[0025] Figure 9 This is a diagram showing an overview of measurements assumed in the sensing system according to the second embodiment.

[0026] Figure 10 This is a diagram showing a configuration example of a sensing system according to a second embodiment.

[0027] Figure 11 This is a diagram showing an example of a high-frequency signal transmitted from the transmitting device according to the third embodiment.

[0028] Figure 12 This is a diagram showing an overview of measurements assumed in the sensing system of the fourth embodiment.

[0029] Figure 13 This is a diagram showing an example of a high-frequency signal transmitted from the transmitting device according to the fourth embodiment.

[0030] Figure 14 This is a diagram showing the concept of the operation of the layer cutout unit of the receiving device according to the fifth embodiment.

[0031] Figure 15 This is a diagram showing the concept of the operation of the focus correction unit of the receiving device according to the fifth embodiment. DETAILED DESCRIPTION

[0032] Hereinafter, a sensing system, a transmitting device, a receiving device, a control circuit, a storage medium, a sensing method, a transmitting method, and a receiving method according to embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0033] Implementation Method 1

[0034] Figure 1 This is a diagram showing an overview of the measurement envisioned in the sensing system 30 of the first embodiment. The sensing system 30 includes a transmitting device 10 and a receiving device 20, and is a system for performing measurements on a measurement object 40. In the sensing system 30, the transmitting device 10 irradiates radio waves from a transmitting array 17 composed of a plurality of transmitting antenna elements 18 to the measurement object 40, and the receiving device 20 receives reflected waves, scattered waves, etc. from the measurement object 40 via a receiving array 21 composed of a plurality of receiving antenna elements 22, thereby performing measurements on the measurement object 40. In the first embodiment, the transmitting device 10 transmits a high-frequency signal as the radio wave irradiation. In the transmitting device 10, the transmitting array 17 has N T The plurality of transmitting antenna elements 18 are used as the transmitting antenna elements 18. In the receiving device 20, the receiving array 21 has N RAs described later, the sensing system 30 is configured to receive antenna elements 22 in N T The transmitting antenna elements 18 and N R The N receiving antenna elements 22 constitute T ×N R The information of the measurement object 40 is extracted from the information of at least one transmission path.

[0035] Figure 2 1 is a diagram showing a configuration example of a sensing system 30 according to Embodiment 1. As described above, the sensing system 30 includes a transmitter 10 and a receiver 20. The transmitter 10 includes a synchronization unit 11, a radar signal generator 12, a code generator 13, a carrier signal generator 14, an encoder 15, a high-frequency signal generator 16, and a transmitter array 17. As described above, the transmitter array 17 includes N T transmitting antenna elements 18 .

[0036] The synchronization unit 11 adjusts the timing of the operations of the various components of the transmitting device 10 and the receiving device 20. The synchronization unit 11 controls the timing of radar signal generation by the radar signal generator 12, code generation by the code generator 13, and carrier signal generation by the carrier signal generator 14 in the transmitting device 10. The radar signal generator 12 generates radar signals at a baseband or intermediate frequency. As described later, radar signals are periodic broadband signals. The code generator 13 generates codes used to separate the high-frequency signal transmitted from the transmitting array 17, which includes multiple transmitting antenna elements 18, into the high-frequency signals transmitted from each transmitting antenna element 18 in the receiving device 20. The carrier signal generator 14 generates a reference carrier used to generate the final high-frequency signal. As described later, the carrier signal generator 14 generates a carrier signal to divide the frequency band available to the transmitting device 10 into multiple sub-bands and periodically switches the sub-bands used in the high-frequency signals transmitted from the multiple transmitting antenna elements 18 to the entire area of ​​the used frequency band.

[0037] The encoding unit 15 performs code multiplication on each of the multiple transmitting antenna elements 18, multiplying the radar signal generated by the radar signal generating unit 12 by the code generated by the code generating unit 13. The high-frequency signal generating unit 16 uses the signal obtained by multiplying the radar signal and the code in the encoding unit 15 and the reference carrier generated by the carrier signal generating unit 14 to generate a high-frequency signal for transmission from each transmitting antenna element 18. The high-frequency signal generating unit 16 is, for example, an upconverter or a frequency multiplier. It uses the code-multiplied radar signal and the carrier signal to generate a high-frequency signal with a bandwidth of a sub-band, and transmits it from the multiple transmitting antenna elements 18. In the transmitting array 17, the transmitting antenna elements 18 transmit the high-frequency signal generated by the high-frequency signal generating unit 16.

[0038] The receiving device 20 includes a receiving array 21, a signal conversion unit 23, a detection unit 24, a correlation processing unit 25, a MIMO transmission path reconstruction unit 26, a layer cutting unit 27, and a focus correction unit 28. As described above, the receiving array 21 includes N R receiving antenna elements 22.

[0039] In the receiving array 21, the receiving antenna elements 22 receive the high-frequency signal transmitted from the transmitting device 10. This high-frequency signal is a reflected wave reflected by the measurement object 40 or a scattered wave scattered by the measurement object 40. Specifically, the receiving antenna elements 22 receive the reflected or scattered waves of the high-frequency signal transmitted from the transmitting device 10. Alternatively, the receiving antenna elements 22 can directly receive the high-frequency signal transmitted from the transmitting device 10, depending on the positional relationship and orientation between the transmitting antenna elements 18 of the transmitting device 10 and the receiving antenna elements 22 of the receiving device 20. The signal converter 23 converts the high-frequency signal received by each receiving antenna element 22 into a baseband or intermediate frequency signal, i.e., down-converts the signal. The signal converter 23, for example, is a down-converter. Using the carrier signal used when generating the high-frequency signal in the transmitting device 10, the signal converter 23 converts the high-frequency signal received by the multiple receiving antenna elements 22 into a received signal in the frequency band of the radar signal used when generating the high-frequency signal in the transmitting device 10.

[0040] The detector 24 is located for each receiving antenna element 22 and uses the radar signal generated by the radar signal generator 12 of the transmitter 10 to detect the baseband or intermediate frequency received signal converted by the signal converter 23, thereby obtaining received information. The received information is the reflected or scattered waves of the high-frequency signal received by each receiving antenna element 22 and includes the high-frequency signals transmitted from the multiple transmitting antenna elements 18. Alternatively, the receiver 20 can obtain received information by using a mixer to mix the baseband or intermediate frequency received signal converted by the signal converter 23. The following describes the case where the detector 24 performs detection. The correlation processing unit 25 is configured for each receiving antenna element 22, and uses the code generated by the code generation unit 13 of the transmitting device 10 to perform correlation processing on the received information obtained by detection by the detection unit 24, thereby separating the received information into signals from each transmitting antenna element 18 of the transmitting device 10. That is, the received signal received by the multiple receiving antenna elements 22 is separated into the signal of each transmitting antenna element 18 sent from the transmitting device 10 for each receiving antenna element 22.

[0041] The MIMO transmission path reconstruction unit 26 uses the signals separated by the correlation processing unit 25 for each transmitting antenna element 18 and each receiving antenna element 22 to reconstruct the state of the transmission path between the transmitting device 10 and the receiving device 20, generating MIMO transmission path information indicating the state of the transmission path. The MIMO transmission path reconstruction unit 26 generates MIMO transmission path information for each frequency bin, which will be described later. In the following description, the MIMO transmission path reconstruction unit may be referred to simply as the transmission path reconstruction unit, and the MIMO transmission path information may be referred to simply as the transmission path information. The layer extraction unit 27 uses the MIMO transmission path information to determine the position of the measurement object 40. Based on the MIMO transmission path information reconstructed by the MIMO transmission path reconstruction unit 26, the layer extraction unit 27 extracts the measurement object 40 along a specific curved surface. Specifically, the layer extraction unit 27 extracts, from the MIMO transmission path information, reflection point information of a layer corresponding to the depth distance of the measurement object 40 as viewed from the multiple receiving antenna elements 22, thereby determining the position of the measurement object 40. The focus correction unit 28 performs focus correction on the determined measuring object 40, and generates and outputs an image as image information of the measuring object 40. As focus correction of the measuring object 40, the focus correction unit 28 performs focus correction corresponding to the position of the layer on the extracted reflection point information.

[0042] The operation of the sensing system 30 will be described. In the transmitting device 10, the synchronization unit 11 controls the radar signal generation timing of the radar signal generation unit 12, the code generation timing of the code generation unit 13, and the carrier frequency switching timing of the carrier signal generation unit 14 based on a frame structure described later.

[0043] Figure 3 : is a diagram showing an example of a high frequency signal transmitted from the transmitting device 10 of Embodiment 1. Figure 3 In FIG, an example of using up-chirp as the radar signal generated by the radar signal generating unit 12 is shown, but the radar signal is not limited to up-chirp. Up-chirp, down-chirp, ZC (Zadoff-Chu) sequence, pseudo-noise (hereinafter referred to as PN (Pseudo Noise)) signal, OFDM (Orthogonal Frequency Division Multiplexing) signal, frequency-stepped signal whose frequency changes stepwise in the time direction, common spread signal, etc. may also be used as long as the spectrum is spread over the entire specific frequency band. The frequency band that can be used by the sensing system 30 is divided into two parts with a bandwidth f B Part N B frequency band. Figure 3 In the example, sub-band 1 to sub-band N are recorded. B The frequency band is sub-band 1 to sub-band N. B They may also partially overlap with each other.

[0044] The radar signal generator 12 generates a periodic broadband signal, typically a chirp signal, in each sub-band as a radar signal. At this time, the synchronization unit 11 instructs the radar signal generator 12 on the start timing of each period. When A is an integer, the period of the broadband signal is set to the chip period T. C That is, the code generation unit 13 generates a code chip period T C A code that is an integer multiple of the radar signal period. Figure 3 The example shown is when A=1. The code generation unit 13 generates a code with a code length of M chips for each transmitting antenna element 18. Figure 3 As shown, the code period T SC =M×T C At this time, the synchronization unit 11 instructs the code generation unit 13 on the start timing of the code cycle. The encoding unit 15 performs code multiplication, multiplying the radar signal generated by the radar signal generation unit 12 by the code generated by the code generation unit 13. The code is generally expressed as ±1. The encoding unit 15 performs the multiplication process as phase modulation, amplitude modulation, frequency modulation, or a combination thereof.

[0045] The transmitting device 10 transmits at least a code period T in each sub-band. SC radar signal, but it can also be repeated through the use of code, throughout the code period T SC The above time (eg Figure 3 T shown B The radar signal is sent during the period of Figure 3 T shown B The period is the sub-band switching period.

[0046] The transmitting device 10 ends the sub-band switching period T in one sub-band. B When transmitting a radar signal, the frequency is switched, that is, the sub-band is switched. The carrier signal generator 14 generates a carrier signal for converting the radar signal encoded by the encoder 15 into a high-frequency signal of each sub-band. The carrier signal generator 14 receives an instruction from the synchronization unit 11 and generates an appropriate carrier signal to switch the sub-band at each sub-band switching period T. B Switching sub-bands. The high-frequency signal generator 16 uses the carrier signal generated by the carrier signal generator 14 to convert the radar signal encoded by the encoder 15 into a high-frequency signal of each sub-band, and transmits it from the transmitting antenna element 18 of the transmitting array 17. The transmitting device 10 is used to switch sub-bands 1 to N. B That is N B The period for transmitting radar signals in the entire frequency band of the sub-bands is set as the frame period T f =N B ×T B The sending device 10 will Figure 3 Subband 1 to subband N are shown B When the high frequency signal is set to 1 frame, through the transmission of 1 frame, that is, in 1 frame period T f Completed 1 measurement.

[0047] Furthermore, the code generated by code generator 13 is used to identify signals between transmit antenna elements 18. Therefore, code generator 13 generates so-called orthogonal codes or quasi-orthogonal codes that minimize cross-correlation between transmit antenna elements 18. Known codes generated by code generator 13 and used for identification between transmit antenna elements 18 include M sequences, Gold codes, Walsh-Hadamard codes, and PN sequences. However, these codes are not limiting as long as they have a high degree of orthogonality.

[0048] In the sensing system 30, the time and frequency of the transmitting device 10 and the receiving device 20 are synchronized, and they operate according to the instructions of the same synchronization unit 11. In addition, the sensing system 30 can also be set to a dual-static structure in which the transmitting device 10 and the receiving device 20 are arranged in physically separated positions. In this case, the transmitting device 10 and the receiving device 20 can be synchronized not only using a wired connection, but also using GPS (Global Positioning System), various wireless links, etc. For example, the sensing system 30 can also be in the following form: the carrier signal generating unit 14 is independently configured with the transmitting device 10 and the receiving device 20, so that the reference signal and the reference signal with the same frequency are shared by the transmitting device 10 and the receiving device 20. Here, as Figure 2 As shown, the operations of the transmitting device 10 and the receiving device 20 will be described by taking a configuration in which the functional units of the transmitting device 10 and the receiving device 20 are connected by wire as an example.

[0049] The receiving device 20 receives the high-frequency signal irradiated from the transmitting device 10 to the measuring object 40 and reflected or scattered by the measuring object 40 through the receiving antenna elements 22 of the receiving array 21. The signal conversion unit 23 uses the carrier signal corresponding to each sub-band generated by the carrier signal generating unit 14 to convert the high-frequency signal received by the receiving antenna elements 22 of the receiving array 21 into a baseband or intermediate frequency signal, that is, to perform down-conversion. The detection unit 24 is configured for each receiving antenna element 22, and uses the radar signal generated by the radar signal generating unit 12 of the transmitting device 10 to detect the baseband or intermediate frequency signal converted by the signal conversion unit 23 to obtain the received information. The received information includes the signals from N in the form received by a specific receiving antenna element 22. T All transmitting antenna elements 18 transmit signals.

[0050] The correlation processing unit 25 performs correlation processing on the received information detected by the detection unit 24 using the code generated by the code generation unit 13 of the transmitting device 10, thereby separating the received information into signals from each transmitting antenna element 18 of the transmitting device 10. In the receiving device 20, the processing of the correlation processing unit 25 is performed for each receiving antenna element 22, thereby obtaining N T ×N R The transmission path information of each sub-band is obtained. The detection processing in the detection unit 24 differs depending on the type of signal used as the radar signal, so a detailed description is omitted here. In the first embodiment, the detection processing in the detection unit 24 can be a universal processing method.

[0051] Regarding the bandwidth f of the sub-band B The extent of expansion depends on the frequency band used by the sensing system 30, various architectures, etc. In particular, when the sensing system 30 uses an ultra-high frequency band such as the terahertz band, there is a high possibility that large fluctuations in frequency characteristics will occur in the sub-band. Therefore, the sensing system 30 can reduce the bandwidth f of the sub-band to B The transmission path information is calculated by dividing the sub-band into multiple frequency bins. Usually, the frequency bin is set to a bandwidth that is considered to be constant in frequency variation within the frequency band. In the receiving device 20, the MIMO transmission path reconstruction unit 26 divides each sub-band into N F frequency bins, calculated in Figure 1 The transmission path information formed between the transmission array 17 of the transmission device 10 and the reception array 21 of the reception device 20 is shown. As a result, the MIMO transmission path reconstruction unit 26 can combine the information of all sub-bands and obtain the N T ×N R ×N F ×N B In the following description, frequency bins are sometimes referred to as frequency bins.

[0052] In this manner, transmitting device 10 transmits a high-frequency signal so as to divide the available frequency band into a plurality of sub-bands and periodically switches the sub-bands used in the high-frequency signals transmitted from a plurality of transmitting antenna elements 18, thereby utilizing the entire frequency band. At this time, MIMO transmission path reconstruction unit 26 generates MIMO transmission path information as MIMO transmission path information, which is a number obtained by multiplying the number of transmitting antenna elements 18 included in transmitting device 10, the number of receiving antenna elements 22 included in receiving device 20, the number of sub-bands, and the number of frequency bins when the bandwidth of the sub-band is divided into a plurality of frequency bins.

[0053] In addition, in order to generate N in space T ×N RMIMO transmission path information, here is the use of N T ×N R On the other hand, by using an approximate method such as interpolation or extrapolation, the number of actual antenna elements can be reduced and N can be generated. T ×N R This process is a common method, so detailed description is omitted here.

[0054] As with the detection process, different methods are used to generate MIMO transmission path information depending on the type of radar signal, detection method, etc. Therefore, the method of generating MIMO transmission path information is not limited here. Figure 3 If the chirp signal shown is a radar signal, receiver 20 detects it and obtains a carrier signal with a frequency difference δf corresponding to the distance from the reflection point. If there are multiple reflection points, the signal becomes a superposition of carrier signals with multiple frequencies. Based on this information, receiver 20 calculates the phase and amplitude characteristics of each frequency bin.

[0055] The obtained MIMO transmission path information includes all the reflection point information of the measurement object 40. The layer clipping unit 27 only clips the reflection point information on a specific curved surface determined by the configuration of the transmitting antenna element 18 and the receiving antenna element 22. In addition, the specific curved surface may also be a specific flat surface. The focus correction unit 28 can obtain a tomographic image of any part of the measurement object 40 by aligning the focus on the aforementioned curved surface. In addition, the order of the processing of the layer clipping unit 27 and the processing of the focus correction unit 28 is different. In addition, when the measurement object 40 is made of a non-transparent material and the main reflection points remain on the surface of the object, the layer clipping processing of the layer clipping unit 27 can be omitted.

[0056] Figure 4 This is a flowchart illustrating the operation of sensing system 30 according to Embodiment 1. In sensing system 30, transmitter 10 generates a high-frequency signal (step S11) and transmits it from transmitter array 17 to object 40 (step S12). Upon receiving the high-frequency signal transmitted from transmitter 10 and reflected or scattered by object 40 (step S13), receiver 20 uses the carrier signal, radar signal, and code to generate MIMO transmission path information indicating the state of the transmission path between transmitter 10 and receiver 20 (step S14). Using this MIMO transmission path information, receiver 20 determines the position of object 40, performs focus correction on object 40, and generates an image of object 40 (step S15).

[0057] Figure 5This is a flowchart showing the operation of the transmission device 10 according to the first embodiment. Figure 5 The flowchart shown represents Figure 4 Detailed description of the operations of step S11 and step S12 in the flowchart shown in FIG. In the transmitting device 10, the synchronization unit 11 controls the generation of the radar signal in the radar signal generating unit 12, the generation of the code in the code generating unit 13, and the generation of the carrier signal in the carrier signal generating unit 14, that is, the timing of each operation (step S21). The radar signal generating unit 12 generates the radar signal as a wideband signal under the control of the synchronization unit 11 (step S22). The code generating unit 13 generates a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements 18 into the high-frequency signal transmitted from each transmitting antenna element 18 in the receiving device 20 under the control of the synchronization unit 11 (step S23). The encoding unit 15 multiplies the radar signal and the code for each of the plurality of transmitting antenna elements 18 (step S24). The carrier signal generator 14 generates a carrier signal under the control of the synchronization unit 11 to divide the frequency band available to the transmitter 10 into multiple sub-bands. The carrier signal generator 14 periodically switches the sub-bands used in the high-frequency signals transmitted from the multiple transmitting antenna elements 18, thereby utilizing the entire frequency band (step S25). The high-frequency signal generator 16 uses the coded radar signal and the carrier signal to generate a high-frequency signal having a bandwidth corresponding to the sub-bands (step S26). The multiple transmitting antenna elements 18 transmit the high-frequency signal (step S27).

[0058] Figure 6 This is a flowchart showing the operation of the receiving device 20 according to the first embodiment. Figure 6 The flowchart shown represents Figure 4The details of the operations of steps S13 to S15 in the flowchart shown are shown. In the receiving device 20, the multiple receiving antenna elements 22 receive the reflected waves or scattered waves of the high-frequency signal transmitted from the transmitting device 10 having the multiple transmitting antenna elements 18 and reflected or scattered by the measurement object 40 (step S31). The signal conversion unit 23 uses the carrier signal used when the transmitting device 10 generates the high-frequency signal to convert the reflected waves or scattered waves of the high-frequency signal received by the multiple receiving antenna elements 22 into a received signal in the frequency band of the radar signal used when the transmitting device 10 generates the high-frequency signal (step S32). The detection unit 24 uses the radar signal generated by the transmitting device 10 to detect the received signal and obtains received information. This received information is the reflected waves or scattered waves of the high-frequency signal received by each receiving antenna element 22 and includes the high-frequency signal transmitted from the multiple transmitting antenna elements 18 (step S33). The correlation processing unit 25 performs correlation processing on the received information using the code used when encoding the radar signal in the transmitter 10, separating the received signal for each receiving antenna element 22 into signals for each transmitting antenna element 18 transmitted from the transmitter 10 (step S34). The MIMO transmission path reconstruction unit 26 uses the separated signals to generate MIMO transmission path information indicating the state of the transmission path between the transmitter 10 and the receiver 20 (step S35). The layer extraction unit 27 uses the MIMO transmission path information to determine the position of the measurement object 40 (step S36). The focus correction unit 28 performs focus correction on the determined position of the measurement object 40 to generate an image of the measurement object 40 (step S37).

[0059] Next, the hardware configuration of each device in the sensing system 30 will be described. In the transmitting device 10, the transmitting array 17 is composed of multiple transmitting antenna elements 18. The synchronization unit 11, radar signal generation unit 12, code generation unit 13, carrier signal generation unit 14, encoding unit 15, and high-frequency signal generation unit 16 are implemented by processing circuits. The processing circuits can be a processor and memory that executes programs stored in memory, or they can be dedicated hardware. The processing circuit is also called a control circuit.

[0060] Figure 7 This diagram shows a configuration example of a processing circuit 90 in the case where the processing circuit for realizing the transmission device 10 according to the first embodiment is realized using a processor 91 and a memory 92 . Figure 7The processing circuit 90 shown is a control circuit having a processor 91 and a memory 92. When the processing circuit 90 is composed of the processor 91 and the memory 92, the various functions of the processing circuit 90 are implemented by software, firmware, or a combination of software and firmware. The software or firmware is described as a program and stored in the memory 92. In the processing circuit 90, the processor 91 reads and executes the program stored in the memory 92, thereby implementing the various functions. In other words, the processing circuit 90 has a memory 92 for storing a program that results in the execution of the processing of the transmitting device 10. This program can also be said to be a program for causing the transmitting device 10 to execute the various functions implemented by the processing circuit 90. This program can be provided by a storage medium storing the program, or it can be provided by other means such as a communication medium.

[0061] The above-described program can be said to be a program that causes the transmitting device 10 to execute the following steps: a radar signal generating step, in which the radar signal generating unit 12 generates a radar signal as a wideband signal; a code generating step, in which the code generating unit 13 generates a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements 18 into the high-frequency signal transmitted from each transmitting antenna element 18 in the receiving device 20; an encoding step, in which the encoding unit 15 multiplies the radar signal and the code for each of the plurality of transmitting antenna elements 18; a carrier signal generating step, in which the carrier signal generating unit 14 generates a carrier signal to divide the frequency band available to the transmitting device 10 into a plurality of sub-bands and periodically switch the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements 18, thereby using the entire area of ​​the frequency band; a high-frequency signal generating step, in which the high-frequency signal generating unit 16 generates a high-frequency signal having a bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmits the signal from the plurality of transmitting antenna elements 18; and a synchronization step, in which the synchronization unit 11 controls the timing of generating the radar signal, the code, and the carrier signal.

[0062] Here, the processor 91 is, for example, a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP (Digital Signal Processor). Furthermore, the memory 92 is, for example, a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), EEPROM (registered trademark) (Electrically EPROM), a magnetic disk, a floppy disk, an optical disk, a compact disk, a minidisc, or a DVD (Digital Versatile Disc).

[0063] Figure 8 This diagram shows an example of a processing circuit 93 in the case where the processing circuit of the transmission device 10 according to the first embodiment is implemented by dedicated hardware. Figure 8 The processing circuit 93 shown may be, for example, a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof. The processing circuit may be partially implemented using dedicated hardware and partially implemented using software or firmware. Thus, the processing circuit can implement the aforementioned functions using dedicated hardware, software, firmware, or a combination thereof.

[0064] While the hardware structure of the transmitting device 10 has been described, the hardware structure of the receiving device 20 is similar. In the receiving device 20, the receiving array 21 is composed of multiple receiving antenna elements 22. The signal conversion unit 23, detection unit 24, correlation processing unit 25, MIMO transmission path reconstruction unit 26, layer extraction unit 27, and focus correction unit 28 are implemented by processing circuits. The processing circuits can be a processor and memory that executes a program stored in memory, or they can be dedicated hardware. Processing circuits are also called control circuits.

[0065] As described above, according to this embodiment, in the sensing system 30, the transmitting device 10 controls the timing of radar signal generation, code generation, and carrier signal generation, generates a high-frequency signal with a sub-band bandwidth, and transmits it from multiple transmitting antenna elements 18. The receiving device 20 receives the high-frequency signal transmitted from the transmitting device 10 and reflected or scattered by the measurement object 40. It uses the carrier signal, radar signal, and code generated by the transmitting device 10 to generate MIMO transmission path information and locate the position of the measurement object 40. This allows the sensing system 30 to improve the resolution when measuring the measurement object 40 at a close distance while using high-frequency signals at low cost. The sensing system 30 obtains the wide-band reflection and scattering information required for high-resolution imaging, enabling imaging at a desired distance, namely, tomography.

[0066] Implementation Method 2

[0067] In the second embodiment, a case where the sensing system includes a plurality of transmitting devices and a plurality of receiving devices will be described.

[0068] Figure 9: is a diagram showing an overview of the measurement assumed in the sensing system 30a of the second embodiment. The sensing system 30a is a system that includes a plurality of transmitting devices 10 and a plurality of receiving devices 20 and performs measurement of the measurement object 40. That is, in the second embodiment, the sensing system 30a is composed of a plurality of transmitting devices 10 and a plurality of receiving devices 20. Figure 9 In the figure, multiple transmitting devices 10 are represented as transmitting devices 10-1 and 10-2, and multiple receiving devices 20 are represented as receiving devices 20-1 and 20-2. However, the number of multiple transmitting devices 10 and multiple receiving devices 20 can be three or more. Sensing system 30a is a system in which multiple transmitting devices 10 and receiving devices 20 are located in close proximity, and the multiple transmitting devices 10 emit radio waves at the same time to perform sensing. In Embodiment 2, since the transmitting arrays 17 of the multiple transmitting devices 10 operate in close proximity, a mechanism is required to suppress interference between the transmitting arrays 17.

[0069] Figure 10 : is a diagram showing a configuration example of a sensing system 30a according to Embodiment 2. Figure 10 In the example of FIG. 1 , the sensing system 30 a includes N transmitting devices 10 - 1 to 10 -N as transmitting devices 10 and N receiving devices 20 - 1 to 20 -N as receiving devices 20 . Figure 10 The structures of the transmitting device 10-1 and the receiving device 20-1 shown are similar to those of the Figure 2 The illustrated transmitter 10 and receiver 20 have the same configuration. However, the synchronization unit 11 of transmitter 10-1 also instructs the other transmitters 10-2 to 10-N and receivers 20-2 to 20-N, which are operating simultaneously, on the timing of their respective operations. In the following description, the transmitters 10-1 to 10-N may be referred to as the transmitter 10, and the receivers 20-1 to 20-N may be referred to as the receiver 20.

[0070] The configurations of transmitting devices 10-2 through 10-N may be identical to that of transmitting device 10-1, or may be such that the synchronization unit 11 is omitted from transmitting device 10-1. If the configurations of transmitting devices 10-2 through 10-N are identical to that of transmitting device 10-1, for example, the synchronization unit 11 of transmitting device 10-1 serves as the master, and the synchronization units 11 of transmitting devices 10-2 through 10-N serve as the slaves. The synchronization unit 11 of transmitting device 10-1 instructs the synchronization units 11 of transmitting devices 10-2 through 10-N on the timing of each component's operation. This allows the synchronization units 11 of transmitting devices 10-2 through 10-N to instruct each component within their own device on the timing of their operation based on the instruction from the synchronization unit 11 of transmitting device 10-1. If the configurations of transmitting devices 10-2 through 10-N are such that the synchronization unit 11 is omitted from transmitting device 10-1, the synchronization unit 11 of transmitting device 10-1 directly instructs each component of transmitting devices 10-2 through 10-N on the timing of their operation. The following description uses as an example a case where the configuration of transmitting devices 10-2 to 10-N is the configuration of transmitting device 10-1 with the synchronization unit 11 deleted, i.e., a case where transmitting devices 10-2 to 10-N do not have the synchronization unit 11. The configuration of receiving devices 20-2 to 20-N is the same as that of receiving device 20-1.

[0071] The operation of the sensing system 30a will be described. The operation of the transmitting device 10-1 and the operation of the receiving device 20-1 are the same as the operation of the transmitting device 10 and the operation of the receiving device 20 in Embodiment 1, respectively. The transmitting device 10-K receives instructions from the synchronization unit 11 of the transmitting device 10-1 and activates its own radar signal generation unit 12 and code generation unit 13 at the same timing as the activation of the radar signal generation unit 12 and code generation unit 13 of the transmitting device 10-1. Note that K is an integer such that 2 ≤ K ≤ N. In this case, the code generation unit 13 of the transmitting device 10-K generates a code that minimizes correlation among the transmitting devices 10-1 to 10-N. Examples of the code generated by the code generation unit 13 of the transmitting device 10-K include M sequences, Gold codes, Walsh-Hadamard codes, and PN sequences, but are not limited to these codes as long as they are highly orthogonal. In the sensing system 30a, the carrier signal generator 14 and the high-frequency signal generator 16 of the transmitting devices 10-1 to 10-N perform the same operation in all the transmitting devices 10-1 to 10-N and switch the carrier frequency at the same timing.

[0072] In this way, the radar signal generators 12, code generators 13, and carrier signal generators 14 of the multiple transmitters 10-1 to 10-N operate synchronously. Furthermore, the code generators 13 of the multiple transmitters 10-1 to 10-N generate codes that exhibit low correlation among the multiple transmitters 10-1 to 10-N. The code generators 13 of the multiple transmitters 10-1 to 10-N generate orthogonal or quasi-orthogonal codes as codes that exhibit low correlation among the multiple transmitters 10-1 to 10-N. In other words, the multiple transmitters 10-1 to 10-N operate synchronously with radar signal generation, code generation, and carrier signal generation, generating codes that exhibit low correlation among the multiple transmitters 10-1 to 10-N.

[0073] The operations of receiving devices 20-2 through 20-N are similar to those of receiving device 20-1, i.e., receiving device 20 in Embodiment 1. The correlation processing unit 25 of receiving device 20-K performs correlation processing using the code used by transmitting device 10-K, suppressing signals from other transmitting devices 10 and extracting only the signal from transmitting device 10-K to generate MIMO transmission path information. In this way, the correlation processing units 25 of multiple receiving devices 20-1 through 20-N perform correlation processing using the code used by the corresponding transmitting device 10.

[0074] In addition, while the second embodiment assumes that the number of transmitting devices 10 and receiving devices 20 is the same, in sensing system 30a, the number of transmitting devices 10 and receiving devices 20 does not necessarily need to be the same. For example, when operating with two transmitting devices 10 (transmitting devices 10-1 and 10-2) and one receiving device 20 (receiving device 20A), receiving device 20A can generate MIMO transmission path information corresponding to two directions and output images corresponding to two directions by using the codes used by transmitting devices 10-1 and 10-2 through correlation processing unit 25. Furthermore, when operating with one transmitting device 10 (transmitting device 10) and two receiving devices 20 (receiving devices 20-1 and 20-2), receiving devices 20-1 and 20-2 can obtain images corresponding to their respective positional relationships by using the codes used by transmitting device 10A.

[0075] As described above, according to this embodiment, in sensing system 30a, multiple transmitters 10-1 to 10-N simultaneously transmit high-frequency signals, and multiple receivers 20-1 to 20-N perform measurements and imaging in parallel. This allows sensing system 30a to achieve faster imaging from multiple directions.

[0076] Implementation 3

[0077] In Embodiment 3, the high-frequency signals transmitted from the plurality of transmitters 10 described in Embodiment 2 are described in detail. The configurations of sensing system 30a, transmitters 10-1 to 10-N, and receivers 20-1 to 20-N in Embodiment 3 are the same as those of sensing system 30a, transmitters 10-1 to 10-N, and receivers 20-1 to 20-N in Embodiment 2.

[0078] The operation of the sensing system 30a according to the third embodiment will be described. Figure 11 This diagram shows an example of high-frequency signals transmitted from transmitting devices 10-1 and 10-2 in Embodiment 3. In Embodiment 3, the operations of transmitting device 10-1 and receiving device 20-1 are identical to those of transmitting device 10-1 and receiving device 20-1 in Embodiment 2, i.e., the operations of transmitting device 10 and receiving device 20 in Embodiment 1. However, the code generator 13 may generate the same code in multiple transmitting devices 10. Transmitting device 10-2, receiving instructions from the synchronization unit 11 of transmitting device 10-1, operates its own radar signal generator 12, code generator 13, and carrier signal generator 14 at the same timing as those of transmitting device 10-1. In this case, transmitting devices 10-1 and 10-2 need to avoid mutual interference. Therefore, the carrier signal generator 14 of transmitting device 10-2 uses a different frequency hopping pattern than the carrier signal generator 14 of transmitting device 10-1. Figure 11 The example in which the transmitting devices 10-1 and 10-2 transmit high frequency signals simultaneously is shown. As shown by the solid line, the transmitting device 10-1 switches the sub-band at a period T B As a unit, the sub-band is switched in the manner of sub-band 1 → sub-band 2 → sub-band 3 → ... to transmit the high frequency signal. On the other hand, as shown by the dotted line, the transmitting device 10-2 switches the sub-band in the sub-band switching cycle T B As a unit, in sub-band N B -1→Subband N B The high frequency signal is transmitted by switching the sub-band in the frequency hopping mode, that is, the sub-band selection mode different from that of the transmitting device 10 - 1 , such as -2 → sub-band 1 → ... .

[0079] In this way, the carrier signal generators 14 of the plurality of transmitting devices 10-1 to 10-N generate carrier signals of different sub-bands at the same time among the plurality of transmitting devices 10-1 to 10-N. Alternatively, the carrier signal generators 14 of the plurality of transmitting devices 10-1 to 10-N generate carrier signals using different frequency hopping patterns among the plurality of transmitting devices 10-1 to 10-N.

[0080] Receiving devices 20-1 and 20-2 receive high-frequency signals using the frequency hopping patterns of paired transmitting devices 10-1 and 10-2, enabling them to obtain reflected or scattered waves from the desired transmitting device 10. Generally, all transmitting devices 10-1 to 10-N use completely non-overlapping frequency hopping patterns. However, in situations where there are many transmitting devices 10, a frequency hopping pattern can be used that simultaneously uses the same sub-band for a portion of the time period. Furthermore, there does not necessarily need to be a one-to-one correspondence between transmitting devices 10 and receiving devices 20; a configuration in which one receiving device 20 corresponds to multiple transmitting devices 10 is also possible. In this case, receiving device 20 can receive signals using the frequency hopping patterns of multiple transmitting devices 10 simultaneously, or using frequency hopping patterns that differ in time division, such as using transmitting device 10-1 for a certain period and transmitting device 10-2 for another period.

[0081] As described above, according to this embodiment, in sensing system 30a, when multiple transmitting devices 10-1 to 10-N simultaneously transmit high-frequency signals, carrier signals of different sub-bands or carrier signals using different frequency hopping patterns are generated simultaneously among the multiple transmitting devices 10-1 to 10-N. Consequently, sensing system 30a can achieve the same effects as in Embodiment 2.

[0082] Implementation 4

[0083] In the fourth embodiment, a case is described in which the principle of synthetic aperture radar (hereinafter referred to as SAR) is applied to reduce the number of antenna elements in the array antennas, namely, the transmitting array 17 and the receiving array 21. The structures of the sensing system 30, transmitting device 10, and receiving device 20 in the fourth embodiment are the same as those of the first embodiment.

[0084] Figure 12 : is a diagram showing an overview of the measurement assumed in the sensing system 30 of the fourth embodiment. Figure 12 In the case shown, N is finally generated in the MIMO transmission path reconstruction unit 26 of the receiving device 20. T ×N R ×N F ×N B However, in the fourth embodiment, the number N of the transmitting antenna elements 18 of the transmitting array 17 is T , and the number N of receiving antenna elements 22 of the receiving array 21 R The number of antenna elements including virtual ones is set to be greater than N. T and NR Less. Figure 12 In the example shown in FIG. 1 , the two blackened rows of antenna elements in transmit array 17 and receive array 21 are actual antenna elements, while the other antenna elements, represented as hollow, are virtual antenna elements. In Embodiment 4, the measurement object 40 is assumed to be moving under known conditions, such as being placed on a belt conveyor 50 or traveling along a predetermined path.

[0085] The operation of sensing system 30 will be described. The operation of transmitting device 10 is the same as that of transmitting device 10 in Embodiment 1. Transmitting device 10 controls transmission timing via synchronization unit 11, generates and encodes radar signals, generates high-frequency signals, and transmits high-frequency signals from transmitting antenna elements 18, which are actual elements of transmitting array 17. Receiving device 20 performs the same processing as in Embodiment 1 using signal conversion unit 23, detection unit 24, correlation processing unit 25, and other means, to obtain MIMO transmission path information corresponding to the positions of the actual elements of transmitting array 17 and receiving array 21.

[0086] Figure 13 SAR is a diagram showing an example of a high frequency signal transmitted from the transmitting device 10 of Embodiment 4. SAR can virtually form a large-scale array antenna by utilizing the movement of the measurement object 40. Figure 13 As shown, first, transmitting device 10 uses transmitting antenna element 18, which is an actual element of transmitting array 17, to transmit high-frequency signals across all sub-bands during frame 1. Receiving device 20 uses receiving antenna element 22, which is an actual element of receiving array 21, to obtain MIMO transmission path information based on the actual element positions of transmitting array 17 and receiving array 21. Next, transmitting device 10 uses transmitting antenna element 18, which is an actual element of transmitting array 17, to transmit high-frequency signals across all sub-bands during frame 2. Receiving device 20 uses receiving antenna element 22, which is an actual element of receiving array 21, to obtain MIMO transmission path information based on the actual element positions of transmitting array 17 and receiving array 21. At this time, since measurement object 40 is moving, sensing system 30 can virtually obtain MIMO transmission path information equivalent to that obtained by measuring with the positions of transmitting antenna element 18 and receiving antenna element 22 shifted.

[0087] The position of the transmitting antenna element 18 and the position of the receiving antenna element 22 are offset depending on the positional relationship between the transmitting array 17, the receiving array 21, the measurement object 40, etc. As a result, the sensing system 30 can obtain MIMO transmission path information about the position of the virtual element that is offset from the actual element by transmitting and receiving high-frequency signals in frame 2. The sensing system 30 can obtain MIMO transmission path information about the position of the virtual element over time in frames 3 and 4, that is, as the measurement object 40 moves, and finally obtain N in the MIMO transmission path reconstruction unit 26. T ×N R ×N F ×N B MIMO transmission path information of elements. In the receiving device 20, the operations of the layer cutout unit 27 and the focus correction unit 28 after the MIMO transmission path reconstruction unit 26 are the same as those of the layer cutout unit 27 and the focus correction unit 28 of the first embodiment. Therefore, even if the actual number of transmission antenna elements 18 in the transmission array 17 of the transmitting device 10 is less than N T And the actual number of elements of the receiving antenna elements 22 of the receiving array 21 of the receiving device 20 is less than N R In the case of N, the receiving device 20 can also be similar to the embodiment 1, based on T ×N R ×N F ×N B The image is output by using the MIMO transmission path information of the elements.

[0088] While the description describes a case where the measurement target 40 moves relative to the transmitting antenna elements 18 of the transmitting array 17 of the transmitting device 10 and the receiving antenna elements 22 of the receiving array 21 of the receiving device 20, this is not limiting. For example, the measurement target 40 may be stationary while the transmitting device 10 and receiving device 20 move. Regarding the transmitting device 10 and receiving device 20, it is not necessary for both the transmitting device 10 and receiving device 20 to move as a whole. It suffices for the transmitting array 17 of the transmitting device 10 to move relative to the measurement target 40, and for the receiving array 21 of the receiving device 20 to move relative to the measurement target 40. In this way, in the sensing system 30, the positions of the multiple transmitting antenna elements 18 of the transmitting device 10 and the multiple receiving antenna elements 22 of the receiving device 20, or the movement of the measurement target 40, change the positions of the multiple transmitting antenna elements 18 of the transmitting device 10 and the multiple receiving antenna elements 22 of the receiving device 20 relative to the measurement target 40. The transmitting device 10 repeatedly transmits high-frequency signals using the entire available frequency band. The MIMO channel reconstruction unit 26 of the receiving device 20 generates channel information based on a larger number of transmitting antenna elements 18 than the actual number of the transmitting device 10 and a larger number of receiving antenna elements 22 than the actual number of the receiving device 20 .

[0089] As described above, according to this embodiment, the sensing system 30 can perform high-resolution measurements and high-resolution imaging with a smaller number of antenna elements by utilizing the movement of the measurement object 40 or the movement of multiple transmitting antenna elements 18 of the transmitting device 10 and multiple receiving antenna elements 22 of the receiving device 20.

[0090] Implementation 5

[0091] In the fifth embodiment, specific operations of the layer cutout unit 27 and the focus correction unit 28 of the receiving device 20 will be described.

[0092] Figure 14 This is a diagram showing the concept of the operation of the layer interception unit 27 of the receiving device 20 of embodiment 5. When the space of the measurement object 40 is divided into small areas, the small areas are called voxels. For example, when the transmitting array 17 of the transmitting device 10 and the receiving array 21 of the receiving device 20 face the same direction, when voxels that are measurement points at the same distance from the array surface of the transmitting array 17 or the receiving array 21 are collected, a curved surface is formed. When the curved surface is considered as a layer, the closer the layer is to the front, the shorter the path from the transmitting antenna element 18 → reflection point → receiving antenna element 22, and therefore the smaller the propagation delay time. The layer interception unit 27 utilizes such properties to extract only the signals within a specific delay time range from the measured received signal, thereby enabling layer interception. In Figure 14, an example is shown in which the layer cutting unit 27 divides and cuts the layers into four layers, L1, L2, L3, and L4, from the immediately preceding layer.

[0093] Figure 15 : is a diagram showing the concept of the operation of the focus correction unit 28 of the receiving device 20 according to the fifth embodiment. Figure 15 In FIG, the radar signal reflected by a particular voxel is shown to be received by the receiving antenna element 22 of the receiving array 21. Assuming that the receiving antenna element 22 in front of the voxel is numbered 0 and the receiving antenna elements 22 are arranged at an element spacing of p, in order to focus on the voxel, the phase rotation ξ expressed by the following equation must be applied to the kth receiving antenna element 22. k .

[0094] ξ k =-2π×(√(d 2 +(kp) 2 )) / λ…(1)

[0095] In formula (1), d is the distance from the array surface to the layer, and λ is the wavelength of the radar signal. In addition, √(d 2 +(kp) 2 ) means (d 2 +(kp) 2 ). If the receiving array 21 is a two-dimensional array antenna, the receiving antenna elements 22 are arranged on a plane. Therefore, the focus correction unit 28 calculates the phase rotation amount based on two dimensions. This phase rotation amount depends on the distance d, that is, it varies between layers. Therefore, the focus correction unit 28 performs focus correction processing for each layer and outputs an image. It is not necessary to apply the layer clipping processing by the layer clipping unit 27 or the focus correction processing by the focus correction unit 28 first; the order can be different.

[0096] Furthermore, when signals traveling in the same transmission direction or arriving from the same direction contain information about reflection points at multiple distances, the layer segmentation process by the layer segmentation unit 27 is necessary. Therefore, if the measurement object 40 is non-transparent to electromagnetic waves and the reflection point is located on the surface of the object, the reflected wave from a specific direction is limited to a single point, and thus the layer segmentation process by the layer segmentation unit 27 can be omitted.

[0097] The configuration described in the above embodiment is merely an example, and can be combined with other known technologies, the embodiments can be combined with each other, and part of the configuration can be omitted or modified without departing from the spirit of the invention.

[0098] Label Description

[0099] 10, 10-1 to 10-N: transmitting device; 11: synchronization unit; 12: radar signal generating unit; 13: code generating unit; 14: carrier signal generating unit; 15: encoding unit; 16: high-frequency signal generating unit; 17: transmitting array; 18: transmitting antenna element; 20, 20-1 to 20-N: receiving device; 21: receiving array; 22: receiving antenna element; 23: signal conversion unit; 24: detection unit; 25: correlation processing unit; 26: MIMO transmission path reproduction unit; 27: layer interception unit; 28: focus correction unit; 30, 30a: sensing system; 40: measurement object; 50: belt conveyor; 90, 93: processing circuit; 91: processor; 92: memory.

Claims

1. A sensing system, characterized in that: The sensing system has: a transmitting device having a plurality of transmitting antenna elements, controlling generation of a radar signal, generation of a code for separating, in a receiving device, the high-frequency signal transmitted from the plurality of transmitting antenna elements into the high-frequency signal transmitted from each transmitting antenna element, and timing for generating a carrier signal that divides a usable frequency band into a plurality of sub-bands and periodically switches the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements so as to use the entire region of the frequency band, multiplying the radar signal by the code for each of the plurality of transmitting antenna elements, generating the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmitting the high-frequency signal from the plurality of transmitting antenna elements; and The receiving device has multiple receiving antenna elements, receives the high-frequency signal sent from the transmitting device and reflected or scattered by the measured object, uses the carrier signal, the radar signal and the code to generate transmission path information indicating the state of the transmission path between the transmitting device and the receiving device, uses the transmission path information to determine the position of the measured object, performs focus correction on the measured object, and generates an image of the measured object.

2. The sensing system according to claim 1, wherein: The receiving device generates the transmission path information by multiplying the number of the plurality of transmitting antenna elements possessed by the transmitting device, the number of the plurality of receiving antenna elements possessed by the receiving device, the number of the sub-bands, and the number of frequency bins when the bandwidth of the sub-bands is divided into a plurality of frequency bins.

3. The sensing system according to claim 1 or 2, characterized in that: The transmitting device generates the code whose chip period is an integer multiple of the period of the radar signal.

4. The sensing system according to any one of claims 1 to 3, wherein: The receiving device determines the position of the measuring object by extracting reflection point information of the layer corresponding to the depth distance of the measuring object when observed from the multiple receiving antenna elements from the transmission path information, and performs focus correction corresponding to the position of the layer on the extracted reflection point information as focus correction of the measuring object.

5. The sensing system according to any one of claims 1 to 4, characterized in that: The sensing system is composed of a plurality of the transmitting devices and a plurality of the receiving devices. The plurality of transmitting devices operate synchronously with respect to generation of the radar signal, generation of the code, and generation of the carrier signal, and generate the code with low correlation among the plurality of transmitting devices. The plurality of receiving devices perform correlation processing using the code used in the corresponding transmitting device.

6. The sensing system according to claim 5, characterized in that The plurality of transmitting devices generate orthogonal codes or quasi-orthogonal codes as the codes having low correlation among the plurality of transmitting devices.

7. The sensing system according to claim 5 or 6, characterized in that: The plurality of transmitting devices generate the carrier signals of different sub-bands at the same time.

8. The sensing system according to claim 5 or 6, characterized in that: The plurality of transmitting devices generate the carrier signal using different frequency hopping patterns among the plurality of transmitting devices.

9. The sensing system according to any one of claims 1 to 8, wherein: While the positions of the plurality of transmitting antenna elements and the plurality of receiving antenna elements relative to the measurement object are changed by the plurality of transmitting antenna elements and the plurality of receiving antenna elements or the measurement object moving, The transmitting device repeatedly transmits the high frequency signal using the entire available frequency band. The receiving device generates the transmission path information based on a number greater than the number of the transmitting antenna elements actually included in the transmitting device and a number greater than the number of the receiving antenna elements actually included in the receiving device.

10. A transmitting device having a plurality of transmitting antenna elements, characterized in that: The sending device has: a radar signal generating unit that generates a radar signal as a wideband signal; a code generating unit for generating a code for separating, in a receiving device, the high-frequency signal transmitted from the plurality of transmitting antenna elements into the high-frequency signal transmitted from each transmitting antenna element; an encoding unit configured to multiply the radar signal and the code for each of the plurality of transmitting antenna elements; a carrier signal generating unit configured to generate a carrier signal so as to divide a frequency band usable by the transmitting apparatus into a plurality of sub-frequency bands and periodically switch the sub-frequency bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements to use the entire frequency band; a high-frequency signal generating unit that generates the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmits the high-frequency signal from the plurality of transmitting antenna elements; and A synchronization unit controls the timing of generating the radar signal, generating the code, and generating the carrier signal.

11. The transmitting device according to claim 10, characterized in that The code generation unit generates the code having a chip period that is an integral multiple of a period of the radar signal.

12. The transmitting device according to claim 10 or 11, characterized in that: A sensing system is formed by a plurality of the transmitting devices and a plurality of the receiving devices. The radar signal generating units, the code generating units, and the carrier signal generating units of the plurality of transmitting devices operate synchronously. The code generation units of the plurality of transmitting devices generate the codes having low correlation among the plurality of transmitting devices.

13. The transmitting device according to claim 12, wherein: The code generation units of the plurality of transmitting devices generate orthogonal codes or quasi-orthogonal codes as the codes having low correlation among the plurality of transmitting devices.

14. The transmitting device according to claim 12 or 13, characterized in that: The carrier signal generating units of the plurality of transmitting devices generate the carrier signals of different sub-bands at the same time among the plurality of transmitting devices.

15. The transmitting device according to claim 12 or 13, characterized in that: The carrier signal generating sections of the plurality of transmitting devices generate the carrier signals using frequency hopping patterns that differ between the plurality of transmitting devices.

16. The transmitting device according to any one of claims 10 to 15, characterized in that: The high-frequency signal is repeatedly transmitted using the entire frequency band while the positions of the plurality of transmitting antenna elements relative to the measurement object are changed by the plurality of transmitting antenna elements or the measurement object moving.

17. A receiving device having a plurality of receiving antenna elements, which receives reflected waves or scattered waves of high-frequency signals transmitted from a transmitting device having a plurality of transmitting antenna elements and reflected or scattered by a measurement object, characterized in that: The receiving device has: a signal conversion unit that converts the reflected waves or scattered waves of the high-frequency signal received by the plurality of receiving antenna elements into a reception signal in a frequency band of the radar signal used when the transmitting device generates the high-frequency signal, using a carrier signal used when the transmitting device generates the high-frequency signal; a detector for detecting the received signal using the radar signal to obtain received information, the received information being the reflected wave or the scattered wave of the high-frequency signal received by each receiving antenna element and including the high-frequency signal transmitted from the plurality of transmitting antenna elements; a correlation processing unit that performs correlation processing on the received information using a code used when encoding the radar signal in the transmitting device, thereby separating the received signal for each receiving antenna element into a signal for each transmitting antenna element transmitted from the transmitting device; a transmission path reproducing unit for generating transmission path information indicating a state of a transmission path between the transmitting device and the receiving device using the separated signal; a layer intercepting unit for determining a position of a measurement object using the transmission path information; as well as A focus correction unit performs focus correction on the measurement object whose position has been determined, and generates an image of the measurement object.

18. The receiving device according to claim 17, wherein: The transmitting device transmits the high-frequency signal so as to divide a usable frequency band into a plurality of sub-frequency bands and periodically switches the sub-frequency bands used in the high-frequency signal transmitted from the plurality of transmitting antenna elements to use the entire frequency band. The transmission path reproduction unit generates the transmission path information obtained by multiplying the number of the plurality of transmitting antenna elements possessed by the transmitting device, the number of the plurality of receiving antenna elements possessed by the receiving device, the number of the sub-bands, and the number of frequency bins when the bandwidth of the sub-bands is divided into a plurality of frequency bins.

19. The receiving device according to claim 17 or 18, characterized in that The layer extraction unit determines the position of the measurement object by extracting, from the transmission path information, information on reflection points of a layer corresponding to the distance in the depth direction of the measurement object when viewed from the plurality of receiving antenna elements. The focus correction unit performs focus correction corresponding to the position of the layer on the extracted reflection point information as focus correction of the measurement object.

20. The receiving device according to any one of claims 17 to 19, characterized in that A sensing system is formed by a plurality of the transmitting devices and a plurality of the receiving devices, wherein the plurality of the transmitting devices generate the codes with low correlation among the plurality of the transmitting devices. The correlation processing units of the plurality of receiving devices perform correlation processing using the codes used in the corresponding transmitting devices.

21. The receiving device according to any one of claims 17 to 20, characterized in that The high-frequency signal is repeatedly transmitted using the entire frequency band available to the transmitting device while changing the positions of the plurality of transmitting antenna elements and the plurality of receiving antenna elements relative to the measurement object by the plurality of transmitting antenna elements and the plurality of receiving antenna elements or the measurement object moving. The transmission path reproducing unit generates the transmission path information based on a number greater than the number of the transmitting antenna elements actually included in the transmitting device and a number greater than the number of the receiving antenna elements actually included in the receiving device.

22. A control circuit for controlling a sensor system having a transmitting device and a receiving device, wherein the transmitting device has a plurality of transmitting antenna elements and the receiving device has a plurality of receiving antenna elements, characterized in that: The control circuit causes the sensor system to: Controlling the generation of radar signals, generation of codes for separating the high-frequency signals transmitted from the plurality of transmitting antenna elements into the high-frequency signals transmitted from each transmitting antenna element in the receiving device, and timing for generating a carrier signal that uses the entire region of the frequency band by dividing a usable frequency band into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements, multiplying the radar signal by the code for each of the plurality of transmitting antenna elements, generating the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmitting the high-frequency signal from the plurality of transmitting antenna elements, It has multiple receiving antenna elements, receives the high-frequency signal sent from the transmitting device and reflected or scattered by the measured object, uses the carrier signal, the radar signal and the code to generate transmission path information indicating the state of the transmission path between the transmitting device and the receiving device, uses the transmission path information to determine the position of the measured object, performs focus correction on the measured object, and generates an image of the measured object.

23. A control circuit for controlling a transmitting device having a plurality of transmitting antenna elements, characterized in that: The control circuit enables the sending device to implement: Generate a radar signal as a wideband signal, generating a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements into the high-frequency signal transmitted from each transmitting antenna element in a receiving device, For each of the plurality of transmitting antenna elements, multiplying the radar signal and the code, generating a carrier signal so as to divide a frequency band usable by the transmitting device into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements to use the entire frequency band; The radar signal multiplied by the code and the carrier signal are used to generate the high-frequency signal having the bandwidth of the sub-band and transmit the signal from the plurality of transmitting antenna elements. The timing of generation of the radar signal, generation of the code, and generation of the carrier signal is controlled.

24. A control circuit for controlling a receiving device having a plurality of receiving antenna elements, the receiving device receiving a reflected wave or a scattered wave of a high-frequency signal transmitted from a transmitting device having a plurality of transmitting antenna elements and reflected or scattered by a measurement object, characterized in that: The control circuit enables the receiving device to implement: The reflected waves or scattered waves of the high-frequency signal received by the plurality of receiving antenna elements are converted into received signals in the frequency band of the radar signal used when the high-frequency signal was generated by the transmitting device using a carrier signal used when the high-frequency signal was generated by the transmitting device, The received signal is detected using the radar signal to obtain received information, the received information being the reflected wave or the scattered wave of the high-frequency signal received by each receiving antenna element and including the high-frequency signal transmitted from the plurality of transmitting antenna elements, performing correlation processing on the received information using a code used when encoding the radar signal in the transmitting device, and separating the received signal for each receiving antenna element into signals for each transmitting antenna element transmitted from the transmitting device; generating transmission path information indicating a state of a transmission path between the transmitting device and the receiving device using the separated signal, Using the transmission path information, the position of the measurement object is determined. Focus correction is performed on the measurement object whose position has been determined, and an image of the measurement object is generated.

25. A storage medium storing a program for controlling a sensor system having a transmitting device and a receiving device, wherein the transmitting device has a plurality of transmitting antenna elements and the receiving device has a plurality of receiving antenna elements, wherein: The program causes the sensor system to: Controlling the generation of radar signals, generation of codes for separating the high-frequency signals transmitted from the plurality of transmitting antenna elements into the high-frequency signals transmitted from each transmitting antenna element in the receiving device, and timing for generating a carrier signal that uses the entire region of the frequency band by dividing a usable frequency band into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements, multiplying the radar signal by the code for each of the plurality of transmitting antenna elements, generating the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmitting the high-frequency signal from the plurality of transmitting antenna elements, It has multiple receiving antenna elements, receives the high-frequency signal sent from the transmitting device and reflected or scattered by the measured object, uses the carrier signal, the radar signal and the code to generate transmission path information indicating the state of the transmission path between the transmitting device and the receiving device, uses the transmission path information to determine the position of the measured object, performs focus correction on the measured object, and generates an image of the measured object.

26. A storage medium storing a program for controlling a transmitting device having a plurality of transmitting antenna elements, characterized in that: The program causes the sending device to implement: Generate a radar signal as a wideband signal, generating a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements into the high-frequency signal transmitted from each transmitting antenna element in a receiving device, For each of the plurality of transmitting antenna elements, multiplying the radar signal and the code, generating a carrier signal so as to divide a frequency band usable by the transmitting device into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements to use the entire frequency band; The radar signal multiplied by the code and the carrier signal are used to generate the high-frequency signal having the bandwidth of the sub-band and transmit the signal from the plurality of transmitting antenna elements. The timing of generation of the radar signal, generation of the code, and generation of the carrier signal is controlled.

27. A storage medium storing a program for controlling a receiving device having a plurality of receiving antenna elements, the receiving device receiving a reflected wave or a scattered wave of a high-frequency signal transmitted from a transmitting device having a plurality of transmitting antenna elements and reflected or scattered by a measurement object, characterized in that: The program causes the receiving device to implement: The reflected waves or scattered waves of the high-frequency signal received by the plurality of receiving antenna elements are converted into received signals in the frequency band of the radar signal used when the high-frequency signal was generated by the transmitting device using a carrier signal used when the high-frequency signal was generated by the transmitting device, The received signal is detected using the radar signal to obtain received information, the received information being the reflected wave or the scattered wave of the high-frequency signal received by each receiving antenna element and including the high-frequency signal transmitted from the plurality of transmitting antenna elements, performing correlation processing on the received information using a code used when encoding the radar signal in the transmitting device, and separating the received signal for each receiving antenna element into signals for each transmitting antenna element transmitted from the transmitting device; generating transmission path information indicating a state of a transmission path between the transmitting device and the receiving device using the separated signal, Using the transmission path information, the position of the measurement object is determined. Focus correction is performed on the measurement object whose position has been determined, and an image of the measurement object is generated.

28. A sensing method, characterized in that: The sensing method comprises: a transmitting step, wherein a transmitting device includes a plurality of transmitting antenna elements, controls generation of a radar signal, generation of a code for separating, at a receiving device, the high-frequency signals transmitted from the plurality of transmitting antenna elements into the high-frequency signals transmitted from each transmitting antenna element, and timing for generating a carrier signal for dividing a usable frequency band into a plurality of sub-bands and periodically switching the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements so as to use the entire region of the frequency band; multiplies the radar signal by the code for each of the plurality of transmitting antenna elements, generates the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmits the signal from the plurality of transmitting antenna elements; as well as A receiving step, wherein the receiving device has multiple receiving antenna elements, receives the high-frequency signal sent from the transmitting device and reflected or scattered by the measured object, uses the carrier signal, the radar signal and the code to generate transmission path information indicating the state of the transmission path between the transmitting device and the receiving device, uses the transmission path information to determine the position of the measured object, performs focus correction on the measured object, and generates an image of the measured object.

29. A transmission method, which is a transmission method of a transmission device having a plurality of transmission antenna elements, characterized in that: The sending method includes: a radar signal generating step in which a radar signal generating unit generates a radar signal as a wideband signal; a code generating step in which a code generating unit generates a code for separating the high-frequency signal transmitted from the plurality of transmitting antenna elements into the high-frequency signal transmitted from each transmitting antenna element in a receiving device; an encoding step in which an encoding unit multiplies the radar signal by the code for each of the plurality of transmitting antenna elements; a carrier signal generating step, wherein the carrier signal generating unit generates a carrier signal so as to divide the frequency band usable by the transmitting apparatus into a plurality of sub-bands and periodically switch the sub-bands used in the high-frequency signals transmitted from the plurality of transmitting antenna elements to use the entire frequency band; a high-frequency signal generating step in which a high-frequency signal generating unit generates the high-frequency signal having the bandwidth of the sub-band using the radar signal multiplied by the code and the carrier signal, and transmits the high-frequency signal from the plurality of transmitting antenna elements; as well as In the synchronization step, a synchronization unit controls the timing of generating the radar signal, generating the code, and generating the carrier signal.

30. A receiving method, comprising: a receiving device having a plurality of receiving antenna elements, and receiving a reflected wave or a scattered wave of a high-frequency signal transmitted from a transmitting device having a plurality of transmitting antenna elements and reflected or scattered by a measurement object; The receiving method includes: a signal conversion step in which a signal conversion unit converts the reflected waves or scattered waves of the high-frequency signal received by the plurality of receiving antenna elements into a reception signal in a frequency band of the radar signal used when the high-frequency signal was generated by the transmitting device, using a carrier signal used when the high-frequency signal was generated by the transmitting device; a detection step in which a detection unit detects the received signal using the radar signal to obtain reception information, the reception information being the reflected wave or the scattered wave of the high-frequency signal received by each receiving antenna element and including the high-frequency signal transmitted from the plurality of transmitting antenna elements; a correlation processing step in which a correlation processing unit performs correlation processing on the received information using a code used when encoding the radar signal in the transmitting device, thereby separating the received signal for each receiving antenna element into signals for each transmitting antenna element transmitted from the transmitting device; a transmission path reproducing step in which a transmission path reproducing unit generates transmission path information indicating a state of a transmission path between the transmitting device and the receiving device using the separated signal; a layer interception step, wherein a layer interception unit determines a position of a measurement object using the transmission path information; as well as In the focus correction step, a focus correction unit performs focus correction on the measurement object whose position has been determined, and generates an image of the measurement object.

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