Anemometer, wind speed calculation method, and program

Abstract

To improve measurement precision by an anemometer.SOLUTION: An anemometer installed in a moving body includes: a first measurement section for performing measurement in a first measurement point and outputting a first measurement result; a second measurement section for performing measurement in a second measurement point and outputting a second measurement result; a third measurement section for performing measurement in a third measurement point and outputting a third measurement result; a fourth measurement section for performing measurement in a fourth measurement point and outputting a fourth measurement result; and a calculation section for calculating a wind speed on the basis of the first measurement result, the second measurement result, the third measurement result, and the fourth measurement result. A horizontal component of an installation plane is a first distance, the horizontal component of the third measurement point and the second measurement point is a second distance, the horizontal component of the fourth measurement point and the second measurement point is a third distance, and the first distance is longer than the second distance and the third distance in a first direction in which the first measurement point and the second measurement point are located in an advance direction of the moving body on an installation surface in which the first measurement point, the third measurement point, and the fourth measurement point are installed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an anemometer, an anemometry method, and a program.

Background Art

[0002] Techniques for measuring wind speed using ultrasonic waves or the like are known.

[0003] Specifically, four ultrasonic transceivers are arranged at the vertices of a square. Next, the wind direction is measured with two pairs of measuring device pairs facing each other along the diagonal of the square. Also, the wind speed is measured with the same two pairs of measuring device pairs. Then, the facing angle of the ultrasonic transceivers is changed based on the measurement results of the wind speed and the wind direction. In this way, a technique is known that enables measurement in a strong wind speed range that could not be measured with conventional ultrasonic anemometers (see, for example, Patent Document 1, etc.).

[0004] Alternatively, after outputting white noise, the white noise is scattered. Next, the scattered white noise is received and converted into an electrical signal. Subsequently, a cross-correlation function is calculated from the converted electrical signal. Then, the wind direction or the wind speed of the wind passing between the speaker that outputs the white noise and the scattering plate is vector-calculated from the cross-correlation function. In this way, a technique is known that makes it less susceptible to the influence of disturbances and improves the measurement accuracy (see, for example, Patent Document 2, etc.).

[0005] Using a wind vane that measures the wind direction in the horizontal and vertical directions and an anemometer that measures the wind speed in the horizontal and vertical directions, data regarding the wind direction and the wind speed is transmitted, and data from other devices is also acquired by wireless communication through multi-hop connection. In this way, a technique is known that can be suitably installed even at high places outdoors, and by installing a plurality of units, information on the wind direction and the wind speed along a predetermined path can be efficiently acquired (see, for example, Patent Document 3, etc.).

[0006] In addition, technologies using a plurality of sensors are also known. First, a wind intensity acquisition means for capturing the oncoming wind in at least three directions on a plane and obtaining wind intensity information for each of the three directions, a two-direction detection means for comparing the magnitudes of the obtained wind intensity information in at least three directions to detect two directions among the wind directions in which the first-place wind intensity information and the second-place wind intensity information are obtained, generating two vectors with the directions of the two directions detected by the two-direction detection means as the directions of the vectors and the wind intensity information in each direction as the magnitudes of the vectors, performing vector addition of these vectors to obtain one addition result vector, a wind information output means for outputting wind information composed of the wind direction and the wind speed, an output control means for outputting the direction of the addition result vector obtained by the vector addition means as wind direction information and the magnitude of the addition result vector as wind speed information to the wind information output means, and a correction coefficient acquisition means for obtaining a correction coefficient based on the comparison result between the wind direction and the wind speed obtained from the addition result vector obtained through several test operations and the wind direction and the wind speed actually measured during the test operations. And the vector addition means multiplies the second-place wind intensity information by the correction coefficient to obtain second-place corrected wind intensity information, and performs vector addition using this second-place corrected wind intensity information to obtain one addition result vector. In this way, a technology is known that has a small configuration and can be easily moved to a required location to measure the wind direction and wind speed (see, for example, Patent Document 4, etc.).

[0007] In addition, there is also known a technology of an anemometer comprising a base plate, an ultrasonic sensor provided on the upper surface side of the base plate for measuring the wind direction and wind speed, and a housing portion provided on the lower surface side of the base plate for housing electronic components. In the anemometer, the base plate is larger than the planar shape of the housing portion, and the edge of the base plate is a wind protection portion for preventing the wind that has collided with the housing portion from flowing around to the upper surface side of the base plate. In this way, a technology for reducing the influence of the wind that has collided with the housing portion on the measurement result is known (see, for example, Patent Document 5, etc.).

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the conventional technology, the measurement accuracy may be low depending on conditions. That is, the conventional technology has a problem of low measurement accuracy.

[0010] An object of the present invention is to improve the measurement accuracy by an anemometer.

Means for Solving the Problems

[0011] To solve the above problems, in one aspect of the present invention, the anemometer is an anemometer installed on a moving body, a first measurement unit that measures at a first measurement point and outputs a first measurement result, a second measurement unit that measures at a second measurement point and outputs a second measurement result, a third measurement unit that measures at a third measurement point and outputs a third measurement result, a fourth measurement unit that measures at a fourth measurement point and outputs a fourth measurement result, and a calculation unit that calculates the wind speed based on the first measurement result, the second measurement result, the third measurement result, and the fourth measurement result. In the installation plane where the first measurement point, the third measurement point, and the fourth measurement point are installed, in a first direction which is the traveling direction of the moving body, the horizontal component of the installation plane between the first measurement point and the second measurement point is a first distance, The horizontal component between the third measurement point and the second measurement point is the second distance, The horizontal component between the fourth measurement point and the second measurement point is the third distance, The first distance is longer than either the second distance or the third distance.

Advantages of the Invention

[0012] According to the present invention, the measurement accuracy by the anemometer can be improved.

Brief Description of the Drawings

[0013]

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Mode for Carrying Out the Invention

[0014] Hereinafter, specific examples will be described with reference to the accompanying drawings. In the following description, the reference numerals in the drawings refer to the same elements.

[0015] FIG. 1 is a diagram showing a first arrangement example (X-Y plane) of a sound wave transmitter / receiver in an anemometer. Hereinafter, one direction is defined as the "Y-axis direction". And the direction orthogonal to the Y-axis direction is defined as the "X-axis direction". Also, the plane formed by X-Y is the horizontal plane. Further, the direction perpendicular to the X-Y plane is defined as the "Z-axis direction". Therefore, the Z-axis direction is the direction of gravity.

[0016] FIG. 2 is a diagram showing a first arrangement example (Y-Z plane) of a sound wave transmitter / receiver in an anemometer.

[0017] The anemometer 10 transmits and receives sound waves at four points to measure the wind speed. For example, at the four measurement points, a first sound wave transmitter / receiver 1, a second sound wave transmitter / receiver 2, a third sound wave transmitter / receiver 3, and a fourth sound wave transmitter / receiver 4 are installed. Each sound wave transmitter / receiver generates data indicating the measurement result.

[0018] The line segment connecting the first measurement point and the second measurement point is referred to as the "first line segment L12". In some cases, the direction in which the first measurement point and the second measurement point are arranged, that is, the direction coinciding with the first line segment L12, is referred to as the "first direction". Also, the first direction coincides with the Y-axis direction.

[0019] Similarly, the line segment connecting the second measurement point and the third measurement point is referred to as the "second line segment L23". In some cases, the direction coinciding with the second line segment L23 is referred to as the "second direction".

[0020] The line segment connecting the second measurement point and the fourth measurement point is referred to as the "third line segment L24". In some cases, the direction coinciding with the third line segment L24 is referred to as the "third direction".

[0021] The distance between the first measurement point and the second measurement point in the X-Y plane, that is, the length of the first line segment L12 in the X-Y plane (i.e., the length of the horizontal component), is referred to as the "first distance D1". Similarly, the distance between the second measurement point and the third measurement point, that is, the length of the second line segment L23 in the X-Y plane, is referred to as the "second distance D2". Also, the distance between the second measurement point and the fourth measurement point, that is, the length of the third line segment L24 in the X-Y plane, is referred to as the "third distance D3".

[0022] [First Arrangement Example of Measurement Points] The following is centered around the second acoustic transceiver 2. Therefore, the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 are arranged around the second acoustic transceiver 2 and in the vicinity of the second acoustic transceiver 2.

[0023] On the X-Y plane, that is, in FIG. 1, with respect to the second acoustic transceiver 2, the first acoustic transceiver 1 is installed at a forward position in the Y-axis direction. Therefore, both the first acoustic transceiver 1 and the second acoustic transceiver 2 are located on the Y-axis (indicated by the Y coordinate. The first acoustic transceiver 1 and the second acoustic transceiver 2 have different Y coordinates.) and have the same position relationship in the X-axis direction (indicated by the X coordinate). Also, the first acoustic transceiver 1 and the second acoustic transceiver 2 have different height relationships (indicated by the Z coordinate).

[0024] The third acoustic transceiver 3 and the fourth acoustic transceiver 4 are arranged symmetrically with respect to the first line segment L12 as the axis of symmetry (symmetrical left and right in FIG. 1). Therefore, the second distance D2 and the third distance D3 are of the same length.

[0025] Furthermore, the second line segment L23 and the third line segment L24 have the same angle in the X-Y plane with respect to the first line segment L12. Therefore, the first line segment L12, the second line segment L23, and the third line segment L24 are installed at angles of "120°" and "240°" clockwise with respect to the Y-axis direction starting from the Y-axis direction as "0°". With such an angular arrangement, the angles formed by the first line segment L12, the second line segment L23, and the third line segment L24 are all "120°". Therefore, the angle formed between the first direction and the second direction is "120°". Similarly, the angle formed between the first direction and the third direction is "120°".

[0026] The Y-Z plane, that is, in Fig. 2, the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 are installed at the same height. On the other hand, the second acoustic transceiver 2 is arranged at a higher position than the first acoustic transceiver 1 and the like. Hereinafter, based on the height at which the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 are arranged, the height at which the second acoustic transceiver 2 is installed is referred to as "installation height H1".

[0027] In the X-Y plane, the first acoustic transceiver 1 is arranged in front with respect to the traveling direction, and the third acoustic transceiver 3 and the fourth acoustic transceiver 4 are arranged behind with respect to the traveling direction. Therefore, in the X-Y plane, the first acoustic transceiver 1 to the fourth acoustic transceiver 4 are arranged in an "inverted Y shape".

[0028] Specifically, in the "inverted Y shape" arrangement, in the traveling direction of the moving body, the first acoustic transceiver 1 is arranged at the most forward position. Then, in the traveling direction of the moving body, moving backward, the second acoustic transceiver 2 is arranged behind the first acoustic transceiver 1 and in front of the third acoustic transceiver 3 and the fourth acoustic transceiver 4. Next, in the traveling direction of the moving body, moving backward, the third acoustic transceiver 3 and the fourth acoustic transceiver 4 are arranged behind the second acoustic transceiver 2 so as to branch from the second acoustic transceiver 2.

[0029] On the other hand, in the "inverted Y shape" arrangement, in the orthogonal direction, the first acoustic transceiver 1 and the second acoustic transceiver 2 are at the same position. In contrast, the third acoustic transceiver 3 is arranged to the right of the second acoustic transceiver 2 with respect to the traveling direction of the moving body. Further, the fourth acoustic transceiver 4 is arranged to the left of the second acoustic transceiver 2 with respect to the traveling direction of the moving body.

[0030] Also, in the vertical direction, the second acoustic transceiver 2 protrudes such that the second acoustic transceiver 2 is at a higher position than the other acoustic transceivers. On the other hand, the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 are arranged on the same plane with the same height.

[0031] Hereinafter, the X-Y plane on which the first acoustic transmitter / receiver 1, the third acoustic transmitter / receiver 3, and the fourth acoustic transmitter / receiver 4 are installed is referred to as the "installation plane". Also, in the following description, the installation plane is used as the height reference. Therefore, the second acoustic transmitter / receiver 2 is arranged at a position higher than the installation plane.

[0032] [Example of Installation on a Moving Body] FIG. 3 is a diagram showing an example of installing an anemometer on a moving body. For example, the anemometer 10 is installed on a moving body such as a vehicle 20. When installing on such a moving body, it is assumed that the main traveling direction of the moving body is in the Y-axis direction. Therefore, the anemometer 10 is installed such that the first line segment L12 coincides with the main traveling direction of the moving body (which also coincides with the Y-axis direction in this example).

[0033] The moving body is not limited to the vehicle 20, and may be a moving body that moves on water such as a ship, or a moving body that moves in the air such as a drone.

[0034] FIG. 4 is a diagram showing an example of the device configuration to be installed on a moving body. For example, the anemometer 10 has dimensions of "250 mm" in the Y-axis direction (the longitudinal direction) and "225 mm" in the X-axis direction (the width direction).

[0035] The anemometer 10 has a two-stage structure with a top plate 12 serving as a roof supported by a support column 13 and a main body 11 serving as a base. And a ventilation path 14 is formed between the top plate 12 and the main body 11. Note that the anemometer 10 is not limited to this structure, as long as the first acoustic transmitter / receiver 1 to the fourth acoustic transmitter / receiver 4 can be arranged in an "inverted Y shape".

[0036] The positions of the first acoustic transmitter / receiver 1 to the fourth acoustic transmitter / receiver 4 do not have to be fixed. For example, the position of the first acoustic transmitter / receiver 1 may be changed manually or by an actuator or the like with respect to the traveling direction. Therefore, the anemometer 10 may have a structure in which the first line segment L12, that is, the distance between the first acoustic transmitter / receiver 1 and the second acoustic transmitter / receiver 2, can be changed after installation.

[0037] FIG. 5 is a diagram showing an example of the internal structure in the device configuration to be installed in the moving body. Hereinafter, the cross-sectional view taken along the line "A-A'" in FIG. 4 will be described.

[0038] With respect to the traveling direction, the anemometer 10 is installed in a direction in which the longitudinal direction coincides. Therefore, the ventilation passage 14 is configured such that wind flows in from the traveling direction. In the figure, the configuration is such that wind flows in from the left to the right (the direction indicated by the arrow in the figure. Hereinafter referred to as "inflow direction 15"). Therefore, in the inflow direction 15, the first acoustic wave transceiver 1 is arranged at the most upstream position. And the second acoustic wave transceiver 2 is arranged downstream of the first acoustic wave transceiver 1 and upstream of the third acoustic wave transceiver 3, etc. in the inflow direction 15. Further, the third acoustic wave transceiver 3 and the fourth acoustic wave transceiver 4 are arranged at the most downstream position.

[0039] However, the inflow direction 15 and the structure of the ventilation passage 14 are not limited to this. For example, the structure of the ventilation passage 14 may be a structure with a branch passage or the like. Therefore, there may be a plurality of inflow directions 15 instead of just one.

[0040] [Example of hardware configuration] FIG. 6 is a diagram showing an example of the hardware configuration. For example, the anemometer 10 includes a microcomputer 31, a main storage device 32, an auxiliary storage device 33, an input device 34, an output device 35, and a communication device 36, etc. And the anemometer 10 connects the first acoustic wave transceiver 1 to the fourth acoustic wave transceiver 4 and transmits and receives data.

[0041] The microcomputer 31 is an example of an arithmetic device and a control device. Therefore, the microcomputer 31 is a device that executes processing in cooperation with the main storage device 32, etc.

[0042] The main storage device 32 is a memory or the like. Also, the auxiliary storage device 33 stores data, programs, etc.

[0043] The input device 34 is a device that inputs operations by the user or data received from an external device, etc.

[0044] The output device 35 is a device that performs output such as displaying to the user or transmitting data to an external device.

[0045] The communication device 36 performs communication for transmitting and receiving data with an external device. Note that the communication is wired, wireless, or a combination thereof.

[0046] In addition, the first to fourth acoustic transceivers 1 to 4 are connected by wire such as a cable or wirelessly by an antenna or the like, and data indicating measurement results and the like is transmitted and received.

[0047] Note that the hardware configuration is not limited to the above configuration. For example, the anemometer 10 may further include an arithmetic device, a control device, a storage device, an input device, an output device, a communication device, a sensor, or an auxiliary device, etc.

[0048] FIG. 7 is a diagram showing an example of a power supply configuration and a communication line configuration. As shown in FIG. 5, in the anemometer 10, the second acoustic transceiver 2 and the like are arranged on the top plate 12 side, that is, at a position away from the main body 11. Therefore, the main body 11 is configured to supply power and perform communication for hardware arranged at a position away from the main body 11 such as the top plate 12 side.

[0049] FIG. 7(a) is a diagram showing a configuration example of the high-frequency transformer 37. For example, the high-frequency transformer 37 has a rectangular shape. In addition, the high-frequency transformer 37 is configured to be used as a high-permeability iron core transformer core for high frequencies.

[0050] The frequency of the high frequency is a frequency of 10 kHz or more. In particular, a frequency of 20 kHz or more is desirable.

[0051] FIG. 7(b) is a schematic diagram showing the power supply of the high-frequency transformer 37. As shown in FIG. 7(a), the high-frequency transformer 37 is configured such that a top plate side coil is disposed on the top plate 12 side and a main body side coil is disposed on the main body 11 side. With such an arrangement of coils, power can be supplied from the main body 11 side to the top plate 12 side at a high frequency.

[0052] When high-frequency power is applied from the main body side to the first coil (the "main body side coil" in FIG. 7(a)), the power is converted into magnetic flux and passes through the core. On the other hand, the magnetic flux is taken out as power by the second coil on the top plate side (the "top plate side coil" in FIG. 7(a)).

[0053] When using a hard metal such as Permalloy, it has the strength that can also be used as a support column. For example, when a high frequency is applied to an iron core, heat is generated and the core consumes power. Therefore, the conversion efficiency tends to deteriorate. On the other hand, when using a metal such as Permalloy, heat generation can be reduced and conversion can be performed with high efficiency. High frequency can transmit a large current with a small number of coil turns.

[0054] Note that the iron core of the high-frequency transformer may be made of a material other than Permalloy. For example, the iron core may be ferrite, or amorphous (these may also be alloys).

[0055] Note that the power supply may be performed wired using a cable or the like.

[0056] Permalloy, which is a high magnetic permeability material, is used for the transformer core. Permalloy is an alloy of nickel and iron containing about 35 to 80% nickel (Ni).

[0057] Communication is configured to use a support column 13 separate from the power supply. Specifically, two optical fibers are passed through the support column 13. Of the two optical fibers, one is used for I2C (registered trademark) (Inter-Integrated Circuit) communication. Then, data is transmitted and received by optical communication using the optical fiber. On the other hand, of the two optical fibers, the other one is used as a communication path for transmitting and receiving the start synchronization signal of transmission and reception of sound. With such a configuration, in the I2C (registered trademark) method, the delay time when a start signal is sent can be reduced.

[0058] As described above, when the configuration also serves as the wiring path of the cable used for communication with the support column 13, the anemometer 10 can be miniaturized compared to a configuration installed separately.

[0059] [First Example of Wind Speed Calculation] FIG. 8 is a diagram for explaining an example of wind speed calculation. Hereinafter, the variables are as follows.

[0060] Lag The distance between the first acoustic transmitter / receiver 1 and the second acoustic transmitter / receiver 2 (hereinafter referred to as "sensor distance Lag"). λ The angle formed by the installation plane (coinciding with the surface of the main body 11) and the first line segment L12 (hereinafter referred to as "tilt angle λ"). Vs Speed of sound Determined by the following formula (1). "T" in the following formula (1) is the absolute temperature of the wind. Hereinafter, it is simply referred to as "speed of sound Vs". Note that the direction from the first acoustic transmitter / receiver 1 to the second acoustic transmitter / receiver 2 (backward) is taken as positive. The unit system is "m / s" Vs = 331.5 + 0.6077 × T (1) Vc Measured wind speed It is a value obtained by adding the moving speed of the moving body to the actual wind speed (hereinafter referred to as "measured wind speed Vc"). The unit system is "m / s" Vx Vx = speed of sound + wind speed + moving speed of the moving body = Vs + Vc (2) Vx1 The speed of sound of the sound wave emitted from the first acoustic transmitter / receiver 1 to the second acoustic transmitter / receiver 2 (backward) at the sensor distance Lag (hereinafter referred to as "first speed of sound Vx1"). The unit system is "m / s" Vx1 = speed of sound + wind speed + moving object's moving speed = Vs + Vc (3) Vx2 is the speed of sound of the sound wave emitted from the second acoustic transceiver 2 to the first acoustic transceiver 1 (forward) at the sensor - to - sensor distance Lag (hereinafter referred to as "the second speed of sound Vx2"). The unit system is "m / s" Vx2 = speed of sound-(wind speed + moving object's moving speed) = Vs - Vc (4) The second speed of sound Vx2 is a calculation based on the direction of the speed of sound, and is a calculation that subtracts (wind speed + moving object's moving speed) Vm is the speed of the moving object (hereinafter referred to as "the moving object speed Vm". Since the moving object moves horizontally, the moving object speed Vm is only the horizontal component). The unit system is "m / s" For example, the moving object speed Vm is the speed measured by GNSS (Global Navigation Satellite System) or a speedometer, etc. Vmc is the moving object speed on the inclination angle λ of the moving object moving horizontally at the moving object speed Vm. Hereinafter, it is referred to as "the moving object speed Vmc on the sensor - to - sensor distance Lag". The unit system is "m / s" Vmc = Vm × cosλ (5) Vwc is the wind speed on the sensor - to - sensor distance Lag in the moving object moving horizontally at Vw. Hereinafter, it is referred to as "the wind speed Vwc on the sensor - to - sensor distance Lag". The unit system is "m / s" Vwc = Vw × cosλ (6) Vw is the horizontal component of the wind speed Vwc on the sensor - to - sensor distance Lag obtained by dividing the wind speed Vwc on the sensor - to - sensor distance Lag by cosλ. Hereinafter, it is referred to as "the output wind speed Vw". The unit system is "m / s" Vw = Vwc ÷ cosλ (7) Tx1 is the measured value of the time taken for the sound wave to propagate from the first acoustic transceiver 1 to the second acoustic transceiver 2 (backward). The unit system is "μs" Vx1 = Lag ÷ Tx1 (8) Tx2 is the measured value of the time taken for the sound wave to propagate from the second acoustic transceiver 2 to the first acoustic transceiver 1 (forward). The unit system is "μs" Vx2 = Lag ÷ Tx2 (9) Tmc is the time occupied by the moving body wind speed in the measured wind speed Vc. The unit system is "μs". Twc is the time occupied by the wind speed in the measured wind speed Vc. The unit system is "μs". The output wind speed Vw is calculated as the measurement result. Note that the wind speed Vwc etc. on the sensor - to - sensor distance Lag may be included in the measurement result.

[0061] Figure 9 is a diagram (part 1) showing an example of a calculation formula. The anemometer 10 finally calculates the output wind speed Vw from the measurement results using the illustrated calculation formula. Specifically, each formula is calculated as follows.

[0062] Formula (10) is a formula showing the relationship between the tilt angle λ, the installation height H1, and the sensor - to - sensor distance Lag. As shown in formula (10), the tilt angle λ from the first acoustic transceiver 1 to the second acoustic transceiver 2 with respect to the surface of the main body 11 is determined by the installation height H1 and the sensor - to - sensor distance Lag.

[0063] Formula (11) is a formula showing the relationship of the sensor - to - sensor distance Lag, that is, the distance that sound waves propagate between the first acoustic transceiver 1 and the second acoustic transceiver 2. As shown in formula (11), the distance that sound waves propagate between the first acoustic transceiver 1 and the second acoustic transceiver 2 is determined by the installation height H1 and the sensor - to - sensor distance Lag.

[0064] As shown in formula (3), sound rides on the wind and travels faster with the tailwind. On the other hand, as shown in formula (4), sound travels slower against the headwind. First, calculate the speed from the propagation times of three sets of sound waves, and perform vector analysis as shown in Figure 8 to calculate the output wind speed Vw.

[0065] For the three sets of sound waves, the propagation time from when they are transmitted from the second acoustic transceiver 2 until they are received at three measurement points: the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 is measured.

[0066] Next, the propagation times are measured for the sound waves transmitted in order from the first acoustic transceiver 1, the third acoustic transceiver 3, and the fourth acoustic transceiver 4 towards the second acoustic transceiver 2 until they are received by the second acoustic transceiver 2.

[0067] As shown in equation (12) of FIG. 9, when each acoustic wave transceiver reciprocates, based on the difference in propagation time between the forward path and the return path, equations (3), (4), and (1), the effects of the tailwind, headwind, and temperature change can be canceled out.

[0068] Next, since the moving object moves, the anemometer 10 performs calculations excluding the influence of the moving object speed Vm. Specifically, the anemometer 10 calculates equation (13) of FIG. 9.

[0069] In the traveling direction, that is, the inflow direction 15, the moving object speed Vm is added to the ground wind speed. Then, the sound wave propagates at a speed obtained by combining the speed of sound of the sound wave transmitted and received by each acoustic wave transceiver, the ground wind speed, and the moving object speed Vm. Therefore, when the moving object speed Vm increases, the ground wind speed is measured with fewer clock counts, so the resolution is likely to decrease. Therefore, in order to maintain the resolution, the first distance D1 is set to a distance longer than the second distance D2 and the third distance D3, that is, a distance with a longer propagation time. Therefore, if moving the same distance, it takes more time for the sound wave to propagate, so the sound wave can be measured with a larger number of clock counts. Therefore, increasing the first distance D1 can increase the resolution. For this reason, among the first distance D1, the second distance D2, and the third distance D3, the first distance D1 has an unbalanced star shape (the same meaning as the shape of an "inverted Y") that is longer than the other distances.

[0070] Note that when the angles formed between the first direction and the second direction and between the first direction and the third direction are both "120°", the influence of the moving object speed Vm is such that if the first direction is "1", the second direction and the third direction both have an influence of "cos120 = -0.5".

[0071] Performing the calculation shown in equation (13) is equivalent to calculating the average of the forward path and the return path, and the speed of sound Vs, which is a component of the speed of sound, is deleted. However, the measured wind speed Vc includes the "wind speed Vwc on the sensor - to - sensor distance Lag" and the "moving object speed Vmc on the sensor - to - sensor distance Lag" on the sensor - to - sensor distance Lag.

[0072] (14) The equation shows the relationship among the measured wind speed Vc, the wind speed Vwc at the sensor - to - sensor distance Lag, and the moving - body speed Vmc at the sensor - to - sensor distance Lag.

[0073] Since the moving - body speed Vmc at the sensor - to - sensor distance Lag is the component of the moving - body speed Vm in the diagonal direction (the direction of the sensor - to - sensor distance Lag), as shown in equations (5) and (6), it is calculated by replacing "Vwc" with "Vmc" and "Vw" with "Vm" in the calculation.

[0074] When the moving direction of the moving body is different from the direction of the anemometer 10, the moving - body speed Vm is converted into a moving - direction vector and set as "Vm".

[0075] When performing the calculation of subtracting the moving - body speed Vmc at the sensor - to - sensor distance Lag from the measured wind speed Vc in equation (13), the wind speed Vwc at the sensor - to - sensor distance Lag is obtained. The wind speed Vwc at the sensor - to - sensor distance Lag is the component in the diagonal direction (the direction of the sensor - to - sensor distance Lag). Therefore, from the wind speed Vwc at the sensor - to - sensor distance Lag, through the calculation of equation (7), the output wind speed Vw, that is, the ground - relative wind speed, is obtained.

[0076] [Experimental Results] Figure 10 is a figure showing the experimental results. The experimental - result table 40 shows the four analysis results with the "analysis number" from "1" to "4". For the variables in the experimental - result table 40, those same as the above are omitted from the description.

[0077] The "Twc difference" is the difference in "Twc" caused by different sensor - to - sensor distances Lag.

[0078] For the four cases where the "analysis number" is from "1" to "4", in all cases, the "wind speed Vw" is 10 (m / s). Similarly, for the four cases where the "analysis number" is from "1" to "4", in all cases, the "speed of sound Vs" is 340 (m / s).

[0079] On the other hand, in the four cases where the "analysis number" is from "1" to "4", the experimental conditions of the sensor - to - sensor distance Lag and the moving body speed Vm are different as follows.

[0080] "Analysis number 1": Lag = 0.1m, Vm = 0 (m / s) "Analysis number 2": Lag = 0.1m, Vm = 30 (m / s) "Analysis number 3": Lag = 0.2m, Vm = 0 (m / s) "Analysis number 4": Lag = 0.2m, Vm = 30 (m / s) As described above, "Analysis number 1" and "Analysis number 2" have experimental conditions with a different sensor - to - sensor distance Lag from "Analysis number 3" and "Analysis number 4". Also, "Analysis number 1" and "Analysis number 3" have experimental conditions with a different moving body speed Vm from "Analysis number 2" and "Analysis number 4".

[0081] For the "measured wind speed Vc" in the first direction, since it is in the same direction as the traveling direction, it includes the influence of the moving body speed Vm. And in the second direction and the third direction, when the angles with respect to the first direction are both "120°", the moving body speed Vm has an influence that is "0.5 times" that in the first direction. That is, for the second direction and the third direction, the influence of the moving body speed Vm on the first direction can be said to be twice.

[0082] Therefore, when the transmitter - receiver is arranged so that the first distance D1, the second distance D2, and the third distance D3 are the same distance, the calculation accuracy at the first distance D1 becomes low.

[0083] When comparing "Analysis number 2" and "Analysis number 4", the "Twc difference" is 6.73 (μs). Therefore, when the sensor - to - sensor distance Lag is doubled, the resolution is doubled. Therefore, the resolution for measuring the wind speed can be improved.

[0084] Equation (15) is a vector calculation formula when the arrangement angle and distance of the transmitter - receiver can be arbitrarily changed.

[0085] In equation (15), "Wx" is the X-axis value in the orthogonal coordinate system. Also, in equation (15), "Wy" is the Y-axis value in the orthogonal coordinate system.

[0086] Hereinafter, in equation (15), assuming three arbitrary sensors "A", "B", and "C", equations (15-1), (15-2), and (15-3) are obtained. Specifically, in equation (15), "Wax" is the value on the X-axis by the sensor named "A". Similarly, in equation (15), "Way" is the value on the Y-axis by the sensor named "A".

[0087] In equation (15), "Wbx" is the value on the X-axis by the sensor named "B". Similarly, in equation (15), "Wby" is the value on the Y-axis by the sensor named "B".

[0088] In equation (15), "Wcx" is the value on the X-axis by the sensor named "C". Similarly, in equation (15), "Wcy" is the value on the Y-axis by the sensor named "C".

[0089] As described above, as shown in equations (15-1), (15-2), and (15-3), each sensor value is decomposed into components on the X-axis and the Y-axis for calculation.

[0090] As shown in equation (15-4), "Wx", which is the component on the X-axis, is calculated by adding each component on the X-axis of the sensor values measured by the sensors "A", "B", and "C".

[0091] Similarly, as shown in equation (15-5), "Wy", which is the component on the Y-axis, is calculated by adding each component on the Y-axis of the sensor values measured by the sensors "A", "B", and "C".

[0092] The left side of equation (15-6) is the wind direction and wind speed value represented by a vector.

[0093] The first distance, the second distance, and the third distance, i.e., the length of the axis, can be changed when calibration is performed again with the windshield on in a windless state. The measurement results of these distances become "Wa", "Wb", and "Wc" in equation (15).

[0094] The angles formed between the respective measurement points can be changed when calibration is performed again with the windshield on in a windless state. The measurement results of these angles become "A", "B", and "C" in equation (15). Specifically, in FIG. 1, since all angles divide 360° equally, "A = B = C = 120°". Also, when measuring while dynamically changing the angle, it is desirable to have an angle measuring device such as an encoder.

[0095] When changing the distance and the angle simultaneously, it is desirable to perform calibration for measuring the distance first.

[0096] Based on equation (15), the vector values of the wind direction and the wind speed are calculated to obtain the moving body wind direction and wind speed.

[0097] (Wx, Wy) in equation (15) are the vector values of the X-axis and the Y-axis calculated after being converted into a rectangular coordinate system.

[0098] (Wax + Wbx + Wcx) and (Way + Wby + Wcy) in equation (15) are the values of (Wx, Wy).

[0099] This calculation formula can be calculated at any angle as long as the axes do not overlap, even if the angle of the axis is other than 120 degrees.

[0100] The length of the axis has nothing to do with equation (15) because the units match in the calculation process of the wind speed.

[0101] [Second Example of Wind Speed Calculation] In the second example, the anemometer 10 is installed on a ship, for example. In the first example, the moving body is a vehicle, and the vehicle mainly has little movement in the horizontal plane, i.e., the pitch axis. On the other hand, the ship described in the second example has rotation of the pitch axis.

[0102] Figure 11 is a diagram for explaining each name in the second example of wind speed calculation. Hereinafter, an example in which the moving body is a ship 50 will be described.

[0103] Similar to the first example, the traveling direction of the ship 50 is set as the "Y-axis direction". And the direction orthogonal to the Y-axis direction is set as the "X-axis direction". The vertical direction is set as the "Z-axis direction". Therefore, the Z-axis direction becomes the gravitational direction.

[0104] Figure 12 is a diagram showing the X-Y plane, that is, the horizontal plane. And the ship 50 is basically a moving body that moves on the horizontal plane.

[0105] In order to prevent the hull of the ship 50 from being washed away by the wind, the ship 50 may travel with the bow facing upwind with respect to the Y-axis direction. Also, the ship 50 may make an angle (for example, about 20° to 30°) with respect to the waves so as not to receive the waves at the bow. For example, Figure 11 is a diagram showing an example in which the bow is directed in the "bow direction 51". Hereinafter, the north direction is referred to as the "magnetic north direction 52". The magnetic north direction 52 is measured by, for example, GNSS or a compass.

[0106] The angle formed by the bow direction 51 with respect to the magnetic north direction 52 is called the "bow magnetic north angle 53". Also, the angle formed by the traveling direction with respect to the magnetic north direction 52 is called the "traveling direction angle 56".

[0107] Figure 12 is a diagram showing an example of calculating the bow direction component. The wind blowing in the traveling direction (which becomes the Y-axis direction) is decomposed into the bow direction 51 and the direction of the bow side wind 58 orthogonal to the bow direction 51.

[0108] Hereinafter, the component decomposed in the bow direction 51 is denoted as the "bow direction component Sh". On the other hand, the component decomposed in the direction of the bow side wind 58 is denoted as the "orthogonal component Sl".

[0109] Figure 13 is a diagram showing an example of deleting the wind in the traveling direction. Assuming that the wind in the traveling direction is "Vp", the "bow direction vector We" is calculated by the calculation of equation (16).

[0110] Figure 14 is a vector diagram of the wind in the bow direction. Assume that the wind blows at an angle of "advancing wind angle θ" with respect to the advancing direction with respect to the magnetic north direction 52.

[0111] Figure 15 is a diagram showing an example of pitching of a ship. The ship 50 undergoes pitching (Pitch rotation, a rotation about the X-axis as the center of rotation) due to waves. Specifically, when the ship 50 pitches in response to waves, the bow moves up and down (in the Z-axis direction). Hereinafter, the angle between the bow and the horizontal caused by pitching is referred to as the "pitching angle α".

[0112] Figure 16 is a diagram showing an example of rolling of a ship. The ship 50 undergoes rolling (Roll rotation, a rotation about the Y-axis as the center of rotation) due to waves. Specifically, when the ship 50 rolls in response to waves, the hull moves in a left-right swaying motion. Hereinafter, the angle between the hull and the horizontal caused by rolling is referred to as the "rolling angle β".

[0113] Figure 17 is a diagram showing the coordinate system in pitching. On the ground, that is, in a state without pitching, it is the "ground coordinate system 60". In contrast, when pitching occurs with the ship 50 having a pitching angle α, the coordinate system on the ship 50 becomes the "pitching coordinate system 61".

[0114] Figure 18 is a diagram showing the coordinate system in rolling. On the ground, that is, in a state without rolling, it is the "ground coordinate system 60". In contrast, when rolling occurs with the ship 50 having a rolling angle β, the coordinate system on the ship 50 becomes the "rolling coordinate system 62".

[0115] Figure 19 is a diagram showing the coordinate system in rolling and pitching. On the ground, that is, in a state without rolling and pitching, it is the "ground coordinate system 60". In contrast, when rolling and pitching occur simultaneously, the coordinate system on the ship 50 becomes the "rolling and pitching coordinate system 63".

[0116] FIG. 20 is a diagram showing an example of the pitching angle. When the state in which pitching occurs in the ship 50 is viewed from the starboard side with respect to the Y-Z plane and the traveling direction, the angle formed by the ground coordinate system 60 and the pitching coordinate system 61 is the pitching angle α.

[0117] To convert from the anemometer 10, that is, the measured value in the pitching coordinate system 61, to the wind in the ground coordinate system 60 (hereinafter referred to as "longitudinal wind Wα"), the calculation of equation (17) is performed. The longitudinal wind Wα is the wind in the Y-axis direction component in the ground coordinate system 60.

[0118] "Vh" in equation (17) is the vector in the bow direction 51 of the output wind speed Vw.

[0119] FIG. 21 is a diagram showing an example of the rolling angle. When the state in which rolling occurs in the ship 50 is viewed from the bow position with respect to the X-Z plane and the traveling direction, the angle formed by the ground coordinate system 60 and the rolling coordinate system 62 is the rolling angle β.

[0120] To convert from the anemometer 10, that is, the measured value in the rolling coordinate system 62, to the wind in the ground coordinate system 60 (hereinafter referred to as "lateral wind Wβ"), the calculation of equation (18) is performed. The lateral wind Wβ is the wind in the X-axis direction component in the ground coordinate system 60.

[0121] "Vl" in equation (18) is the vector in the direction orthogonal to the bow direction 51 of the output wind speed Vw.

[0122] If the ship 50 is tilted by waves or the like, the anemometer 10 installed on the ship 50 will deviate from the case where the position relationship with respect to the ground is in a stationary state.

[0123] FIG. 22 is a diagram showing examples of a plurality of moving body coordinate systems. The installation height on the ship 50 is the position on the installation height axis 64. For example, the position on the installation height axis 64 is the height of the mast provided on the ship 50. Therefore, depending on the height of the mast, the coordinate system in the moving body becomes, for example, the "first moving body coordinate system 65" or the "second moving body coordinate system 66".

[0124] Let the first projection vector 67 and the second projection vector 68 be vectors projected onto the position of the normal line from the first moving body coordinate system 65 or the second moving body coordinate system 66 to the ground coordinate system 60.

[0125] The lengths and directions of the first projection vector 67 and the second projection vector 68 are the same. Therefore, even if the heights are different, such as in the combination of the first moving body coordinate system 65 and the second moving body coordinate system 66, the lengths and directions of the vectors projected onto the ground coordinate system 60 are the same.

[0126] Since the first projection vector 67 and the second projection vector 68 are vectors on the ship 50, in order to obtain the wind direction and wind speed relative to the ground (the wind direction and wind speed relative to the ground are also referred to as "true wind direction and wind speed"), calculations are performed to align from the bow direction 51 to the magnetic north direction 52.

[0127] FIG. 23 is a diagram (part 2) showing an example of a calculation formula.

[0128] The travel direction wind angle θ is specified by, for example, GNSS or the like. Also, the bow magnetic north azimuth 53 is specified by, for example, a gyrocompass provided on the ship 50. Hereinafter, the bow magnetic north azimuth 53 is referred to as "δ".

[0129] In addition, on ships, GPS is received and distributed, for example, according to the RS-422 communication standard. By this distribution, even for devices that need position information and are located in places where GPS radio waves cannot reach (for example, the bottom of the ship, etc.), the devices do not require GPS-related devices.

[0130] The anemometer 10 is installed outside the ship, for example. Even in such an installation location, when installing the anemometer 10, wiring such as pulling in the information defined by NMEA (National Marine Electronics Association) to above the mast with an RS-422 cable or the like can be made unnecessary.

[0131] Equation (19) is an equation for calculating the bow-direction wind angle φ. This calculation is a process of keeping the anti-earth direction of the vector and the wind speed value as they are and changing the way of calling the wind direction to the anti-earth angle.

[0132] Equation (20) is an equation for calculating the wind direction relative to the earth. The "wind direction relative to the earth Wd" (that is, the left side of Equation (20).) is determined by the sum of the bow magnetic north azimuth 53 which is "δ", the bow-direction wind angle φ calculated by Equation (19), and the course-direction wind angle θ.

[0133] [Example of Sound Wave Transmission and Reception Timing] FIG. 24 is a diagram showing an example of the sound wave transmission and reception timing. For example, as shown in "transmission timing", an example will be described in which transmission is performed at the timings of the first transmission timing TM01 and the second transmission timing TM02.

[0134] For example, a sound wave is transmitted from the second sound wave transmitter 2 of the anemometer 10 toward the first sound wave transmitter 1. Therefore, in this example, the second sound wave transmitter 2 serves as the transmitter. On the other hand, the first sound wave transmitter 1 serves as the receiver. Thus, in this example, the first sound wave transmitter 1 receives the sound wave transmitted by the second sound wave transmitter 2. Note that the relationship between the transmitter and the receiver is set as appropriate.

[0135] For example, when the wind speed is "0 m / s", that is, under the condition of no wind, the sound wave transmitted at the "transmission timing" is received at the timing of "reception timing (wind speed 0 m / s)". Specifically, the sound wave transmitted at the first transmission timing TM01 is received at the timing of the eleventh reception timing TM11 under the condition of no wind. Similarly, the sound wave transmitted at the second transmission timing TM02 is received at the timing of the twelfth reception timing TM12 under the condition of no wind.

[0136] When the wind speed is "100 m / s", that is, under the condition that the wind blows from the transmission side to the reception side, the transmitted sound wave is received at the timing of "reception timing (wind speed 100 m / s)". Specifically, the sound wave transmitted at the first transmission timing TM01 is received at the timing of the twenty-first reception timing TM21 under the condition that the wind blows from the transmission side to the reception side. Similarly, the sound wave transmitted at the second transmission timing TM02 is received at the timing of the twenty-second reception timing TM22 under the condition that the wind blows from the transmission side to the reception side.

[0137] Thus, when the condition is that the wind blows from the transmission side to the reception side, the sound wave becomes faster due to the wind than under the condition of no wind. Therefore, compared with the condition of no wind, the reception timing is earlier under the condition that the wind blows from the transmission side to the reception side.

[0138] When the wind speed is "-100 m / s", that is, under the condition that the wind blows from the reception side to the transmission side, the transmitted sound wave is received at the timing of "reception timing (wind speed -100 m / s)". Specifically, the sound wave transmitted at the first transmission timing TM01 is received at the timing of the thirty-first reception timing TM31 under the condition that the wind blows from the reception side to the transmission side. Similarly, the sound wave transmitted at the second transmission timing TM02 is received at the timing of the thirty-second reception timing TM32 under the condition that the wind blows from the reception side to the transmission side.

[0139] Thus, when the condition is that the wind blows from the receiving side towards the transmitting side, the sound wave will be slower due to the wind than in the condition without wind. Therefore, compared with the condition without wind, under the condition that the wind blows from the receiving side towards the transmitting side, the reception timing will be delayed.

[0140] As described above, the reception timing varies depending on the wind condition. Therefore, the receivable timing (hereinafter, the receivable timing is indicated by "window 70") is set to have a time width. Specifically, the window 70 is set so that it can receive even when the wind speed is from "-100 m / s" to "100 m / s".

[0141] On the other hand, in the range outside the window 70, for example, the received sound wave is preferably processed as noise. The noise is, for example, a reflected wave or the like. When the window 70 is set in this way, even when noise is mixed in at a timing that is too fast or too slow, there is no influence of the noise, and the wind speed can be accurately measured.

[0142] Also, the time zone for receiving the window 70 may be further filtered by the volume of the sound wave. That is, a threshold is set in advance, and a sound wave with a volume smaller than the threshold is processed as noise when received. Similarly, a sound wave with a volume larger than the threshold is processed as noise when received. Note that the thresholds for large volume and small volume are set separately, and two types are set, such as the so-called "upper limit value" and "lower limit value". In this way, if noise can be further filtered by volume, the measurement can be made more accurately.

[0143] [Overall processing example] FIG. 25 is a diagram showing an overall processing example. For example, the anemometer 10 executes the following overall processing to execute the anemometry method.

[0144] In step S01, the anemometer 10 outputs the first measurement result.

[0145] In step S02, the anemometer 10 outputs the second measurement result.

[0146] In step S03, the anemometer 10 outputs a third measurement result.

[0147] In step S04, the anemometer 10 outputs a fourth measurement result.

[0148] Steps S01 to S04 are, for example, executed in parallel. However, steps S01 to S04 may be executed in sequence.

[0149] For example, when a sound wave is transmitted from the second sound wave transceiver 2 and received by the first sound wave transceiver 1, the measurement result is output as the first measurement result. On the other hand, when a sound wave is reciprocated between the second sound wave transceiver 2 and the first sound wave transceiver 1, the result of the forward path is output as the first measurement result, and the result of the return path is output as the second measurement result.

[0150] In step S05, the anemometer 10 calculates the wind speed based on the first to fourth measurement results.

[0151] By steps S01 to S04, at the first measurement point, the second measurement point, the third measurement point, and the fourth measurement point, sound wave transmission and reception are performed, and the first to fourth measurement results are measured at each measurement point.

[0152] [Functional configuration example] FIG. 26 is a diagram showing a functional configuration example. For example, the anemometer 10 includes a first measurement unit 10F1, a second measurement unit 10F2, a third measurement unit 10F3, a fourth measurement unit 10F4, and a calculation unit 10F5.

[0153] The first measurement unit 10F1 performs a first measurement procedure for measuring at the first measurement point and outputting a first measurement result. For example, the first measurement unit 10F1 is realized by the first sound wave transceiver 1 or the like.

[0154] The second measurement unit 10F2 performs a second measurement procedure for measuring at the second measurement point and outputting a second measurement result. For example, the second measurement unit 10F2 is realized by the second sound wave transceiver 2 or the like.

[0155] The third measurement unit 10F3 performs a third measurement procedure for measuring at the third measurement point and outputting a third measurement result. For example, the third measurement unit 10F3 is realized by the third acoustic wave transceiver 3 or the like.

[0156] The fourth measurement unit 10F4 performs a fourth measurement procedure for measuring at the fourth measurement point and outputting a fourth measurement result. For example, the fourth measurement unit 10F4 is realized by the fourth acoustic wave transceiver 4 or the like.

[0157] The calculation unit 10F5 performs a calculation procedure for calculating the wind speed based on the first measurement result, the second measurement result, the third measurement result, and the fourth measurement result. For example, the calculation unit 10F5 is realized by a microcomputer 31 or the like.

[0158] The first measurement unit 10F1 to the fourth measurement unit 10F4 are arranged, for example, in an "inverted Y" shape or the like with respect to the traveling direction of the moving body as shown in FIG. 1. Specifically, the first distance is longer than either the second distance or the third distance. Therefore, the second measurement unit 10F2 is located in front in the traveling direction compared to the other measurement units.

[0159] Among the first measurement unit 10F1 to the fourth measurement unit 10F4, the first measurement unit 10F1, the third measurement unit 10F3, and the fourth measurement unit 10F4 are installed on the same installation plane, that is, at the same height. On the other hand, it is desirable that the second measurement unit 10F2 be installed at a position higher than the first measurement unit 10F1, the third measurement unit 10F3, and the fourth measurement unit 10F4.

[0160] With the configuration of the positional relationship as described above, the measurement accuracy by the anemometer 10 can be improved.

[0161] [Example of mounting on a drone]

[0162] [Example of the first correction method] FIG. 27 is a diagram showing a first example in the case of mounting on a drone. In a so-called multi-copter type drone, the influence of the wind generated by the propeller is corrected.

[0163] The rotation control of the drone's propellers is performed by Pulse Width Modulation (PWM) control. Specifically, the PWM signal 80 is output through the amplifier 81. After being amplified by the amplifier 81, the PWM signal 80 is smoothed. Then, by the A / D converter 82, the PWM signal 80 is digitized, that is, converted into digital data. After becoming digital data, the digital data is synthesized by the bit synthesis circuit 83.

[0164] Figure 28 is a diagram showing a first example of bit synthesis. The synthesized data is transmitted by the radio 84 (for example, performing wireless communication with Bluetooth (registered trademark), etc.).

[0165] The drone pre-stores the wind speed measured in a windless state. Hereinafter, the data to be stored is referred to as a "correction vector".

[0166] As shown in Figure 28, the synthesized data is the number of propellers to the power of the resolution of the A / D converter 82. For example, if there are 4 propellers with a 4-bit A / D converter 82, the synthesized data is 16 bits. Therefore, 65536 rows of combinations are required.

[0167] In this way, the correction vector is pre-stored. Then, subtracting the correction vector from the measurement result can correct the influence of the propellers.

[0168] [Second Example of Correction Method] Figure 29 is a diagram showing a second example when mounted on a drone. In the second example, a microphone 90 is installed on the drone. The microphone 90 is installed for each propeller.

[0169] The sound data of the sound of the propellers cutting the wind recorded by the microphone 90 is subjected to FFT (Fast Fourier Transform). Then, in the FFT analysis, the peak value is obtained.

[0170] Figure 30 shows an example of the FFT analysis result. After obtaining the peak values, frequency bands are numbered as in the example of spectrum number conversion. The synthesized data passes through a circuit for bit synthesis and is transmitted by the wireless device.

[0171] Similar to the first correction method example, the drone stores in advance the wind speed measured in a windless state as a "correction vector".

[0172] Figure 31 is a diagram showing a second example of bit synthesis. In the second correction method example, the synthesized data is the number of propellers to the power of the resolution of the A / D converter 82. For example, if there are 4 propellers with a 4-bit A / D converter 82, the synthesized data is 16 bits. Therefore, 65536 rows of combinations are required.

[0173] In the case of the fundamental frequency and the 15th harmonic frequency, since there are 16 frequencies, they are classified into 16 levels. For example, in the case of 32 frequencies, they are classified into groups of 2 frequencies each, and the information is compressed into 16 levels.

[0174] The directional microphone is used to avoid the influence of other propeller sounds.

[0175] In a moving body such as a drone where the influence of acceleration due to rapid direction changes or speed increases or decreases cannot be ignored, correction is performed by obtaining the influence as the speed over time through time integration of the accelerometer.

[0176] [Other arrangement examples] The measurement points may be arranged as follows.

[0177] Figure 32 is a diagram showing a first modified example of the arrangement. For example, the third measurement point and the fourth measurement point may be narrowly expanded in the X-axis direction. In this way, the first measurement point, the third measurement point, and the fourth measurement point may be arranged at unequal angles.

[0178] FIG. 33 is a diagram showing a second modification of the arrangement. The third measurement point and the fourth measurement point may be located in front of the second measurement point with respect to the traveling direction.

[0179] FIG. 34 is a diagram showing a third modification of the arrangement. Thus, the arrangement of the measurement points does not have to be symmetric.

[0180] [Other Embodiments] When a computer such as the microcomputer 31 receives the wind direction and wind speed vectors from a plurality of measurement points, various applications become possible.

[0181] When measuring with a plurality of anemometers 10, the measurement at a "point" becomes a measurement on a "line". For example, when a plurality of fishing boats measure while moving, the "surface", that is, the change in wind over the entire fishing ground can be grasped. In this way, when the wind speed can be measured on a "surface", the dangerous areas of the fishing ground or the tacit knowledge that can only be empirically known about the points of the fishing ground can be known as formal knowledge by quantifying it.

[0182] For example, when the sway of rough waves is corrected, the anemometer 10 can obtain the wind direction and wind speed under a typhoon with the same result as in normal times. Therefore, the accuracy of meteorological information can be improved. For example, the fixed-point observation attached to the buoy is less affected by rough waves and is measured with the accuracy in normal times.

[0183] For example, when measuring the wind state of a highway with a single vehicle, unmeasured parts may occur. Therefore, if a plurality of drivers measure the wind with the anemometer 10 in their respective vehicles and transmit the information on the wind during driving to the information center, the wind from the start point to the end point of the road can be known all at once. By displaying this information on an electronic bulletin board, it can be provided as information for the driver's destination. Also, it can be realized in a small size and at low cost. Therefore, it can be used for the public interest by spreading.

[0184] For example, based on the results measured by the anemometer 10, when the radio beacon on the highway transmits information about the wind, the wind direction and speed to the destination can be displayed on a car navigation system or the like. Therefore, dangerous locations can be identified and the selection of a circuit can be made.

[0185] For example, the anemometer 10 can be installed beside the runway or the like, and it is less likely to become an obstacle to takeoff and landing. Specifically, when the anemometer 10 is placed vertically or horizontally, it can monitor the downburst at the airport.

[0186] When the runway length is 4000 m or the like, the wind on a long runway is often not uniform. Therefore, by installing a plurality of them beside the runway, the downburst or crosswind conditions of the entire runway can be monitored. In this way, the safety of airplanes at the airport can be improved.

[0187] The anemometer 10 is portable. For example, in mountain climbing, observing the updraft speed, angle, and temperature of the valley wind provides useful information for making decisions on advancing or retreating. If a GPS is built into the anemometer 10, the latitude, longitude, and altitude can be obtained. Then, the current position on the map can be grasped. In addition, the built-in gyrocompass has the function of a magnetic compass. In this way, the safety of mountain climbing can be improved.

[0188] In fire fighting activities, the wind direction and speed are often useful information as an indicator for preventive water spraying to avoid fire spread or for evacuation. For example, when installed on the roof of a fire truck, measurements can be made by multiple fire trucks. Then, based on the multiple measurement results, the wind direction and speed and the position information are displayed on the map with arrows. In this way, it can be used to determine the preventive water spraying area and the evacuation route based on the presence or absence of a fire whirlwind or the judgment of the fire spread direction.

[0189] In a forest fire (wildfire), the direction in which the fire spreads can be inferred from the angle of attack, wind speed, and direction of the wind running up the mountain. It can be used as an indicator when setting up a blank area by logging trees in advance to prevent the spread of fire. For example, if it is portable, it can be carried by firefighters. And while a three-dimensional wind vane anemometer etc. needs to be kept horizontal, for the anemometer 10, the angle of attack can be read by an inclinometer just by pointing it at the wind.

[0190] For example, it can be mounted on a multi-copter type drone etc. By observing the wind direction and wind speed in the drone airspace in this way, the measurement results can be utilized as traffic information of the drone. For example, accidents caused by the wind can be prevented. For example, since the wind is often different from that on the ground at an altitude of 10 m etc., local wind information can be utilized.

[0191] For example, if the anemometer 10 is mounted on a drone for pesticide spraying and spraying is carried out while measuring the wind direction and wind speed, waste-free spraying can be performed.

[0192] For example, the state of the wind over a golf course can be measured by a drone and used for leisure activities such as golf.

[0193] It is also possible to use it for academic verification of three-dimensional meteorology by simultaneously measuring the wind speed, wind direction, and temperature on the ground, at sea, and in the air.

[0194] For example, it can be attached to migratory birds or wild animals to observe their ecology. For example, if various data such as position, wind direction and speed, temperature, acceleration, or inclination are recorded, it can be used as data for a precise investigation of the white stork crossing the Himalayas. Since the white stork flies for two weeks, the recording is done at a recording time interval that can record that period. Continuous measurement is not necessarily required, and by making measurements at several-minute intervals, battery consumption can be suppressed, and it is also possible to perform observations while charging by incorporating a solar cell.

[0195] For example, the flying of dust in a clean room or a sterile room increases sharply when people enter the room. The air flow serves as a reference for the indoor placement of equipment that dislikes dust. The anemometer 10 can be fixedly measured. Also, the anemometer 10 can measure the micro wind direction and wind speed, and can be installed horizontally or vertically, so that three-dimensional measurement of the micro wind individual wind speed can be performed. Therefore, the anemometer 10 can provide information that serves as an index for the optimal intensity and direction of air conditioning.

[0196] For example, when the anemometer 10 is attached to a person, it becomes possible to analyze the behavior pattern due to climate change.

[0197] For example, when the anemometer 10 is fixedly used, the horizontal extension during the installation work and the work of aligning the tip of the wind direction and wind speed meter to the north are not required.

[0198] [Other Embodiments] There may be five or more measurement points. Also, multiple measurements may be taken at one measurement point.

[0199] The wind speed calculation method may be realized by a program (including firmware and a configuration in which some processes are executed by a processing circuit or the like). That is, it may be a configuration in which an information processing apparatus or an information processing system that executes processing based on a program causes an arithmetic unit, a control unit, and a storage unit to cooperate to execute processing.

[0200] Note that each component does not have to be integrated. That is, each device may be a configuration combining a plurality of devices. For example, it may be a configuration of an information processing system that executes processing with a plurality of information processing devices. Therefore, the information processing system may execute processing in parallel, redundantly, or distributively.

[0201] Note that the present invention is not limited to each of the embodiments exemplified above. Therefore, the present invention can be added or modified in components without departing from the technical gist. Thus, all technical matters included in the technical idea described in the claims are the subject of the present invention. The embodiments exemplified above are preferred specific examples in practice. And those skilled in the art can realize various modified examples from the disclosed content, and such modified examples are included in the technical scope described in the claims.

Explanation of Signs

[0202] 1: First acoustic transceiver 2: Second acoustic transceiver 3: Third acoustic transceiver 4: Fourth acoustic transceiver 10: Anemometer 10F1: First measurement unit 10F2: Second measurement unit 10F3: Third measurement unit 10F4: Fourth measurement unit 10F5: Calculation unit 11: Main body 12: Top plate 13: Support column 14: Ventilation path 15: Inflow direction 20: Vehicle 50: Ship 51: Bow direction 52: Magnetic north direction 53: Bow magnetic north azimuth 56: Course angle 58: Bow side wind 60: Ground coordinate system 61: Pitching coordinate system 62: Rolling coordinate system 63: Pitching coordinate system 64: Installation height axis 65: First moving body coordinate system 66: Second moving body coordinate system 67: First projection vector 68: Second projection vector 70: Window D1: First distance D2: Second distance D3: Third distance H1: Installation height L12: First line segment L23: Second line segment L24: Third line segment Lag: Distance between sensors Sh: Bow direction component Sl: Orthogonal component TM01: First transmission timing TM02: Second transmission timing TM11: 11th reception timing TM12: 12th reception timing TM21: 21st reception timing TM22: 22nd reception timing TM31: 31st reception timing TM32: 32nd reception timing Vc: Measured wind speed Vm: Moving body speed Vmc: Moving body speed Vs: Sound speed Vw: Output wind speed Vwc: Wind speed Vx1: First sound speed Vx2: Second sound speed Wd: Wind direction relative to the ground We: Bow direction vector Wα: Wind Wβ: Left - right wind α: Pitching angle β: Rolling angle θ: Angle of wind in the traveling direction λ: Tilt angle φ: Angle of wind direction in the bow direction

Claims

1. An anemometer installed on a moving body, a first measurement unit that measures at a first measurement point and outputs a first measurement result; a second measurement unit that measures at a second measurement point and outputs a second measurement result; a third measurement unit that measures at a third measurement point and outputs a third measurement result; a fourth measurement unit that measures at a fourth measurement point and outputs a fourth measurement result; a calculation unit that calculates the wind speed based on the first measurement result, the second measurement result, the third measurement result, and the fourth measurement result, wherein, in the installation plane where the first measurement point, the third measurement point, and the fourth measurement point are installed, in a first direction which is the traveling direction of the moving body, the horizontal component of the installation plane between the first measurement point and the second measurement point is a first distance, the horizontal component between the third measurement point and the second measurement point is a second distance, the horizontal component between the fourth measurement point and the second measurement point is a third distance, and the first distance is longer than either the second distance or the third distance Anemometer.

2. The second measurement point is at a position higher than the first measurement point, the third measurement point, and the fourth measurement point in the vertical direction, and the first measurement point, the third measurement point, and the fourth measurement point are at the same height in the vertical direction The anemometer according to claim 1.

3. The second distance and the third distance are equal distances, and the first distance is 1.5 times or more the distance of the second distance and the third distance The anemometer according to claim 1.

4. The calculation unit calculates the wind speed based on sound waves traveling back and forth through the first distance, the second distance, and the third distance The anemometer according to claim 1.

5. For the sound waves, the reception timing is set relative to the transmission timing The anemometer according to claim 4.

6. The sound waves are filtered by volume during reception The anemometer according to claim 4.

7. measures the pitching angle and the rolling angle of the moving body, and calculates the ground wind speed based on the pitching angle and the rolling angle The anemometer according to claim 1.

8. stores a correction vector of the moving body in a windless state, and the calculation unit corrects the wind speed based on the correction vector The anemometer according to claim 1.

9. A power supply configuration that extracts the power applied to the first coil with the second coil, wherein the cores of the first coil and the second coil serve as supports The anemometer according to claim 1. ​

10. A wind speed calculation method executed by an anemometer installed on a moving body, a first measurement procedure for measuring at a first measurement point and outputting a first measurement result; a second measurement procedure for measuring at a second measurement point and outputting a second measurement result; a third measurement procedure for measuring at a third measurement point and outputting a third measurement result; a fourth measurement procedure for measuring at a fourth measurement point and outputting a fourth measurement result; including a calculation procedure for calculating the wind speed based on the first measurement result, the second measurement result, the third measurement result, and the fourth measurement result; in the installation plane where the first measurement point, the third measurement point, and the fourth measurement point are installed, in a first direction which is the traveling direction of the moving body, between the first measurement point and the second measurement point, the horizontal component of the installation plane is a first distance; the horizontal component between the third measurement point and the second measurement point is a second distance; the horizontal component between the fourth measurement point and the second measurement point is a third distance; the first distance is longer than either the second distance or the third distance Wind speed calculation method.

11. A program for executing the wind speed calculation method according to Claim 10.

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