JP6839807B2 - Estimator and program - Google Patents

Description

The present disclosure relates to an estimation device that estimates the posture of a living body by using a wireless signal.

As a method of knowing the position of a person or the like, a method of using a wireless signal has been studied (see, for example, Patent Documents 1 to 3). Patent Document 1 discloses a method for detecting a living body using a Doppler sensor, and Patent Document 2 discloses a method for detecting human movements and biological information using a Doppler sensor and a filter. Patent Document 3 discloses that the position and state of a person to be detected can be known by analyzing a component including a Doppler shift using a Fourier transform. Further, Patent Document 4 discloses a method of estimating the position and state of a living body by machine learning based on channel information of a plurality of antennas and various sensor information, and Patent Document 5 discloses a plurality of antennas, an ultrasonic radar, and the like. A method for estimating the state of a living body using a plurality of antennas is disclosed.

Special Table 2014-512526 Gazette International Publication No. 2014/141319 Japanese Unexamined Patent Publication No. 2015-117772 Japanese Unexamined Patent Publication No. 2014-190724 Japanese Unexamined Patent Publication No. 2005-292129 Japanese Unexamined Patent Publication No. 2001-159678

However, in order to improve the accuracy of estimating the posture of a living body by using a wireless signal, further improvement is required.

In order to achieve the above object, the estimation device according to one aspect of the present invention is an estimation device, and the processor included in the estimation device transmits a transmission signal to a predetermined range in which a living body can exist. A part of the N transmitted signals transmitted by N (N is a natural number of 2 or more) transmitting antenna elements includes a reflected signal reflected by the living body, and M (M is 2). The N received signals received by each of the above natural number) receiving antenna elements are acquired, and from each of the N received signals received in each of the M receiving antenna elements in a predetermined period, the said A first matrix of N × M having each complex transmission function indicating the propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements as a component was calculated, and the first matrix of N × M was calculated. By extracting the second matrix corresponding to the predetermined frequency range, the second matrix corresponding to the component affected by the vital activity including at least one of the breathing, the heartbeat, and the body movement of the living body is extracted. Using the second matrix, the position where the living body exists with respect to the N transmitting antenna elements and the M receiving antenna element is estimated, and the transmitting antenna having the estimated position and the N transmitting antenna elements. Based on the position of and the position of the receiving antenna having the M receiving antenna elements, the first distance indicating the distance between the living body and the transmitting antenna and the distance between the living body and the receiving antenna are determined. The indicated second distance is calculated, the RCS (Radar cross-section) value for the living body is calculated using the first distance and the second distance, and the calculated RCS value and the memory included in the estimation device are provided. The posture of the living body is estimated by using the information indicating the correspondence between the RCS value and the posture of the living body stored in.

In order to achieve the above object, the program according to one aspect of the present invention is transmitted to a computer using N transmitting antenna elements (N is a natural number of 2 or more) with respect to a predetermined range in which a living body can exist. A part of the transmitted signals of the N transmitted signals includes the reflected signal reflected by the living body, and N received by each of the receiving antenna elements of M (M is a natural number of 2 or more). From each of the N received signals received in a predetermined period in each of the M receiving antenna elements by acquiring a signal, the N transmitting antenna elements and the M receiving antenna elements each. By calculating the first matrix of N × M having each complex transfer function showing the propagation characteristics between the antennas as a component and extracting the second matrix corresponding to the predetermined frequency range in the first matrix, the living body The second matrix corresponding to the component affected by vital activity including at least one of breathing, heartbeat and body movement is extracted, and the second matrix is used to extract the N transmitting antenna elements and the M elements. The position where the living body exists with respect to the receiving antenna element of the above is estimated, the estimated position, the position of the transmitting antenna having the N transmitting antenna elements, and the position of the receiving antenna having the M receiving antenna elements. Based on, the first distance indicating the distance between the living body and the transmitting antenna and the second distance indicating the distance between the living body and the receiving antenna are calculated, and the first distance and the second distance are calculated. The RCS (Radar cross-section) value for the living body is calculated by using the information, and the calculated RCS value and the information indicating the correspondence between the RCS value and the posture of the living body stored in the memory provided in the computer are shown. And, are used to execute the process of estimating the posture of the living body.

In order to achieve the above object, the antenna according to one embodiment of the present invention is a sensor, each of which transmits N transmission signals to a predetermined range in which a living body can exist (N is a natural number of 2 or more). A transmitting antenna having the transmitting antenna element of the above, and N receiving signals including a reflected signal in which a part of the N transmitting signals transmitted by the N transmitting antenna elements is reflected by the living body. A receiving antenna having M receiving antenna elements (M is a natural number of 2 or more), a circuit, and a memory, each of which receives a signal, is provided, and the circuit is predetermined in each of the M receiving antenna elements. Each complex transmission function indicating the propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements from each of the N received signals received in the period is used as a component. By calculating the first matrix of N × M and extracting the second matrix corresponding to the predetermined frequency range in the first matrix, the influence of vital activity including at least one of the breathing, heartbeat, and body movement of the living body. The second matrix corresponding to the received component is extracted, and the position where the living body exists with respect to the sensor is estimated using the second matrix, and the estimated position, the position of the transmitting antenna, and the above. Based on the position of the receiving antenna, the first distance indicating the distance between the living body and the transmitting antenna and the second distance indicating the distance between the living body and the receiving antenna are calculated, and the first distance and the first distance are calculated. Using the second distance, an RCS (Radar cross-section) value for the living body is calculated, and the correspondence between the calculated RCS value, the RCS value stored in the memory, and the posture of the living body is determined. Using the information shown, the posture of the living body is estimated.

According to the present invention, the posture of a living body can be estimated in a short time and with high accuracy by using a wireless signal.

FIG. 1 is a block diagram showing an example of the configuration of the sensor according to the first embodiment. FIG. 2 is a block diagram showing a functional configuration of a circuit and a memory according to the first embodiment. FIG. 3 shows an example of information showing the correspondence relationship in the first embodiment. FIG. 4 is a flowchart showing an example of the operation of the sensor according to the first embodiment. FIG. 5 is a block diagram showing an example of the configuration of the sensor according to the second embodiment. FIG. 6 is a block diagram showing a functional configuration of a circuit and a memory according to a second embodiment. FIG. 7 shows an example of information showing the correspondence relationship in the second embodiment. FIG. 8 is a diagram showing an outline of an experiment carried out to confirm the effect of the sensor of the second embodiment. FIG. 9 is a diagram showing the experimental results using the experimental system shown in FIG. FIG. 10 is a diagram showing specific examples of the first RCS range to the fourth RCS range and specific examples of the first height range to the fourth height range obtained from the experimental results.

(Knowledge that became the basis of the present invention)
The inventors have conducted a detailed study on the prior art for estimating the state of a living body using a wireless signal. As a result, it was found that the methods of Patent Document 1 and Patent Document 2 can detect the presence or absence of a person, but cannot detect the direction, position, size, posture, etc. of the person. ..

Further, it has been found that the method of Patent Document 3 has a problem that it is difficult to detect the direction in which a living body such as a person exists and the position where the living body exists in a short time and with high accuracy. This is because the frequency change due to the Doppler effect derived from biological activity is extremely small, and in order to observe this frequency change by Fourier transform, it is essential to observe for a long time (for example, several tens of seconds) while the living body is stationary. is there. Also, in general, a living body rarely keeps the same posture or position for several tens of seconds.

Further, it was found that Patent Document 4 has a problem that machine learning must be performed for each user, and Patent Document 5 has an installation problem and a cost problem of installing a plurality of ultrasonic antennas in a wide range of the ceiling. It was.

As a result of repeated research on the above problems, the inventors use the propagation characteristics and scattering cross section of the reflected signal transmitted from the transmitting antenna including the antenna elements placed at different positions and reflected by the living body. As a result, we have found that it is possible to estimate the direction, position, size, posture, etc. of the living body in a short time and with high accuracy, and have reached the present disclosure.

That is, the sensor according to one aspect of the present invention is a sensor and has N (N is a natural number of 2 or more) transmitting antenna elements, each of which transmits a transmission signal to a predetermined range in which a living body can exist. Each of the transmitting antenna and the N transmitting signals transmitted by the N transmitting antenna elements receive N receiving signals including a reflected signal reflected by the living body. The circuit includes a receiving antenna having M receiving antenna elements (M is a natural number of 2 or more), a circuit, and a memory, and the circuit is received by each of the M receiving antenna elements in a predetermined period. The first of N × M, which comprises each complex transmission function indicating the propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements from each of the N received signals. By calculating the matrix and extracting the second matrix corresponding to the predetermined frequency range in the first matrix, it corresponds to the component affected by the vital activity including at least one of the respiration, heartbeat and body movement of the living body. The second matrix is extracted, and the position of the living body with respect to the sensor is estimated using the second matrix, and the estimated position, the position of the transmitting antenna, and the position of the receiving antenna are determined. Based on the above, a first distance indicating the distance between the living body and the transmitting antenna and a second distance indicating the distance between the living body and the receiving antenna are calculated, and the first distance and the second distance are used. Then, the RCS (Radar cross-section) value for the living body is calculated, and the calculated RCS value and the information stored in the memory indicating the correspondence between the RCS value and the posture of the living body are used. The posture of the living body is estimated.

Therefore, it is possible to estimate the position where the living body exists and the posture of the living body at the position in a short time and with high accuracy.

In addition, the predetermined period may be approximately half of at least one cycle of respiration, heartbeat, and body movement of the living body.

Therefore, it is possible to effectively estimate the position where the living body exists and the posture of the living body at the position.

Further, the circuit may estimate whether or not the living body is in a posture facing the direction perpendicular to the arrangement direction of the transmitting antenna and the receiving antenna.

Further, the N is a natural number of 3 or more, and at least 3 of the N transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and the M is 3 or more. It is a natural number, and at least three of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively, and the information indicating the correspondence is the information of the living body with respect to the sensor. The vertical position, which is the position in the vertical direction, the RCS value, and the correspondence between the postures of the living body are shown, and the postures of the living body associated with the information indicating the correspondence are upright, sitting, and sitting. The circuit estimates the three-dimensional position including the vertical position using the second matrix, and the estimated three-dimensional position, the calculated RCS value, and the memory. It is possible to estimate whether the living body is in an upright position, a sitting position, a sitting position, or a lying position by using the information indicating the correspondence relationship stored in the above.

Therefore, it is possible to estimate the three-dimensional position where the living body exists and the posture of the living body at the three-dimensional position in a short time and with high accuracy.

It should be noted that the present invention is not only realized as an apparatus, but also realized as an integrated circuit provided with processing means provided in such an apparatus, or as a method in which the processing means constituting the apparatus is used as a step. Can be realized as a program that causes a computer to execute, or can be realized as information, data, or a signal indicating the program. Then, the programs, information, data and signals may be distributed via a recording medium such as a CD-ROM or a communication medium such as the Internet.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that all of the embodiments described below show a preferred specific example of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept of the present invention will be described as arbitrary components constituting the more preferable form. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

(Embodiment 1)
FIG. 1 is a block diagram showing an example of the configuration of the sensor according to the first embodiment.

As shown in FIG. 1, the sensor 10 includes a transmitting antenna 20, a receiving antenna 30, a circuit 40, and a memory 41. The sensor 10 emits microwaves from the transmitting antenna 20 to the living body 50 such as a human, and receives the reflected waves reflected by the living body 50 by the receiving antenna 30. Here, the angle formed by the first reference direction arbitrarily set with respect to the transmitting antenna 20 and the first living body direction, which is the direction from the transmitting antenna 20 to the living body 50, is defined as θ _T. Similarly, a second reference direction which is arbitrarily set to the receiving antenna 30, and the angle theta _R from the receiving antenna 30 and the second living direction is the direction of the living body 50. The first reference direction, the first biological direction, the second reference direction, and the second biological direction are directions on the horizontal plane.

The transmitting antenna 20 has N transmitting antenna elements 21 (N is a natural number of 2 or more). The transmitting antenna 20 has an array antenna in which N transmitting antenna elements 21 are arranged side by side in a first predetermined direction on a horizontal plane. Each of the N transmitting antenna elements 21 transmits a transmission signal to a predetermined range in which a living body can exist. That is, the transmitting antenna 20 transmits N transmission signals to a predetermined range from different N positions. The predetermined range in which the living body can exist is a detection range in which the sensor 10 detects the presence of the living body.

Specifically, each of the N transmitting antenna elements 21 emits microwaves as transmission signals to a living body 50 such as a human being. The N transmitting antenna elements 21 may transmit a signal subjected to different modulation processing for each transmitting antenna element 21 as a transmitting signal. Further, each of the N transmitting antenna elements 21 may sequentially switch and transmit a modulated signal or an unmodulated signal. The modulation process may be performed by the transmitting antenna 20. In this way, by setting the transmission signals transmitted from the N transmission antenna elements 21 to different transmission signals for each of the N transmission antenna elements 21, the transmission signal received by the reception antenna 30 is transmitted. The antenna element 21 can be specified. As described above, the transmitting antenna 20 may include a circuit for performing the modulation process.

The receiving antenna 30 has M receiving antenna elements 31 (M is a natural number of 2 or more). The receiving antenna 30 has an array antenna in which M receiving antenna elements 31 are arranged side by side in a second predetermined direction on a horizontal plane. Each of the M receiving antenna elements 31 receives N reception signals including a reflection signal which is a signal reflected by the living body 50 among the N transmission signals. The receiving antenna 30 frequency-converts a received signal composed of microwaves and converts it into a low-frequency signal. The receiving antenna 30 outputs the signal obtained by converting it into a low frequency signal to the circuit 40. That is, the receiving antenna 30 may include a circuit for processing the received signal.

The circuit 40 executes various processes for operating the sensor 10. The circuit 40 is composed of, for example, a processor that executes a control program and a volatile storage area (main storage device) that is used as a work area used when the control program is executed. The volatile storage area is, for example, RAM (Random Access Memory). The circuit 40 may be configured by a dedicated circuit for performing various processes for operating the sensor 10. That is, the circuit 40 may be a circuit that performs software processing or may be a circuit that performs hardware processing.

The memory 41 is a non-volatile storage area (auxiliary storage device), and is, for example, a ROM (Read Only Memory), a flash memory, an HDD (Hard Disk Drive), or the like. The memory 41 stores, for example, information used for various processes for operating the sensor 10.

Next, the functional configuration of the circuit 40 will be described with reference to FIG.

FIG. 2 is a block diagram showing a functional configuration of a circuit and a memory according to the first embodiment.

The circuit 40 includes a complex transfer function calculation unit 410, a biological component calculation unit 420, a position estimation processing unit 430, an RCS calculation unit 440, and a posture estimation unit 450.

The complex transfer function calculation unit 410 calculates the complex transfer function from the received signal converted into the low frequency signal. The complex transfer function represents the propagation loss and phase rotation between each transmitting antenna element 21 and each receiving antenna element 31. The complex transfer function is a complex matrix having an M × N component when the number of transmitting antenna elements is N and the number of receiving antenna elements is M. Hereinafter, this complex matrix will be referred to as a complex transfer function matrix. The estimated complex transfer function matrix is output to the biological component calculation unit 420. That is, the complex transfer function calculation unit 410 has N transmission antenna elements 21 and M reception antenna elements from each of the plurality of reception signals received in each of the M reception antenna elements 31 in a predetermined period. 31 A first matrix of N × M is calculated, which is composed of each complex transfer function showing the propagation characteristics with each of them.

The biological component calculation unit 420 separates the complex transfer function matrix component obtained from the received signal passing through the living body 50 and the complex transfer function matrix component obtained from the received signal not passing through the living body 50. The component that has passed through the living body 50 is a component that fluctuates with time due to biological activity. Therefore, the component that has passed through the living body 50 is, for example, a component other than the direct current from the component obtained by Fourier transforming the component of the complex transfer function matrix in the time direction, assuming that the components other than the living body 50 are stationary. Can be extracted by taking out. Further, the component that has passed through the living body 50 can be extracted, for example, by extracting a component whose difference from the result observed when the living body 50 does not exist in a predetermined range exceeds a predetermined threshold value. In this way, the biological component calculation unit 420 calculates the extracted complex transfer function matrix component as a biological component by extracting the complex transfer function matrix component obtained from the received signal including the reflected signal passing through the living body 50. .. That is, the biological component calculation unit 420 extracts the second matrix corresponding to the predetermined frequency range in the first matrix, and thereby, the component affected by the vital activity including at least one of the respiration, heartbeat, and body movement of the living body. The second matrix corresponding to is extracted. The predetermined frequency range is, for example, a frequency derived from vital activity including at least one of the above-mentioned respiration, heartbeat, and body movement of the living body. The predetermined frequency range is, for example, a frequency in the range of 0.1 Hz or more and 3 Hz or less. This makes it possible to extract biological components affected by vital activity of 50 parts of the living body due to the movement of the heart, lungs, diaphragm, and internal organs, or vital activity of hands, feet, and the like. The parts of the living body 50 due to the movement of the heart, lungs, diaphragm, and internal organs are, for example, the epigastrium of a human being.

Here, the biological component is a matrix having an M × N component, and is extracted from the complex transfer function obtained from the received signal observed by the receiving antenna 30 in a predetermined period. Therefore, it is assumed that the biological component has frequency response or time response information. The predetermined period is approximately half the period of at least one cycle of respiration, heartbeat, and body movement of the living body.

The biological component calculated by the biological component calculation unit 420 is output to the position estimation processing unit 430. The position estimation processing unit 430 estimates the position of the living body using the calculated biological components. That is, the position estimation processing unit 430 estimates the position where the living body 50 exists with respect to the sensor 10 by using the second matrix. The position estimation, both angle and departure angle theta _T and the arrival angle theta _R to the receiving antenna 30 from the transmitting antenna 20 is estimated, biological 50 by trigonometry from the departure angle theta _T were estimated and the arrival angle theta _R Estimate the position of.

The RCS calculation unit 440 calculates the scattering cross section (RCS: Radar Cross Section) using the biological component and the estimated position. Specifically, the RCS calculation unit 440 uses the living body 50 and the transmitting antenna 20 based on the estimated position, the position of the transmitting antenna 20, and the position of the receiving antenna 30 in order to calculate the scattering cross section. The distance RT indicating the distance from and the distance RR indicating the distance between the living body 50 and the receiving antenna 30 are calculated. The RCS calculation unit 440 calculates the propagation distance from the calculated distance RT and the distance RR, and calculates the RCS using the calculated propagation distance and the intensity of the biological component. The position of the transmitting antenna 20 and the position of the receiving antenna 30 may be stored in the memory 41 in advance.

The posture estimation unit 450 uses the RCS value calculated by the RCS calculation unit 440 and the information 42 stored in the memory 41 indicating the correspondence between the RCS value and the posture of the living body 50, and the posture of the living body 50. To estimate. As shown in FIG. 3, the information 42 indicating the correspondence between the RCS value stored in the memory 41 and the posture of the living body 50 is associated with each posture shown in supine, cross-legged, sitting and upright in advance. Information indicating the range of RCS values obtained. The supine position indicates a supine position, and the sitting position indicates a sitting position on a chair.

For example, the supine position is associated with the first RCS range, the crossed legs are associated with the second RCS range, the seat is associated with the third RCS range, and the upright position corresponds to the fourth RCS range. It is attached. The first RCS range to the fourth RCS range are ranges of different RCS values.

と定義する。ここでｔは時刻を表す。式１の各成分をフーリエ変換すると、

のような周波数応答行列が得られる。ここでｆは周波数を表しており、周波数応答行列の各成分は複素数である。この周波数応答行列には、生体５０を経由する伝搬成分と、生体５０以外を経由する伝搬成分との両方が含まれている。生体以外が静止していると考えられる場合、周波数応答行列の直流成分、すなわちＧ（０）は生体以外の伝搬成分を主として含んでいるものと考えられる。これは、生体の呼吸、心拍および体動の少なくともいずれかを含むバイタル活動によってドップラーシフトが発生するため、生体を経由する成分はｆ＝０以外に含まれると考えられるからである。さらに、生体の呼吸または心拍の周波数およびその高調波を考えると、ｆ＜３〔Ｈｚ〕の範囲に生体由来の成分が多く存在するものと考えられる。したがって、例えば０〔Ｈｚ〕＜ｆ＜３〔Ｈｚ〕の所定周波数範囲のＧ（ｆ）を取り出せば、生体成分を効果的に抽出することができる。 Next, the details of the operating principle of the sensor 10 of the first embodiment will be described using a mathematical formula. Here, a method of extracting a biological component using a Fourier transform will be described. The process described here is performed by the circuit 40. The complex transfer function matrix between the transmitting antenna 20 and the receiving antenna 30

Is defined as. Here, t represents the time. When each component of Equation 1 is Fourier transformed,

A frequency response matrix such as Here, f represents a frequency, and each component of the frequency response matrix is a complex number. This frequency response matrix includes both a propagation component that passes through the living body 50 and a propagation component that passes through other than the living body 50. When it is considered that a non-living body is stationary, the DC component of the frequency response matrix, that is, G (0) is considered to mainly contain a propagating component other than the living body. This is because the Doppler shift occurs due to vital activity including at least one of respiration, heartbeat, and body movement of the living body, and therefore, it is considered that the component passing through the living body is contained other than f = 0. Further, considering the frequency of respiration or heartbeat of the living body and its harmonics, it is considered that many components derived from the living body are present in the range of f <3 [Hz]. Therefore, for example, if G (f) in a predetermined frequency range of 0 [Hz] <f <3 [Hz] is extracted, the biological component can be effectively extracted.

のようにベクトル形式に並び替える。これを生体成分ベクトルと定義する。ここで｛・｝^Ｔは転置を表す。生体成分ベクトルｇ（ｆ）から相関行列を、

によって計算する。ここで、｛・｝^Ｈは複素共役転置を表す。さらにＲは０〔Ｈｚ〕＜ｆ＜３〔Ｈｚ〕の間で平均化されている。この平均化によって、後述の位置推定精度が向上することが知られている。次に、算出した相関行列Ｒを固有値分解することで、当該相関行列Ｒの固有ベクトルＵとその複素共役転置ベクトルＵ^Ｈを算出する。 Next, a biological position estimation method using the biological component G (f) will be described. The biological component matrix G (f),

Sort in vector format like. This is defined as a biological component vector. Here, {・} ^T represents transpose. A correlation matrix is obtained from the biological component vector g (f).

Calculated by. Here, {・} ^H represents a complex conjugate transpose. Further, R is averaged between 0 [Hz] <f <3 [Hz]. It is known that this averaging improves the position estimation accuracy described later. Then, the calculated correlation matrix R by eigenvalue decomposition to calculate the eigenvector U and its complex conjugate transposed vector U ^H of the correlation matrix R.

The eigenvector in Equation 5 is represented by Equation 6 shown below.

と表される。ここで、ｄｉａｇ［・］とは［・］内の要素を対角項に持つ対角行列を表す。回路４０は、以上の情報を用いて、検出対象となる生体５０の位置推定を行う。ここでは一例としてＭＵＳＩＣ法に基づく位置推定方法について説明する。ＭＵＳＩＣ法ではステアリングベクトルと呼ばれる方向ベクトルと式６で示した固有ベクトルとを用いることによって方向や位置を推定する方法である。式３で示した生体成分ベクトルは、本来のＭ×Ｎ行列を変形して得られる。生体５０の位置推定を行うためには、これに対応してステアリングベクトルを定義する必要がある。送信アンテナ２０の第１基準方向から出発角θ_Ｔの第１生体方向のステアリングベクトルと、受信アンテナ３０の第２基準方向から到来角θ_Ｒの第２生体方向のステアリングベクトルとは、それぞれ、

と表される。ここで、ｋは波数を表し、ｄはアンテナアレーの各アンテナ素子の素子間隔を表す。なお、本実施の形態では素子間隔が一定のリニアアレーアンテナを想定している。ｄは、例えば、送信アンテナ２０においては、複数の送信アンテナ素子２１のうち互いに隣接する２つの送信アンテナ素子２１の間隔を表す。また、ｄは、受信アンテナ３０においては、複数の受信アンテナ素子３１のうち互いに隣接する２つの受信アンテナ素子３１の間隔を表す。これらのステアリングベクトルのクロネッカ積を求めると、 Here, ui _{represents the eigenvector of the i-} th column, and the number of elements is NM. D is a diagonal matrix whose diagonal elements are eigenvalues.

It is expressed as. Here, diag [・] represents a diagonal matrix having elements in [・] as diagonal terms. The circuit 40 uses the above information to estimate the position of the living body 50 to be detected. Here, a position estimation method based on the MUSIC method will be described as an example. The MUSIC method is a method of estimating a direction and a position by using a direction vector called a steering vector and an eigenvector represented by the equation 6. The biological component vector represented by Equation 3 is obtained by modifying the original M × N matrix. In order to estimate the position of the living body 50, it is necessary to define the steering vector corresponding to this. The steering vector from the first reference direction of the transmitting antenna 20 to _{the first living body direction having a starting angle θ T} and the steering vector from the second reference direction of the receiving antenna 30 to the second living body direction having an _{arrival angle θ R are respectively.}

It is expressed as. Here, k represents the wave number, and d represents the element spacing of each antenna element of the antenna array. In this embodiment, a linear array antenna with a constant element spacing is assumed. For example, in the transmitting antenna 20, d represents the distance between two transmitting antenna elements 21 adjacent to each other among the plurality of transmitting antenna elements 21. Further, d represents the distance between two receiving antenna elements 31 adjacent to each other among the plurality of receiving antenna elements 31 in the receiving antenna 30. The Kronecker product of these steering vectors

となる。ここで

はクロネッカ積を表す演算子である。ａ（θ_Ｔ，θ_Ｒ）は、ＭＮ×１の要素を持つベクトルであり、出発角θ_Ｔと到来角θ_Ｒとの２変数を持つ関数となる。以降、ａ（θ_Ｔ，θ_Ｒ）をステアリングベクトルと定義する。検出範囲内に存在する生体の数をＬとすると、評価関数

によって生体位置を特定する。ここで、式１１の評価関数はＭＵＳＩＣスペクトラムと呼ばれており、送信アンテナ２０および受信アンテナ３０のそれぞれから検出対象へ向かう方向の組み合わせ（θ_Ｔ，θ_Ｒ）において極大を取る。極大に対応するθ_Ｔおよびθ_Ｒから、三角法を用いて検出対象である生体５０の位置を特定できる。ここで、Ｌは検出対象の数を表す。つまり、固有ベクトルの数ＭＮは検出対象の数Ｌより大きい必要がある。

Will be. here

Is an operator that represents the Kronecker product. a (θ _T , θ _R ) is a vector having an element of MN × 1, and is a function having two variables of a _{starting angle θ T} and an arrival angle θ _R. Hereinafter, a (θ _T , θ _R ) is defined as a steering vector. If the number of living organisms existing in the detection range is L, the evaluation function

The position of the living body is specified by. Here, the evaluation function of Equation 11 is called the MUSIC spectrum, and maximizes _{the combination of directions (θ T} , θ _R ) from each of the transmitting antenna 20 and the receiving antenna 30 toward the detection target. _{From θ T} and θ _R corresponding to the maximum, the position of the living body 50 to be detected can be specified by using trigonometry. Here, L represents the number of detection targets. That is, the number MN of the eigenvectors needs to be larger than the number L of the detection targets.

と計算することができる。ここでρｉｊは行列

の（ｉ，ｊ）番目の要素を表している。一方、ｊ番目の送信アンテナ素子２１から生体５０を経由してｉ番目の受信アンテナ素子３１に到達する電力は、

と表される。ここで、Ｐｔは、送信電力を表す。なお、全ての送信アンテナ素子２１から等しい電力が送信されているものとする。Ｇｔは送信アンテナ２０の動作利得を表し、Ｇｒは受信アンテナ３０の動作利得を表し、ｒ１は送信アンテナ２０から生体５０までの距離を表し、ｒ２は生体５０から受信アンテナ３０までの距離を表す。距離ｒ１および距離ｒ２は式１１により推定した位置から容易に計算することができる。すると、式１２で定義される電力伝達係数は、ρｉｊ＝Ｐｒｉｊ／Ｐｔで表されるので、散乱断面積は、

により計算することができる。なお、ここで取り扱う散乱断面積では、生体５０全体の散乱断面積ではなく、呼吸、心拍、体動などの生体５０のバイタル活動の影響を受けることにより生じた変動成分に対応する散乱面積だけが考慮されている。さらに、全要素を平均して

によって平均散乱断面積を求める。以降、

を単に散乱断面積と呼称する。 Further, the RCS value is obtained from Equation 12, and the posture of the living body 50 is estimated from the position of the living body 50 and the RCS value. Assuming that the frequency range to be extracted is f1 to f2 (f1 <f2), the power transfer coefficient is obtained from the channel component reflected and observed from the living body.

Can be calculated. Where ρij is a matrix

Represents the (i, j) th element of. On the other hand, the electric power that reaches the i-th receiving antenna element 31 from the j-th transmitting antenna element 21 via the living body 50 is

It is expressed as. Here, Pt represents the transmission power. It is assumed that equal power is transmitted from all the transmitting antenna elements 21. Gt represents the operating gain of the transmitting antenna 20, Gr represents the operating gain of the receiving antenna 30, r1 represents the distance from the transmitting antenna 20 to the living body 50, and r2 represents the distance from the living body 50 to the receiving antenna 30. The distance r1 and the distance r2 can be easily calculated from the positions estimated by the equation 11. Then, the power transfer coefficient defined by Equation 12 is represented by ρij = Prij / Pt, so that the scattering cross section is

Can be calculated by. In the scattering cross section dealt with here, only the scattering area corresponding to the fluctuation component generated by being affected by the vital activity of the living body 50 such as respiration, heartbeat, and body movement is not the scattering cross section of the whole living body 50. It is being considered. In addition, average all the elements

The average scattering cross section is calculated by. Or later,

Is simply referred to as the scattering cross section.

Needless to say, for example, when the vital component and the body movement component of the living body are further separated and measured, the frequency range of the equation 12 may be adjusted and the subsequent processing may be performed.

Next, the operation of the sensor 10 in the first embodiment will be described with reference to a flowchart.

FIG. 4 is a flowchart showing an example of the operation of the sensor according to the first embodiment.

In the sensor 10, the N transmitting antenna elements 21 of the transmitting antenna 20 transmit N transmitting signals using the N transmitting antenna elements 21 to a predetermined range in which the living body 50 can exist (S11).

The M receiving antenna elements 31 of the receiving antenna 30 receive N receiving signals including a plurality of reflected signals reflected by the living body 50 from the N transmitting signals transmitted by the transmitting antenna 20 (S12).

In the circuit 40, from each of the N received signals received in each of the M receiving antenna elements 31 in a predetermined period, between each of the N transmitting antenna elements 21 and each of the M receiving antenna elements 31. The first matrix of N × M is calculated with each complex transfer function showing the propagation characteristics of (S13) as a component (S13).

The circuit 40 extracts a second matrix corresponding to a predetermined frequency range in the first matrix, and thereby corresponds to a component affected by vital activity including at least one of respiration, heartbeat, and body movement of the living body 50. Two matrices are extracted (S14).

The circuit 40 estimates the position of the living body 50 with respect to the sensor 10 using the second matrix (S15).

The circuit 40 includes a distance r1 indicating the distance between the living body 50 and the transmitting antenna 20 based on the estimated position, the position of the transmitting antenna 20, and the position of the receiving antenna 30, and the living body 50 and the receiving antenna 30. The distance r2 indicating the distance of is calculated (S16).

The circuit 40 calculates the RCS value for the living body 50 using the first distance and the second distance (S17).

The circuit 40 estimates the posture of the living body 50 using the calculated RCS value and the information 42 stored in the memory 41 indicating the correspondence between the RCS value and the posture of the living body 50 (S18).

According to the sensor 10 according to the present embodiment, it is possible to estimate the position where the living body 50 exists and the posture of the living body at the position in a short time and with high accuracy.

The sensor 10 detects the presence of the living body 50 by detecting a moving part. Therefore, for example, by using this, it is possible to estimate whether the human is in a living state and in an upright, sitting, cross-legged, or lying posture. This makes it possible to effectively confirm the survival of humans. In addition, since it is possible to confirm the survival of a human without analyzing the image captured by the camera, it is possible to confirm the survival of a human while protecting the privacy of the human.

(Embodiment 2)
FIG. 5 is a block diagram showing an example of the configuration of the sensor according to the second embodiment. FIG. 6 is a block diagram showing a functional configuration of a circuit and a memory according to a second embodiment.

The sensor 10A in the second embodiment has an arrangement of N transmitting antenna elements 21A included in the transmitting antenna 20A and M receiving antenna elements 31A included in the receiving antenna 30A as compared with the sensor 10 in the first embodiment. The way of doing is different. It is also different that N and M are natural numbers of 3 or more, respectively.

The transmitting antenna 20A has N transmitting antenna elements 21A. Transmitting antenna 20A is lined _{N x} pieces in the horizontal direction (x-direction), and vertical direction _{N z} number in (z direction) is rectangular arranged side by side, N number _{(N = N x × N z} ) It has an array antenna composed of the transmitting antenna element 21A of the above. That is, at least three of the N transmitting antenna elements 21A are arranged at different positions in the vertical direction and the horizontal direction.

The receiving antenna 30A has M receiving antenna elements 31A. Receiving antenna 30A is lined _{M x} pieces in the horizontal direction (x-direction), and, _{M z} pieces in the vertical direction (z-direction) is rectangular arranged side by side, M pieces _{(M = M x × M z} ) It has an array antenna composed of the receiving antenna element 31A of the above. That is, at least three of the M receiving antenna elements 31A are arranged at different positions in the vertical direction and the horizontal direction.

_{Here, let φ T} be the angle formed by the first reference direction, which is a direction on the horizontal plane arbitrarily set with respect to the transmitting antenna 20A, and the first living body direction, which is the direction from the transmitting antenna 20A to the living body 50A. .. Further, the elevation angle of the living body 50A, which is the angle formed by the vertical direction and the first living body direction, is set to θ _T. Further, the elevation angle of the living body 50A, which is the angle formed by the second reference direction, which is a direction on the horizontal plane arbitrarily set with respect to the receiving antenna 30A, and the second living body direction, which is the direction from the receiving antenna 30A to the living body 50A. _Let φ R. Further, the angle formed by the vertical direction and the second living body direction is θ _R. Assuming that the central coordinates of the part where the living body 50A is performing vital activity are (x _b , y _b , z _{b ), the directions (θ T} , θ _R , depending on the positional relationship between the transmitting antenna 20A, the receiving antenna 30A, and the living body 50A) φ _T , φ _R ) and coordinates (x _b , y _b , z _b ) can be converted to each other.

Further, the sensor 10A is different from the sensor 10 in the processing performed by the circuit 40A. Biological 50A is, for example, a living organism is carried out most strongly vital activities compared to the ambient at a height z _b. The living body 50A has, for example, an abdomen having the largest displacement of the body surface due to respiration. In the sensor 10A of the present embodiment, in addition to the position of the living body 50 in the horizontal plane estimated by the sensor 10 in the first embodiment, the vertical position zb (position in the z-axis direction) which is the position of the living body 50A in the vertical direction of, for example, the abdomen. ) Estimates the three-dimensional position including the height. That is, the circuit 40A of the sensor 10A of the present embodiment uses the three-dimensional position estimation processing unit 430A that performs the process of estimating the three-dimensional position instead of the position estimation processing unit 430 of the circuit 40 of the first embodiment. Have.

Further, the sensor 10A is different from the sensor 10 in the information 42A indicating the correspondence stored in the memory 41. In the present embodiment, the information 42A indicating the correspondence between the RCS value stored in the memory 41 and the posture of the living body 50 is, as shown in FIG. 7, each posture shown in supine, cross-legged, sitting and upright. Information indicating a range of RCS values and a range of heights associated with in advance. For example, the supine is associated with the first RCS range and the first height range, the crossed legs are associated with the second RCS range and the second height range, and the chair is associated with the third RCS range and the third. It is associated with a height range, and upright is associated with a fourth RCS range and a fourth height range. The first RCS range to the fourth RCS range are ranges of different RCS values. Further, the first height range to the fourth height range are different height ranges.

Since the other configurations of the sensor 10A are the same as those of the sensor 10, the same reference numerals as those in the first embodiment will be added to the configurations, and the description thereof will be omitted.

The sensor 10A of the present embodiment estimates the vertical position of the living body 50 in the vertical direction in addition to the position of the living body 50 in the horizontal plane estimated by the sensor 10 in the first embodiment.

を得る。Ｒは実施の形態１と同様に０〔Ｈｚ〕＜ｆ＜３〔Ｈｚ〕の間で平均化されている。 Next, the details of the operating principle of the sensor 10A of the second embodiment will be described using a mathematical formula. Equations 1 to 4 are processed in the same manner as in the first embodiment, and the correlation matrix is obtained from the biological component according to the equation 4.

To get. R is averaged between 0 [Hz] <f <3 [Hz] as in the first embodiment.

および

を計算する。以降では、ＭＵＳＩＣ法を用いた高さ方向を含む位置推定方法について説明する。送信アンテナ２０Ａから生体５０Ａへ向かう（θＴ、φＴ）方向を示すステアリングベクトルと、受信アンテナ３０Ａから生体５０Ａへ向かう（θＲ、φＲ）方向を示すステアリングベクトルとは、それぞれ、

と表される。ここで、

と表される。ここで、ｋは波数を表し、ｄ_Ｔｘおよびｄ_Ｔｚはそれぞれ送信アンテナ素子２１Ａのｘ方向およびｚ方向における素子間隔を表し、ｄ_Ｒｘおよびｄ_Ｒｚはそれぞれ受信アンテナ素子３１Ａのｘ方向およびｚ方向における素子間隔を表す。なお、本実施の形態では素子間隔が同一の方向においては一定のリニアアレーアンテナを想定している。 Next, the correlation matrix R calculated in the same manner as in Equation 5 is decomposed into eigenvalues.

and

To calculate. Hereinafter, a position estimation method including the height direction using the MUSIC method will be described. The steering vector indicating the direction from the transmitting antenna 20A toward the living body 50A (θT, φT) and the steering vector indicating the direction from the receiving antenna 30A toward the living body 50A (θR, φR) are respectively.

It is expressed as. here,

It is expressed as. Here, k represents the wave number, d _Tx and d _Tz represent the element spacing of the transmitting antenna element 21A in the x direction and the z direction, respectively, and d _{Rx and d Rz} represent the receiving antenna element 31A in the x direction and the z direction, respectively. Represents the element spacing. In this embodiment, a linear array antenna is assumed to be constant in the directions in which the element spacings are the same.

となる。ステアリングベクトルａ（θ_Ｔ，φ_Ｔ，θ_Ｒ，φ_Ｒ）は、ＭＮ×１の要素を持つベクトルであり、出発角θＴ、φＴと到来角θＲ、φＲとの４変数を持つ関数となる。以降、ａ（θ_Ｔ，φ_Ｔ，θ_Ｒ，φ_Ｒ）をステアリングベクトルと定義する。検出範囲内に存在する生体の数をＬとすると、評価関数

によって生体位置を特定する。実施の形態１と同様に、式２２のＭＵＳＩＣスペクトラムの極大点を探索することで、鉛直位置を含む、送信アンテナ２０Ａおよび受信アンテナ３０Ａから見た生体５０Ａの３次元位置を特定できる。 d _Tx represents, for example, the distance between two transmitting antenna elements 21A adjacent to each other in the x direction among the plurality of transmitting antenna elements 21A. d _Tz represents, for example, the distance between two transmitting antenna elements 21A adjacent to each other in the z direction among the plurality of transmitting antenna elements 21A. Further, d _Rx represents, for example, the distance between two receiving antenna elements 31A adjacent to each other in the x direction among the plurality of receiving antenna elements 31A. Further, d _Rz represents, for example, the distance between two receiving antenna elements 31A adjacent to each other in the z direction among the plurality of receiving antenna elements 31A. The Kronecker product of these steering vectors

Will be. The steering vector a (θ _T , φ _T , θ _R , φ _R ) is a vector having an element of MN × 1, and is a function having four variables of starting angles θ T, φ T and arrival angles θ R, φ R. Hereinafter, a (θ _T , φ _T , θ _R , φ _R ) is defined as a steering vector. If the number of living organisms existing in the detection range is L, the evaluation function

The position of the living body is specified by. Similar to the first embodiment, by searching for the maximum point of the MUSIC spectrum of the formula 22, the three-dimensional position of the living body 50A as seen from the transmitting antenna 20A and the receiving antenna 30A including the vertical position can be specified.

The description of the operation of the sensor 10A in the present embodiment will be omitted because it can be explained by estimating the three-dimensional position in the estimation of the position of the living body in step S15 of the flowchart described with reference to FIG.

FIG. 8 is a diagram showing an outline of an experiment carried out to confirm the effect of the sensor of the second embodiment.

As shown in FIG. 8, the transmitting antenna 20A is a square array antenna configured by arranging 4 × 4 = 16 transmitting antenna elements 21A. The transmitting antenna element 21A is a patch antenna. The receiving antenna 30A is a square array antenna configured by arranging 4 × 4 = 16 receiving antenna elements 31A. The receiving antenna element 31A is a patch antenna. Both the transmitting antenna element 21A and the receiving antenna element 31A are arranged so that the element spacing is 0.5 wavelength.

There was one subject, and measurements were taken in four states: upright, sitting (sitting on a chair), cross-legged (agura), and supine (supine). The position of the subject is (X, Y) = (5.0, 1.0) m. In postures other than supine, the subject is facing the antenna direction (Y direction). In the supine position, the subject is pointing his foot toward the antenna (Y direction). Observation was performed for about 5 seconds per experiment.

FIG. 9 is a diagram showing the experimental results using the experimental system shown in FIG. In FIG. 9, the horizontal axis represents the estimated height zb, and the vertical axis represents the calculated scattering cross section (RCS: Radar Cross Section).

As shown in FIG. 9, it can be seen that the region where the height and the RCS value are distributed differs depending on the posture. That is, it can be confirmed that the posture of the subject can be estimated from the estimated height and the calculated RCS value. For example, as shown in FIG. 10, by setting the information 42A indicating the correspondence relationship, the estimated three-dimensional position, the calculated RCS value, and the information indicating the correspondence relationship stored in the memory 41 are stored. With 42A, it is possible to estimate whether the living body 50A is in an upright, sitting, cross-legged, or supine position. Note that FIG. 10 is a diagram showing specific examples of the first RCS range to the fourth RCS range obtained from the experimental results and specific examples of the first height range to the fourth height range. The first RCS range to the fourth RCS range of FIG. 10 can also be applied to the first RCS range to the fourth RCS range of the information 42 indicating the correspondence relationship of the first embodiment.

According to the sensor 10A according to the present embodiment, it is possible to estimate the three-dimensional position where the living body 50 exists and the posture of the living body at the position in a short time and with high accuracy.

In each of the above embodiments, each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory. Here, the software that realizes the sensors 10, 10A, etc. of each of the above embodiments is the following program.

That is, this program includes a transmitting antenna having N (N is a natural number of 2 or more) transmitting antenna elements, a receiving antenna having M receiving antenna elements (M is a natural number of 2 or more), and a circuit in the computer. This is an estimation method using a sensor provided with a memory, and N transmission signals are transmitted using N transmission antenna elements to a predetermined range in which a living body can exist, and the transmitted N transmission signals are transmitted. A part of the transmitted signal receives N received signals including the reflected signal reflected by the living body by using each of the plurality of receiving antenna elements, and each of the M receiving antenna elements receives the signals in a predetermined period. N × M, each of which is a component of each complex transmission function indicating the propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements from each of the N received signals. By calculating the first matrix of the above and extracting the second matrix corresponding to the predetermined frequency range in the first matrix, it was affected by the vital activity including at least one of the breathing, the heartbeat and the body movement of the living body. The second matrix corresponding to the component is extracted, and the position where the living body exists with respect to the sensor is estimated using the second matrix, and the estimated position, the position of the transmitting antenna, and the receiving antenna of the receiving antenna are estimated. Based on the position, the first distance indicating the distance between the living body and the transmitting antenna and the second distance indicating the distance between the living body and the receiving antenna are calculated, and the first distance and the second distance are calculated. The RCS (Radar cross-section) value for the living body is calculated using the distance, and the calculated RCS value and the information indicating the correspondence between the RCS value and the posture of the living body stored in the memory are used. , Are used to execute an estimation method that estimates the posture of the living body.

Although the sensors 10 and 10A according to one or more aspects of the present invention have been described above based on the embodiments, the present invention is not limited to the embodiments. As long as it does not deviate from the gist of the present invention, one or more of the present embodiments may be modified by those skilled in the art, or may be constructed by combining components in different embodiments. It may be included within the scope of the embodiment.

In the above embodiment, the sensors 10 and 10A are supposed to estimate whether the living body is in an upright, sitting, cross-legged, or recumbent posture, but the present invention is not limited to this. For example, it may be estimated whether or not the living body is in a posture facing the direction perpendicular to the alignment direction of the transmitting antennas 20 and 20A and the receiving antennas 30 and 30A. Specifically, it may be estimated whether the posture is facing the y direction in FIG. 1 or 5 or the posture is lateral to the y direction. For example, when a human faces the y direction, the RCS value becomes smaller than when the human faces the y direction. The posture oriented sideways with respect to the y direction is a posture facing the x direction.

In the first embodiment, the N transmitting antenna elements 21 are arranged side by side in the first predetermined direction on the horizontal plane, and the M receiving antenna elements 31 are arranged side by side in the second predetermined direction on the horizontal plane. It was supposed to be placed, but it is not limited to this. That is, the first predetermined direction and the second predetermined direction are not limited to the direction on the horizontal plane, but may be, for example, a direction on a plane including a vertical direction, or a direction on a plane inclined from the horizontal plane. May be good. In this case, the circuit 40 estimates the position of the living body on the plane including the first predetermined direction and the second predetermined direction.

The present invention can be used as a sensor and an estimation method for estimating the direction and position of a moving body using a wireless signal. In particular, the direction estimation method and direction mounted on measuring instruments that measure the direction and position of moving objects including living bodies and machines, home appliances that control according to the direction and position of moving objects, and monitoring devices that detect the intrusion of moving objects. It can be used for estimation methods, position estimation methods, and at most estimation devices using scattered cross sections.

10, 10A Sensor 20, 20A Transmitting antenna 21, 21A Transmitting antenna element 30, 30A Receiving antenna 31, 31A Receiving antenna element 40, 40A Circuit 41 Memory 42, 42A Information indicating correspondence 50, 50A Living body 410 Complex transfer function calculation unit 420 Biological component calculation unit 430 Position estimation processing unit 430A Three-dimensional position estimation processing unit 440 RCS calculation unit 450 Attitude estimation unit

Claims (5)

It ’s an estimator,
The processor included in the estimation device
A part of the N transmission signals transmitted by the N transmission antenna elements (N is a natural number of 2 or more) that each transmits a transmission signal to a predetermined range in which a living body can exist is N received signals received by each of the M receiving antenna elements (M is a natural number of 2 or more) including the reflected signal reflected by the living body are acquired.
Propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements from each of the N received signals received in each of the M receiving antenna elements in a predetermined period. Calculate the first matrix of N × M with each complex transfer function indicating
By extracting the second matrix corresponding to the predetermined frequency range in the first matrix, the second matrix corresponding to the component affected by the vital activity including at least one of the respiration, heartbeat and body movement of the living body. Extract and
Using the second matrix, the positions where the living body exists with respect to the N transmitting antenna elements and the M receiving antenna elements are estimated.
Based on the estimated position, the position of the transmitting antenna having the N transmitting antenna elements, and the position of the receiving antenna having the M receiving antenna elements, the distance between the living body and the transmitting antenna is determined. The first distance to be shown and the second distance to show the distance between the living body and the receiving antenna are calculated.
Using the first distance and the second distance, an RCS (Radar cross-section) value for the living body is calculated.
The posture of the living body is estimated by using the calculated RCS value and the information indicating the correspondence between the RCS value and the posture of the living body stored in the memory included in the estimation device.
Estimator. The predetermined period is approximately half of at least one cycle of the body's respiration, heartbeat, and body movement.
The estimation device according to claim 1. The processor
It is estimated whether or not the living body is in a posture facing the direction perpendicular to the arrangement direction of the transmitting antenna and the receiving antenna.
The estimation device according to claim 1 or 2. The N is a natural number of 3 or more.
Of the N transmitting antenna elements, at least three transmitting antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively.
The M is a natural number of 3 or more.
At least three of the M receiving antenna elements are arranged at different positions in the vertical direction and the horizontal direction, respectively.
The information indicating the correspondence is the correspondence between the vertical position, the RCS value, and the posture of the living body, which are the positions in the vertical direction in which the living body exists with respect to the N transmitting antenna elements and the M receiving antenna elements. Shows,
The posture of the living body associated with the information indicating the correspondence includes upright, sitting, cross-legged, and supine.
The processor
Using the second matrix, the three-dimensional position including the vertical position is estimated.
Using the estimated three-dimensional position, the calculated RCS value, and the information indicating the correspondence relationship stored in the memory, the living body is upright, sitting, cross-legged, and Estimate which posture is in the supine position,
The estimation device according to any one of claims 1 to 3. On the computer
A part of the transmitted signals of N transmitted signals transmitted by using N transmitting antenna elements (N is a natural number of 2 or more) with respect to a predetermined range in which a living body can exist is a reflected signal reflected by the living body. To acquire N received signals received using each of M (M is a natural number of 2 or more) receiving antenna elements including.
Propagation characteristics between each of the N transmitting antenna elements and each of the M receiving antenna elements from each of the N received signals received in each of the M receiving antenna elements in a predetermined period. Calculate the first matrix of N × M with each complex transfer function indicating
By extracting the second matrix corresponding to the predetermined frequency range in the first matrix, the second matrix corresponding to the component affected by the vital activity including at least one of the respiration, heartbeat and body movement of the living body. Extract and
Using the second matrix, the positions where the living body exists with respect to the N transmitting antenna elements and the M receiving antenna elements are estimated.
Based on the estimated position, the position of the transmitting antenna having the N transmitting antenna elements, and the position of the receiving antenna having the M receiving antenna elements, the distance between the living body and the transmitting antenna is determined. The first distance to be shown and the second distance to show the distance between the living body and the receiving antenna are calculated.
Using the first distance and the second distance, an RCS (Radar cross-section) value for the living body is calculated.
Using the calculated RCS value and the information indicating the correspondence between the RCS value and the posture of the living body stored in the memory provided in the computer, the process of estimating the posture of the living body is executed.
program.

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