Environmental state measurement device and setting method for environmental state measurement device

Abstract

In an environmental state measurement device (1), a plurality of acoustic wave units (10) are positioned on respective outer peripheries of a plurality of boundary planes (BP) that virtually demarcate a space to be measured (MS). The plurality of sound wave units (10) includes a transmitting unit (10S) that directionally transmits sound waves and a receiving unit (10R) that directionally receives sound waves. Each acoustic wave unit (10) is disposed in a posture in which a pointing axis indicating the maximum intensity of the directivity of transmission or reception is inclined at a predetermined angle with respect to each boundary plane (BP) that forms a corner portion of the space (MS) to be measured, the acoustic wave unit (10) being located at the corner portion.

Description

Technical Field

[0001] The present disclosure relates to an environmental state measurement device and a setting method of the environmental state measurement device. Background Art

[0002] Until now, there have been known devices that use sound waves to measure the environmental state of a space. As an example of such an environmental state measuring device, a wind speed distribution measuring device that measures the wind speed distribution of a measured space is disclosed in Patent Document 1. The wind speed distribution measuring device in Patent Document 1 includes a plurality of transmitters that send sound waves and a plurality of receivers that receive sound waves.

[0003] In the wind speed distribution measuring device, for each propagation path from the transmitter to the receiver, the propagation time of the sound wave propagating from the transmitter to the receiver is calculated by using the direct sound from the transmitter and the reflected sound obtained by the direct sound being reflected by the receiver and then reflected again by the transmitter, and the wind speed between the transmitter and the receiver is calculated based on the propagation time of the sound wave.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2019-138891 Summary of the invention

[0007] -Technical problem to be solved by the invention-

[0008] In the wind speed distribution measuring device of Patent Document 1, in order to accurately calculate the propagation time of the sound wave on the propagation path, the transmitter and the receiver are arranged opposite to each other. Generally speaking, when a transmitter that transmits sound waves in a direction and a receiver that receives sound waves in a direction are used, the transmitter and the receiver that form the propagation path between the two are arranged opposite to each other.

[0009] However, when measuring the environmental state of the measured space in three dimensions, if the installation postures of each transmitter and each receiver are set in the same manner so that a specific transmitter and a specific receiver are opposite to each other in a direction parallel to the boundary plane that defines the measured space, then due to the orientation and positional relationship between the transmitter and the receiver that is not opposite to the transmitter, effective sound wave propagation cannot be performed in the propagation path between these transmitters and receivers, resulting in data loss. Even if data loss occurs only in part of the propagation path, data for calculating the environmental state will be insufficient, thereby reducing the reliability of the measurement result.

[0010] The purpose of the present disclosure is to improve the reliability of the measurement results of an environmental state measurement device.

[0011] -Technical solutions to solve technical problems-

[0012] The first aspect of the present disclosure is directed to an environmental state measuring device 1. The environmental state measuring device 1 of the first aspect includes a plurality of acoustic wave units 10 arranged around a measured space MS. The acoustic wave units 10 are located on the periphery of each of a plurality of boundary planes BP, and the plurality of boundary planes BP virtually delimit the measured space MS. The plurality of acoustic wave units 10 include a transmitting unit 10S and a receiving unit 10R, wherein the transmitting unit 10S transmits acoustic waves in a directionally manner and the receiving unit 10R receives acoustic waves in a directionally manner. The environmental state measuring device 1 measures the environmental state of the measured space MS based on the propagation characteristics of the acoustic waves propagating between the transmitting unit 10S and the receiving unit 10R. At least a portion of the acoustic wave units 10 are arranged in the following posture: the directional axis DA representing the maximum intensity of the directivity of transmission or reception is tilted at a specified angle relative to at least one of the boundary planes BP where the acoustic wave unit 10 is located.

[0013] In the first aspect, at least a portion of the acoustic wave unit 10 is set to a specified tilted posture. The specified tilted posture is: the directional axis DA of the acoustic wave unit 10, which represents the maximum intensity of the directivity of sending or receiving, is tilted at a specified angle relative to at least one of the boundary planes BP where the acoustic wave unit 10 is located. In this way, effective sound wave propagation can be carried out in the propagation path P between the transmitting unit 10S and the receiving unit 10R that are not opposite to each other, and data defects can be suppressed. As a result, the reliability of the measurement results of the environmental state measuring device 1 can be improved.

[0014] According to a second aspect of the present disclosure, based on the environmental state measuring device 1 of the first aspect, the acoustic wave unit 10 is located at a corner of the measured space MS. In the environmental state measuring device 1, the acoustic wave unit 10 located at a corner of the measured space MS is set in the following posture: the directional axis DA is inclined at a predetermined angle relative to each of the plurality of boundary planes BP forming the corner.

[0015] In the second aspect, the acoustic wave unit 10 located at the corner of the measured space MS is set to a prescribed tilted posture. The prescribed tilted posture is: the directional axis DA is tilted at a prescribed angle relative to each of the multiple boundary planes BP forming the corner of the measured space MS. This is conducive to effective acoustic wave propagation on the propagation path P between the transmitting unit 10S and the receiving unit 10R arranged in a three-dimensional manner, and suppressing data loss.

[0016] According to a third aspect of the present disclosure, based on the environmental state measuring device 1 of the first or second aspect, the prescribed angle is set according to the attenuation amount of the sound wave of each propagation path P associated with the sound wave unit 10 set at the angle.

[0017] In the third aspect, the setting angle of the sound wave unit 10 is set according to the attenuation of the sound wave on each propagation path P associated with the sound wave unit 10. If the attenuation of the sound wave on the propagation path P is large, effective sound wave propagation cannot be performed on the propagation path P. Therefore, by determining the setting angle of the sound wave unit 10, the attenuation of the sound wave on each propagation path P is converged within a specified range, thereby enabling effective sound wave propagation on each of the above-mentioned propagation paths P.

[0018] In the fourth aspect of the present disclosure, based on the environmental state measuring device 1 of the third aspect, the attenuation of the sound wave is calculated based on the transmission directivity and the reception directivity for the propagation path P, and the distance attenuation related to the propagation path P between the transmitting unit 10S and the receiving unit 10R.

[0019] In the fourth aspect, the attenuation of the sound wave is calculated based on the transmission directivity and the receiving directivity with respect to the propagation path P, and the distance attenuation between the transmitting unit 10S and the receiving unit 10R related to the propagation path P. As for the sound wave propagating in the specified propagation path P, the lower the transmission directivity with respect to the propagation path P, the more attenuation it has, the lower the receiving directivity with respect to the propagation path P, the more attenuation it has, and the greater the distance attenuation with respect to the propagation path P between the transmitting unit 10S and the receiving unit 10R, the more attenuation it has. In this way, if the attenuation of the sound wave on the propagation path P is calculated based on the transmission directivity and the receiving directivity with respect to the propagation path P, which are closely related to the attenuation of the sound wave, and the distance attenuation with respect to the propagation path P, the attenuation can be calculated with high accuracy.

[0020] The fifth aspect of the present disclosure is based on the environmental state measuring device 1 of any one of the first to fourth aspects. For the multiple acoustic wave units 10 located on the periphery of the same boundary plane BP, the angles formed by the directional axes DA relative to the same boundary plane BP are set to be the same angle as each other.

[0021] In the fifth aspect, the installation posture of the plurality of acoustic wave units 10 located on the periphery of the same boundary plane BP is determined so that the angle formed by the directional axis DA relative to the same boundary plane BP is the same in each acoustic wave unit 10. Thus, the setting related to the installation angle of the plurality of acoustic wave units 10 can be simplified.

[0022] According to the sixth aspect of the present disclosure, based on the environmental state measuring device 1 of any one of the first to fifth aspects, the acoustic wave unit 10 is located at a corner of the measured space MS. In the environmental state measuring device 1, a pair of the acoustic wave units 10 located at mutually adjacent corners of the measured space MS on the periphery of the same boundary plane BP are arranged in a linearly symmetrical posture relative to an imaginary reference line RL1 to RL12 passing through the middle position of the pair of acoustic wave units 10 when viewed from a direction orthogonal to the boundary plane BP.

[0023] In the sixth aspect, the installation postures of a pair of acoustic wave units 10 located at adjacent corners of the measured space MS on the periphery of the same boundary plane BP are set to have a predetermined line-symmetric relationship. This simplifies the setting of the installation angles of the plurality of acoustic wave units 10.

[0024] According to the seventh aspect of the present disclosure, based on the environmental state measuring device 1 of any one of the first to sixth aspects, the plurality of boundary planes BP include first boundary planes BP1, BP3, BP5 and second boundary planes BP2, BP4, BP6 that are opposite to each other. In the environmental state measuring device 1, a pair of the acoustic wave units 10 corresponding to each other in positional relationship of the first boundary planes BP1, BP3, BP5 and the second boundary planes BP2, BP4, BP6 respectively include a transmitting element 12 that realizes the function of the transmitting unit 10S and a receiving element 14 that realizes the function of the receiving unit 10R, and the transmitting element 12 and the receiving element 14 are independent of each other. The pair of acoustic wave units 10 are arranged in a posture in which the positional relationship of the transmitting element 12 and the receiving element 14 is the same relative to an imaginary reference plane RP1-RP3 set at an intermediate position between the first boundary planes BP1, BP3, BP5 and the second boundary planes BP2, BP4, BP6.

[0025] In the seventh aspect, a pair of acoustic wave units 10 corresponding to each other in positional relationship in the first boundary planes BP1, BP3, BP5 and the second boundary planes BP2, BP4, BP6 respectively include a transmitting element 12 and a receiving element 14 independent of each other. The transmitting element 12 of one acoustic wave unit 10 and the receiving element 14 of another acoustic wave unit 10, as well as the receiving element 14 of one acoustic wave unit 10 and the transmitting element 12 of another acoustic wave unit 10 respectively form different propagation paths P between each other. It is assumed that the transmitting element 12 and the receiving element 14 in this pair of acoustic wave units 10 have the same positional relationship relative to the imaginary reference planes RP1 to RP3. Thus, the length difference of each propagation path P formed between a pair of acoustic wave units 10 can be reduced. This is conducive to simplifying the measurement of the environmental state measuring device 1.

[0026] The eighth aspect of the present disclosure is directed to a method for setting an environmental state measuring device 1. The method for setting the environmental state measuring device 1 of the eighth aspect sets a plurality of acoustic wave units 10 including a transmitting unit 10S for directional transmission of acoustic waves and a receiving unit 10R for directional reception of acoustic waves at positions separated from each other, so that a measured space MS is demarcated by a plurality of boundary planes BP, and the acoustic wave units 10 are located on the periphery of the plurality of boundary planes BP. In the method for setting the environmental state measuring device 1, for each of the propagation paths P of the acoustic waves associated with at least a portion of the acoustic wave units 10, the attenuation of the acoustic waves is calculated based on the transmission directivity, the reception directivity, and the distance attenuation between the transmitting unit 10S and the receiving unit 10R associated with the propagation path P. The angle of the setting posture of at least a portion of the acoustic wave units 10 is determined based on the attenuation of the acoustic waves of each of the propagation paths P, which is the angle at which the directional axis DA representing the maximum intensity of the directivity of transmission or reception is tilted relative to at least one of the boundary planes BP where the acoustic wave unit 10 is located.

[0027] In the eighth aspect, for each of the propagation paths P of the sound waves associated with at least a portion of the sound wave unit 10, the attenuation of the sound waves is calculated based on the transmission directivity, reception directivity, and distance attenuation between the transmission unit 10S and the reception unit 10R associated with the propagation path P. If the attenuation of the sound waves on the propagation path P is calculated based on the transmission directivity and reception directivity for the propagation path P, and the distance attenuation associated with the propagation path P, the attenuation of the sound waves on the propagation path P can be calculated with high accuracy. In the setting method, the angle of the setting posture of at least a portion of the sound wave unit 10 is determined. The setting angle is the angle at which the pointing axis DA is inclined relative to at least one boundary plane BP where the sound wave unit 10 is located, and is determined based on the attenuation of the sound waves on each propagation path P associated with the sound wave unit 10. At this time, by determining the setting angle of the sound wave unit 10, the attenuation of the sound waves on each propagation path P converges within a specified range, thereby enabling effective sound wave propagation on each of the above-mentioned propagation paths P. As a result, the reliability of the measurement results of the environmental state measurement device 1 can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a diagram showing a schematic structure of an environmental state measurement device according to an embodiment;

[0029] Figure 2 is a block diagram of an environmental state measuring device;

[0030] Figure 3 is a perspective view showing a schematic structure of an acoustic wave unit;

[0031] Figure 4 is a graph showing the frequency characteristics of a transmitting element;

[0032] Figure 5 is a diagram showing the directional characteristics of a transmitting element;

[0033] Figure 6 is a graph showing the frequency characteristics of a receiving element;

[0034] Figure 7 is a diagram showing the directional characteristics of a receiving element;

[0035] Figure 8 It is a diagram of the arrangement of multiple acoustic wave units relative to the measured space;

[0036] Fig. 9 This is a top view showing an example of the setting state and propagation path of multiple sound wave units from the vertical direction. Fig. 9 In the figure, the acoustic wave units and propagation paths located on the periphery of the upper surface of the boundary are shown, and the acoustic wave units and propagation paths located on the periphery of the lower surface of the boundary are shown with characters in brackets;

[0037] Fig.10 This is a first side view showing an example of the setting state and propagation path of multiple sound wave units from one side. Fig.10 In the figure, the acoustic wave units and propagation paths on the periphery of the third boundary side are shown, and the acoustic wave units and propagation paths on the periphery of the fourth boundary side are shown with characters in brackets;

[0038] Fig.11 is a second side view showing an example of the setting state and propagation path of multiple sound wave units from the other side. Fig.11 , the acoustic wave units and propagation paths located on the outer periphery of the fifth boundary side are shown, and the acoustic wave units and propagation paths located on the outer periphery of the sixth boundary side are shown with characters in brackets;

[0039] Fig.12 The third side view is a view showing an example of the setting state and propagation path of a plurality of acoustic wave units from the main viewing direction of the first dividing vertical plane. Fig.12 , showing the acoustic wave unit and propagation path located on the periphery of the first dividing vertical plane;

[0040] Fig.13 This is a top view showing an example of the setting state of multiple acoustic wave units together with the directional axes from the vertical direction. Fig.13 In the figure, the acoustic wave units and the directional axes located on the periphery of the upper surface of the boundary are shown, and the acoustic wave units and the directional axes located on the periphery of the lower surface of the boundary are shown with characters in brackets;

[0041] Fig.14 This is a first side view showing an example of the arrangement of a plurality of acoustic wave units together with the directional axes from one side. Fig.14 In the figure, the acoustic wave units and their directional axes on the outer periphery of the third boundary side are shown, and the acoustic wave units and their directional axes on the outer periphery of the fourth boundary side are shown with characters in brackets;

[0042] Fig.15 is a second side view showing an example of the arrangement of a plurality of acoustic wave units together with the directional axis from the other side. Fig.15 In the figure, the acoustic wave units and their directional axes on the outer periphery of the fifth boundary side are shown, and the acoustic wave units and their directional axes on the outer periphery of the sixth boundary side are shown with characters in brackets;

[0043] Fig.16 is a third side view showing an example of the setting state of a plurality of acoustic wave units together with the directional axis from the main viewing direction of the first dividing vertical plane, Fig.16 The acoustic wave unit and its directional axis located on the periphery of the first dividing vertical plane are shown;

[0044] Fig.17 is a graph showing the distance attenuation characteristics of an acoustic wave unit;

[0045] Fig.18 It is a conceptual diagram used to illustrate the transmission angle and the reception angle;

[0046] Fig.19 is a table showing, by way of example, the relationship between the setting angle of the acoustic wave unit and the angular attenuation;

[0047] Fig. 20 is a graph showing, by way of example, the relationship between the setting angle of the acoustic wave unit and the total angular attenuation;

[0048] Fig.21 is a flowchart showing the main part of the setting method of the environmental state measurement device;

[0049] Fig. 22 is a table showing, by way of example, the total attenuation of sound waves on each propagation path associated with the first sound wave unit and related information when each sound wave unit is at an initially set angle;

[0050] Fig.23 is a table showing, by way of example, the total attenuation of the sound waves on each propagation path of the first sound wave unit after the angle of each sound wave unit is changed and related information thereof;

[0051] Fig.24 is a diagram showing an example of the change in the setting angle of the sound wave unit, which is equivalent to Fig.16 ;

[0052] Fig.25 is a diagram showing an example of the change in the setting angle of the sound wave unit, which is equivalent to Fig.14 ;

[0053] Fig.26 1 is a diagram showing a schematic configuration of an environmental state measurement device according to a modified example. DETAILED DESCRIPTION

[0054] The following is a detailed description of exemplary embodiments with reference to the accompanying drawings. It should be noted that the accompanying drawings are used to conceptually illustrate the technology of the present disclosure. Therefore, in the accompanying drawings, in order to facilitate the understanding of the technology of the present disclosure, the size, ratio or quantity may be exaggerated or simplified as needed.

[0055] (Implementation Method)

[0056] - Configuration of environmental status measuring device -

[0057] The environmental state measuring device 1 of this embodiment is a device for measuring the environmental state of the measured space MS using sound waves. The measured space MS is set in, for example, an indoor space IS of various facilities or residences. The environmental state includes the wind speed and the temperature of the air in the measured space MS. An air treatment device may be provided in the indoor space IS. The air treatment device is, for example, a ventilator, an air purifier, an air conditioner, etc.

[0058] 〈Measured space〉

[0059] like Figure 1 As shown, the measured space MS is virtually delimited by a plurality of boundary planes BP. The measured space MS in this example is a three-dimensional space in the shape of a rectangular parallelepiped. The boundary planes BP that delimit the measured space MS are composed of six boundary planes BP. The six boundary planes BP are the boundary upper surface BP1, the boundary lower surface BP2, the first boundary side surface BP3, the second boundary side surface BP4, the third boundary side surface BP5, and the fourth boundary side surface BP6.

[0060] The upper boundary surface BP1 defines the upper boundary of the measured space MS. The lower boundary surface BP2 defines the lower boundary of the measured space MS. The upper boundary surface BP1 and the lower boundary surface BP2 are respectively rectangular imaginary surfaces extending in the horizontal direction, and are opposite to each other in the up-down direction. The upper boundary surface BP1 is an example of a first boundary plane, and the lower boundary surface BP2 is an example of a second boundary plane. The vertices of the upper boundary surface BP1 and the vertices of the lower boundary surface BP2 are located at corresponding positions in the up-down direction, and overlap with each other when viewed from a top view.

[0061] The first boundary side BP3, the second boundary side BP4, the third boundary side BP5 and the fourth boundary side BP6 are respectively rectangular imaginary surfaces extending in the vertical direction to define the outer peripheral boundary of the measured space MS. The first boundary side BP3 and the second boundary side BP4 are opposite to each other in the horizontal direction. The first boundary side BP3 is an example of a first boundary plane, and the second boundary side BP4 is an example of a second boundary plane. The third boundary side BP5 and the fourth boundary side BP6 are respectively at right angles to the first boundary side BP3 and the second boundary side BP4, and are opposite to each other in the horizontal direction. The third boundary side BP5 is an example of a first boundary plane, and the fourth boundary side BP6 is an example of a second boundary plane.

[0062] The boundary upper surface BP1, the first boundary side surface BP3 and the third boundary side surface BP5 are adjacent to each other and have a common vertex to form the first corner portion C1 of the measured space MS. The boundary upper surface BP1, the first boundary side surface BP3 and the fourth boundary side surface BP6 are adjacent to each other and have a common vertex to form the second corner portion C2. The boundary upper surface BP1, the second boundary side surface BP4 and the fourth boundary side surface BP6 are adjacent to each other and have a common vertex to form the third corner portion C3 of the measured space MS. The boundary upper surface BP1, the second boundary side surface BP4 and the third boundary side surface BP5 are adjacent to each other and have a common vertex to form the fourth corner portion C4 of the measured space MS.

[0063] The boundary lower surface BP2, the first boundary side surface BP3 and the third boundary side surface BP5 are adjacent to each other and have a vertex in common to form the fifth corner C5 of the measured space MS. The boundary lower surface BP2, the first boundary side surface BP3 and the fourth boundary side surface BP6 are adjacent to each other and have a vertex in common to form the sixth corner C6. The boundary lower surface BP2, the second boundary side surface BP4 and the fourth boundary side surface BP6 are adjacent to each other and have a vertex in common to form the seventh corner C7 of the measured space MS. The boundary lower surface BP2, the second boundary side surface BP4 and the third boundary side surface BP5 are adjacent to each other and have a vertex in common to form the eighth corner C8 of the measured space MS.

[0064] The first corner C1 and the third corner C3, the second corner C2 and the fourth corner C4 are respectively in a diagonal position relationship in the boundary upper surface BP1. The fifth corner C5 and the seventh corner C7, the sixth corner C6 and the eighth corner C8 are respectively in a diagonal position relationship in the boundary lower surface BP2. The measured space MS is virtually divided by the first dividing vertical plane VP1 and the second dividing vertical plane VP2. The first dividing vertical plane VP1 and the second dividing vertical plane VP2 are respectively rectangular imaginary planes extending in the vertical direction and are orthogonal to each other.

[0065] The first dividing vertical plane VP1 is formed by connecting the vertices shared by the upper boundary surface BP1, the first boundary side surface BP3 and the third boundary side surface BP5, the vertices shared by the upper boundary surface BP1, the second boundary side surface BP4 and the fourth boundary side surface BP6, the vertices shared by the lower boundary surface BP2, the first boundary side surface BP3 and the third boundary side surface BP5, and the vertices shared by the lower boundary surface BP2, the second boundary side surface BP4 and the fourth boundary side surface BP6. The first dividing vertical plane VP1 is set to divide the measured space MS along a diagonal direction.

[0066] The second dividing vertical plane VP2 is formed by connecting the vertices shared by the upper boundary surface BP1, the first boundary side surface BP3 and the fourth boundary side surface BP6, the vertices shared by the upper boundary surface BP1, the second boundary side surface BP4 and the third boundary side surface BP5, the vertices shared by the lower boundary surface BP2, the first boundary side surface BP3 and the fourth boundary side surface BP6, and the vertices shared by the lower boundary surface BP2, the second boundary side surface BP4 and the third boundary side surface BP5. The second dividing vertical plane VP2 is set to divide the measured space MS along the direction of another diagonal line.

[0067] In the measured space MS, the boundary upper surface BP1, the boundary lower surface BP2, the first boundary side surface BP3, the second boundary side surface BP4, the third boundary side surface BP5, the fourth boundary side surface BP6, the first dividing vertical plane VP1 and the second dividing vertical plane VP2 respectively constitute the measurement plane MP for measuring the environmental state.

[0068] 〈Environmental status measuring device〉

[0069] like Figure 2 As shown, the environmental state measuring device 1 includes a plurality of acoustic wave units 10 , a coordinate measuring section 20 , and a controller 30 .

[0070] 〈Sound Wave Unit〉

[0071] The plurality of sound wave units 10 are composed of eight sound wave units 10. The eight sound wave units 10 include a first sound wave unit 10A, a second sound wave unit 10B, a third sound wave unit 10C, a fourth sound wave unit 10D, a fifth sound wave unit 10E, a sixth sound wave unit 10F, a seventh sound wave unit 10G, and an eighth sound wave unit 10H. Hereinafter, the first to eighth sound wave units 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H are simply referred to as "sound wave units 10" without being distinguished.

[0072] Each acoustic wave unit 10 is driven by a built-in battery and has a wireless communication function such as Wi-Fi (registered trademark) and infrared communication. Eight acoustic wave units 10 are arranged at dispersed positions with intervals around the measured space MS. The acoustic wave units 10 are located on the outer periphery of each of the six boundary planes BP. Figure 8 As shown, the acoustic wave unit 10 of this example is arranged at each corner of the measured space MS.

[0073] Specifically, the first acoustic wave unit 10A is arranged at the first corner C1 of the measured space MS, the second acoustic wave unit 10B is arranged at the second corner C2 of the measured space MS, the third acoustic wave unit 10C is arranged at the third corner C3 of the measured space MS, the fourth acoustic wave unit 10D is arranged at the fourth corner C4 of the measured space MS, the fifth acoustic wave unit 10E is arranged at the fifth corner C5 of the measured space MS, the sixth acoustic wave unit 10F is arranged at the sixth corner C6 of the measured space MS, the seventh acoustic wave unit 10G is arranged at the seventh corner C7 of the measured space MS, and the eighth acoustic wave unit 10H is arranged at the eighth corner C8 of the measured space MS.

[0074] Although not shown in the figure, each acoustic wave unit 10 is supported by an independent support body. Each support body extends in a vertical direction. Each support body is provided with a height adjustment mechanism, and the height adjustment mechanism is used to adjust the height of the supported acoustic wave unit 10. For example, the height of each acoustic wave unit 10 arranged in the first to fourth corners C1, C2, C3, and C4, and the height of each acoustic wave unit 10 arranged in the fifth to eighth corners C5, C6, C7, and C8 are respectively set at the same height position by the height adjustment mechanism. An angle adjustment mechanism for adjusting the setting angle of the acoustic wave unit 10 is provided on the support body. The angle adjustment mechanism is configured to be able to adjust at least the pitch angle and the yaw angle of the roll angle, pitch angle, and yaw angle of the acoustic wave unit 10.

[0075] like Figure 3 As shown, in the acoustic wave unit 10, a roll axis A1, a pitch axis A2, and a yaw axis A3 are defined. The roll axis A1 is an axis that passes through the center of the acoustic wave unit 10 in the front-rear direction. The pitch axis A2 is an axis that is orthogonal to the roll axis A1 and passes through the center of the acoustic wave unit 10 in the width direction. The yaw axis A3 is an axis that is orthogonal to the roll axis A1 and the pitch axis A2 and passes through the center of the acoustic wave unit 10 in the height direction. The setting posture of each acoustic wave unit 10 is set by the rotation angle (roll angle) around the roll axis A1, the rotation angle (pitch angle) around the pitch axis A2, and the rotation angle (yaw angle) around the yaw axis A3.

[0076] The eight acoustic wave units 10 include a transmitting unit 10S for transmitting acoustic waves and a receiving unit 10R for receiving acoustic waves. Each acoustic wave unit 10 of this example serves as both the transmitting unit 10S and the receiving unit 10R. Each acoustic wave unit 10 includes a transmitting element 12 and a receiving element 14 that are independent of each other. When the acoustic wave unit 10 is observed from the front, the transmitting element 12 and the receiving element 14 are arranged on the front surface of the acoustic wave unit 10 and at positions that are equidistant from a center point CP where the roll axis A1 intersects the front surface in the direction along the yaw axis A3.

[0077] The first acoustic wave unit 10A has a first transmitting element 12a and a first receiving element 14a. The second acoustic wave unit 10B has a second transmitting element 12b and a second receiving element 14b. The third acoustic wave unit 10C has a third transmitting element 12c and a third receiving element 14c. The fourth acoustic wave unit 10D has a fourth transmitting element 12d and a fourth receiving element 14d. The fifth acoustic wave unit 10E has a fifth transmitting element 12e and a fifth receiving element 14e. The sixth acoustic wave unit 10F has a sixth transmitting element 12f and a sixth receiving element 14f. The seventh acoustic wave unit 10G has a seventh transmitting element 12g and a seventh receiving element 14g. The eighth acoustic wave unit 10H has an eighth transmitting element 12h and an eighth receiving element 14h. Hereinafter, the first to eighth transmitting elements 12a, 12b, 12c, 12d, 12e, 12f, 12g, and 12h are simply referred to as “transmitting elements 12” when not being distinguished, and the first to eighth receiving elements 14a, 14b, 14c, 14d, 14e, 14f, 14g, and 14h are simply referred to as “receiving elements 14” when not being distinguished.

[0078] The transmitting element 12 realizes the function of the transmitting unit 10S (sound wave transmitting function). Figure 4 The frequency characteristics shown in FIG. 1 have a mountain-shaped characteristic, that is, there is a peak frequency at 40kHz, and as the frequency changes from the peak frequency to the low-frequency side and the high-frequency side, the sound pressure level gradually decreases. The transmitting element 12 is configured to be directional. The directional transmitting element 12 only transmits sound waves in a directional manner within a specified angle range. The transmitting element 12 in this example has Figure 5 The directional characteristics shown.

[0079] Figure 5The relationship between the emission angle of the sound wave transmitted by the transmitting element 12 and the transmission intensity at each emission angle is shown. The transmitting element 12 exhibits the following transmission directivity: the transmission intensity of the sound wave emitted in the normal direction (0°) of the transmitting surface of the transmitted sound wave is the strongest, and the larger the emission angle, the weaker the transmission intensity (that is, the attenuation of the sound wave becomes larger). The transmitting element 12 has a transmission directivity axis DA1 representing the maximum transmission intensity (maximum transmission power). The transmitting element 12 in this example will expand to an angle range of approximately 90° with the transmission directivity axis DA1 as the center as the directivity angle.

[0080] The receiving element 14 realizes the function of the receiving unit 10R (sound wave receiving function). Figure 6 The frequency characteristics shown in FIG. 1 and FIG. 2 have a mountain-shaped characteristic, that is, there is a peak frequency at 40 kHz, and as the frequency changes from the peak frequency to the low frequency side and the high frequency side, the sensitivity gradually decreases. The receiving element 14 is configured to be directional. The directional receiving element 14 only receives sound waves in a directional manner within a specified angle range. The receiving element 14 in this example has Figure 7 The directional characteristics shown.

[0081] Figure 7 The relationship between the incident angle of the sound wave received by the receiving element 14 and the receiving sensitivity at each incident angle is shown. The receiving element 14 exhibits the following receiving directivity: the receiving sensitivity of the sound wave incident from the normal direction (0°) of the receiving surface receiving the sound wave is the strongest, and the larger the receiving angle, the weaker the receiving sensitivity (that is, the attenuation of the sound wave becomes larger). The receiving element 14 has a receiving directivity axis DA2 representing the maximum intensity of reception (maximum receiving sensitivity). The receiving element 14 of this example will expand to an angle range of approximately 90° with the receiving directivity axis DA2 as the center as the directivity angle.

[0082] like Figure 3 As shown, the transmitting surface of the transmitting element 12 and the receiving surface of the receiving element 14 are located in the same plane of each acoustic wave unit 10. In each acoustic wave unit 10 of this example, the transmitting directional axis DA1 and the receiving directional axis DA2 extend in parallel to each other in the same direction. Hereinafter, when the transmitting directional axis DA1 and the receiving directional axis DA2 are not distinguished, they are referred to as "directional axis DA". The directional axis DA will be referred to in the following references. Figures 17 to 20 Each acoustic wave unit 10 is provided in a posture where the transmission surface of the transmission element 12 and the reception surface of the reception element 14 face the inside of the measurement space MS.

[0083] The first acoustic wave unit 10A sends and receives acoustic waves within the range from the first boundary side BP3 to the third boundary side BP5 when viewed from a top view, and within the range from the boundary upper surface BP1 to the lower side in the vertical direction when viewed from a side view. The second acoustic wave unit 10B sends and receives acoustic waves within the range from the first boundary side BP3 to the fourth boundary side BP6 when viewed from a top view, and within the range from the boundary upper surface BP1 to the lower side in the vertical direction when viewed from a side view. The third acoustic wave unit 10C sends and receives acoustic waves within the range from the second boundary side BP4 to the fourth boundary side BP6 when viewed from a top view, and within the range from the boundary upper surface BP1 to the lower side in the vertical direction when viewed from a side view. The fourth acoustic wave unit 10D sends and receives acoustic waves within the range from the second boundary side BP4 to the third boundary side BP5 when viewed from a top view, and within the range from the boundary upper surface BP1 to the lower side in the vertical direction when viewed from a side view.

[0084] The fifth acoustic wave unit 10E sends and receives acoustic waves within the range from the first boundary side BP3 to the third boundary side BP5 as viewed from a top view, and within the range from the boundary lower surface BP2 to the upper side in the vertical direction as viewed from a side view. The sixth acoustic wave unit 10F sends and receives acoustic waves within the range from the first boundary side BP3 to the fourth boundary side BP6 as viewed from a top view, and within the range from the boundary lower surface BP2 to the upper side in the vertical direction as viewed from a side view. The seventh acoustic wave unit 10G sends and receives acoustic waves within the range from the second boundary side BP4 to the fourth boundary side BP6 as viewed from a top view, and within the range from the boundary lower surface BP2 to the upper side in the vertical direction as viewed from a side view. The eighth acoustic wave unit 10H sends and receives acoustic waves within the range from the second boundary side BP4 to the third boundary side BP5 as viewed from a top view, and within the range from the boundary lower surface BP2 to the upper side in the vertical direction as viewed from a side view.

[0085] like Figures 9 to 12 As shown, multiple sound wave units 10 form multiple propagation paths Pmn (m=1, 2, ... 8; m corresponds to the "th" subsequent identification number of the sending element 12) (n=1, 2, ... 8; n corresponds to the "th" subsequent identification number of the receiving element 14). Hereinafter, without distinguishing between which pair of sound wave units 10 the propagation path Pmn is formed, it is referred to as "propagation path P".

[0086] There are two propagation paths P between each pair of acoustic wave units 10 that perform transmission and reception. The two propagation paths P are a propagation path P formed between the transmitting element 12 of one acoustic wave unit 10 and the receiving element 14 of another acoustic wave unit 10, and a propagation path P formed between the receiving element 14 of one acoustic wave unit 10 and the transmitting element 12 of another acoustic wave unit 10. In the measured space MS of this example, fifty-six propagation paths P are formed.

[0087] The fifty-six propagation paths P are all propagation paths for propagating direct waves. A direct wave is a sound wave that is transmitted from one of a pair of sound wave units 10 associated with the propagation path P and reaches the other sound wave unit 10 without colliding with the wall surface WL of the indoor space MS. In the measured space MS, a propagation path for propagating reflected waves can be formed between a pair of sound wave units 10. A reflected wave is a sound wave that is transmitted from one of a pair of sound wave units 10 associated with the propagation path P and reaches the other sound wave unit 10 after being reflected on the wall surface WL of the indoor space MS.

[0088] Each acoustic wave unit 10 is arranged in the following posture: the directional axis DA is inclined at a specified angle relative to at least one boundary plane BP on the periphery of the acoustic wave unit 10. Each acoustic wave unit 10 in this example is arranged in the following posture: the directional axis DA is inclined at a specified angle relative to three boundary planes BP, respectively, wherein the three boundary planes BP form a corner portion of the measured space MS, and the acoustic wave unit 10 is located in the corner portion. As for the setting angle of the acoustic wave unit 10, at least the pitch angle and the yaw angle can be adjusted by the angle adjustment mechanism of the supporting body supporting the acoustic wave unit 10.

[0089] The first acoustic wave unit 10A is arranged in the following posture: the directional axis DA is inclined relative to the boundary upper surface BP1, the first boundary side surface BP3 and the third boundary side surface BP5. The second acoustic wave unit 10B is arranged in the following posture: the directional axis DA is inclined relative to the boundary upper surface BP1, the first boundary side surface BP3 and the fourth boundary side surface BP6. The third acoustic wave unit 10C is arranged in the following posture: the directional axis DA is inclined relative to the boundary upper surface BP1, the second boundary side surface BP4 and the fourth boundary side surface BP6. The fourth acoustic wave unit 10D is arranged in the following posture: the directional axis DA is inclined relative to the boundary upper surface BP1, the second boundary side surface BP4 and the third boundary side surface BP5.

[0090] The fifth acoustic wave unit 10E is arranged in the following posture: the directional axis DA is inclined relative to the boundary lower surface BP2, the first boundary side surface BP3 and the third boundary side surface BP5. The sixth acoustic wave unit 10F is arranged in the following posture: the directional axis DA is inclined relative to the boundary lower surface BP2, the first boundary side surface BP3 and the fourth boundary side surface BP6. The seventh acoustic wave unit 10G is arranged in the following posture: the directional axis DA is inclined relative to the boundary lower surface BP2, the second boundary side surface BP4 and the fourth boundary side surface BP6. The eighth acoustic wave unit 10H is arranged in the following posture: the directional axis DA is inclined relative to the boundary lower surface BP2, the second boundary side surface BP4 and the third boundary side surface BP5.

[0091] In the environmental state measurement device 1 of this example, first to third constraints described below are added to the installation postures of the first to eighth acoustic wave units 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H.

[0092] (1) The first constraint

[0093] like Figure 13 to Figure 16 As shown, the angles formed by the directional axes DA of the four acoustic wave units 10 located on the periphery of the same boundary plane BP with respect to the same boundary plane BP are set to be the same angle as each other.

[0094] Specifically, the directional axes DA of the first acoustic wave unit 10A, the second acoustic wave unit 10B, the third acoustic wave unit 10C, and the fourth acoustic wave unit 10D are at the same angle relative to the boundary upper surface BP1. The directional axes DA of the fifth acoustic wave unit 10E, the sixth acoustic wave unit 10F, the seventh acoustic wave unit 10G, and the eighth acoustic wave unit 10H are at the same angle relative to the boundary lower surface BP2. The directional axes DA of the first acoustic wave unit 10A, the second acoustic wave unit 10B, the fifth acoustic wave unit 10E, and the sixth acoustic wave unit 10F are at the same angle relative to the first boundary side surface BP3.

[0095] The directional axes DA of the third acoustic wave unit 10C, the fourth acoustic wave unit 10D, the seventh acoustic wave unit 10G, and the eighth acoustic wave unit 10H form the same angle with respect to the second boundary side BP4. The directional axes DA of the first acoustic wave unit 10A, the fourth acoustic wave unit 10D, the fifth acoustic wave unit 10E, and the eighth acoustic wave unit 10H form the same angle with respect to the third boundary side BP5. The directional axes DA of the second acoustic wave unit 10B, the third acoustic wave unit 10C, the sixth acoustic wave unit 10F, and the seventh acoustic wave unit 10G form the same angle with respect to the fourth boundary side BP6.

[0096] (2) Second constraint

[0097] like Figure 13 to Figure 15 As shown, a pair of acoustic wave units 10 located at adjacent corners of the measured space MS on the periphery of the same boundary plane BP are arranged in a linearly symmetrical posture relative to an imaginary baseline RL1~RL12 passing through the middle position of the pair of acoustic wave units 10 when viewed from a direction orthogonal to the boundary plane BP.

[0098] like Fig.13 As shown, the setting posture of the first acoustic wave unit 10A and the setting posture of the second acoustic wave unit 10B, and the setting posture of the third acoustic wave unit 10C and the setting posture of the fourth acoustic wave unit 10D are respectively line-symmetric with respect to an imaginary reference line RL1 passing through the middle positions of the first acoustic wave unit 10A and the setting posture of the fourth acoustic wave unit 10D, and the setting posture of the second acoustic wave unit 10B and the setting posture of the third acoustic wave unit 10C are respectively line-symmetric with respect to an imaginary reference line RL2 ... third acoustic wave unit 10C are respectively line-symmetric with respect to an imaginary reference line RL2 passing through the middle positions of the first acoustic wave unit 10A and the setting posture of the fourth acoustic wave unit 10D.

[0099] like Fig.13 As shown in the brackets, the setting posture of the fifth acoustic wave unit 10E and the setting posture of the sixth acoustic wave unit 10F, and the setting posture of the seventh acoustic wave unit 10G and the setting posture of the eighth acoustic wave unit 10H are respectively line-symmetric with respect to an imaginary reference line RL3 passing through their respective middle positions when viewed from a direction orthogonal to the boundary lower surface BP2. The setting posture of the fifth acoustic wave unit 10E and the setting posture of the eighth acoustic wave unit 10H, and the setting posture of the sixth acoustic wave unit 10F and the setting posture of the seventh acoustic wave unit 10G are respectively line-symmetric with respect to an imaginary reference line RL4 passing through their respective middle positions when viewed from a direction orthogonal to the boundary lower surface BP2.

[0100] like Fig.14 As shown, the setting posture of the first acoustic wave unit 10A and the setting posture of the second acoustic wave unit 10B, and the setting posture of the fifth acoustic wave unit 10E and the setting posture of the sixth acoustic wave unit 10F are respectively line-symmetric with respect to an imaginary reference line RL5 passing through their respective middle positions when viewed from a direction orthogonal to the first boundary side surface BP3. The setting posture of the first acoustic wave unit 10A and the setting posture of the fifth acoustic wave unit 10E, and the setting posture of the second acoustic wave unit 10B and the setting posture of the sixth acoustic wave unit 10F are respectively line-symmetric with respect to an imaginary reference line RL6 passing through their respective middle positions when viewed from a direction orthogonal to the first boundary side surface BP3.

[0101] like Fig.14As shown in the brackets, the setting posture of the third acoustic wave unit 10C and the setting posture of the fourth acoustic wave unit 10D, and the setting posture of the seventh acoustic wave unit 10G and the setting posture of the eighth acoustic wave unit 10H are respectively line-symmetric with respect to an imaginary reference line RL7 passing through their respective middle positions when viewed from a direction orthogonal to the second boundary side BP4. The setting posture of the third acoustic wave unit 10C and the setting posture of the seventh acoustic wave unit 10G, and the setting posture of the fourth acoustic wave unit 10D and the setting posture of the eighth acoustic wave unit 10H are respectively line-symmetric with respect to an imaginary reference line RL8 passing through their respective middle positions when viewed from a direction orthogonal to the second boundary side BP4.

[0102] like Fig.15 As shown, the setting posture of the second acoustic wave unit 10B and the setting posture of the third acoustic wave unit 10C, and the setting posture of the sixth acoustic wave unit 10F and the setting posture of the seventh acoustic wave unit 10G are respectively line-symmetric with respect to an imaginary reference line RL9 passing through their respective middle positions when viewed from a direction orthogonal to the fourth boundary side BP6. The setting posture of the second acoustic wave unit 10B and the setting posture of the sixth acoustic wave unit 10F, and the setting posture of the third acoustic wave unit 10C and the setting posture of the seventh acoustic wave unit 10G are respectively line-symmetric with respect to an imaginary reference line RL10 passing through their respective middle positions when viewed from a direction orthogonal to the fourth boundary side BP6.

[0103] like Fig.15 As shown in the brackets, the setting posture of the first acoustic wave unit 10A and the setting posture of the fourth acoustic wave unit 10D, and the setting posture of the fifth acoustic wave unit 10E and the setting posture of the eighth acoustic wave unit 10H are respectively line-symmetric with respect to an imaginary reference line RL11 passing through their respective middle positions when viewed from a direction orthogonal to the third boundary side BP5. The setting posture of the first acoustic wave unit 10A and the setting posture of the fifth acoustic wave unit 10E, and the setting posture of the fourth acoustic wave unit 10D and the setting posture of the eighth acoustic wave unit 10H are respectively line-symmetric with respect to an imaginary reference line RL12 passing through their respective middle positions when viewed from a direction orthogonal to the third boundary side BP5.

[0104] (3) The third constraint

[0105] like Figure 13 to Figure 16 As shown, a pair of acoustic wave units 10 that are in a corresponding positional relationship with each other on the peripheries of two opposite boundary planes BP are arranged in a posture where the positional relationship of the transmitting element 12 and the receiving element 14 is the same relative to an imaginary reference plane RP1~RP3 set at a middle position between the two boundary planes BP.

[0106] The pair of acoustic wave units 10 are set in a posture in which the pitch angle of the acoustic wave unit 10 is tilted in an opposite direction relative to the reference planes RP1 to RP3. In this example, the pair of acoustic wave units 10 are set in a posture in which the transmitting element 12 is relatively far away and the receiving element 14 is relatively close relative to the reference planes RP1 to RP3. The pair of acoustic wave units 10 can also be set in a posture in which the transmitting element 12 is relatively close and the receiving element 14 is relatively far away relative to the reference planes RP1 to RP3.

[0107] The first acoustic wave element 10A and the fifth acoustic wave element 10E, the second acoustic wave element 10B and the sixth acoustic wave element 10F, the third acoustic wave element 10C and the seventh acoustic wave element 10G, and the fourth acoustic wave element 10D and the eighth acoustic wave element 10H are respectively in the reverse posture relative to the reference plane RP1. The first acoustic wave element 10A and the fourth acoustic wave element 10D, the second acoustic wave element 10B and the third acoustic wave element 10C, the fifth acoustic wave element 10E and the eighth acoustic wave element 10H, the sixth acoustic wave element 10F and the seventh acoustic wave element 10G are respectively in the reverse posture relative to the reference plane RP2. The first acoustic wave element 10A and the second acoustic wave element 10B, the fourth acoustic wave element 10D and the third acoustic wave element 10C, the fifth acoustic wave element 10E and the sixth acoustic wave element 10F, and the eighth acoustic wave element 10H and the seventh acoustic wave element 10G are respectively in the reverse posture relative to the reference plane RP3.

[0108] As described above, since constraints are imposed on the installation postures of the first to eighth sound wave units 10A, 10B, 10C, 10D, 10E, 10F, 10G, and 10H, the lengths of the two propagation paths P formed between a pair of sound wave units 10 for transmitting and receiving are equal, that is, the propagation distances. The propagation distance is the straight-line distance between the transmitting element 12 and the receiving element 14 for transmitting and receiving sound waves.

[0109] For example, for each propagation path P associated with the first acoustic wave unit 10A, the propagation distances of the two propagation paths P12 and P21 formed between the first acoustic wave unit 10A and the second acoustic wave unit 10B, the propagation distances of the two propagation paths P13 and P31 formed between the first acoustic wave unit 10A and the third acoustic wave unit 10C, the propagation distances of the two propagation paths P14 and P41 formed between the first acoustic wave unit 10A and the fourth acoustic wave unit 10D, the propagation distances of the two propagation paths P15 and P41 formed between the first acoustic wave unit 10A and the fifth acoustic wave unit 10E, The propagation distance of P51, the propagation distance of the two propagation paths P16 and P61 formed between the first acoustic wave unit 10A and the sixth acoustic wave unit 10F, the propagation distance of the two propagation paths P17 and P71 formed between the first acoustic wave unit 10A and the seventh acoustic wave unit 10G, and the propagation distance of the two propagation paths P18 and P81 formed between the first acoustic wave unit 10A and the eighth acoustic wave unit 10H are respectively equal to each other and are the same as the distance between the pair of acoustic wave units 10 (strictly speaking, the distance between the central points CP of the pair of acoustic wave units 10). The above content also applies to the propagation paths Pmn related to the other second to eighth acoustic wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H.

[0110] The setting angle of each sound wave unit 10 is set according to the attenuation of the sound wave for each propagation path P related to the sound wave unit 10. The attenuation of the sound wave refers to the sound pressure level attenuated from the time when one sound wave unit 10 of a pair of sound wave units 10 for transmission and reception transmits to the time when the other sound wave unit 10 receives. The attenuation of the sound wave is calculated based on the attenuation caused by the transmission directivity and the reception directivity for the propagation path P, and the distance attenuation related to the propagation path P between the pair of sound wave units 10.

[0111] The distance attenuation between a pair of sound wave units 10 means that the sound wave attenuates according to the propagation distance of the sound wave. The energy of the sound wave sent from the sound wave unit 10 is weakened as it moves away from the sound wave unit 10, and the sound pressure level becomes smaller before it is received by the sound wave unit 10 that forms the transmitting and receiving pair. Fig.17 As shown, the attenuation of the sound wave caused by distance attenuation is determined by the propagation distance of the sound wave, and increases as the propagation distance becomes longer. Therefore, the longer the distance between a pair of sound wave units 10 for transmitting and receiving, the greater the attenuation of the sound wave caused by distance attenuation.

[0112] The transmission directivity for the propagation path P means that the emission intensity of the sound wave will change according to the transmission angle θ1 of the sound wave. Fig.18As schematically shown, the transmission angle θ1 is the angle between the transmission directional axis DA1 and the propagation path P. The amount of acoustic wave attenuation caused by the transmission directivity is determined by the directional characteristics of the transmission element 12, and the attenuation increases as the transmission angle θ1 increases. Hereinafter, the attenuation of acoustic waves caused by the transmission directivity is referred to as "angle attenuation of the transmission element 12".

[0113] The reception directivity for the propagation path P means that the reception sensitivity of the sound wave will change according to the reception angle θ2 of the sound wave. Fig.18 As schematically shown, the receiving angle θ2 is the angle between the receiving directional axis DA2 and the propagation path P. The amount of sound wave attenuation caused by the receiving directivity is determined by the directional characteristics of the receiving element 14, and the attenuation increases as the receiving angle θ2 increases. Hereinafter, the attenuation of the sound wave caused by the receiving directivity is referred to as "angle attenuation of the receiving element 14".

[0114] Fig.19 The relationship between the setting angle of the acoustic wave unit 10 and the angular attenuation of the transmitting element 12, the angular attenuation of the receiving element 14, and the total angular attenuation is shown. The setting angle of the acoustic wave unit 10 here is the angle between the directional axes DA of a pair of acoustic wave units 10 for transmitting and receiving relative to the propagation path P. In addition, the total angular attenuation refers to the total angular attenuation generated on the propagation path P due to the angular attenuation of the transmitting element 12 and the angular attenuation of the receiving element 14.

[0115] like Fig.19 As shown, the larger the setting angle of the acoustic wave unit 10 is, the greater the angular attenuation of the transmitting element 12 and the angular attenuation of the receiving element 14 will be. As a result, Fig. 20 As shown in Figure 2, the total angular attenuation of the propagation path P becomes larger. Fig.19 In the figure, for the sake of convenience, what is recorded is the case where the setting angles of a pair of acoustic wave units 10 for transmitting and receiving are the same, but in fact, in the pair of acoustic wave units 10 for transmitting and receiving, the transmitting angle θ1 formed by the transmitting directional axis DA1 relative to the propagation path P, and the receiving angle θ2 formed by the receiving directional axis DA2 relative to the propagation path P are different from each other.

[0116] The sound wave attenuation of each propagation path P refers to the total sound wave attenuation caused by distance attenuation and composite angle attenuation. The composite angle attenuation is described below. The total attenuation is calculated by logarithmic calculation based on the sound wave attenuation caused by distance attenuation and the sound wave attenuation caused by composite angle attenuation. The setting angle of each sound wave unit 10 is set so that the total attenuation of the sound wave is less than a specified value on any propagation path P related to the sound wave unit 10. The specified value here is set to a value that can carry out effective sound wave propagation in the propagation path P in any combination of a pair of sound wave units 10 for transmission and reception (that is, the value of the total attenuation that should be suppressed for effective sound wave propagation).

[0117] With respect to the plurality of acoustic wave units 10 whose setting postures are set in this manner, when the measured space MS is not in a cubic shape, etc., an arbitrary combination of a pair of acoustic wave units 10 for transmitting and receiving may not face each other directly. The setting postures of the acoustic wave units 10 are changed according to the setting postures of any one of the acoustic wave units 10 based on the first to third constraints. For example, if the setting angle of the first acoustic wave unit 10A is changed, the setting angles of the second to eighth acoustic wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H will also be changed to satisfy the first to third constraints.

[0118] 〈Coordinate Measurement Department〉

[0119] The coordinate measuring unit 20 measures three-dimensional coordinates related to the shape of the indoor space IS and three-dimensional coordinates related to the position of each acoustic wave unit 10. The coordinate measuring unit 20 is composed of a three-dimensional laser measuring device.

[0120] 〈Controller〉

[0121] The controller 30 includes a microcomputer and a storage device (specifically, a semiconductor memory), wherein the microcomputer is mounted on a control substrate and the storage device stores software for operating the microcomputer. The controller 30 is connected to each acoustic wave unit 10 and the coordinate measuring unit 20 via a wireless or wired communication line. A part or all of the controller 30 may be set in the acoustic wave unit 10 or in a server on the network.

[0122] The controller 30 has a storage unit 32 and a calculation unit 34. The storage unit 32 stores the three-dimensional coordinates measured by the coordinate measuring unit 20. The storage unit 32 stores a plurality of propagation paths P and the propagation distances in each of the propagation paths P in association with each other. For a pair of sound wave units 10 that transmit and receive sound waves, the calculation unit 34 measures the propagation time from when one sound wave unit 10 transmits a sound wave to when the other sound wave unit 10 receives the sound wave. The calculation unit 34 calculates the wind speed and air temperature at each measurement plane MP of the measured space MS by a known method based on the data stored in the storage unit 32 and the propagation time of the sound waves of each propagation path P.

[0123] As described above, the environmental state measurement device 1 measures environmental states such as wind speed and air temperature of the measurement space MS based on propagation characteristics (propagation time in this example) of sound waves propagating between a pair of sound wave units 10 that transmit and receive sound waves.

[0124] - Setting method of environmental status measuring device -

[0125] The method of setting the above-mentioned structure of the environmental state measuring device 1 is described. In the setting of the environmental state measuring device 1, a plurality of acoustic wave units 10 are arranged at dispersed positions spaced apart from each other, thereby defining a plurality of boundary planes BP, the acoustic wave units 10 are located on the periphery of the boundary planes BP, and the measured space MS is divided by the plurality of the boundary planes BP.

[0126] In the setting method of the environmental state measuring device 1, for each of the propagation paths P of the sound waves associated with at least a portion of the sound wave unit 10, the total attenuation of the sound waves is calculated based on the transmission directivity, reception directivity, and distance attenuation between a pair of sound wave units 10 that transmit and receive the sound waves associated with the propagation path P. The angle of the setting posture of the sound wave unit 10 is determined based on the total attenuation of the sound waves of each propagation path P, which is the angle at which the directional axis DA is inclined relative to each boundary plane BP forming the corner portion where the sound wave unit 10 is located.

[0127] The controller 30 determines the installation angle of each acoustic wave unit 10 based on the shape and size of the measured space MS as the measurement object, the number and installation positions of the acoustic wave units 10 input by the operator.

[0128] Specifically, if Fig.21 As shown, first, in step ST1, the operator determines the measured space MS (the shape and size of the space MS). In this example, a rectangular space with a length of 10m, a width of 10m, and a height of 2m is used as the measured space MS. The operator inputs the data of the shape and size of the measured space MS that have been determined into the controller 30.

[0129] Next, in step ST2, the user determines the number and installation positions of the acoustic wave units 10 to be installed in the measured space MS determined in step ST1. In this example, the number of acoustic wave units 10 is eight, and the installation positions of the acoustic wave units 10 are respectively eight corners of the measured space MS. The operator inputs the data of the number and installation positions of the determined acoustic wave units 10 into the controller 30.

[0130] Next, in step ST3, for the plurality of acoustic wave units 10 whose number and arrangement positions have been determined in step ST2, the controller 30 calculates the distance between the acoustic wave units 10 for each pair of acoustic wave units 10 for transmission and reception. Fig. 22 As shown, the distances between the first acoustic wave unit 10A and the second to eighth acoustic wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H are calculated. The storage unit 32 stores the calculated distances between the acoustic wave units 10 .

[0131] Next, in step ST4, the controller 30 uses the distance between each pair of acoustic wave units 10 for transmitting and receiving stored in the storage unit 32 as the propagation distance of the corresponding propagation path P, and calculates the attenuation of the acoustic wave caused by the distance attenuation for each propagation path P. For example, Fig. 22 As shown, the attenuation of the sound wave due to distance attenuation in each propagation path P between the first sound wave unit 10A and the second to eighth sound wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H is calculated. The storage unit 32 stores the calculated attenuation of the sound wave due to distance attenuation in each propagation path P.

[0132] Next, in step ST5, the controller 30 determines the initial setting angle of each acoustic wave unit 10. The initial setting angle of each acoustic wave unit 10 in this example is an angle in a posture in which each directional axis DA is directed toward the center of the measured space MS. Therefore, a pair of acoustic wave units 10 located on the diagonal line of the measured space MS face each other in the posture at the initial setting angle.

[0133] Next, in step ST6, the controller 30 calculates the attenuation of the sound wave caused by the synthetic angle attenuation of each propagation path P. At this time, the setting angle (the direction of the pointing axis DA) of each sound wave unit 10 is known. In step ST6, first, the controller 30 calculates, for each propagation path P, the transmitting angle formed by the transmitting pointing axis DA1 of the sound wave unit 10 relative to the propagation path P, and the receiving angle formed by the receiving pointing axis DA2 of the sound wave unit 10 relative to the propagation path P.

[0134] The transmission angle and the receiving angle relative to each propagation path P are equivalent to the composite angle Ac of a pair of acoustic wave units 10 associated with the propagation path P. Fig.16 As shown, the composite angle Ac of a pair of acoustic wave units 10 refers to the angle formed by the directional axis DA of each acoustic wave unit 10 relative to the composite line CL drawn in the middle of the two propagation paths P between the pair of acoustic wave units 10. The composite line CL is defined as a line connecting the central points CP of a pair of acoustic wave units 10 for transmission and reception.

[0135] The composite angle Ac is the angle of inclination relative to the horizontal direction and the vertical direction. Figure 13 to Figure 15 As shown in FIG. 1 , the composite angle Ac can be regarded as the composite angle a1 in the horizontal direction and the composite angle a2 in the vertical direction. The composite angle a1 in the horizontal direction is the angle when the pointing axis DA and the composite line CL as the object are viewed from the front on the horizontal plane. The composite angle a2 in the vertical direction is the angle when the pointing axis DA and the composite line CL as the object are viewed from the front on the vertical plane. For example, Fig. 22 As shown, the combined angle a1 in the horizontal direction and the combined angle a2 in the vertical direction between the first acoustic wave element 10A and the second to eighth acoustic wave elements 10B, 10C, 10D, 10E, 10F, 10G, and 10H are respectively obtained.

[0136] The controller 30 calculates the attenuation of the sound wave on the propagation path P caused by the angular attenuation of the transmitting element 12, that is, the transmission attenuation, for each of the composite angles a1 in the horizontal direction and a2 in the vertical direction related to each propagation path P, based on the directional characteristics of the transmitting element 12. The controller 30 calculates the attenuation of the sound wave on the propagation path P caused by the angular attenuation of the receiving element 14, that is, the reception attenuation, for each of the composite angles a1 in the horizontal direction and a2 in the vertical direction related to each propagation path P, based on the directional characteristics of the receiving element 14.

[0137] Furthermore, the controller 30 calculates the total angular attenuation in the horizontal direction by adding the transmission attenuation of the sound wave and the reception attenuation of the sound wave in the propagation path P for the composite angle a1 in the horizontal direction related to each propagation path P. The controller 30 calculates the total angular attenuation in the vertical direction by adding the transmission attenuation of the sound wave and the reception attenuation of the sound wave in the propagation path P for the composite angle a2 in the vertical direction related to each propagation path P.

[0138] Then, the controller 30 combines the sum of the horizontal angle attenuation and the sum of the vertical angle attenuation for each propagation path P by logarithmic calculation, thereby calculating the attenuation of the sound wave caused by the combined angle attenuation. Fig. 22As shown in the figure, the total horizontal angle attenuation, the total vertical angle attenuation and the combined angle attenuation of each propagation path P between the first sound wave unit 10A and the second to eighth sound wave units 10B, 10C, 10D, 10E, 10F, 10G and 10H are calculated. The storage unit 32 stores the calculated attenuation of the sound wave caused by the combined angle attenuation of each propagation path P.

[0139] Next, in step ST7, the controller 30 calculates the total attenuation of the sound wave in each propagation path P based on the attenuation of the sound wave caused by the distance attenuation in each propagation path P and the attenuation of the sound wave caused by the composite angle attenuation in each propagation path P, which are stored in the storage unit 32. Fig. 22 As shown, the total attenuation of each propagation path P between the first acoustic wave unit 10A and the second to eighth acoustic wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H is calculated. The storage unit 32 stores the calculated total attenuation of the acoustic wave in each propagation path P.

[0140] Next, in step ST8, the controller 30 determines whether the total attenuation of the sound waves in each propagation path P stored in the storage unit 32 is less than a specified value. In step ST8, when it is determined that the total attenuation of the sound waves in all propagation paths P is less than the specified value (in the case of "yes"), the process proceeds to step ST10 to determine the setting angle of each sound wave unit 10, and the setting of the setting angle of each sound wave unit 10 is completed.

[0141] On the other hand, in step ST8, as long as the total attenuation of the sound waves of a part of the propagation path P is greater than the specified value, the process proceeds to step ST9. In step ST9, the setting angle of each sound wave unit 10 related to the problematic propagation path P in which the total attenuation of the sound waves is greater than the specified value is changed. Here, the setting angle of each sound wave unit 10 is changed in a direction that tilts the directional axis DA toward the propagation path P side as the object.

[0142] In step ST9, the setting angles of the acoustic wave units 10 associated with the acoustic wave unit 10 to be changed and subject to the first to third constraints will also be changed according to the first to third constraints. In this example, when the setting angle of the acoustic wave unit 10 associated with a propagation path P is changed, the setting angles of all the acoustic wave units 10 will be changed. The setting angle of the acoustic wave unit 10 can be changed by only shifting a specified angle from the initial setting angle, or the setting angle can be changed to a specific angle so that the total attenuation of the acoustic wave of the problematic propagation path P is improved.

[0143] For example, in step ST8, 32 dB is set as the predetermined value of the judgment standard. Fig. 22 As shown, the total attenuation of the sound waves of each propagation path P between the first sound wave unit 10A and the fifth sound wave unit 10E among the multiple sound wave units 10 at the initial setting angle is above the specified value. The total attenuation of the sound waves of each propagation path P between the second sound wave unit 10B and the sixth sound wave unit 10F, each propagation path P between the third sound wave unit 10C and the seventh sound wave unit 10G, and each propagation path P between the fourth sound wave unit 10D and the eighth sound wave unit 10H, which have the same positional relationship as the first sound wave unit 10A and the fifth sound wave unit 10E, is also above the specified value. Therefore, the controller 30 determines "No" in step ST8 and proceeds to step ST9.

[0144] And, in Fig. 22 In the example shown in FIG. 1 , in step ST9, for example, the installation angle (elevation angle) of each acoustic wave unit 10 is changed so that the vertical composite angle a2 between the first acoustic wave unit 10A and the third acoustic wave unit 10C is changed from 8° to 30°. Fig.24 and Fig.25 As shown, the setting postures of the first acoustic wave unit 10A and the fifth acoustic wave unit 10E, the setting postures of the second acoustic wave unit 10B and the sixth acoustic wave unit 10F, and the setting postures of the third acoustic wave unit 10C and the seventh acoustic wave unit 10G are such that the directional axes DA are inclined toward the propagation path P between the two acoustic wave units 10, and the directional axes DA intersect with each other. The same applies to the setting postures of the fourth acoustic wave unit 10D and the eighth acoustic wave unit 10H, which are not shown in the figure.

[0145] After the change of the setting angle of the sound wave unit 10 is completed in step ST9, the process returns to step ST6, and the subsequent steps ST6, ST7, ST8, and ST9 are performed until the judgment condition in step ST8 is satisfied. Then, when the judgment condition in step ST8 is satisfied, the process proceeds to step ST10 as described above, and the setting angle of each sound wave unit 10 is determined, and the setting of the setting angle of each sound wave unit 10 is completed.

[0146] for Fig. 22 In the example shown in FIG. 1 , after changing the setting angle of each acoustic wave unit 10, the composite angle a2 in the vertical direction between the first acoustic wave unit 10A and the second to eighth acoustic wave units 10B, 10C, 10D, 10E, 10F, 10G, and 10H is calculated again, as shown in FIG. Fig.23 Then, in steps ST6 and ST7, the attenuation of the sound waves caused by the synthetic angle attenuation on each propagation path P and the total attenuation of the sound waves are recalculated.

[0147] like Fig.23 As shown by the underline in , the attenuation of the sound wave caused by the synthetic angle attenuation and the total attenuation of each propagation path P between the first sound wave unit 10A and the second to eighth sound wave units 10B, 10C, 10D, 10E, 10F, 10G, 10H are recalculated. In this case, the total attenuation on each propagation path P between the first sound wave unit 10A and the fifth sound wave unit 10E is -30.3dB, so it is judged as "yes" in step ST8, and the setting angle of each sound wave unit 10 is determined.

[0148] In setting the environmental state measuring device 1, the operator sets the plurality of acoustic wave units 10 at the specified dispersed positions around the measured space MS according to the setting angles of the acoustic wave units 10 determined as described above. The setting of the environmental state measuring device 1 can also be performed by temporarily setting the plurality of acoustic wave units 10 at the initial setting angles and then adjusting the setting angles of the acoustic wave units 10.

[0149] - Features of the embodiment -

[0150] In the environmental state measuring device 1 of this embodiment, a plurality of acoustic wave units 10 are respectively arranged in a prescribed tilted posture. The prescribed tilted posture is: the directional axis DA of each acoustic wave unit 10 is tilted at a prescribed angle relative to each boundary plane BP where the acoustic wave unit 10 is located. Thus, in the propagation path P between a pair of acoustic wave units 10 that are not opposite to each other, effective acoustic wave propagation can be performed, and data loss can be suppressed. As a result, the reliability of the measurement result of the environmental state measuring device 1 can be improved.

[0151] In the environmental state measuring device 1 of this embodiment, the acoustic wave unit 10 located at each corner of the measured space MS is set to a prescribed tilted posture. The prescribed tilted posture is: the directional axis DA is tilted at a prescribed angle relative to each of the multiple boundary planes BP forming the corner of the measured space MS. This is conducive to effective acoustic wave propagation in the propagation path P between a pair of acoustic wave units 10 arranged in a three-dimensional manner for transmitting and receiving acoustic waves, and suppressing data loss.

[0152] In the environmental state measuring device 1 of this embodiment, the setting angle of the sound wave unit 10 is set according to the attenuation of the sound wave on each propagation path P associated with the sound wave unit 10. If the attenuation of the sound wave on the propagation path P is large, effective sound wave propagation cannot be performed on the propagation path P. Therefore, by determining the setting angle of the sound wave unit 10, the attenuation of the sound wave on each propagation path P is converged within a specified range (a range smaller than a specified value), so that effective sound wave propagation can be performed on each of the above-mentioned propagation paths P.

[0153] In the environmental state measuring device 1 of this embodiment, the attenuation of sound waves is calculated based on the transmission directivity and the receiving directivity with respect to the propagation path P, and the distance attenuation between a pair of sound wave units 10 and related to the propagation path P. As for the sound waves propagating in the propagation path P, the lower the transmission directivity with respect to the propagation path P, the more attenuation there is, the lower the receiving directivity with respect to the propagation path P, the more attenuation there is, and the greater the distance attenuation with respect to the propagation path P between a pair of sound wave units 10, the more attenuation there is. In this way, if the attenuation of sound waves on the propagation path P is calculated based on the transmission directivity and the receiving directivity with respect to the propagation path P, which are closely related to the attenuation of sound waves, and the distance attenuation with respect to the propagation path P, the attenuation thereon can be calculated with high accuracy.

[0154] In the environmental state measuring device 1 of this embodiment, the setting posture of the plurality of acoustic wave units 10 located on the periphery of the same boundary plane BP is determined so that the angle formed by the directional axis DA relative to the same boundary plane BP is the same in each acoustic wave unit 10. Thus, the setting related to the setting angle of the plurality of acoustic wave units 10 can be simplified.

[0155] In the environmental state measuring device 1 of this embodiment, the installation posture of a pair of acoustic wave units 10 located at adjacent corners of the measured space MS on the periphery of the same boundary plane BP is determined so that, when viewed from a direction orthogonal to the boundary plane BP, they are in a line-symmetric relationship with respect to an imaginary reference line RL1 to RL12 passing through the middle position of the pair of acoustic wave units 10. Thus, the setting related to the installation angle of the plurality of acoustic wave units 10 can be simplified.

[0156] In the environmental state measuring device 1 of this embodiment, two acoustic wave units 10 in a corresponding positional relationship on the periphery of a pair of boundary planes BP facing each other respectively include a transmitting element 12 and a receiving element 14 independent of each other. The positional relationship of the transmitting element 12 and the receiving element 14 in the two acoustic wave units 10 relative to the imaginary reference planes RP1 to RP3 is the same. Thus, the length difference of each propagation path P formed between the pair of acoustic wave units 10 can be reduced. This is conducive to simplifying the measurement of the environmental state measuring device 1.

[0157] In the setting method of the environmental state measurement device 1 of this embodiment, for each of the propagation paths P of the sound waves associated with each sound wave unit 10, the attenuation of the sound waves is calculated based on the transmission directivity and reception directivity associated with the propagation path, and the distance attenuation associated with the propagation path P between a pair of sound wave units 10. If the total attenuation of the sound waves on the propagation path P is calculated based on the transmission directivity and reception directivity for the propagation path P and the distance attenuation associated with the propagation path P, the total attenuation of the sound waves on the propagation path P can be calculated with high accuracy.

[0158] Furthermore, in the setting method of the environmental state measurement device 1 of this embodiment, the angle of each sound wave unit 10 in the setting posture is determined. The setting angle is the angle at which the pointing axis DA is inclined relative to each boundary plane BP forming the corner of the measured space MS, and the sound wave unit 10 is located in the corner, and the setting angle is determined according to the attenuation of the sound wave on each propagation path P related to the sound wave unit 10. At this time, by determining the setting angle of the sound wave unit 10, the attenuation of the sound wave on each propagation path P is converged within a specified range (a range smaller than a specified value), so that effective sound wave propagation can be performed on the above-mentioned propagation paths P. As a result, the reliability of the measurement results of the environmental state measurement device 1 can be improved.

[0159] (Other embodiments)

[0160] The above-mentioned embodiment may also adopt the following structure.

[0161] The number of the acoustic wave units 10 is not limited to eight, and may be nine or more. For example, when it is desired to improve the resolution of the environmental state measurement at each measurement plane MP, Fig.26 As shown, it is sufficient to increase the number of acoustic wave units 10 located on the periphery of each measurement plane BP. The number of acoustic wave units 10 may be seven or less, and may be appropriately changed according to the shape and size of the measured space MS.

[0162] Only a portion of the acoustic wave units 10 among the plurality of acoustic wave units 10 may be arranged so that the pointing axis DA is inclined at a prescribed angle relative to each boundary plane BP, wherein each boundary plane BP forms a corner of the measured space MS, wherein the acoustic wave unit 10 is located at the corner. In other words, as long as at least a portion of the acoustic wave units 10 are arranged so that the pointing axis DA is inclined at a prescribed angle relative to at least one boundary plane BP where the acoustic wave unit 10 is located, effective acoustic wave propagation on all propagation paths P can be ensured.

[0163] In the acoustic wave unit 10, as long as the transmitting surface of the transmitting element 12 and the receiving surface of the receiving element 14 face the front side, the transmitting directional axis DA1 and the receiving directional axis DA2 may also face different directions from each other. In this case, the acoustic wave unit 10 is configured so that the transmitting directional axis DA1 or the receiving directional axis DA2 is tilted relative to at least one boundary plane BP where the acoustic wave unit 10 is located.

[0164] The acoustic wave unit 10 may include a transmitting and receiving element having the functions of the transmitting element 12 and the receiving element 14 as an integrated element, instead of providing the transmitting element 12 and the receiving element 14 as independent elements.

[0165] The plurality of acoustic wave units 10 may include a transmitting unit 10S and a receiving unit 10R as independent units. For example, the plurality of acoustic wave units 10 may be composed of a plurality of transmitting units 10S having only a transmitting function and a plurality of receiving units 10R having only a receiving function.

[0166] The plurality of acoustic wave units 10 may include an acoustic wave unit 10 that functions as both a transmitting unit 10S and a receiving unit 10R, an acoustic wave unit 10 that functions only as a transmitting unit 10S, and an acoustic wave unit 10 that functions only as a receiving unit 10R.

[0167] The environmental state measurement device 1 can measure environmental states other than the wind speed and air temperature of the measurement space MS. For example, the environmental state measurement device 1 can also measure the pressure of the air in the measurement space MS as the environmental state.

[0168] In the environmental state measurement device 1, at least one of the first to third constraints may not be imposed on the installation postures of the plurality of acoustic wave units 10. The installation postures of the respective acoustic wave units 10 may also be determined independently so that the total attenuation of the acoustic waves on all propagation paths P is less than a specified value.

[0169] In the setting of the environmental state measuring device 1 , the installation angle of each acoustic wave unit 10 may be determined by a computer prepared separately from the controller 30 , or may be determined by a server on the network.

[0170] The above embodiments and modifications are described, but it is understood that various changes can be made to the scheme and specific circumstances without departing from the spirit and scope of the claims. As long as the functions of the objects of the present disclosure are not affected, the above embodiments and modifications can also be appropriately combined and replaced.

[0171] The words "first", "second", "third", etc. mentioned above are only used to distinguish sentences containing the above words, and do not limit the quantity and order of the sentences.

[0172] - Industrial Applicability -

[0173] In summary, the present disclosure is useful for an environmental state measurement device and a setting method for an environmental state measurement device.

[0174] - Explanation of symbols -

[0175] BP Boundary Plane

[0176] BP1 Boundary upper surface (first boundary plane)

[0177] BP2 Boundary lower surface (second boundary plane)

[0178] BP3 first boundary side (first boundary plane)

[0179] BP4 Second boundary side (second boundary plane)

[0180] BP5 Third boundary side (first boundary plane)

[0181] BP6 Fourth boundary side (second boundary plane)

[0182] DA Directional Axis

[0183] MS Measured Space

[0184] P Propagation Path

[0185] RL1~RL12 baseline

[0186] RP1~RP3 reference surface

[0187] 1 Environmental status measurement device

[0188] 10 Sound wave unit

[0189] 10S Sending Unit

[0190] 10R Receiver Unit

[0191] 12 Sending Components

[0192] 14 Receiving element

Claims

1. An environmental state measuring device, comprising a plurality of sound wave units (10) arranged around a measured space (MS), wherein the sound wave units (10) are located on the periphery of each of a plurality of boundary planes (BP), wherein the plurality of boundary planes (BP) virtually delimit the measured space (MS), wherein the plurality of sound wave units (10) include a transmitting unit (10S) and a receiving unit (10R), wherein the transmitting unit (10S) transmits sound waves in a directionally manner, and the receiving unit (10R) receives sound waves in a directionally manner, wherein the environmental state measuring device measures the environmental state of the measured space (MS) according to the propagation characteristics of the sound waves propagating between the transmitting unit (10S) and the receiving unit (10R), wherein: At least a portion of the acoustic wave unit (10) is arranged in the following posture: a directional axis (DA) representing the maximum intensity of the directivity of transmission or reception is inclined at a specified angle relative to at least one of the boundary planes (BP) where the acoustic wave unit (10) is located.

2. The environmental state measuring device according to claim 1, characterized in that: The acoustic wave unit (10) is arranged at a corner of the measured space (MS), The acoustic wave unit (10) located at a corner of the measured space (MS) is arranged in a posture such that the directional axis (DA) is inclined at a predetermined angle relative to each of a plurality of boundary planes (BP) forming the corner.

3. The environmental state measuring device according to claim 1 or 2, characterized in that: The prescribed angle is set according to the attenuation amount of the sound wave in each propagation path (P) associated with the sound wave unit (10) arranged at the angle.

4. The environmental state measuring device according to claim 3, characterized in that: The attenuation amount of the sound wave is calculated based on the transmission directivity and reception directivity for the propagation path (P) and the distance attenuation between the transmission unit (10S) and the reception unit (10R) related to the propagation path (P).

5. The environmental state measuring device according to claim 1 or 2, characterized in that: For a plurality of the acoustic wave units (10) located on the periphery of the same boundary plane (BP), the angles formed by the directional axes (DA) relative to the same boundary plane (BP) are set to be the same angle as each other.

6. The environmental state measuring device according to claim 1 or 2, characterized in that: The acoustic wave unit (10) is arranged at a corner of the measured space (MS), A pair of the acoustic wave units (10) located at adjacent corners of the measured space (MS) on the periphery of the same boundary plane (BP) are arranged in a linearly symmetrical posture relative to an imaginary reference line (RL1-RL12) passing through the middle position of the pair of acoustic wave units (10) when viewed from a direction orthogonal to the boundary plane (BP).

7. The environmental state measuring device according to claim 1 or 2, characterized in that: The plurality of boundary planes (BP) include first boundary planes (BP1, BP3, BP5) and second boundary planes (BP2, BP4, BP6) that are opposite to each other, A pair of the acoustic wave units (10) corresponding to each other in the first boundary plane (BP1, BP3, BP5) and the second boundary plane (BP2, BP4, BP6) respectively include a sending element (12) for realizing the function of the sending unit (10S) and a receiving element (14) for realizing the function of the receiving unit (10R), wherein the sending element (12) and the receiving element (14) are independent of each other. The pair of sound wave units (10) are arranged in a posture in which the positional relationship between the transmitting element (12) and the receiving element (14) is the same relative to an imaginary reference plane (RP1-RP3) set at a middle position between the first boundary plane (BP1, BP3, BP5) and the second boundary plane (BP2, BP4, BP6).

8. A method for setting an environmental state measuring device, wherein a plurality of sound wave units (10) including a transmitting unit (10S) for directional sound wave transmission and a receiving unit (10R) for directional sound wave reception are arranged at positions separated from each other, so that a measured space (MS) is delimited by a plurality of boundary planes (BP), wherein the sound wave units (10) are located on the periphery of the plurality of boundary planes (BP), characterized in that: For each of the propagation paths (P) of the sound waves associated with at least a portion of the sound wave unit (10), the attenuation of the sound waves is calculated based on the transmission directivity, the reception directivity, and the distance attenuation between the transmission unit (10S) and the reception unit (10R) associated with the propagation path (P). The angle of the setting posture of at least a part of the sound wave unit (10) is determined according to the attenuation of the sound wave of each of the propagation paths (P), and the angle is the angle at which the directional axis (DA) representing the maximum intensity of the directivity of sending or receiving is inclined relative to at least one of the boundary planes (BP) where the sound wave unit (10) is located.

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