Sensing device, method with sensing device and program

Abstract

To prevent a direct wave from interfering with an indirect wave.SOLUTION: A sensing device 20 includes a radio wave reception section 20a configured to receive a sensing signal from a sensing transmitter 10, a channel matrix estimation section 20b configured to estimate a channel matrix based on the sensing signal, a transmission source specification section 20c configured to determine a direct wave out of the received sensing signal, a filter section 20d configured to remove frequency components having a phase fluctuation period equal to or less than a predetermined value from the channel matrix corresponding to the direct wave among the estimated channel matrices, and a Fourier transformation execution section 20e configured to perform a Fourier transformation on the estimated channel matrix.SELECTED DRAWING: Figure 11

Description

[Technical Field]

[0001] The present invention relates to a sensing device, a method using the sensing device, and a program, and more particularly to a sensing device, a method using the sensing device, and a program that prevent interference caused by direct waves when detecting an object to be detected. [Background technology]

[0002] The Third Generation Partnership Project (3GPP (registered trademark)) has defined wireless communication specifications called 5G NR (Fifth Generation New Radio), and technological development of these wireless specifications is progressing.

[0003] Following 5G NR, 6G systems, the sixth generation of wireless communication specifications, are also being considered. For 6G systems, technical specifications related to sensing solutions are being considered. Sensing solutions use the Doppler effect to detect targets by analyzing changes in the frequency spectrum of emitted radio waves.

[0004] Patent Document 1 discloses a technique in which a transmitting station transmits a search radio wave to a receiving station, and the receiving station receives and detects the search radio wave, thereby detecting a target. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 3040984 specification Summary of the Invention [Problem to be solved by the invention]

[0006] The technology described in Patent Document 1 detects the echo delay time from when the direct wave of the search radio wave is received until the echo is received when detecting a target object using the search radio wave from a transmitting station.

[0007] When detecting a target using radio waves from a transmitting station, as in the technology described in Patent Document 1, the receiving station receives radio waves directly from the transmitting station, i.e., direct waves, and radio waves reflected from other objects, i.e., indirect waves. The direct waves can interfere with the indirect waves. The technology described in Patent Document 1 does not prevent interference from direct waves.

[0008] In view of the above circumstances, the present invention provides a technique for preventing interference of direct waves with indirect waves that may occur when identifying a detection target. [Means for solving the problem]

[0009] In order to achieve the above object, the sensing device (20) of the present invention includes a radio wave receiving unit (20a) configured to receive a sensing signal from a sensing transmitter (10), a channel matrix estimation unit (20b) configured to estimate a channel matrix based on the sensing signal, a transmission source identification unit (20c) configured to determine a direct wave from the received sensing signal, a filter unit (20d) configured to remove frequency components that fall within a predetermined phase fluctuation period from the channel matrix corresponding to the direct wave from the estimated channel matrix, and a Fourier transform execution unit (20e) configured to execute a Fourier transform on the estimated channel matrix.

[0010] Furthermore, a method performed by the sensing device (20) of the present invention includes receiving a sensing signal from a sensing transmitter (10), estimating a channel matrix based on the sensing signal, determining a direct wave from the received sensing signal, removing frequency components that fall below a predetermined phase fluctuation period from the channel matrix corresponding to the direct wave from the estimated channel matrix, and performing a Fourier transform on the estimated channel matrix.

[0011] According to the above configuration, it is possible to prevent interference of the direct wave with the indirect wave by removing a specific frequency component of the direct wave. Note that the above configuration may achieve other effects instead of or in addition to the above effect. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 illustrates a sensing system. [Figure 2] FIG. 2 is a block diagram showing a schematic hardware configuration of a sensing transmitter. [Figure 3] FIG. 2 is a block diagram showing a schematic functional configuration of a sensing transmitter. [Figure 4] FIG. 2 is a block diagram showing a schematic hardware configuration of a sensing receiver. [Figure 5] FIG. 2 is a block diagram showing a schematic functional configuration of a sensing receiver. [Figure 6] FIG. 2 is a block diagram showing a schematic functional configuration of the sensing device. [Figure 7] FIG. 1 is a diagram illustrating an outline of receiving a direct wave and an indirect wave. [Figure 8] FIG. 2 is a diagram illustrating an outline of a sensing device and a method for calculating a distance to a detection target. [Figure 9] 10A and 10B are diagrams illustrating an outline of interference of a direct wave of a sensing signal with an indirect wave. [Figure 10] FIG. 10 is a diagram illustrating an outline of removing low-frequency components of a direct wave of a sensing signal. [Figure 11]4 is a flowchart showing sensing processing according to the first embodiment. [Figure 12] FIG. 1 shows ODFM data. [Figure 13] FIG. 10 illustrates a channel matrix estimated based on a reference signal and a phase. [Figure 14] 10 is a flowchart showing a sensing process according to the second embodiment. [Figure 15] 10 is a flowchart showing sensing processing according to the third embodiment. [Figure 16] 10 is a flowchart showing sensing processing according to the fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this specification and drawings, elements that can be similarly described will be designated by the same reference numerals, and redundant description will be omitted.

[0014] The embodiments described below are merely examples of configurations that can realize the present invention. Each of the following embodiments can be modified or changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions. Not all combinations of elements included in each of the following embodiments are necessarily essential for realizing the present invention, and some elements can be omitted as appropriate. Therefore, the scope of the present invention is not limited to the configurations described in each of the following embodiments. As long as there are no mutual contradictions, configurations that combine multiple configurations described in the following embodiments can also be adopted.

[0015] 1. First embodiment 1.1 Sensing system

[0016] In the first embodiment, a sensing channel and / or a sensing signal, which are defined separately from wireless communication, is used for radio waves used to perform sensing. Hereinafter, in this embodiment, a "sensing signal" is used to perform sensing. The sensing signal may be used interchangeably with the sensing channel.

[0017] In a first embodiment, sensing is performed by multiple devices. Sensing performed by multiple devices in this manner is referred to as "cooperative sensing." Cooperative sensing may be used interchangeably with group sensing, collaborative sensing, bistatic sensing, and multistatic sensing.

[0018] In collaborative sensing, sensing is performed by at least a sensing transmitter that transmits a sensing signal for performing sensing and a sensing receiver that receives the sensing signal. Sensing involves receiving a sensing signal transmitted to an object to be detected, such as a person or an obstacle, and analyzing changes in the frequency spectrum of the sensing signal to detect the object. Hereinafter, an object detected by sensing will be referred to as a "detection target." Detection targets include people, animals, objects, etc.

[0019] The sensing signal transmitted by the sensing transmitter is reflected from the target and its frequency spectrum changes due to the Doppler effect. The sensing receiver receives the sensing signal and analyzes the change in the frequency spectrum of the sensing signal to detect the target.

[0020] 1, the sensing system S according to the first embodiment includes one or more sensing transmitters 10 and one or more sensing receivers 20. The sensing receiver 20 may be referred to as a "sensing device" because it detects a detection target based on a sensing signal.

[0021] The sensing transmitter 10 transmits a sensing signal and a communication signal to the sensing receiver 20. As mentioned above, a sensing signal is a signal used to perform sensing, whereas a communication signal is a signal used to convey predetermined information to the sensing receiver 20. A communication signal may be used interchangeably with a communication channel.

[0022] The sensing transmitter 10 may be a device that wirelessly communicates with the sensing receiver 20, such as a user equipment (UE) that operates in accordance with the 3GPP 5G NR specification, or a terminal device that complies with other older or newer 3GPP specifications.

[0023] The sensing transmitter 10 may be, for example, a mobile phone terminal such as a smartphone, a tablet terminal, a laptop PC, a communication module, a communication card, or an IoT device such as a surveillance camera or a robot. The sensing transmitter 10 may be a vehicle (e.g., a car, a train, etc.) or a device provided therein. The sensing transmitter 10 may be a transport vehicle other than a vehicle (e.g., a ship, an airplane, etc.) or a device provided therein. The sensing transmitter 10 may be a sensor or a device provided therein. Note that the sensing transmitter 10 may be called a terminal, a mobile station, a mobile terminal, a mobile device, a mobile unit, a subscriber station, a subscriber terminal, a subscriber device, a subscriber unit, a wireless station, a wireless terminal, a wireless device, a wireless unit, a remote station, a remote terminal, a remote device, a remote unit, etc. The sensing transmitter 10 may be a device adapted for one or more of enhanced Mobile Broadband (eMBB), Ultra-Reliable and Low Latency Communications (URLLC), and massive Machine Type Communications (mMTC).

[0024] The sensing receiver 20 receives a sensing signal and a communication signal from the sensing transmitter 10. The sensing receiver 20 may be a device that wirelessly communicates with the sensing transmitter 10, and may be, for example, a base station device that operates in accordance with the 3GPP 5G NR specification. The sensing receiver 20 may also be a base station device that complies with other older or newer 3GPP specifications.

[0025] In the embodiment, the sensing transmitter 10 corresponds to a terminal device and the sensing receiver 20 corresponds to a base station device, but such a configuration is merely an example. For example, the sensing transmitter 10 may correspond to a base station device and the sensing receiver 20 may correspond to a terminal device. Furthermore, both the sensing transmitter 10 and the sensing receiver 20 may correspond to a terminal device. In other words, the sensing transmitter 10 may be any wireless communication device that transmits a sensing signal. The sensing receiver 20 may be any wireless communication device that receives a sensing signal.

[0026] 2, the sensing transmitter 10 includes, as hardware elements, a processor 101, a memory 102, an input / output interface 103, a transceiver 104, and an antenna 105. The above elements provided in the sensing transmitter 10 are connected to each other by an internal bus. Note that the sensing transmitter 10 may include hardware elements other than the elements shown in FIG. 2.

[0027] The processor 101 is a computing element that realizes various functions of the sensing transmitter 10. The processor 101 may be a SoC (System-on-a-Chip) that includes elements such as a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and a memory controller.

[0028] The memory 102 is configured by at least one storage medium such as a RAM (Random Access Memory) or an eMMC (embedded Multi Media Card). The memory 102 is an element that temporarily or permanently stores programs and data used to execute various processes in the sensing transmitter 10. The programs include one or more instructions for operating the sensing transmitter 10. The processor 101 implements the functions of the sensing transmitter 10 by loading the programs stored in the memory 102 into the memory 102 and / or a system memory (not shown) and executing them.

[0029] The input / output interface 103 is an interface that accepts operations on the sensing transmitter 10 and supplies them to the processor 101, and also presents various information to the user. The input / output interface 103 is, for example, a touch panel.

[0030] The transceiver 104 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The transceiver 104 transmits and receives wireless signals to and from the sensing receiver 20 via an antenna 105.

[0031] 3, the sensing transmitter 10 has, as functional blocks, a control unit 110 and a communication unit 120. The communication unit 120 has at least one transmission unit 121 and at least one reception unit 122.

[0032] The control unit 110 may include at least one processor 101 and at least one memory 102. In other words, the control unit 110 may be realized by the processor 101 and the memory 102. The control unit 110 executes various control processes in the sensing transmitter 10. For example, the control unit 110 controls wireless communication with the sensing receiver 20 via the communication unit 120. That is, the control unit 110 transmits and receives data / information / messages via the communication unit 120.

[0033] The communication unit 120 includes a transceiver 104 and an antenna 105. In other words, the communication unit 120 is realized by the transceiver 104 and the antenna 105. The communication unit 120 wirelessly communicates with the sensing receiver 20 by transmitting and receiving radio signals to and from the sensing receiver 20. Two or more transceivers 104 and two or more antennas 105 may be included in the communication unit 120.

[0034] The control unit 110 operates to execute various processes in the sensing transmitter 10 of this embodiment.

[0035] 4, the sensing receiver 20 has, as hardware elements, a processor 201, a memory 202, a network interface 203, a transceiver 204, and an antenna 205. The above elements provided in the sensing receiver 20 are connected to each other by an internal bus. Note that the sensing receiver 20 may have hardware elements other than the elements shown in FIG. 4.

[0036] The processor 201 is a computing element that realizes various functions of the sensing receiver 20. The processor 201 may be a CPU, and may further include other processors such as a GPU.

[0037] The memory 202 is configured by at least one storage medium such as a ROM (Read Only Memory), a RAM, an HDD (Hard Disk Drive), or an SSD (Solid State Drive). The memory 202 is an element that temporarily or permanently stores programs and data used to execute various processes in the sensing receiver 20. The programs include one or more instructions for operating the sensing receiver 20. The processor 201 implements the functions of the sensing receiver 20 by loading the programs stored in the memory 202 into the memory 202 and / or a system memory (not shown) and executing them.

[0038] The network interface 203 is an interface used to send and receive signals to and from other sensing receivers 20 and the core network 30 .

[0039] The transceiver 204 is a circuit that performs various signal processing to realize wireless communication, and includes a baseband processor and an RF circuit. The transceiver 204 transmits and receives wireless signals to and from the sensing receiver 10 via an antenna 205.

[0040] 5, the sensing receiver 20 has, as functional blocks, a control unit 210, a communication unit 220, and a network communication unit 230. The communication unit 220 has at least one transmission unit 221 and at least one reception unit 222.

[0041] The control unit 210 may include at least one processor 201 and at least one memory 202. In other words, the control unit 210 may be realized by the processor 201 and the memory 202. The control unit 210 executes various control processes in the sensing receiver 20. For example, the control unit 210 controls wireless communication with the sensing transmitter 10 via the communication unit 220. That is, the control unit 210 transmits and receives data / information / messages via the communication unit 220. Furthermore, for example, the control unit 210 controls communication with other nodes (e.g., other sensing receivers 20, nodes of the core network 30) via the network communication unit 230.

[0042] The communication unit 220 includes a transceiver 204 and an antenna 205. In other words, the communication unit 220 is realized by the transceiver 204 and the antenna 205. The communication unit 220 wirelessly communicates with the sensing transmitter 10 by transmitting and receiving radio signals to and from the sensing transmitter 10. Two or more transceivers 204 and two or more antennas 205 may be included in the communication unit 220.

[0043] The network communication unit 230 includes the network interface 203. In other words, the network communication unit 230 is realized by the network interface 203. The network interface 203 transmits and receives signals to and from the network (and, by extension, the other nodes described above).

[0044] The control unit 210 operates to execute various processes in the sensing receiver 20 of this embodiment.

[0045] 1.2 Functional configuration of the sensing device The functional configuration of the sensing receiver 20 will be described below. The sensing receiver 20 is the entity that performs sensing according to the first embodiment, and therefore will be referred to as the "sensing device 20" hereinafter. As shown in Fig. 6, the sensing device 20 has a radio wave receiving unit 20a, a channel matrix estimating unit 20b, a transmission source identifying unit 20c, a filter unit 20d, and a Fourier transform executing unit 20e, which are logical functional blocks for performing sensing according to the first embodiment.

[0046] The radio wave receiving unit 20a receives a sensing signal from the sensing transmitter 10. The radio wave receiving unit 20a also receives a communication signal from the sensing transmitter 10. The radio wave receiving unit 20a is realized by the communication unit 220 / transmitter / receiver 204 and the antenna 205.

[0047] The channel matrix estimation unit 20b measures the phase variation when the sensing signal propagates from the sensing transmitter 10 to the sensing device 20. The measured phase is expressed as a channel matrix. The channel matrix estimation unit 20b is realized by the control unit 210 / processor 201.

[0048] The transmission source identification unit 20c calculates the distance to the sensing transmitter 10, with the sensing device 20 as the base point, based on the sensing signal from the sensing transmitter 10. The transmission source identification unit 20c also calculates the distance to the sensing transmitter 10 based on the communication signal from the sensing transmitter 10. The transmission source identification unit 20c is realized by the control unit 210 / processor 201.

[0049] The filter unit 20d calculates a predetermined phase fluctuation period based on the distance from the sensing device 20 to the sensing transmitter 10. Then, the filter unit 20d removes frequency components equal to or less than the calculated phase fluctuation period, i.e., low-frequency components, from the channel matrix. The filter unit 20d is realized by the control unit 210 / processor 201.

[0050] The Fourier transform execution unit 20e executes a Fourier transform on the channel matrix to calculate the distance from the sensing device 20 to the detection target. The Fourier transform execution unit 20e is realized by the control unit 210 / processor 201.

[0051] 1.3 Interference of direct waves with interference waves In the above-described collaborative sensing, the entity that transmits the sensing signal is different from the entity that receives and analyzes the sensing signal. The sensing device 20 receives the sensing signal transmitted from the sensing transmitter 10. The sensing signal includes a sensing signal received directly from the sensing transmitter 10, i.e., a direct wave, and a sensing signal received after being reflected from another object, i.e., an indirect wave.

[0052] The following provides an overview of how the sensing device 20 receives direct waves and indirect waves. As shown in Fig. 7, the sensing device 20 receives a sensing signal transmitted from the sensing transmitter 10. The sensing device 20 detects detection objects SO1 and SO2 based on the sensing signal.

[0053] The sensing signal is reflected from the detection target SO1 and reaches the sensing device 20. The path of this sensing signal is represented as paths P1-1 and P1-2. The sensing signal is also reflected from the detection target SO2 and reaches the sensing device 20. The path of this sensing signal is represented as paths P2-1 and P2-2. Furthermore, the sensing signal reaches the sensing device 20 from the sensing transmitter 10. The path of this sensing signal is represented as path P3.

[0054] Hereinafter, the sensing signal passing through paths P1-1 and P1-2 will be referred to as sensing signal A. The sensing signal passing through paths P2-1 and P2-2 will be referred to as sensing signal B. The sensing signal passing through path P3 will be referred to as sensing signal C. Sensing signals A and B are reflected waves, and sensing signal C is a direct wave.

[0055] In conventional sensing technologies, for example, when calculating the distance to a detection target, a channel matrix is ​​estimated from a sensing signal and a Fourier transform such as DFT is performed on the channel matrix to calculate the distance. At this time, the received sensing signal includes a direct wave and an indirect wave. When performing the Fourier transform, interference between the direct wave and the indirect wave occurs, which can make it difficult to properly detect the detection target.

[0056] An outline of interference of a direct wave with an indirect wave will be described with reference to FIGS. 8 and 9. In the example shown in FIG. 8, the sensing device 20 calculates the distance r2 to the detection target SO2. As described above, the sensing device 20 receives a sensing signal C, which is a direct wave, and a sensing signal B, which is an indirect wave. Conventional sensing techniques do not determine whether a sensing signal is a direct wave. Therefore, the sensing device 20 not only calculates the distance r2 to the detection target SO2 based on the sensing signal B, but also calculates the distance r1 to the sensing transmitter 10 based on the sensing signal C.

[0057] To calculate the distances r1 and r2, the received powers of the sensing signals B and C are expressed as radar cross-section (RCS) values ​​in dBsm. The received power P of the sensing signal C is r is calculated by the following formula (1):

number

number

[0058] As shown in Fig. 9, when the sensing device 20 receives sensing signals B and C, it measures the phase variation for each of them and estimates the channel matrix. In Fig. 9, the phase variation measured for sensing signal C is represented as pv1, and the phase variation measured for sensing signal B is represented as pv2.

[0059] Then, the sensing device 20 performs a Fourier transform on the channel matrix corresponding to the phase fluctuations pv1 and pv2. By performing the Fourier transform, the distance r1 to the transmitter 10 and the distance r2 to the detection target SO2 are expressed by the DFT frequency. By performing the Fourier transform, the signal strength and distance of the sensing signal C received directly from the sensing transmitter 10 and the sensing signal B received after being reflected from the detection target SO2 are expressed as shown in the lower part of FIG.

[0060] The lower part of FIG. 9 shows the signal strength and distance r1 of sensing signal C obtained by performing a Fourier transform on phase fluctuation pv1. p1 indicates the peak of the signal strength of sensing signal C. Similarly, the lower part of FIG. 9 shows the signal strength and distance r2 of sensing signal B obtained by performing a Fourier transform on phase fluctuation pv2. p2 indicates the peak of the signal strength of sensing signal B.

[0061] Conventional sensing technology receives both a direct wave sensing signal and an indirect wave sensing signal, and performs a Fourier transform on the channel matrix corresponding to the received sensing signal. As shown in the lower part of Figure 9, the peak p2 of the signal strength of sensing signal B after the Fourier transform is lower than the signal strength of sensing signal C. In this state, the target cannot be detected accurately from sensing signal B. This can occur when the propagation times of the sensing signals are close to each other when the Fourier transform is performed on the channel matrix of the sensing signals.

[0062] 1.4 Removal of low frequency components of the direct wave The sensing device 20 according to the first embodiment removes low-frequency components from the channel matrix corresponding to sensing signals that can be considered as direct waves among the sensing signals received from the sensing transmitter 10. By removing the low-frequency components, the signal strength peak p1 of sensing signal C becomes lower, as shown in the lower part of FIG. 10 . As a result, the signal strength peak p2 of sensing signal B exceeds the signal strength of sensing signal C. In this way, interference of direct waves with indirect waves can be prevented, enabling accurate detection of the detection target.

[0063] In the example described above, the sensing device 20 detects the detection targets SO1 and SO2 shown in Fig. 7, and therefore the sensing signal received directly from the sensing transmitter 10 is not required to detect the detection targets SO1 and SO2. In the first embodiment, the direct wave component is substantially canceled by removing the low frequency component from the channel matrix corresponding to the sensing signal that can be considered as a direct wave.

[0064] An overview of the sensing process according to the first embodiment will be described with reference to Fig. 11. In the process shown in Fig. 11, the sensing device 20 calculates the distances to the detection targets SO1 and SO2 shown in Fig. 7 based on the sensing signal from the sensing transmitter 10.

[0065] In step S1101, the radio wave receiving unit 20a of the sensing device 20 receives sensing signals. The received sensing signals include sensing signals A, B, and C.

[0066] Next, in step S1102, the channel matrix estimation unit 20b of the sensing device 20 measures the phase fluctuation when the sensing signal propagates from the sensing transmitter 10 to the sensing device 20, and estimates the channel matrix. The channel matrix is ​​estimated for each of the sensing signals A, B, and C.

[0067] The sensing signal is a carrier wave modulated by Orthogonal Frequency Division Multiplexing (OFDM), in which data symbols are transmitted on multiple subcarriers arranged orthogonally.

[0068] In OFDM, a reference signal (RS) is periodically arranged in the subcarrier direction, the symbol direction, or both directions. The sensing transmitter 10 arranges a reference signal with a known initial phase when transmitting a sensing signal. In the example shown in FIG. 12, data is represented by blocks with white frames, and RSs are represented by blocks with black frames. As shown in FIG. 12, RSs are periodically arranged in both the subcarrier direction and the symbol direction.

[0069] The channel matrix estimation unit 20b generates a channel matrix representing phase fluctuations from the difference between a reference signal whose initial phase is known and each phase in the received sensing signal. In the example shown in Fig. 13, the signal showing the highest phase fluctuation is represented by a grid block. The signal showing the second highest phase fluctuation is represented by a checkerboard block. The signal showing the third highest phase fluctuation is represented by a diamond block. The signal showing the fourth highest phase fluctuation is represented by a diagonal-line block. The signal showing the fifth highest phase fluctuation is represented by a vertical-line block.

[0070] In this way, the channel matrix estimation unit 20b estimates the channel matrix representing the phase fluctuation based on the sensing signal.

[0071] Next, in step S1103, the transmission source identification unit 20c of the sensing device 20 calculates the source of the sensing signal, i.e., the distance to the sensing transmitter 10, with the sensing device 20 as the base point, based on the sensing signal from the sensing transmitter 10. The distance calculated here is also the distance that the sensing signal C propagates from the sensing transmitter 10 to the sensing device 20. As described above, the distance to the transmission source is calculated from the DFT frequency obtained by performing a Fourier transform on the channel matrix.

[0072] As described above, the sensing device 20 receives sensing signals A, B, and C. The transmission source identification unit 20c determines whether the received sensing signals are sensing signals received directly from the sensing transmitter 10, that is, whether they are direct waves. Of the sensing signals A, B, and C, sensing signal C is the sensing signal received directly from the sensing transmitter 10. Therefore, the transmission source identification unit 20c calculates the distance to the transmission source based on sensing signal C.

[0073] The direct wave, i.e., sensing signal C, arrives at the sensing device 20 earlier than the indirect waves, i.e., sensing signals A and B. Using this fact, the transmission source identification unit 20c selects, as the direct wave, the sensing signal that arrives earliest among the sensing signals received by the radio wave receiving unit 20a. Then, the transmission source identification unit 20c calculates the distance to the transmission source based on the selected sensing signal.

[0074] Alternatively, the distance to the transmitter may be calculated based on a communication signal transmitted from the sensing transmitter 10. In this case, the radio wave receiving unit 20a receives the communication signal from the sensing transmitter 10. As described above, the communication signal is a signal used to transmit predetermined information to the sensing receiver 20. The communication signal includes location information of the sensing transmitter 10.

[0075] The sensing transmitter 10 receives, via the transceiver 104 and the antenna 105, GNSS signals from a satellite positioning system (GNSS) that indicate the location of the sensing transmitter 10. The sensing transmitter 10 communicates location information about its own location to the sensing device 20 using communication signals.

[0076] The transmission source identification unit 20c calculates the distance to the transmission source based on the position of the sensing device 20 itself and the position of the sensing transmitter 10 indicated by the position information.

[0077] Next, in step S1104, the filter unit 20d of the sensing device 20 calculates a phase fluctuation period based on the distance to the transmission source calculated in step S1103. Then, the filter unit 20d removes frequency components equal to or less than the calculated phase fluctuation period from the channel matrix corresponding to the sensing signal C determined to be a direct wave. In other words, the filter unit 20d calculates a threshold frequency for removing low-frequency components, in other words, a threshold frequency for passing high-frequency components.

[0078] The distance from the sensing device 20 to the transmission source, i.e., the distance the sensing signal propagates, is proportional to the phase fluctuation of the signal. The longer the distance the sensing signal propagates, the greater the attenuation of the signal strength, and the closer its frequency characteristics become to those of an indirect wave. For example, by utilizing this, the filter unit 20d calculates the phase fluctuation period so that when the distance to the transmission source is long, only higher frequency components are filtered.

[0079] To calculate the phase fluctuation period, a mapping table showing the correlation between the distance from the sensing device 20 to the transmission source and the frequency characteristics of the sensing signal may be created, for example, based on experimentally obtained values. In step S1104, the phase fluctuation period may be calculated by referring to this mapping table.

[0080] The process in step S1104 substantially cancels the signal component of sensing signal C. In this way, the detection objects SO1 and SO2 can be detected based on sensing signals A and B without interference from sensing signal C.

[0081] In step S1105, the Fourier transform execution unit 20e calculates the distance from the sensing device 20 to the detection target SO1 by performing a Fourier transform on the channel matrix corresponding to sensing signal A out of the channel matrices estimated in step S1102. The distance is calculated from the DFT frequency. Similarly, the Fourier transform execution unit 20e calculates the distance from the sensing device 20 to the detection target SO2 by performing a Fourier transform on the channel matrix corresponding to sensing signal B out of the channel matrices estimated in step S1102.

[0082] The channel matrices corresponding to sensing signals A and B are selected corresponding to sensing signals other than the sensing signals determined to be direct waves in step S1103. In the process in step S1105, the direct wave component is substantially canceled, so the Fourier transform performing unit 20e can detect the detection target based on the indirect wave without interference from the direct wave caused by performing the Fourier transform.

[0083] The first embodiment has been described above. According to the first embodiment, the direct wave component is substantially canceled by removing the low-frequency component from the channel matrix corresponding to the direct wave. In this way, it is possible to improve the accuracy of detecting the detection target without interference from the direct wave caused by performing the Fourier transform.

[0084] In the first embodiment, an example of calculating the distance from the sensing device 20 to the detection target has been described, but the sensing device 20 is not limited to measuring the distance to the detection target. The first embodiment may be applied to any process of performing a Fourier transform on a channel matrix corresponding to a sensing signal when performing sensing.

[0085] 2. Second embodiment Next, a second embodiment will be described. In the first embodiment, the phase fluctuation period for removing low-frequency components from the channel matrix corresponding to the direct wave was calculated based on the distance from the sensing device to the sensing transmitter. With this method, if there is a detection target between the sensing device and the sensing transmitter, it may not be possible to sufficiently cancel the direct wave component. In the second embodiment, the phase fluctuation period is calculated based on the direction from the sensing device to the sensing transmitter.

[0086] When the sensing transmitter moves, it is assumed that the sensing transmitter may be in any direction relative to the sensing device, and in such a case, the frequency characteristics of the sensing signal received directly from the sensing transmitter will differ depending on the direction of the sensing transmitter relative to the sensing device.

[0087] In the second embodiment, this fact is utilized to calculate the phase fluctuation period based on the orientation of the sensing transmitter. The configuration of the sensing system in the second embodiment is similar to the configuration of the sensing system described in the first embodiment, so a detailed description thereof will be omitted. Furthermore, the configurations of the sensing transmitter and sensing receiver in the second embodiment are similar to the configurations of the sensing transmitter and sensing receiver described in the first embodiment, so a detailed description thereof will be omitted.

[0088] An overview of the sensing process according to the second embodiment will be described with reference to Fig. 14. In the process shown in Fig. 14, the sensing device 20 also calculates the distances to the detection targets SO1 and SO2 shown in Fig. 7 based on the sensing signal from the sensing transmitter 10.

[0089] In step S1401, the radio wave receiving unit 20a of the sensing device 20 receives sensing signals. The received sensing signals include sensing signals A, B, and C.

[0090] Next, in step S1402, the channel matrix estimation unit 20b of the sensing device 20 measures the phase fluctuation when the sensing signal propagates from the sensing transmitter 10 to the sensing device 20, and estimates the channel matrix. The channel matrix is ​​estimated for each of the sensing signals A, B, and C.

[0091] Next, in step S1403, the transmission source identification unit 20c of the sensing device 20 calculates the direction of the transmission source of the sensing signal, i.e., the sensing transmitter 10, with the sensing device 20 as the base point, based on the sensing signal from the sensing transmitter 10. The direction of the transmission source is calculated, for example, by providing multiple antennas 205 in the sensing device 20 and based on the phase difference of the sensing signals received by each of the antennas 205.

[0092] In step S1403, the direction to the transmission source is calculated based on the direct wave, that is, the sensing signal C. Whether or not the sensing signal C is a direct wave is determined in the same manner as in the first embodiment, and therefore detailed description thereof will be omitted.

[0093] Alternatively, the direction to the transmitter may be calculated based on a communication signal transmitted from the sensing transmitter 10. In this case, the radio wave receiving unit 20a receives the communication signal from the sensing transmitter 10. The communication signal includes location information of the sensing transmitter 10.

[0094] The transmission source identification unit 20c calculates the direction to the transmission source based on the position of the sensing device 20 itself and the position of the sensing transmitter 10 indicated by the position information.

[0095] Next, in step S1404, the filter unit 20d of the sensing device 20 calculates a phase fluctuation period based on the direction to the transmission source calculated in step S1403. Then, the filter unit 20d removes frequency components that are equal to or less than the calculated phase fluctuation period from the channel matrix corresponding to the sensing signal C determined to be a direct wave.

[0096] As described above, the frequency characteristics of the sensing signal C differ depending on the direction of the transmitter relative to the sensing device 20, so the phase fluctuation period is calculated based on the direction to the transmitter. To calculate the phase fluctuation period, a mapping table showing the correlation between the direction from the sensing device 20 to the transmitter and the frequency characteristics of the sensing signal may be created, for example, based on experimentally obtained values. In step S1404, the phase fluctuation period may be calculated by referring to this mapping table.

[0097] Next, in step S1405, the Fourier transform execution unit 20e calculates the distance from the sensing device 20 to the detection target SO1 by performing a Fourier transform on the channel matrix corresponding to the sensing signal A, among the channel matrices estimated in step S1402. The distance is calculated from the DFT frequency. A similar process is performed on the sensing signal B.

[0098] The second embodiment has been described above. According to the second embodiment, the direct wave component is substantially canceled based on the direction of the sensing transmitter with the sensing device as the base point. In this way, even if there is a detection target between the sensing device and the sensing transmitter, the direct wave component can be sufficiently canceled.

[0099] 3. Third embodiment Next, a third embodiment will be described. In the first embodiment, the phase fluctuation period for removing low-frequency components from the channel matrix corresponding to the direct wave was calculated based on the distance from the sensing device to the sensing transmitter. With this method, if there is a detection target between the sensing device and the sensing transmitter, it may not be possible to sufficiently cancel the direct wave component. In the third embodiment, the phase fluctuation period is calculated based on the speed at which the sensing transmitter moves.

[0100] When the sensing transmitter moves, the frequency characteristics of the sensing signal received directly from the sensing transmitter vary depending on the speed at which the sensing transmitter moves.

[0101] In the third embodiment, this fact is utilized to calculate the phase fluctuation period based on the speed of the sensing transmitter. The configuration of the sensing system in the third embodiment is similar to the configuration of the sensing system described in the first embodiment, so a detailed description thereof will be omitted. Furthermore, the configurations of the sensing transmitter and sensing receiver in the third embodiment are similar to the configurations of the sensing transmitter and sensing receiver described in the first embodiment, so a detailed description thereof will be omitted.

[0102] An overview of the sensing process according to the third embodiment will be described with reference to Fig. 15. In the process shown in Fig. 15, the sensing device 20 also calculates the distances to the detection targets SO1 and SO2 shown in Fig. 7 based on the sensing signal from the sensing transmitter 10.

[0103] In step S1501, the radio wave receiving unit 20a of the sensing device 20 receives sensing signals. The received sensing signals include sensing signals A, B, and C.

[0104] Next, in step S1502, the channel matrix estimation unit 20b of the sensing device 20 measures the phase fluctuation when the sensing signal propagates from the sensing transmitter 10 to the sensing device 20, and estimates the channel matrix. The channel matrix is ​​estimated for each of the sensing signals A, B, and C.

[0105] Next, in step S1503, the transmission source identification unit 20c of the sensing device 20 calculates the transmission source of the sensing signal, i.e., the moving speed of the sensing transmitter 10, based on the sensing signal from the sensing transmitter 10. The moving speed of the sensing transmitter 10 is calculated, for example, based on the phase difference between sensing signals received by the antenna 205 consecutively in time.

[0106] In step S1503, the speed of the transmission source is calculated based on the direct wave, that is, the sensing signal C. Whether or not the sensing signal C is a direct wave is determined in the same manner as in the first embodiment, and therefore detailed description thereof will be omitted.

[0107] Alternatively, the speed of the transmitter may be calculated based on a communication signal transmitted from the sensing transmitter 10. In this case, the radio wave receiving unit 20a receives the communication signal from the sensing transmitter 10. The communication signal includes speed information of the sensing transmitter 10.

[0108] The sensing transmitter 10 includes an acceleration sensor (not shown). The control unit 110 of the sensing transmitter 10 calculates the speed at which the sensing transmitter 10 itself is moving by integrating data detected by the acceleration sensor. The sensing transmitter 10 transmits speed information relating to the speed at which the sensing transmitter 10 itself is moving to the sensing device 20 using a communication signal.

[0109] The transmission source identification unit 20c calculates the speed of the transmission source based on the speed information transmitted from the sensing transmitter 10.

[0110] Next, in step S1504, the filter unit 20d of the sensing device 20 calculates a phase fluctuation period based on the speed of the transmission source calculated in step S1503. Then, the filter unit 20d removes frequency components that are equal to or less than the calculated phase fluctuation period from the channel matrix corresponding to the sensing signal C determined to be a direct wave.

[0111] As described above, the frequency characteristics of the sensing signal C vary depending on the speed of the transmitter, so the phase fluctuation period is calculated based on the speed of the transmitter. To calculate the phase fluctuation period, a mapping table showing the correlation between the speed of the transmitter and the frequency characteristics of the sensing signal may be created, for example, based on experimentally obtained values. In step S1504, the phase fluctuation period may be calculated by referring to this mapping table.

[0112] In step S1505, the Fourier transform execution unit 20e calculates the distance from the sensing device 20 to the detection target SO1 by performing a Fourier transform on the channel matrix corresponding to the sensing signal A, among the channel matrices estimated in step S1502. The distance is calculated from the DFT frequency. A similar process is performed on the sensing signal B.

[0113] The third embodiment has been described above. According to the third embodiment, the direct wave component is substantially canceled based on the speed at which the sensing transmitter moves. In this way, even if there is a detection target between the sensing device and the sensing transmitter, the direct wave component can be sufficiently canceled.

[0114] In the first embodiment, the phase fluctuation period for removing low-frequency components from the channel matrix corresponding to the direct wave is calculated based on the distance from the sensing device to the sensing transmitter. In the second embodiment, the phase fluctuation period is calculated based on the direction to the sensing transmitter from the sensing device as the base point. In the third embodiment, the phase fluctuation period is calculated based on the speed at which the sensing transmitter moves.

[0115] The above-mentioned distance, direction, and speed are calculated in the manner described in each embodiment, and the phase fluctuation period may be calculated based on any one of the distance, direction, and speed, or any combination thereof. In other words, the phase fluctuation period for removing low-frequency components from the channel matrix corresponding to the direct wave may be calculated based on any one of the distance from the sensing device to the sensing transmitter, the direction from the sensing device to the sensing transmitter, and the speed at which the sensing transmitter moves, or any combination thereof.

[0116] 4. Fourth embodiment Next, a fourth embodiment will be described. In the first to third embodiments, the sensing signal that arrives earliest among the sensing signals received by the sensing device is selected, and low-frequency components are removed from the channel matrix corresponding to the selected sensing signal. In the first to third embodiments, it is assumed that the sensing device always receives the direct wave, but in cases where there are many obstacles between the sensing device and the sensing transmitter, the sensing device does not always receive the direct wave. If the sensing device does not receive the direct wave, interference of the direct wave with the indirect wave cannot occur.

[0117] In the fourth embodiment, a case is assumed in which the sensing device does not receive direct waves. The configuration of the sensing system in the fourth embodiment is similar to the configuration of the sensing system described in the first embodiment, so a detailed description thereof will be omitted. Furthermore, the configurations of the sensing transmitter and sensing receiver in the fourth embodiment are similar to the configurations of the sensing transmitter and sensing receiver described in the first embodiment, so a detailed description thereof will be omitted.

[0118] An overview of the sensing process according to the fourth embodiment will be described with reference to Fig. 16. In the process shown in Fig. 16, the sensing device 20 also calculates the distances to the detection targets SO1 and SO2 shown in Fig. 7 based on the sensing signal from the sensing transmitter 10.

[0119] In step S1601, the radio wave receiving unit 20a of the sensing device 20 receives sensing signals. The received sensing signals include sensing signals A, B, and C.

[0120] Next, in step S1602, the channel matrix estimation unit 20b of the sensing device 20 measures phase fluctuations when the sensing signals propagate from the sensing transmitter 10 to the sensing device 20, and estimates a channel matrix. A channel matrix is ​​estimated for each of the sensing signals A, B, and C. Then, the channel matrix estimation unit 20b performs a Fourier transform on the estimated channel matrix to calculate the signal strength of each.

[0121] Next, in step S1603, the transmission source identification unit 20c of the sensing device 20 selects a sensing signal that can be regarded as a direct wave from among the sensing signals A, B, and C received in step S1001, based on the calculated signal strength. In this embodiment, sensing signal C is selected.

[0122] The direct wave, i.e., sensing signal C, is less attenuated than the indirect wave, i.e., sensing signals A and B. Utilizing this, the transmission source identification unit 20c selects, from among the sensing signals received by the radio wave receiving unit 20a, a sensing signal having a certain level of signal strength as the sensing signal to be used to identify the location of the transmission source. When there are multiple sensing signals having a certain level of signal strength, the transmission source identification unit 20c selects the sensing signal having the strongest signal strength.

[0123] The selection of the sensing signal in step S1603 may be performed based on the signal strength of the sensing signal that arrived earliest from the sensing device, as described in the first embodiment. In other words, whether the sensing signal that arrived earliest is the sensing signal directly received from the sensing transmitter 10 is determined depending on whether the signal strength of the sensing signal that arrived earliest is at a certain level.

[0124] If it is determined in step S1603 that there is no sensing signal having a certain level of signal strength, the process proceeds to step S1606. Alternatively, the process may resume from step S1601 after waiting for a certain period of time, taking into consideration that the sensing device 20 may not be able to receive direct waves due to a temporary cause.

[0125] In step S1604, the transmission source identification unit 20c of the sensing device 20 calculates the position of the transmission source, the direction to the transmission source, and / or the speed of the transmission source based on the sensing signal selected as a direct wave in step S1603. The position of the transmission source, the direction to the transmission source, and / or the speed of the transmission source have been described in the first to third embodiments, so detailed description thereof will be omitted.

[0126] Next, in step S1605, the filter unit 20d of the sensing device 20 calculates a phase fluctuation period based on any one or any combination of the position of the transmitter, the direction to the transmitter, and / or the speed of the transmitter calculated in step S1604. Then, the filter unit 20d removes frequency components that are equal to or less than the calculated phase fluctuation period from the channel matrix corresponding to the sensing signal C determined to be a direct wave.

[0127] Next, in step S1606, the Fourier transform execution unit 20e calculates the distance from the sensing device 20 to the detection target SO1 by performing a Fourier transform on the channel matrix corresponding to the sensing signal A, among the channel matrices estimated in step S1602. The distance is calculated from the DFT frequency. A similar process is performed on the sensing signal B.

[0128] The fourth embodiment has been described above. According to the fourth embodiment, the location of the transmitter is identified based on a sensing signal having a certain level of signal strength. In this way, it is possible to improve the efficiency of the process of canceling direct waves by taking into account an environment in which the sensing device does not receive direct waves.

[0129] 5. Variations Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to the above-described embodiments. It is to be understood that the above-described embodiments are merely examples and that various modifications are possible.

[0130] The words, phrases, and other expressions used in the above embodiments are merely examples and may be replaced with substantially identical or similar expressions. In particular, since the technology according to the above embodiments relates to technical specifications, the expressions in the above embodiments may be replaced with substantially identical or similar expressions in technical specifications (e.g., technical specifications cited in this specification).

[0131] The information transmitted and received in the above embodiment may be contained in the same or a different message or element already described in the technical specifications, or may be contained in a newly defined message or element. The information transmitted and received in the above embodiment may be transmitted and received using a different layer and / or a different channel than those in the above embodiment.

[0132] The means and / or functions provided by the devices described in the above embodiments can be provided by software recorded in a tangible memory device and a computer that executes the software, software alone, hardware alone, or a combination thereof. For example, if any of the above devices is provided by electronic circuits that are hardware, it can be provided by digital circuits including a large number of logic circuits, or analog circuits.

[0133] The device described in the above embodiment executes a program stored in a non-transitory tangible storage medium, and the execution of the program executes a method corresponding to the program.

[0134] 6. Notes Some or all of the above embodiments and modified examples may be described as, but are not limited to, the following notes. Hereinafter, a relationship is expressed in which a note that is subordinate to multiple notes is subordinate to another note that is subordinate to multiple notes. All of the following subordinate relationships of notes are included in the above embodiments.

[0135] (Appendix 1) A sensing device (20), a radio wave receiving unit (20a) configured to receive a sensing signal from the sensing transmitter (10); a channel matrix estimation unit (20b) configured to estimate a channel matrix based on the sensing signal; a transmission source identification unit (20c) configured to determine direct waves from the received sensing signals; a filter unit (20d) configured to remove frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; a Fourier transform performing unit (20e) configured to perform a Fourier transform on the estimated channel matrix; A sensing device comprising:

[0136] (Appendix 2) the transmission source identification unit is further configured to calculate a distance to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on the distance. 2. The sensing device of claim 1.

[0137] (Appendix 3) 3. The sensing device according to claim 2, wherein the transmission source identification unit is further configured to calculate the distance from a sensing signal corresponding to a direct wave among the received sensing signals.

[0138] (Appendix 4) the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including location information regarding a location of the sensing transmitter; The source identification unit is further configured to calculate the distance based on the location information. 3. The sensing device of claim 2.

[0139] (Appendix 5) the source identification unit is further configured to calculate a direction to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on the azimuth. 5. A sensing device according to any one of claims 1 to 4.

[0140] (Appendix 6) 6. The sensing device according to claim 5, wherein the transmission source identification unit is further configured to calculate the direction from a sensing signal corresponding to a direct wave among the received sensing signals.

[0141] (Appendix 7) the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including location information regarding a location of the sensing transmitter; The transmission source identification unit is further configured to calculate the direction based on the location information. 6. The sensing device of claim 5.

[0142] (Appendix 8) the transmission source identification unit is further configured to calculate a speed at which the sensing device is moving; The filter unit is further configured to calculate the phase fluctuation period based on the velocity. A sensing device according to any one of appendices 1 to 7.

[0143] (Appendix 9) 9. The sensing device according to claim 8, wherein the transmission source identification unit is further configured to calculate the velocity from a sensing signal corresponding to a direct wave among the received sensing signals.

[0144] (Appendix 10) the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including speed information relating to a speed at which the sensing transmitter is moving; The source identification unit is further configured to calculate the speed based on the speed information. 9. The sensing device of claim 8.

[0145] (Appendix 11) the source identification unit is further configured to calculate a direction to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on either or both of the distance and the orientation. 5. A sensing device according to any one of claims 2 to 4.

[0146] (Appendix 12) the transmission source identification unit is further configured to calculate a speed at which the sensing device is moving; The filter unit is further configured to calculate the phase fluctuation period based on any one or any combination of the distance, the orientation, and the velocity. 12. The sensing device of claim 11.

[0147] (Appendix 13) 13. The sensing device according to any one of claims 1 to 12, wherein the transmission source identification unit is further configured to determine that the sensing signal that arrives earliest among the received sensing signals is a direct wave.

[0148] (Appendix 14) 14. The sensing device according to any one of claims 1 to 13, wherein the transmission source identification unit is further configured to determine whether the sensing signal is a direct wave based on signal strength.

[0149] (Appendix 15) the transmission source identification unit determines whether the sensing signal has a certain level of signal strength; If there is no sensing signal with a certain level of signal strength, after a certain time has elapsed, the radio wave receiving unit is further configured to receive a sensing signal from the sensing transmitter; The transmission source identification unit is further configured to determine whether the sensing signal has a certain level of signal strength. 15. The sensing device of claim 14.

[0150] (Appendix 16) the sensing signal includes a reference signal; the channel matrix estimator is further configured to estimate the channel matrix based on phases of the reference signal and the sensing signal. 16. A sensing device according to any one of claims 1 to 15.

[0151] (Appendix 17) the sensing signal is modulated by an orthogonal frequency division multiplexing method; the reference signals are periodically arranged in a subcarrier direction, a symbol direction, or both directions; the channel matrix estimation unit is further configured to estimate the channel matrix based on a reference signal, of the arranged reference signals, whose initial phase is known when the sensing transmitter transmits the sensing signal. 17. The sensing device of claim 16.

[0152] (Appendix 18) A method performed by a sensing device (20), comprising: receiving a sensing signal from a sensing transmitter (10); estimating a channel matrix based on the sensing signal; determining a direct wave from the received sensing signal; removing frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; performing a Fourier transform on the estimated channel matrix; A method comprising:

[0153] (Appendix 19) When executed, the processor (101) in the sensing device (20) receiving a sensing signal from a sensing transmitter (10); estimating a channel matrix based on the sensing signal; determining a direct wave from the received sensing signal; removing frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; performing a Fourier transform on the estimated channel matrix; A program that executes.

[0154] (Appendix 20) When executed, the processor (101) in the sensing device (20) receiving a sensing signal from a sensing transmitter (10); estimating a channel matrix based on the sensing signal; determining a direct wave from the received sensing signal; removing frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; performing a Fourier transform on the estimated channel matrix; A computer-readable non-transitory tangible recording medium storing a program for executing the above.

[0155] The disclosures of the above prior art documents and references are incorporated herein by reference. [Explanation of symbols]

[0156] 10 sensing transmitter, 101 processor, 102 memory, 104 transceiver, 110 control unit, 120 communication unit, 20 sensing receiver, 201 processor, 202 memory, 204 transceiver, 210 control unit, 220 communication unit

Claims

1. A sensing device (20), a radio wave receiving unit (20a) configured to receive a sensing signal from a sensing transmitter (10); a channel matrix estimation unit (20b) configured to estimate a channel matrix based on the sensing signal; a transmission source identification unit (20c) configured to determine direct waves from the received sensing signals; a filter unit (20d) configured to remove frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; a Fourier transform performing unit (20e) configured to perform a Fourier transform on the estimated channel matrix; A sensing device comprising:

2. the transmission source identification unit is further configured to calculate a distance to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on the distance. The sensing device according to claim 1 .

3. The sensing device according to claim 2 , wherein the transmission source identification unit is further configured to calculate the distance from a sensing signal corresponding to a direct wave among the received sensing signals.

4. the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including location information regarding a location of the sensing transmitter; The source identification unit is further configured to calculate the distance based on the location information. The sensing device according to claim 2 .

5. the source identification unit is further configured to calculate a direction to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on the azimuth. The sensing device according to claim 1 .

6. The sensing device according to claim 5 , wherein the transmission source identification unit is further configured to calculate the direction from a sensing signal corresponding to a direct wave among the received sensing signals.

7. the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including location information regarding a location of the sensing transmitter; The transmission source identification unit is further configured to calculate the direction based on the location information. The sensing device according to claim 5 .

8. the transmission source identification unit is further configured to calculate a speed at which the sensing device is moving; The filter unit is further configured to calculate the phase fluctuation period based on the velocity. The sensing device according to claim 1 .

9. The sensing device according to claim 8 , wherein the transmission source identification unit is further configured to calculate the velocity from a sensing signal corresponding to a direct wave among the received sensing signals.

10. the radio wave receiver is further configured to receive a communication signal from the sensing transmitter, the communication signal including speed information relating to a speed at which the sensing transmitter is moving; The source identification unit is further configured to calculate the speed based on the speed information. The sensing device according to claim 8 .

11. the source identification unit is further configured to calculate a direction to the sensing device; The filter unit is further configured to calculate the phase fluctuation period based on either or both of the distance and the orientation. The sensing device according to claim 2 .

12. the transmission source identification unit is further configured to calculate a speed at which the sensing device is moving; The filter unit is further configured to calculate the phase fluctuation period based on any one or any combination of the distance, the orientation, and the velocity. The sensing device according to claim 11 .

13. The sensing device according to claim 1 , wherein the transmission source identification unit is further configured to determine that the sensing signal that arrives earliest among the received sensing signals is a direct wave.

14. The sensing device according to claim 1 , wherein the transmission source identification unit is further configured to determine whether the sensing signal is a direct wave based on signal strength.

15. the transmission source identification unit determines whether the sensing signal has a certain level of signal strength; If there is no sensing signal with a certain level of signal strength, after a certain time has elapsed, the radio wave receiving unit is further configured to receive a sensing signal from the sensing transmitter; The transmission source identification unit is further configured to determine whether the sensing signal has a certain level of signal strength. The sensing device according to claim 14.

16. the sensing signal includes a reference signal; the channel matrix estimator is further configured to estimate the channel matrix based on phases of the reference signal and the sensing signal. The sensing device according to claim 1 .

17. the sensing signal is modulated by an orthogonal frequency division multiplexing method; the reference signals are periodically arranged in a subcarrier direction, a symbol direction, or both directions; the channel matrix estimation unit is further configured to estimate the channel matrix based on a reference signal, of the arranged reference signals, whose initial phase is known when the sensing transmitter transmits the sensing signal. The sensing device according to claim 16.

18. A method performed by a sensing device (20), comprising: receiving a sensing signal from a sensing transmitter (10); estimating a channel matrix based on the sensing signal; determining a direct wave from the received sensing signal; removing frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; performing a Fourier transform on the estimated channel matrix; A method comprising:

19. When executed, the processor (101) in the sensing device (20) receiving a sensing signal from a sensing transmitter (10); estimating a channel matrix based on the sensing signal; determining a direct wave from the received sensing signal; removing frequency components having a phase fluctuation period equal to or shorter than a predetermined period from the channel matrix corresponding to the direct wave among the estimated channel matrices; performing a Fourier transform on the estimated channel matrix; A program that executes.

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