Sensor, control method and system

Abstract

The sensor (110) includes a complex transfer function calculation section (301) that calculates a complex transfer function from a received signal, a reflection coefficient calculation section (302) that calculates a complex transfer function when a detection object is disposed at one of the L positions, and calculates an ideal complex transfer function that is a theoretical value of the position at which the detection object is disposed, for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, a variety of normalization sections (303) that calculate a normalized reflection coefficient in which the reflection coefficient is normalized, a reflection coefficient interpolation section (304) that performs interpolation calculation of the reflection coefficient using the normalized reflection coefficient for each coordinate used for position estimation of the detection object, thereby calculating an interpolated reflection coefficient, and a position estimation section (306) that performs correction of the position estimation using a steering vector determined based on the positions of the transmission antenna element and the reception antenna element, and the interpolated reflection coefficient.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a sensor, a control method, and a system that estimate a position of a living body using a wireless signal. BACKGROUND

[0002] As a method of knowing the position of a person or the like, a method using a wireless signal has been studied (for example, refer to Patent Documents 1 to 3). A method of living body detection using a Doppler sensor is disclosed in Patent Document 1, and a method of detection of human motion and living body information using a Doppler sensor and a filter is disclosed in Patent Document 2. In Patent Document 3, it is disclosed that by using Fourier transform to analyze a component including a Doppler shift, it is possible to know the position and state of a person who is a detection target. In Patent Document 4, a method of performing correction of an array antenna for estimating the position of a person using a wireless signal is disclosed.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-512526

[0006] Patent Document 2: International Publication No. 2014 / 141519

[0007] Patent Document 3: Japanese Patent Application Laid-Open No. 2015-117972

[0008] Patent Document 4: Japanese Patent No. 6256681 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] However, in the method of Patent Document 4, there is a problem that correction cannot be sufficiently performed for an antenna having directivity. This is because, if it is an ideal non-directional antenna, there is no angle characteristic in the radiation characteristic, but since a general antenna has a physical length, in a case where a correction value is taken at a point while there is an angle characteristic, the angle range in which the correction value can be effectively used is limited.

[0011] The present disclosure was completed in view of the above circumstances, and aims to provide a sensor that can perform correction of an apparatus in a short time and with high accuracy in a simple method in a device that estimates the position of a living body using a wireless signal.

[0012] MEANS FOR SOLVING THE PROBLEM

[0013] The sensor of the technical solution of the present disclosure includes a transmission antenna unit having N (N is a natural number of 2 or more) transmission antenna elements that transmit a signal to a predetermined space; a reception antenna unit that receives the signal transmitted by the transmission antenna unit during a predetermined period, and has M (M is a natural number of 2 or more) reception antenna elements that receive a reception signal; a complex transfer function calculation unit that calculates a complex transfer function based on the reception signal; a reflection coefficient calculation unit that calculates a complex transfer function when a detection object is arranged at one of L (L is a natural number of 2 or more) positions, and calculates an ideal complex transfer function as a theoretical value of the position where the detection object is arranged for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function; a normalized reflection coefficient calculation unit that calculates a normalized reflection coefficient by normalizing the reflection coefficient by a predetermined method; an interpolated reflection coefficient calculation unit that performs interpolation calculation of the reflection coefficient using the normalized reflection coefficient for each coordinate used for position estimation of the detection object by a predetermined method, thereby calculating an interpolated reflection coefficient; and a position estimation unit that performs correction of position estimation based on a predetermined method using a steering vector determined based on positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

[0014] In addition, these general or specific technical solutions can be implemented not only by a system, apparatus, integrated circuit, computer program, or computer-readable CD-ROM and the like recording medium, but also by any combination of the system, apparatus, integrated circuit, computer program, and recording medium.

[0015] Effects of the Invention

[0016] According to the present disclosure, in a device for position estimation of a living body using a wireless signal, the calibration of the device can be performed in a simple manner, in a short time, and with high accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural diagram showing an example of the structure of the sensor in the embodiment.

[0018] Figure 2 is a diagram for explaining Figure 1 the steering vector and phase error of the receiver shown in FIG. 8.

[0019] Figure 3 is a structural diagram showing Figure 1 an example of the detailed structure of the reception circuit shown in FIG. 9.

[0020] Figure 4 is a diagram showing the configuration of the experimental device.

[0021] Figure 5 is a graph representing a concept of a coordinate of position estimation by an experiment using an estimation method of the embodiment.

[0022] Figure 6 is a flowchart representing an estimation process of an estimation device in the embodiment.

[0023] Figure 7 is a structure diagram representing a modification example of a structure of a sensor in the embodiment.

[0024] Figure 8 is a calculation result example of position estimation by an existing method as a prior example in the embodiment.

[0025] Figure 9 is a calculation result example of position estimation by the embodiment.

[0026] Figure 10 is a graph representing an example of a cumulative probability distribution (CDF: Cumulative Distribution Function) of position estimation errors based on an existing method and the method of the embodiment. DETAILED DESCRIPTION

[0027] (Insight as a basis of the present disclosure)

[0028] As a method of knowing the position or the like of a person, a method of utilizing a wireless signal has been studied.

[0029] For example, a method of living body detection using a Doppler sensor is disclosed in Patent Literature 1, and a method of detection of human motion or living body information using a Doppler sensor and a filter is disclosed in Patent Literature 2.

[0030] Further, a technology of transmitting a wireless signal to a prescribed area, receiving a wireless signal reflected by a detection object with a plurality of antennas, and estimating a complex transfer function between the transmitting and receiving antennas is disclosed, for example, in Patent Literature 3.

[0031] A method of calibration of an array antenna for estimating a position of a person using a wireless signal is disclosed in Patent Literature 4. More specifically, a detection object is arranged at a known position, a complex transfer function matrix between a transmitter and a receiver is measured, a correlation matrix is calculated based on a frequency response of the complex transfer function, and a correction value of a steering vector is calculated using the case where the position of the detection object is known. According to the above, a method of calibration of an array antenna for estimating a position of a person using a wireless signal is disclosed in Patent Literature 4.

[0032] However, the method of Patent Document 4 above cannot cope with the calibration of an antenna having a characteristic in directivity. This is because, in the case of using an antenna having no directivity, if a calibration value is taken at one point, it can be spread to all measurement positions, but in an antenna having a characteristic in directivity, a change occurs in the radiation phase or radiation signal strength depending on the position.

[0033] Generally, a dipole antenna has uniform radiation characteristics in the same plane, while a patch antenna has uniform radiation characteristics in the front. That is, the characteristics in the same plane of the dipole antenna or the front characteristics of the patch antenna are uniform in the antenna elements (for example, the receiving antenna elements 121 to 123 shown in the drawing) regardless of the angle θ. Figure 2

[0034] However, there is no antenna having uniform radiation characteristics in a spherical shape in all directions. Furthermore, in a civil product such as a Wi-Fi (registered trademark) wireless device, in order to optimize the radiation characteristics in all directions, an antenna having irregular directivity such as an inverted F antenna is sometimes used.

[0035] Thus, in the case of using an antenna having irregular directivity, the antenna characteristics (for example, the antenna characteristics 221 to 223 shown in the drawing) of the antenna elements vary depending on the angle θ. Therefore, in order to be able to estimate the position of a living body in all angles, if the calibration value is calculated without considering the directivity of the antenna, the estimation accuracy of the direction or position of the person decreases.

[0036] Thus, in the related art, there is a problem that the calibration value for estimating the position of a living body using a wireless signal cannot be calculated corresponding to all angles.

[0037] Therefore, the inventors conceived a sensor or the like that calculates the calibration value for estimating the position of a living body using a wireless signal corresponding to all angles in view of this situation.

[0038] ​The sensor of the technical solution of the present disclosure includes: a transmission antenna unit having N (N is a natural number of 2 or more) transmission antenna elements that transmit signals to a specified space; a reception antenna unit that receives signals transmitted by the transmission antenna unit during a specified period, and has M (M is a natural number of 2 or more) reception antenna elements that receive the received signals; a complex transfer function calculation unit that calculates a complex transfer function based on the received signals; a reflection coefficient calculation unit that calculates a complex transfer function when a detection object is arranged at one of L (L is a natural number of 2 or more) positions, and calculates an ideal complex transfer function as a theoretical value of the position where the detection object is arranged for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function; a normalized reflection coefficient calculation unit that calculates a normalized reflection coefficient by normalizing the reflection coefficient by a specified method; an interpolated reflection coefficient calculation unit that performs interpolation calculation of the reflection coefficient for each coordinate used for position estimation of the detection object using the normalized reflection coefficient by a specified method, thereby calculating an interpolated reflection coefficient; and a position estimation unit that performs correction of position estimation based on a specified method using a steering vector determined based on the positions of the transmission antenna elements and the reception antenna elements, and the interpolated reflection coefficient.

[0039] According to the above technical solution, the sensor can perform position estimation of a living body by correcting the position estimation with high precision even when the sensor has an antenna with directivity. According to the present technology, the living body position estimation technology can be applied to a communication device having an antenna with a wide radiation range (e.g., an inverted F antenna or a metal plate antenna) compared to an antenna with a simple shape or a specific characteristic (e.g., a dipole antenna, a monopole antenna, or a patch antenna). Thus, the precision of the position estimation of the sensor having an antenna with a wide radiation range can be improved. Therefore, the sensor can perform correction of the device in a simple method in a short time and with high precision in a device that performs position estimation of a living body using a wireless signal.

[0040] In addition, the sensor of the technical solution of the present disclosure includes a transmission antenna unit having N (N is a natural number of 2 or more) transmission antenna elements that transmit a signal to a predetermined space; a reception antenna unit that receives the signal transmitted by the transmission antenna unit during a predetermined period, and has M (M is a natural number of 2 or more) reception antenna elements that receive the received signal; a complex transfer function calculation unit that calculates a complex transfer function based on the received signal; a reflection coefficient calculation unit that calculates a complex transfer function when a detection object is arranged at one of L (L is a natural number of 2 or more) positions, and calculates an ideal complex transfer function as a theoretical value of the position where the detection object is arranged for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function; a normalized reflection coefficient calculation unit that calculates a normalized reflection coefficient by normalizing the reflection coefficient by a predetermined method; and a memory that stores the normalized reflection coefficient.

[0041] According to the above technical solution, the sensor can correct the position estimation with high precision even when the antenna has directivity, which helps to estimate the position of the living body. According to the present technology, the living body position estimation technology can be applied to a communication device having an antenna with a wide radiation range (e.g., an inverted F antenna or a metal plate antenna) compared to an antenna with a simple shape or a specific characteristic (e.g., a dipole antenna, a monopole antenna, or a patch antenna). Thus, the precision of the position estimation using a sensor having an antenna with a wide radiation range can be improved. Therefore, the sensor can correct the device in a short time and with high precision in a device that estimates the position of the living body using a wireless signal.

[0042] For example, the sensor can include an interpolation reflection coefficient calculation unit that reads out the normalized reflection coefficient from the memory, and performs interpolation calculation of the reflection coefficient using the normalized reflection coefficient for each coordinate of the position estimation of the detection object by a predetermined method, thereby calculating an interpolated reflection coefficient; and a position estimation unit that performs correction of the position estimation based on a predetermined method using a steering vector determined based on the positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

[0043] According to the above-described technical solution, the sensor can perform position estimation of the living body by correcting the position estimation with high precision even when the sensor has an antenna with directivity. According to the present technology, the living body position estimation technology can be applied to a communication device having an antenna with a wide radiation range (for example, an inverted F antenna or a metal plate antenna) as compared to an antenna with a limited radiation direction but with a simple shape or characteristics (for example, a dipole antenna, a monopole antenna, or a patch antenna). Thus, the precision of position estimation using a sensor having an antenna with a wide radiation range can be improved. Therefore, the sensor can perform correction of the device in a short time and with high precision in a simple manner in a device that performs position estimation of a living body using a wireless signal.

[0044] For example, the position estimation unit can include a modified steering vector calculation unit that calculates a modified steering vector using the steering vector and the interpolated reflection coefficient modified steering vector, and the position estimation unit can perform correction of the position estimation using the modified steering vector calculated by the modified steering vector calculation unit.

[0045] According to the above-described technical solution, the sensor uses a modified steering vector obtained by using correction of a steering vector and an interpolated reflection coefficient to perform correction of position estimation, and thus can more easily perform configuration of the device in a short time and with high precision.

[0046] For example, the normalized reflection coefficient calculation unit can normalize the phase in the frequency direction using the received signal of a specified antenna element of the M received antenna elements.

[0047] According to the above-described technical solution, the sensor uses a received signal having a phase normalized in the frequency direction to perform position estimation. Thus, the sensor can perform correction of the device in a short time and with high precision in a simple manner in a device that performs position estimation of a living body using a wireless signal.

[0048] For example, the normalized reflection coefficient calculation unit can also normalize the phase for each measurement position.

[0049] According to the above-described technical solution, the sensor uses a received signal having a phase normalized for each measurement position to perform position estimation. Thus, the sensor can perform correction of the device in a short time and with high precision in a simple manner in a device that performs position estimation of a living body using a wireless signal.

[0050] The control method of the technical solution of the present disclosure is a control method of a sensor provided with a transmission antenna section having N (N is a natural number of 2 or more) transmission antenna elements that transmit a signal to a prescribed space and a reception antenna section having M (M is a natural number of 2 or more) reception antenna elements that receive a signal transmitted by the transmission antenna section during a prescribed period, the control method calculates a complex transfer function from the reception signal, calculates a complex transfer function when a detection object is disposed at one of L (L is a natural number of 2 or more) positions for each of the L positions, and calculates an ideal complex transfer function that is a theoretical value of a position at which the detection object is disposed for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, calculates a standardized reflection coefficient after the reflection coefficient is standardized by a prescribed method, performs an interpolation calculation of a reflection coefficient using the standardized reflection coefficient for each coordinate used for position estimation of a detection object by a prescribed method, thereby calculating an interpolated reflection coefficient, and performs correction of position estimation based on a prescribed method using a steering vector determined based on respective positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

[0051] According to the above technical solution, the same effect as the above sensor is achieved.

[0052] The system of the technical solution of the present disclosure is a system provided with the above sensor and a server, the sensor transmits a result of the position estimation to the server, and the server receives the result of the position estimation transmitted by the sensor.

[0053] According to the above technical solution, the same effect as the above sensor is achieved.

[0054] Furthermore, the present disclosure can be realized not only as a device but also as an integrated circuit provided with a processing unit of such a device, or as a method in which a processing unit constituting the device is taken as a step, or as a program in which a computer executes these steps, or as information, data, or a signal representing the program. Furthermore, these programs, information, data, and signals can be distributed via a recording medium such as a CD-ROM or a communication medium such as the Internet.

[0055] In addition, the sensor of the present disclosure includes a device that estimates a position of a living body, and is also sometimes referred to as a position estimation device or the like.

[0056] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In addition, each of the embodiments described below indicates one preferred specific example of the present disclosure. The numerical values, shapes, materials, component elements, arrangement positions of component elements, connection modes, steps, order of steps, and the like shown in the following embodiments are examples, and are not intended to limit the present disclosure. In addition, regarding the component elements in the following embodiments that are not described in the component elements of the independent technical solution representing the most general concept of the present disclosure, they are described as arbitrary component elements constituting a more preferred mode. Furthermore, in the present specification and drawings, component elements having substantially the same function structure are denoted by the same reference numerals, and thus repeated description is sometimes omitted.

[0057] (Embodiment)

[0058] Hereinafter, with reference to the drawings, a correction method of the sensor 110 in the embodiment for performing the living body position estimation of the living body 60 as the detection object (or estimation object) will be described.

[0059] [Structure of Sensor 110]

[0060] Figure 1 is a structural diagram showing an example of the structure of the sensor 110 in the present embodiment. Figure 2 is a diagram for explaining Figure 1 the steering vector and the phase error of the receiver 10 shown in Figure 3 is a diagram for explaining Figure 1 the detailed structure of the reception circuit 40 shown in Figure 4 is a diagram for explaining the arrangement of the experimental apparatus. Figure 5 is a diagram showing the concept of the coordinates of the position estimation performed by the experiment using the estimation method of the present embodiment.

[0061] The sensor 110 in the present disclosure is configured to include a receiver 10 and a transmitter 11.

[0062] The receiver 10 is configured to include an M R (M R is a natural number of 2 or more) number of reception antenna elements, a reception unit 30, a reception circuit 40, and a memory 50.

[0063] The transmitter 11 is configured to include an M T (M T is a natural number of 1 or more) number of transmission antenna elements, a transmission unit 31, and a transmission circuit 41.

[0064] Figure 4 shows the arrangement of the experimental apparatus of the present embodiment. The receiver 10 and the transmitter 11 are arranged apart by 4 m, for example, and a prescribed region A1 is taken as the measurement range.

[0065] M T A transmitting antenna element sends a transmitting signal to a designated area A1 containing the organism 60. The transmitting signal is a high-frequency signal such as microwave generated by a transmitter 11, etc.

[0066] The organism 60 is a person or similar entity. The organism 60 is the object of estimation by the sensor 110; it is the organism whose position is to be estimated. The defined region A1 refers to a pre-determined spatial range that includes the organism 60. In other words, the defined region A1 is the space used by the sensor 110 to estimate the position of the organism 60.

[0067] For example, in this embodiment, when the organism is positioned in Figure 4 In the state of the marked × position, the receiving unit 30 receives the first received signal, and the receiving circuit 40 calculates the reflection coefficient. Then, for Figure 5 The intersections of the auxiliary lines shown are fine grids. By calculating the interpolation value of the reflection coefficient and correcting the turning vector, the position estimation accuracy of the organism 60 is improved.

[0068] The transmitting antenna section 21 has M T A transmitting antenna element, and for example transmits a first transmitting signal to a designated area A1 of the organism 60 containing the measurement object.

[0069] The receiving antenna section 20 has M R A receiving antenna element is configured at the corner of a designated area A1. The receiving antenna section 20 uses M... R A receiving antenna element receives a first received signal containing a reflected signal obtained by reflecting a signal transmitted by a living organism 60 during a specified period.

[0070] [Sender 11]

[0071] In this embodiment, the receiver 10 and transmitter 11 are respectively disposed at the corners of a designated area A1. The transmitter 11 transmits a signal to the designated area A1 containing a living organism 60 such as a human. Then, the receiver 10 receives a received signal containing a reflected signal obtained by the reflection of the transmitted signal by the living organism 60. For example, two sets of receiver 10 and two sets of transmitter 11 may be used, and the two receivers 10 and the two transmitters 11 may be disposed at the four corners of the designated area A1.

[0072] like Figure 1 As shown, the transmitting unit 31 uses M T A single antenna element transmits a signal to a designated area A1. More specifically, the transmitting unit 31 uses M... T Each antenna element transmits microwaves as a signal to a living organism such as a human being 60. Furthermore, the transmitting unit 31 uses M... TThe antenna elements can transmit an unmodulated transmission signal or a transmission signal that has been subjected to modulation processing. In the case of transmitting a transmission signal that has been subjected to modulation processing, the transmission circuit 41 can also include a circuit for performing modulation processing.

[0073] In addition, the frequency used as an example in the present embodiment is 2.4 GHz, but any frequency such as 5 GHz or a millimeter wave band can be used. In addition, the transmission antenna elements and the reception antenna elements can be used in common. Furthermore, the transmission antenna elements and the reception antenna elements can be shared with the hardware of a wireless device such as a Wi-Fi router or a Wi-Fi sub.

[0074] [Receiver 10]

[0075] In addition, the reception antenna section 20 uses M R antenna elements to receive a reception signal including a signal obtained by reflecting a transmission signal by the living body 60, that is, a reflection signal, during a prescribed period. The reception section 30 outputs the received reception signal to the reception circuit 40. In addition, the reception section 30 can include a circuit for processing the reception signal. In this case, the reception section 30 can perform frequency conversion on the received reception signal and convert it into a low-frequency signal. Furthermore, the reception section 30 can perform demodulation processing on the reception signal. Then, the reception section 30 outputs the signal obtained by the frequency conversion and / or the demodulation processing to the reception circuit 40.

[0076] In addition, in the example shown in Figure 1 , the transmission section 31 and the reception section 30 are each provided for transmission and reception, but are not limited thereto. The number of antenna elements can be four, eight, or more, and the transmission section 31 and the reception section 30 can be included in one sensor 111 as shown in Figure 7 . Furthermore, the transmission antenna section 21 and the reception antenna section 20 can be shared.

[0077] [Memory 50]

[0078] The memory 50 is an auxiliary storage device having a nonvolatile storage area, and is, for example, a ROM (Read Only Memory), a flash memory, an HDD (Hard Disk Drive), or the like. The memory 50 stores, for example, information used for various processes for causing the sensor 110 to operate.

[0079] In the present embodiment, as shown in Figure 1 , the experimental apparatus is configured to include the receiver 10 and the transmitter 11.

[0080] [Reception circuit 40]

[0081] The receiving circuit 40 performs various processes to activate the sensor 110. The receiving circuit 40 is configured, for example, to include a processor (e.g., a CPU) for executing control programs and a volatile storage area (main storage device) used as a working area for executing the control program. This storage area is, for example, RAM (Random Access Memory).

[0082] The receiving circuit 40 temporarily stores the first received signal obtained from the receiving unit 30 in the storage area for a predetermined period of time. The receiving circuit 40 may also temporarily store the phase and amplitude of the first received signal in the storage area for a predetermined period of time. In this embodiment, the receiving circuit 40 temporarily stores the received signal obtained from the receiving unit 30 in the storage area for a predetermined period of time.

[0083] Furthermore, the receiving circuit 40 may also be composed of dedicated circuitry for performing various processes to activate the sensor 110. That is, the receiving circuit 40 may be a circuit for software processing or a circuit for hardware processing. In addition, the receiving circuit 40 may also have a non-volatile storage area.

[0084] Next, the functional structure of the receiving circuit 40 will be explained.

[0085] like Figure 3 As shown, the receiving circuit 40 includes a complex transfer function calculation unit 301, a reflection coefficient calculation unit 302, various standardization units 303, a reflection coefficient interpolation unit 304, a steering vector correction unit 305, and a position estimation unit 306. The structure of the receiving circuit 40 will be described in detail below.

[0086] <Complex Transfer Function Calculation Unit 301>

[0087] The complex transfer function calculation unit 301 uses the first received signal stored in the storage area of ​​the receiving circuit 40 to calculate the complex transfer function H(t). The first received signal may also be a signal that extracts only the predetermined frequency components contained in the signal received by the receiving unit 30. The predetermined frequency components may include, for example, the frequency of human breathing (e.g., about 0.15 Hz to about 0.5 Hz).

[0088] Here, the M-type receiver 10 will be used. r Each receiving antenna element and transmitter 11 has M t The complex transfer function H(t) obtained when a MIMO (Multiple-Input and Multiple-Output) array antenna consisting of transmitting antenna elements is arranged around the organism 60 is expressed by the following (Equation 1).

[0089] [Math. 1]

[0090]

[0091] Here, in (Formula 1), M r denotes the antenna element number of the receiver 10, M t denotes the antenna element number of the transmitter 11.

[0092] [Math. 2]

[0093]

[0094] denotes the complex channel response from the M t antenna of the transmitter 11 to the M r antenna of the receiver 10, and t denotes the observation time.

[0095] Next, the complex transfer function calculation section 301 calculates the frequency response matrix HF(ω) of the complex transfer function H(t). The frequency response matrix HF(ω) is represented by (Formula 2).

[0096] [Math. 3]

[0097]

[0098] Here, ω is a frequency range corresponding to the living body.

[0099] <Reflection coefficient calculation section 302>

[0100] The reflection coefficient calculation section 302 calculates the reflection coefficient. In the calculation of the reflection coefficient, the reflection coefficient calculation section 302 calculates the complex transfer function when the detection object is disposed at one of the L positions (L is a natural number of 2 or more) and calculates the ideal complex transfer function, which is a theoretical value, of the position at which the detection object is disposed for each of the L positions, and calculates the reflection coefficient using the complex transfer function and the ideal complex transfer function.

[0101] Specifically, the reflection coefficient calculation section 302 calculates the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function by simulation for the position at which the living body 60 is disposed.

[0102] At this time, the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function can also be calculated by implementing a wave simulation in which an ideal reflecting plate such as an iron plate is arranged at the arrangement position of the living body 60. Further, the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function corresponding to the arrangement position can be acquired by being read out from the memory 50 in which the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function are stored in advance as the reflection coefficient 51.

[0103] Next, the reflection coefficient calculation section 302 calculates the reflection coefficient Γ and the frequency response ΓF of the reflection coefficient by (Equation 3), (Equation 4) below.

[0104] [Math. 4]

[0105]

[0106] [Math. 5]

[0107]

[0108] Here,

[0109] [Math. 6]

[0110]

[0111] is an operator called Hadamard division, meaning division by each element of a matrix.

[0112] <Various Normalization Sections 303>

[0113] The various normalization sections 303 calculate normalized reflection coefficients in which the reflection coefficients are normalized by a prescribed method. The various normalization sections 303 correspond to the normalized reflection coefficient calculation section.

[0114] Specifically, the various normalization sections 303 normalize the reflection coefficients by the method shown below. As normalization based on the antenna number, for example, in order to normalize with antenna 1 as a reference, calculation is performed using (Equation 5) below.

[0115] [Math. 7]

[0116] hf' mn (k) = hf mn (k) / hf 11 (k) (Equation 5)

[0117] Here, m is the receiving antenna number, n is the transmitting antenna number, and k is the frequency number of FFT (Fast Fourier Transformation). Here, hf mnStandardization based on antenna number can be performed using antennas other than 1, or averaging can be performed using (Equation 6).

[0118]

Mathematical Expression 8

[0119]

[0120] In addition, various standardization sections 303 can calculate the average phase value using (Equation 7) in addition to using standardization or averaging based on antenna number.

[0121]

Mathematical Expression 9

[0122]

[0123] but,

[0124]

Mathematical Formula 10

[0125]

[0126] Established.

[0127] In addition, various standardization sections 303 can perform frequency averaging in addition to standardization, averaging or phase averaging based on antenna number.

[0128]

Mathematical Expression 11

[0129]

[0130] Here, K is the maximum value of the FFT frequency index.

[0131] In addition, various standardization sections 303 can standardize the phase in the frequency direction.

[0132] In addition, the various standardization sections 303 can also standardize the phase at each measurement location.

[0133] In this way, various standardization departments 303 sequentially arrange the organisms 60 in, for example... Figure 4 At the nine positions indicated by the mark ×, and with the organism 60 positioned in each of the designated positions, the receiving unit 30 receives the first received signal and calculates the reflection coefficient Γ or the frequency response ΓF of the reflection coefficient a predetermined number of times.

[0134] Here, the various normalization units 303 can also store the normalized reflection coefficient Γ or the frequency response of the reflection coefficient ΓF in the memory 50. Also, the various normalization units 303 can also read out and reuse the normalized reflection coefficient Γ or the frequency response of the reflection coefficient ΓF by the other sensors 110 added in number. This is because the radiation pattern or the radiation phase characteristic of the antenna differs little due to the mass production, so the antennas can be shared, and, in contrast, the reflection coefficient interpolation needs to be recalculated each time the position is set to change.

[0135] <Reflection coefficient interpolation unit 304>

[0136] The reflection coefficient interpolation unit 304 performs interpolation calculation of the reflection coefficient using the normalized reflection coefficient for each coordinate for position estimation of the detection target by a prescribed method, thereby calculating an interpolated reflection coefficient. The reflection coefficient interpolation unit 304 corresponds to an interpolated reflection coefficient calculation unit.

[0137] Specifically, the reflection coefficient interpolation unit 304 sets the coordinates of the sites prescribed in advance as (Xi, Yi) (i = 1, 2,..., I), and defines the reflection coefficient vector observed at the coordinates as Gi. The reflection coefficients of the sites other than I need to be found by interpolation. The coordinates (Xi, Yi) for estimating the position of the living body 60 are two-dimensionally distributed, so two-dimensional interpolation is needed. The interpolation method can be, for example, linear interpolation or spline interpolation. The reflection coefficient interpolation unit 304 calculates the reflection coefficient Γ(X, Y) for the coordinates (X, Y) for which the steering vector is found by the above interpolation based on the reflection coefficients Gi ~ Gi.

[0138] <Steering vector correction unit 305>

[0139] When the steering vector for the site (X, Y) in the MIMO radar is defined as a(X, Y), the steering vector correction unit 305 can calculate the corrected steering vector a'(X, Y) as shown in (Formula 10).

[0140] [Math. 12]

[0141] a'(X, Y) = a(X, Y) © Γ(X, Y) (Formula 10)

[0142] Here,

[0143] [Math. 13]

[0144] ©

[0145] The © indicates the Hadamard product which means the product of each element of the vectors.

[0146] <Position estimation unit 306>

[0147] The position estimation section 306 performs correction of the position estimation based on a prescribed method using the steering vector and the interpolation reflection coefficient determined based on the positions of the respective transmission antenna elements and reception antenna elements. In addition, the position estimation section 306 calculates a corrected steering vector in which the steering vector is corrected using the steering vector and the interpolation reflection coefficient. The functional section that calculates the corrected steering vector is also referred to as a corrected steering vector calculation section. In a case where the corrected steering vector calculation section calculates the corrected steering vector, the position estimation section 306 performs correction of the position estimation using the corrected steering vector corrected by the corrected steering vector calculation section.

[0148] Specifically, the position estimation section 306 can perform position estimation of the living body using the steering vector obtained by correction by the steering vector correction section 305 and using the existing MUSIC algorithm or the like. In addition, the position estimation section 306 performs correction of the position estimation based on a prescribed method using the steering vector and the interpolation reflection coefficient determined based on the positions of the respective transmission antenna elements and reception antenna elements.

[0149] Further, in the reflection coefficient vector calculated at I, sometimes a random phase is multiplied by the entire reflection coefficient vector. This is due to the period of respiration or heartbeat of the living body and the time relationship with the observation timing. In this case, by multiplying the entire reflection coefficient vector by an appropriate phase, it is possible to improve the accuracy of the interpolation described above.

[0150] When e jθi As the phase correction coefficient of the reflection coefficient for the i-th site, the position estimation section 306 can calculate the reflection coefficient vector Γi' in which the phase is corrected as shown in (Formula 11).

[0151] [Formula 14]

[0152]

[0153] When the j-th element of the reflection coefficient vector Γi' is defined as γ' ij , it is possible to calculate the variance of the phase between the prescribed sites from (Formula 12).

[0154] [Formula 15]

[0155]

[0156] Here, j is the number of elements of each Γi'. The position estimation section 306 calculates the phase correction coefficients θ1 to θI that minimize such a variance. This calculation method can use a general method such as random search or steepest gradient method.

[0157] Thus, Figure 1The illustrated sensor 110 is able to estimate the position of the living body 60 by processing the reception signal received by the reception section 30 in the reception circuit 40.

[0158] [Operation of sensor 110]

[0159] The operation of the sensor 110 configured as above will be described. Figure 6 is a flowchart showing an example of the operation of the sensor 110 in the present embodiment.

[0160] In the present embodiment, as an example, the living body 60 is sequentially arranged at the 9 marks X illustrated in Figure 4 The transmitter 11 and the receiver 10 are arranged at the lower left and lower right of the illustrated prescribed area Al, respectively, and the first reception signal is received by the reception section 30 in the state where the living body is arranged at the mark X, the reflection coefficient is calculated by the reception circuit 40, and the correction of the steering vector is performed for Figure 5 The interpolation value of the reflection coefficient is calculated at the intersection of the illustrated auxiliary lines, that is, the fine grid, and the position estimation accuracy of the living body 60 is improved by the correction of the steering vector.

[0161] In this example, the interval of the marks X of Figure 4 and Figure 5 is set to 1 m, and the grid interval of Figure 5 is set to 10 cm, but the interval of the marks X can be set to 1.5 m and the grid interval can be set to 15 cm, etc. in accordance with the application destination, and these intervals can be changed.

[0162] In the present embodiment, as an example, the living body 60 is sequentially arranged at the 9 marks X illustrated in Figure 4 and the reflection coefficient corresponding to each position is acquired. The sensor 110 transmits M T number of transmission signals to the prescribed area Al, and receives the reflection signal reflected by the living body 60 arranged at the mark X as M R number of first reception signals (S401).

[0163] More specifically, the sensor 110 transmits the first transmission signal to the prescribed area Al including the living body 60 using M T number of transmission antenna elements. Also, the sensor 110 receives the first reception signal including the reflection signal obtained by the living body 60 reflecting the first transmission signal for a prescribed period using M R number of reception antenna elements.

[0164] Here, as illustrated in Figure 4 , the receiver 10 and the transmitter 11 are used. Here, the receiver 10 and the transmitter 11 can be as illustrated in Figure 4The configuration shown can be a two-unit structure, or a four-unit structure, or any number of units as long as there are two or more. Furthermore, square patch antennas with four elements are used as both the receiving and transmitting antenna elements. More specifically, each transmitter 11 and receiver 10 has four square patch antennas for both transmitting and receiving, positioned at a height of 0.9m above the ground. Here, the transmitter 11 and receiver 10 may or may not share these antennas.

[0165] Next, sensor 110 calculates the complex transfer function based on the multiple first received signals acquired in step S401. More specifically, first, sensor 110 calculates the complex transfer function based on M... T ×M R The first received signal is used to calculate the complex transfer function as the complex transfer function H(t), and the M T ×M R The first received signal is M R Each receiving antenna element receives data from M. T The signal obtained by the first transmitted signal transmitted by the transmitting antenna element to the organism 60 and the reflected signal reflected by the organism 60 (S402).

[0166] Next, sensor 110 calculates the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function for the location where the organism 60 is positioned, through simulation. At this time, the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function can also be calculated by performing an electromagnetic wave simulation in which an ideal reflector such as an iron plate is positioned at the location of the organism 60. Furthermore, the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function corresponding to the positioning location can be pre-stored in memory 50 as reflection coefficient 51 and read out. Next, sensor 110 calculates the reflection coefficient Γ using the complex transfer function H(t) and the ideal complex transfer function H'(t), and calculates the frequency response ΓF of the reflection coefficient using the frequency response of the complex transfer function and the frequency response HF'(ω) of the ideal complex transfer function (S403).

[0167] Next, sensor 110 calculates the average value of the antenna number, the normalization or averaging, and the phase for the reflection coefficient Γ and the frequency response ΓF of the reflection coefficient (S404).

[0168] Thus, sensor 110, when positioning organism 60, for example... Figure 4 In the state of the nine positions indicated by the mark ×, the receiving unit 30 receives the first received signal and calculates the normalized reflection coefficient Γ or the frequency response ΓF of the normalized reflection coefficient.

[0169] Next, the sensor 110 sets the coordinates of the points prescribed in advance as (Xi, Yi) (i = 1, 2,..., I). Hereinafter, in the description of the present embodiment, I = 9 is assumed as an example.

[0170] The sensor 110 defines the reflection coefficient vector observed at the coordinates (Xi, Yi) as Gi, and obtains the reflection coefficients at the points other than the nine points by interpolation. Since the coordinates (Xi, Yi) used for estimating the position of the living body 60 are distributed in two dimensions, two-dimensional interpolation is performed. The interpolation method can be, for example, linear interpolation or spline interpolation.

[0171] The sensor 110 calculates the reflection coefficient G(X, Y) with respect to the coordinates (X, Y) at which the steering vector is obtained, based on the reflection coefficients Gi to G9, by the above-described interpolation. In the example of Fig. 4, the coordinates at which the steering vector is obtained are set at intervals of 0.1 m, and the interpolation calculation of the reflection coefficient G(X, Y) is performed at intervals of 0.1 m in order to perform the position estimation throughout the prescribed region Al of 4 m x 4 m. Figure 5

[0172] Next, the sensor 110 defines the steering vector with respect to the point (X, Y) in the MIMO radar as a(X, Y), and calculates the corrected steering vector a'(X, Y) (S406).

[0173] Next, the sensor 110 can perform the living body position estimation using the steering vector thus obtained, using the existing MUSIC algorithm or the like (S407).

[0174] [Effects and the like]

[0175] In the environment for the test shown in Fig. 4, the sensor 110 arranges the living body 60 at intervals of 1 m in the prescribed region Al and transmits the transmission wave from the transmitter 11, and receives the first reception signal by the receiver 10. Figure 4 Then, the sensor 110 calculates the ideal complex transfer function H'(t) and the frequency response HF'(ω) of the ideal complex transfer function by simulation with respect to the positions at which the living body 60 is arranged.

[0176] Next, the sensor 110 calculates the reflection coefficient G by the complex transfer function H(t) and the ideal complex transfer function H'(t), and further calculates the frequency response GF of the reflection coefficient by the frequency response HF(ω) of the complex transfer function and the frequency response HF'(ω) of the ideal complex transfer function.

[0177] Next, the sensor 110 calculates the standardization or averaging based on the antenna number and the average value of the phase with respect to the reflection coefficient G and the frequency response GF of the reflection coefficient.

[0178]

[0179] ​​Next, sensor 110 defines the coordinates of the pre-defined locations as (Xi, Yi) and the reflection coefficient vector observed at coordinates (Xi, Yi) as Γi. It then calculates the reflection coefficients for locations other than the nine designated locations through interpolation. Furthermore, since the coordinates (Xi, Yi) used to estimate the position of the organism 60 are two-dimensionally distributed, two-dimensional interpolation is performed. Based on the reflection coefficients Γ1 to Γ9, sensor 110 calculates the reflection coefficient Γ(X, Y) for the coordinates (X, Y) from which the turning vector is calculated using the aforementioned interpolation. Then, sensor 110 defines the turning vector for location (X, Y) in the MIMO radar as a(X, Y) and calculates the corrected turning vector a'(X, Y). Sensor 110 can then use this obtained turning vector to estimate the organism's position using existing MUSIC algorithms, etc.

[0180] In the sensor 110 equipped with a directional antenna that has been corrected as described above, the reflection coefficient is measured at several points with different relative angles or positions to the transmitter 11 or receiver 10. Furthermore, by standardizing and interpolating the measured reflection coefficients, the reflection coefficients at coordinates other than the measured points can be corrected for the steering vector, thereby improving the accuracy of the organism's position estimation.

[0181] Next, the experimental results based on simulations will be described for the sensor disclosed herein.

[0182] <Experimental Conditions>

[0183] In this experiment, the element spacing of the antenna array was set to 0.5 wavelengths, one side of the ground plane was set to 121.4 mm, the short side of the patch was set to 6.47 mm, and the long side was set to 19.6 mm. The experiment was designed as a 4x4m... 2 It is conducted in an indoor environment. Figure 4 In the environment shown, a 4×4 MIMO structure is used, with two sets of 4-element inverted-F antenna arrays serving as transmitter 11 and receiver 10, respectively. The coordinates of transmitter 11 and receiver 10 are set to (4, 0) m and (0, 0) m, respectively, and the SNR (Signal-to-Noise Ratio) is set to 10 dB.

[0184] <Experimental Results>

[0185] This represents an example of the position estimation result when the coordinates of the test subject are set to (3, 3) m. Figure 8 This is an example of the calculation results of position estimation performed using existing methods as a precedent. Figure 9 This is an example of the calculation results for position estimation performed through the implementation method. Here, results using a conventional method that uses the steering vector as a reference for the feed point are also shown.

[0186] In the existing method, the position estimation error is about 0.6 m, but in the proposed method, it is improved to 0.1 m. Figure 10 An example of a cumulative probability distribution (CDF: Cumulative Distribution Function) representing the position estimation error of the existing method and the method of the present embodiment is shown. If the CDF 50% value is considered, it is known that the error of the existing method is 0.94 m, but the error of the proposed method is 0.2 m, and the positioning error can be greatly improved.

[0187] (Modified example)

[0188] In addition, in the embodiment, an example in which the steering vector and the interpolated reflection coefficient are used to calculate the corrected steering vector is described, but it is not limited thereto. For example, the steering vector and the interpolated reflection coefficient can be calculated, a correction value can be calculated using the steering vector and the interpolated reflection coefficient, and in addition, the position information estimated using the initial method can be corrected.

[0189] In addition, in the embodiment, an example in which all of the antenna number-based normalization based on (Formula 5) and (Formula 6), the phase normalization of each frequency based on (Formula 7) and (Formula 8), and the complex number-based normalization of the frequency direction based on (Formula 9) are performed by the various normalization units 303, but it is not limited thereto. For example, one of the antenna number-based normalization, the phase normalization of each frequency, and the complex number-based normalization of the frequency direction can be performed.

[0190] In addition, a system including the above-described sensor also has the same effect as the above-described sensor. Here, the system includes the above-described sensor and a server. The above-described sensor transmits the result of the position estimation to the server. The server receives the result of the position estimation transmitted by the sensor.

[0191] As described above, the sensor of the present embodiment can perform position estimation of a living body by highly accurately correcting position estimation even when an antenna having directivity is provided. According to the present technology, the living body position estimation technology can be applied to a communication device in which an antenna having a wide radiation range, i.e., a wide communication range (for example, an inverted F antenna or a metal plate antenna) is used, compared to an antenna having a simple shape or a specific characteristic (for example, a dipole antenna, a monopole antenna, or a patch antenna). Thus, the precision of position estimation using a sensor provided with an antenna having a wide radiation range can be improved. Therefore, the sensor can perform correction of the device in a simple manner in a short time and with high precision in a device that performs position estimation of a living body using a wireless signal.

[0192] In addition, the sensor can perform the position estimation of the living body with high precision by correcting the position estimation even when the antenna having directivity is provided. According to the present technology, the living body position estimation technology can be applied to a communication device of an antenna having a wide radiation range, that is, a wide communication range, such as an inverted F antenna or a metal plate antenna, as compared with an antenna having a simple shape or a simple characteristic, such as a dipole antenna, a monopole antenna, or a patch antenna. Thus, the precision of the position estimation using the sensor provided with the antenna having the wide radiation range can be improved. Therefore, the sensor can perform the correction of the device in a short time and with high precision in a simple manner in the apparatus that performs the position estimation of the living body using the wireless signal.

[0193] In addition, the sensor can perform the position estimation of the living body with high precision by correcting the position estimation even when the antenna having directivity is provided. According to the present technology, the living body position estimation technology can be applied to a communication device of an antenna having a wide radiation range, that is, a wide communication range, such as an inverted F antenna or a metal plate antenna, as compared with an antenna having a simple shape or a simple characteristic, such as a dipole antenna, a monopole antenna, or a patch antenna. Thus, the precision of the position estimation using the sensor provided with the antenna having the wide radiation range can be improved. Therefore, the sensor can perform the correction of the device in a short time and with high precision in a simple manner in the apparatus that performs the position estimation of the living body using the wireless signal.

[0194] In addition, the sensor performs the position estimation using the corrected steering vector obtained by using the correction of the steering vector and the interpolated reflection coefficient. Thus, the sensor can easily perform the configuration of the device in a short time and with high precision.

[0195] In addition, the sensor performs the position estimation using the received signal having the phase normalized in the frequency direction. Thus, the sensor can perform the correction of the device in a short time and with high precision in a simple manner in the apparatus that performs the position estimation of the living body using the wireless signal.

[0196] In addition, the sensor performs the position estimation using the received signal having the phase normalized for each measurement position. Thus, the sensor can perform the correction of the device in a short time and with high precision in a simple manner in the apparatus that performs the position estimation of the living body using the wireless signal.

[0197] Further, in the above-described embodiments, each constituent element can be configured by a dedicated hardware or realized by executing a software program suitable for each constituent element. Each constituent element can also be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded in a recording medium such as a hard disk or a semiconductor memory. Here, the software of the sensor and the like realizing the above-described embodiments is a program as follows.

[0198] That is, the program is a program that causes a computer to execute a control method of a sensor provided with a transmission antenna section having N (N is a natural number of 2 or more) transmission antenna elements that transmit a signal to a prescribed space and a reception antenna section that receives a signal transmitted by the transmission antenna section for a prescribed period, has M (M is a natural number of 2 or more) reception antenna elements that receive the received signal, calculates a complex transfer function from the received signal, calculates a complex transfer function when a detection object is disposed at one of L (L is a natural number of 2 or more) positions for each of the L positions, and calculates an ideal complex transfer function that is a theoretical value of a position at which the detection object is disposed for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, calculates a normalized reflection coefficient after normalizing the reflection coefficient by a prescribed method, performs an interpolation calculation of a reflection coefficient using the normalized reflection coefficient for each coordinate used for position estimation of a detection object by a prescribed method, thereby calculating an interpolated reflection coefficient, and performs correction of position estimation based on a prescribed method using a steering vector determined based on positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

[0199] The above describes the sensor and the like of one or more technical solutions based on the embodiments, but the present disclosure is not limited to the embodiments. As long as the gist of the present disclosure is not deviated from, a manner obtained by implementing various modifications that a person skilled in the art can think of to the present embodiment, a manner constructed by combining the constituent elements in different embodiments can also be included in the scope of one or more technical solutions.

[0200] Industrial applicability

[0201] The present disclosure can be utilized in an estimation device and an estimation method that estimate a living body using a wireless signal, and in particular, can be utilized in a sensor, an estimation device, and an estimation method mounted in a home appliance that performs control corresponding to a living body, a monitoring device that detects intrusion of a living body, and the like.

[0202] Explanation of reference signs

[0203] 10 receiver

[0204] 20 reception antenna section

[0205] 30 reception section

[0206] 40 reception circuit

[0207] 50 memory

[0208] 51 reflection coefficient

[0209] 60 organism

[0210] 11 transmitter

[0211] 21 transmission antenna section

[0212] 31 transmission section

[0213] 41 transmission circuit

[0214] 110, 111 sensor

[0215] 121, 122, 123 reception antenna element

[0216] 221, 222, 223 antenna characteristic

[0217] 301 complex transfer function calculation section

[0218] 302 reflection coefficient calculation section

[0219] 303 various normalization sections

[0220] 304 reflection coefficient interpolation section

[0221] 305 steering vector correction section

[0222] 306 position estimation section

[0223] A1 prescribed region

Claims

1. A sensor, wherein, Possessing: a transmission antenna section having N transmission antenna elements that transmit a signal to a prescribed space, N being a natural number of 2 or more; a reception antenna section that receives a signal transmitted by the transmission antenna section during a prescribed period, having M reception antenna elements that receive the received signal, M being a natural number of 2 or more; a complex transfer function calculation section that calculates a complex transfer function from the received signal; a reflection coefficient calculation section that calculates a complex transfer function when a detection object is disposed at one of L positions for each of the L positions, and calculates an ideal complex transfer function that is a theoretical value of a position at which the detection object is disposed for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, L being a natural number of 2 or more; a normalized reflection coefficient calculation section that calculates a normalized reflection coefficient in which the reflection coefficient is normalized by a prescribed method; an interpolated reflection coefficient calculation section that calculates an interpolated reflection coefficient by interpolating the normalized reflection coefficient for each coordinate used for position estimation of the detection object by a prescribed method; and a position estimation section that performs correction of position estimation based on a prescribed method using a steering vector determined based on positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

2. A sensor, wherein, Possessing: a transmission antenna section having N transmission antenna elements that transmit a signal to a prescribed space, N being a natural number of 2 or more; a reception antenna section that receives a signal transmitted by the transmission antenna section during a prescribed period, having M reception antenna elements that receive the received signal, M being a natural number of 2 or more; a complex transfer function calculation section that calculates a complex transfer function from the received signal; a reflection coefficient calculation section that calculates a complex transfer function when a detection object is disposed at one of L positions for each of the L positions, and calculates an ideal complex transfer function that is a theoretical value of a position at which the detection object is disposed for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, L being a natural number of 2 or more; a normalized reflection coefficient calculation section that calculates a normalized reflection coefficient in which the reflection coefficient is normalized by a prescribed method; and a memory that stores the normalized reflection coefficient.

3. The sensor of claim 2, wherein, Possessing: an interpolated reflection coefficient calculation section that reads out the normalized reflection coefficient from the memory, and calculates an interpolated reflection coefficient by interpolating the normalized reflection coefficient for each coordinate used for position estimation of the detection object by a prescribed method; and a position estimation section that performs correction of position estimation based on a prescribed method using a steering vector determined based on positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

4. The sensor according to claim 1, wherein the position estimation section includes a corrected steering vector calculation section that calculates a corrected steering vector in which the steering vector is corrected using the steering vector and the interpolated reflection coefficient, The position estimation unit performs correction of the position estimation using the corrected steering vector corrected by the corrected steering vector calculation unit.

5. The sensor according to claim 1, 3 or 4, wherein The normalized reflection coefficient calculation unit normalizes the phase in the frequency direction using the received signal of the prescribed antenna element among the M receive antenna elements.

6. The sensor according to claim 5, wherein The normalized reflection coefficient calculation unit also normalizes the phase for each measurement position.

7. A control method of a sensor provided with a transmission antenna unit and a reception antenna unit, wherein The transmission antenna unit has N transmission antenna elements that transmit a signal to a prescribed space, N being a natural number of 2 or more, The reception antenna unit receives the signal transmitted by the transmission antenna unit during a prescribed period, has M reception antenna elements that receive the received signal, M being a natural number of 2 or more, The control method, calculates a complex transfer function from the received signal, calculates a complex transfer function when a detection object is disposed at one of the L positions for each of the L positions, and calculates an ideal complex transfer function that is a theoretical value of the position where the detection object is disposed for each of the L positions, and calculates a reflection coefficient using the complex transfer function and the ideal complex transfer function, L being a natural number of 2 or more, calculates a normalized reflection coefficient that normalizes the reflection coefficient by a prescribed method, performs an interpolation calculation of the reflection coefficient using the normalized reflection coefficient for each coordinate of the position estimation of the detection object by a prescribed method, thereby calculating an interpolated reflection coefficient, performs correction of the position estimation based on a prescribed method using a steering vector determined based on the respective positions of the transmission antenna elements and the reception antenna elements and the interpolated reflection coefficient.

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