JP5698942B2 - Phased array Doppler soda system - Google Patents

Description

  The present invention relates to a Doppler soda (Doppler exploration device) used for measuring the wind direction and wind speed in the sky, and more particularly to a Doppler soda system that performs bistatic measurement.

  The Doppler soda used to measure the wind direction and speed of the sky at every altitude, for example, radiates sound waves toward the atmosphere above the sky, causing density discontinuities and fluctuations due to temperature rise and temperature fluctuation regions, etc. Receive weak reflected or scattered waves generated at discontinuities or fluctuations in the acoustic characteristics of the atmosphere. Then, by calculating the Doppler shift amount of the frequency in the received signal, the moving speed of the density fluctuation region that causes the reflection or scattering corresponding to the received signal, that is, the wind direction / wind speed at that location is calculated. Since the time from the transmission of the sound wave to the reception depends on the altitude of the density fluctuation region, it is possible to measure the wind at each desired altitude. In this case, one component of the wind speed is obtained by one receiver. Can do. In addition to general observations of the upper atmosphere, such Doppler soders can be placed around airfield runways, for example to monitor wind shear, downburst, and wake turbulence, or It can be used for site surveys of wind power generation facilities.

  As a method of observing the wind direction and speed of the sky with a Doppler soda, a monostatic method that emits and receives sound waves in the same place, and a bistatic that emits sound waves in one place and receives sound waves in multiple places There is a method.

  In the case of a monostatic system that emits and receives sound waves in one place, only the moving speed of the density fluctuation region in the line-of-sight direction is known from the Doppler shift amount, so only from the result of emitting sound waves in one direction, The wind direction and speed cannot be determined. Therefore, sound waves (acoustic beams) are emitted from one place in three or more directions, and the Doppler shift amount in each direction is obtained to determine the wind direction and wind speed in the sky. At this time, since the acoustic beams in each direction pass through positions distant from each other in the sky, it is necessary to assume that the wind direction and the wind speed are constant at the same altitude surface in the sky. This assumption is almost true in the sky over flat terrain, but this assumption is not established in the sky over complicated terrain with large undulations, and correct measurement cannot be performed. Under this assumption, it is difficult to capture changes in wind speed that occur instantaneously, such as gusts on a small scale.

  In Patent Document 1, Patent Document 2 and Non-Patent Document 1, by using a phased array type acoustic wave transmitter / receiver, an acoustic beam is radiated from one place in a plurality of directions and reflected from each direction. A monostatic phased array type Doppler soda capable of receiving waves or scattered waves is disclosed.

  In order to solve the above-mentioned problems of the monostatic method, in the bistatic method, a transmitter / receiver is installed at one place to radiate an acoustic beam and receive a reflected wave or scattered wave. Installs microphone receivers at two or more other locations to receive reflected waves or scattered waves, and determines the Doppler shift amount in a total of three or more directions to determine the wind direction and wind speed for each altitude. In the bistatic method, since the radiation direction of the acoustic beam is usually fixed (for example, in the vertical direction), the incoming direction of the reflected wave or scattered wave differs depending on the altitude when viewed from the reception microphone receiver. It will be. Therefore, in order to obtain the altitude distribution of the wind direction and wind speed, a microphone with a relatively wide directivity is used, which makes it more susceptible to noise and the high resolution due to the direction dependency of the reception sensitivity. Becomes worse. Furthermore, in the case of the bistatic method, the transmitter and microphone receiver are the same because the installation location required as one of the applications is a complex terrain area such as a hilly or mountainous area where the wind direction and wind speed are not uniform. If it is not possible to arrange at an altitude, an error occurs in measurement unless correction calculation corresponding to the altitude difference is performed.

  In both the monostatic method and the bistatic method, the radiated acoustic beam expands as it propagates to the sky, so that the spatial resolution in the horizontal plane deteriorates as the distance range (altitude) increases. Further, when the acoustic beam is radiated in an oblique direction rather than a vertical direction, there is a problem that the position corresponding to the measured wind direction and wind speed is shifted in the horizontal direction according to the altitude.

JP-A-9-89917 Japanese Patent Laid-Open No. 10-325843

Yasushi Kojima, Shigeo Hirai, Shinichiro Nakajima, Yoshiki Ito, “Development of 5-Beam Phased Array Doppler Soda”, Kaijo Technical Report, No. 6, 40-49, July 1997

  When using the Doppler soda to measure the wind direction and wind speed over the sky, the conventional system has a problem that the spatial resolution is not sufficient and it is difficult to obtain the wind direction and wind speed values at any position in the sky. there were.

  An object of the present invention is to provide a Doppler soda system capable of obtaining wind direction and wind speed values at arbitrary positions in the sky with sufficient spatial resolution and sufficient time resolution, that is, instantaneous wind speed without performing time averaging.

  The phased array type Doppler soda system of the present invention is configured as a phased array by arranging a plurality of first acoustic elements for transmission and reception, and radiates an acoustic beam to the sky and receives scattered waves from the acoustic beam. A transducer and a plurality of second acoustic elements for reception are arranged to form a phased array and receive scattered waves from the acoustic beam. At least the transducer is arranged at a location different from the transducer Two receivers, drive signal generation means for generating a drive signal to each of the plurality of first acoustic elements with a phase difference for each first acoustic element, and reception by the plurality of first acoustic elements First phase synthesizing means for synthesizing the received signal with a phase difference for each first acoustic element, and signals received by a plurality of second acoustic elements of the corresponding receiver provided for each receiver For each second acoustic element Controlling the acoustic beam emission direction by controlling the phase difference in the second phase synthesizing unit, the drive signal generating unit, the first phase synthesizing unit, and each of the second phase synthesizing units. The incoming Doppler shift component in the extracted received signal is extracted by controlling only the incoming direction of the received scattered wave, extracting only the received signal based on the scattered wave from any measurement position in the sky, and extracting the Doppler extracted Control means for calculating the wind direction and the wind speed at the measurement position based on the shift component.

  Bistatic Doppler soda system uses phased array type transmitter and receiver and at least two receivers, respectively, and phase synthesis technology for acoustic beam radiation and scattered wave reception from acoustic beam It is possible to arbitrarily set the spatial position where the acoustic beam is irradiated and the incoming direction when receiving the scattered wave, that is, away from the irradiation position of the acoustic beam. It is possible to receive scattered waves from the same space, not from the same space, and to determine the wind direction and wind speed at an arbitrary position in the sky. As a result, it is possible not only to determine the height distribution of wind direction and wind speed directly above the installation position of the transducer, but also to obtain the wind direction and wind speed vertical distribution at any point instantly and accurately without time averaging. Is possible.

  In addition, when applying the phase synthesis technique to the phased array type transducer or each acoustic element constituting the receiver, the radiation beam is converged to the focal position with the desired position as the focal point, The spatial resolution in wind direction and wind direction measurement can be further improved by allowing the scattered wave from the position to be phase-combined in phase and selectively receiving the scattered wave from the focal position.

It is a block diagram which shows the structure of the phased array type | mold Doppler soda system of one Embodiment of this invention. It is a top view which shows an example of arrangement | positioning of the transducer element in a transducer and a receiver, or a wave receiving element. It is a figure explaining beam scanning. It is a figure which shows an example of arrangement | positioning of a transmitter / receiver and a receiver in the example which applied the phased array type | mold Doppler soda system based on this invention to the monitoring of a wind shear. (A), (b) is a figure explaining the convergence of the beam by a phase difference. (A) is a top view which shows an example of arrangement | positioning of a transmitter / receiver and a receiver, (b) is a figure explaining calculating | requiring a wind direction and a wind speed for every altitude. (A) is a top view which shows another example of arrangement | positioning of a transmitter / receiver and a receiver, (b) is a figure explaining calculating | requiring a wind direction and a wind speed for every altitude. (A) is a top view which shows the case where a transmitter / receiver and each receiver are installed in the place where an altitude differs, (b) is a figure explaining calculating | requiring a wind direction and a wind speed for every altitude.

  Next, a preferred embodiment of the present invention will be described with reference to the drawings.

  The phased array type Doppler soda system according to the embodiment of the present invention shown in FIG. 1 is a bistatic type used for obtaining the wind direction and wind speed in the sky, and can be broadly divided into a transmission / reception unit 110 and a transmission / reception unit. The wave unit 110 is connected to the wave receiving units 130a and 130b disposed at two or more places different from the wave unit 110, and is connected to the wave receiving and receiving unit 110 and the wave receiving units 130a and 130b to control these units and perform wind measurement calculation ( CPU (central processing unit) 100 as control means for performing calculation of wind direction and wind speed, and position information supply unit 140 that supplies information on the arrangement positions of the wave transmitting / receiving unit 110 and the wave receiving units 130a and 130b to the CPU 100, It is equipped with. When the transmitting / receiving unit 110 and the receiving units 130a and 130b are arranged at known points, or when the relative positional relationship between these units is fixed, information on the positional relationship is displayed. Since it can be held in the CPU 100 as fixed information, it is not necessary to provide the position information supply unit 140. Also, the sound speed changes depending on the environmental temperature, and as a result, the wavelength also changes. As the wavelength changes, the angle of the acoustic beam formed by the phase synthesis technique changes slightly. Therefore, in this embodiment, a temperature information supply unit 141 that supplies information indicating the environmental temperature to the CPU 100 may be provided. Based on the temperature information input from the temperature information supply unit 141, the CPU 100 corrects the wind direction / wind speed calculation formula, compensates for the contribution of the change in the angle of the acoustic beam depending on the temperature, and executes wind measurement calculation.

  The transmission / reception unit 110 includes a phased array type transmitter / receiver (TR) 111. In the transducer 111, an acoustic element that emits a sound wave according to a drive signal that is an electrical signal and receives an external sound wave and converts it into an electrical signal is, for example, M rows and N columns (M and N are both 2). (Integer above). As such a transducer, for example, the one described in Patent Document 1 can be used. In the following description, as shown in FIG. 2, the transducer 111 arranges the acoustic elements 150 in 16 rows and 16 columns, and by removing 10 acoustic elements at each of the four corners, octagons are obtained. It is assumed that 216 acoustic elements 150 are arranged in the region. The hand over of the transducer 111 is about 100 cm, for example.

  In addition, the transmission / reception unit 110 includes a transmission control unit 112, a RAM (random access memory) 113, a phase difference signal generation unit 114, a filter 115, and a transmission wave matrix switching unit 116 for radiating an acoustic beam from the transducer 111. And a transmission amplifier 117. In this Doppler soda system, the CPU 100 generates a transmission waveform signal to be applied to each acoustic element as digital data, and the RAM 113 is used as a lookup table that holds such a transmission waveform signal. That is, the RAM 113 stores waveform data to be applied as a drive signal to each acoustic element 150 as digital data having a phase difference based on the transmission waveform signal sent from the CPU 100. The phase difference signal generator 114 is configured as a digital / analog converter (D / A) or a clock generator, reads waveform data from the RAM 113, and applies an analog signal (or a signal to be applied as a drive signal to each acoustic element). Clock signal). The filter 115 shapes the analog signal or clock signal from the phase difference signal generation unit 114 and supplies it to the transmission wave matrix switching unit 116.

  In the present embodiment, as described above, each acoustic element is classified into several to a dozen groups, such as for each column or row in the transducer 111, and the same group according to the radiation direction of the acoustic beam. In place of driving the acoustic elements with the same phase difference, a total of 216 types of drive signals having phase differences are individually generated for each of the 216 acoustic elements included in the transducer 111. Also good. In that case, it is possible to irradiate any space in the sky. The transmission wave matrix switching unit 116 switches the arrangement of the acoustic elements in order to select a combination of acoustic elements that are driven with the same phase difference in accordance with the direction in which the acoustic beam is desired to be emitted. This switching is actually performed by mapping which phase difference signal is supplied to the signal line provided for each acoustic element. A transmission amplifier 117 is provided for each signal line for each acoustic element. Each transmission amplifier 117 amplifies the power of the signal from the transmission wave matrix switching unit 116 and drives each acoustic element via the separation circuit 118 provided for each acoustic element. The transmission control unit 112 controls the RAM 113, the phase difference signal generation unit 114, the filter 115, and the transmission wave matrix switching unit 116 so that the acoustic beam is emitted in the direction specified by the CPU 110.

  The separation circuit 118 switches and separates transmission and reception in an acoustic element provided in the transducer 111, applies a signal from the transmission amplifier 117 to the corresponding acoustic element, and receives a signal received by the acoustic element. Is sent to a receiving amplifier 119 provided for each acoustic element.

  In addition to the reception amplifier 119 provided for each acoustic element, the transmission / reception unit 110 further processes a reception wave matrix switching unit 120, a filter 121, analog / digital in order to process a signal received by each acoustic element. A converter (A / D) 122, a phase synthesis unit 123, and a reception control unit 124 are provided.

  The transducer 111 needs to receive scattered sound waves from the emitted acoustic beam as efficiently as possible. Therefore, the received wave matrix switching unit 120 controls the directivity when the transmitter / receiver 111 receives the scattered sound wave by selecting a combination of acoustic elements that synthesizes the received signals with the same phase difference. The arrangement of the acoustic elements is switched so that the maximum sensitivity direction (that is, the direction of the received acoustic beam) is a desired direction. In practice, the switching is performed by selecting signals to be processed with the same phase difference from the signals from the acoustic elements amplified by the respective receiving amplifiers 119 and adding and combining the selected signals. This is performed by executing each of the plurality of phase differences.

  The filter 121 shapes the signal from the received wave matrix switching unit 120, and the analog / digital converter 122 converts the waveform-shaped signal into a digital signal. The phase synthesizer 123 samples and synthesizes the signals from the analog / digital converter 122 with a phase difference so as to extract scattered sound waves from a desired direction, and outputs the combined received signals to the CPU 100. In other words, the phase synthesizer 123 forms the sensitivity of the received acoustic beam as a whole in the phased array transducer. The reception control unit 124 controls the reception wave matrix switching unit 120, the filter 121, the analog / digital converter 122, and the phase synthesis unit 123 so as to receive the scattered wave from the direction specified by the CPU 100.

  The wave receiving units 130a and 130b are equivalent to those obtained by removing the acoustic beam radiation function from the wave transmitting / receiving unit 110. The wave receiving units 130a and 130b include a phased array type wave receiver (R) 131 and are equivalent to those in the wave transmitting / receiving unit 110. A reception amplifier 119, a reception wave matrix switching unit 120, a filter 121, an analog / digital converter 122, a phase synthesizer 123, and a reception control unit 124 are provided. In the receiver 131, acoustic elements that receive external sound waves and convert them into electrical signals are arranged in, for example, M ′ rows and N ′ columns (M ′ and N ′ are integers of 2 or more). As such a wave receiver, the same one as the above-described wave transmitter / receiver 111 but having only a wave receiving function can be used. The number of acoustic elements provided may be the same or different between the transmitter / receiver 111 and the receiver 131. In the following description, similarly to the transducer 111, for example, a receiver in which 216 acoustic elements are arranged in an octagonal region is used.

  Next, the operation of such a phased array type Doppler soda system will be described.

  It is assumed that the wave transmitting / receiving unit 110 and the wave receiving units 130a and 130b are arranged at three points that are not on the same straight line, and one point in the sky where the wind direction and the wind speed are to be measured is set as a measurement position. First, the CPU 100 directs the acoustic beam radiated from the transmitter / receiver 111 to the measurement position, and when the scattered acoustic wave is received by the transmitter / receiver 111 and each receiver 131, the received acoustic beam is moved toward the measurement position. The phase difference for each acoustic element in the wave transmitting / receiving unit 110 and the wave receiving units 130a and 130b is set so as to face. Then, the CPU 100 sets the frequency of the sound wave in the acoustic beam, and writes the waveform data corresponding to the set frequency in the RAM 113 of the transmission / reception unit 110. As a result, the phase difference technology is applied by the phase difference signal generation unit 114, the filter 115, and the transmission wave matrix switching unit 116, and each acoustic element of the transmitter / receiver 111 is driven via the transmission amplifier 117, and the previously set measurement is performed. An acoustic beam is emitted in the direction of the position.

  This acoustic beam is scattered by the density fluctuation region in the atmosphere and received by the transducer 111 and each receiver 131. At this time, the direction of the received acoustic beam in the transmitter / receiver 111 and each receiver 131 is changed by the phase synthesis technique realized by the received wave matrix switching unit 120, the filter 121, the analog / digital converter 122, and the phase synthesis unit 123. As a result, the reception signal based on the sound wave scattered at the measurement position is output from the transmission / reception unit 110 and the reception units 130a and 130b to the CPU 100. The CPU 100 obtains a Doppler shift component in the scattered sound wave by applying FFT (Fast Fourier Transform) to each received signal and extracts the Doppler velocity, and extracts the three directions (the transmitting / receiving unit 110 and the receiving units 130a and 130b). The wind direction and the wind speed at the measurement position are calculated from the Doppler velocity in the direction of the received acoustic beam in each of the above. Note that the sound waves received by the transmitter / receiver 111 and each receiver 131 may include scattered sound waves from other than the measurement position, but from the measurement position using the round-trip propagation time of the sound wave. Only the sound wave of can be captured.

  In order to investigate the wind direction and wind speed distribution in the vertical direction at the same point, while changing the radiation direction of the acoustic beam and the direction of the received acoustic beam so that the plane position of the measurement position is the same and only the altitude is different, that is, While performing beam scanning, the acoustic beam emission and the scattered sound wave reception may be repeatedly executed to obtain measurement results according to altitude. By performing measurement by performing beam scanning, since the radiation acoustic beam and the reception acoustic beam intersect only at a specific altitude, the measurement altitude can be distinguished, and the data acquisition efficiency and wind measurement accuracy are improved.

  When performing beam scanning, sound leakage to the surroundings may occur if the acoustic beam radiation direction is an oblique direction deviated from the vertical direction. Therefore, the direction of the received acoustic beam is measured at a receiver installed at a location different from the transmitter / receiver so that the transmitter / receiver always emits an acoustic beam vertically upward and receives scattered waves from vertically above. You may make it perform the beam scanning changed according to an altitude. In this case, since only the wind direction and wind speed above the position of the transducer can be obtained, when trying to obtain the wind direction and wind velocity above an arbitrary point, the transducer and each receiver In all of the above, beam scanning is performed.

  Here, the beam scanning for obtaining the vertical distribution of the wind direction and the wind speed over an arbitrary point will be further described with reference to FIG. In the following, for the sake of explanation, the transmitting / receiving unit is represented by the transmitter / receiver TR, and the two receiving units are respectively indicated by the receiver R. In the bistatic type measurement, when the wind direction and the wind speed at an arbitrary position other than the vertical direction of the position of the transducer are to be obtained, the direction of the acoustic beam radiated from the transducer is changed, that is, It is necessary to shake the beam in the radiated acoustic beam. The frequency of the acoustic beam may be the same, but as described later, it is preferable to use a sound wave having a lower frequency at a higher altitude. At this time, if a receiver R that is unidirectional and cannot change the maximum sensitivity direction is used, the receiver R is located at an equidistant position from the transmitter / receiver TR (" Scattered sound waves from a conventional cut scatterer ”are received, and scattered sound waves from a position shifted in the horizontal direction due to altitude are received.

  On the other hand, the direction of the received acoustic beam at the receiver is also changed in accordance with the beam scanning with the radiated acoustic beam from the transmitter / receiver, so that an arbitrary point can be obtained as shown by a thick broken line in FIG. For example, the wind direction and the wind speed in the vertical range in the range from 50 m to 100 m above the altitude can be determined for each altitude. Of course, it is possible to measure the wind direction and the wind speed in a desired altitude range by changing the angle range in which the beam is swung in the beam scanning.

  Next, the arrangement of the transducer and the receiver in this phased array type Doppler soda system will be described. FIG. 4 shows an example of the arrangement of transducers and receivers when monitoring wind shear, microburst, wake turbulence and the like at an airfield.

  Two sets of phased array type Doppler soda systems are arranged outside the two ends of the runway 300 so as not to obstruct the aircraft in operation, as shown in FIGS. Depending on the length of the runway, the two Doppler soder systems are separated by about 1500-3000 m, indicated by the spacing of the transducer TR. In each Doppler soda system, the transmitter / receiver TR and the two receivers R are arranged at a distance of about 100 m from each other so that each occupies the apex of an equilateral triangle, for example. With such a configuration, generally, the wind direction and the wind speed at an arbitrary altitude above the arbitrary point inside or near the triangle formed by the transmitter / receiver TR and the two receivers R are represented. It becomes possible to measure. Further, if necessary, the installation position of the transmitter / receiver TR and the receiver R can be changed as indicated by the dotted line in the figure.

  By arranging the phased array Doppler soder system in this way, for example, in airports, the wind shear region directly above the runway is monitored, and at the same time, the wake turbulence caused by the main wing of a large aircraft, especially in the sky around both ends of the runway Can be monitored.

  In addition, as an application example of the phased array type Doppler soda system based on the present invention, the wind direction and the wind speed at a plurality of spatially separated points are remotely sensed from a fixed point on the ground in a complex terrain such as mountains. There is something to monitor by. In this example, for example, the wind conditions at a plurality of points where the installation of the wind power generator is scheduled can be examined.

  In the present invention, since the phased array type transducer and receiver are used, the emitted acoustic beam and the received acoustic beam can be converged to a specific position. Accordingly, as shown in FIGS. 5A and 5B, if acoustic elements are arranged along a spherical surface in a phased array type transducer, and these acoustic elements are driven in the same phase, the acoustic beam is a spherical surface. The position of the center of the sphere corresponding to is taken as the focal point and converges at that focal point. Similarly, in the case of a receiver, when acoustic elements are arranged on a spherical surface and received signals from those acoustic elements are synthesized with the same phase, the sound wave is received with the highest sensitivity at the position of the center of the sphere corresponding to the spherical surface. become. Therefore, in the present invention, an acoustic element is arranged on the concave surface so that a focal point is formed at a spatial position (altitude and azimuth) to be measured in the transmitter / receiver, and the radiated acoustic beam and the received acoustic beam are located at the spatial position. You may make it converge with.

  Alternatively, as shown in FIGS. 5 (a) and 5 (b), the acoustic element itself is arranged on a plane, and the same effect as that arranged on the concave surface is produced, so that the acoustic beam converges at the focal point. A drive signal may be supplied with a phase difference applied to the acoustic element, and the received signal may be synthesized with the phase difference. As a result of driving the acoustic element with a phase difference, it is possible to obtain an effect as if the acoustic element is arranged on an apparently concave virtual radiation surface. In that case, by adjusting the phase difference, the convergence height of the beam can be changed, or the horizontal position of the place where the beam converges can be changed.

  With such a configuration, it is possible to measure the wind direction and the wind speed without reducing the spatial resolution even at a high altitude position where the distance from the transmitter / receiver or the receiver increases.

  By the way, when the frequency of the sound wave in the emitted acoustic beam is low, although the attenuation of the sound wave is small, the measurement accuracy of the Doppler shift amount is low, the wind measurement accuracy is low, and the spatial resolution is also low. On the other hand, when the frequency of the sound wave is high, attenuation of the sound wave increases, but wind measurement accuracy and spatial resolution are improved. In general, when measuring the wind direction and wind speed above the sky, more accurate measurement results are required for low altitudes closer to the ground surface, and so much accuracy is often not required for high altitudes. Therefore, while performing the beam scanning described above, the sound wave frequency is sequentially switched so that a relatively high frequency sound wave is used for the low altitude and a relatively low frequency sound wave is used for the high altitude. Can be measured. By using a low frequency for high altitude, the measurable distance range becomes large, and the wind direction and wind speed can be measured to an extremely high altitude.

  FIGS. 6A and 6B show such measurement examples. Here, as shown in FIG. 6A, the first receiver R is disposed at a position 100 m (first distance L1) east from the transmitter / receiver TR, and the transmitter / receiver T- The second receiver R is arranged at a position 100 m (second distance L2) away from R, and the frequency of the sound wave is used, and frequency sweeping is performed using six types from F1 to F6 from the highest. The wind direction / velocity distribution in the altitude range from 50m to 200m is measured. In this case, the wind direction / velocity distribution at an altitude of 50 m is measured by F1 which is the highest frequency, the measurement is performed at an altitude of 70 m by F2 which is the next highest frequency, and F6 which is the lowest frequency is F6. Is used to measure at an altitude of 200 m.

Here, the resolution of the wind speed according to the frequency of the sound wave will be described. When the frequency of the sound wave to be used is f ₀ and the frequency resolution when extracting the Doppler shift component based on the received signal is Δf, the wind speed resolution ΔV is
ΔV = C · Δf / 2f ₀
Represented by C is a constant. From this equation, it can be seen that if the frequency resolution Δf is constant, the wind speed resolution ΔV increases as the operating frequency f ₀ increases.

  By performing beam scanning, the measurement altitude is better separated, but in addition to this, by performing frequency sweep so as to change the frequency used for each altitude as described above, the measurement altitude can be further separated, Data acquisition efficiency is further improved. Note that the use of a plurality of conventional sound wave frequencies has been performed, but this is performed only for the purpose of increasing the number of data.

  In the configuration shown in FIGS. 6A and 6B, the acoustic beam is radiated intermittently, but is radiated using only a single frequency F1, or transmitted / received from a diagonally upward transducer. May be used as the frequencies F1 to F6.

  FIGS. 7A and 7B show an arrangement that enables measurement of the wind direction and wind speed to an altitude higher than that shown in FIGS. 6A and 6B.

  Regarding the angular distribution of the intensity of the scattered sound wave when the acoustic beam is scattered by the density fluctuation region, the component that propagates in the opposite direction of the acoustic beam propagation direction (reflection component) is not the maximum, but the acoustic beam propagation It is known that the strength is maximized in a direction forming an angle of 40 ° to 70 ° when viewed from the opposite direction. Therefore, when measuring at a higher altitude, it is better to increase the distance between the transmitter and receiver to a certain extent, even if the attenuation associated with the longer propagation distance of sound waves is taken into account. A signal will be obtained. Therefore, for example, to obtain the vertical distribution of wind direction and wind speed up to an altitude of 400 m, a receiver R is provided at a position 100 m and 300 m away from the transmitter / receiver TR, and further, A receiver R is provided at a position 100 m and 300 m away from the wave transmitter T-R to the north. The receiver located 100 m from the transmitter / receiver TR is a low-altitude receiver, and the one located 300 m is a high-altitude receiver. And in the measurement of the wind direction and the wind speed in the range from 50m to 200m, as in the case shown in FIGS. 6 (a) and 6 (b), the six frequencies F1 to F6 for each altitude are used. The data acquired by the wave transmitter T-R and the data acquired by the two low-altitude wave receivers R located 100 m from the wave transmitter / receiver TR are used. Furthermore, for the measurement of wind direction and speed in the range of altitude 200m to 400m, the data acquired by the transmitter / receiver TR and the transmitter / receiver T- using the sound waves of six frequencies F7 to F12 for each altitude. Data acquired by two high altitude receivers R located 300 m from R are used. Among the frequencies F7 to F12, the frequency F7 is the highest, which is used for measurement at an altitude of around 200 m. Hereinafter, a sound wave having a lower frequency is used as the altitude increases. A low frequency F12 is used for the measurement. The transmitter / receiver TR radiates acoustic beams having frequencies F1 to F6 in order, and then radiates acoustic beams having frequencies F7 to F12 in order.

  In this way, by varying the distance between the emission position and the reception position of the acoustic beam according to the altitude of the measurement position, it is possible to ensure an appropriate beam scattering angle regardless of the altitude at which the measurement is to be performed. It is possible to receive a scattered sound wave from a density fluctuation region in which temperature fluctuation and wind speed fluctuation are combined at a strong level, and the S / N ratio (signal-to-noise ratio) can be improved. Specifically, by setting the scattering angle of the acoustic beam to be in the above range, the signal intensity is increased several times, so that the S / N ratio of the received signal is also improved several times.

Next, an example will be described in which the phased array type Doppler soda system according to the present invention is arranged on a ground surface that is not flat such as a mountain or a hilly area. When the phased array type Doppler soda system is arranged on the ground surface which is not flat, the elevations of the transmitter / receiver TR and the at least two receivers R are different from each other. 8A and 8B show a case where the elevation of the transmitter / receiver TR is h ₀ and the elevations of the two receivers R are h ₁ and h ₂ , respectively. Viewed from transducer T-R, one of the receivers R, the distance is a L _1, the azimuth angle is theta ₁ clockwise from due north, elevation is a [psi _1. Similarly, the other receiver R has a distance L _{2 as} viewed from the transmitter / receiver TR, θ ₂ counterclockwise from true north in the horizontal direction, and an elevation angle ψ ₂ . Because the elevation of the two receivers is different, when the position indicated by point P in the figure is taken as the measurement position, the elevation angle to point P is α ₁ in one receiver, while the other receiver is Then α ₂ .

  In this way, when there is a difference in altitude between the transmitter and the receiver, if the correction is not performed on the obtained result, an error occurs in the altitude value and the obtained wind direction / velocity value. Thus, in the case of beam scanning, if the elevation difference is not taken into account, it is not possible to guarantee that the radiated acoustic beam and each received acoustic beam intersect at a desired position, and as a result, the scattered sound wave itself cannot be received. It becomes.

  Therefore, in this example, the position of the transmitter / receiver and the receiver are measured using a GPS (global positioning system) sensor or a range finder that can perform azimuth / tilt measurement. The measurement result is supplied to the CPU 100 via the information supply unit 140 (see FIG. 1). The CPU 100 automatically executes the alignment of each acoustic beam and the calculation of the wind direction / velocity by software control. Calculation under software control is performed under the condition that the three-dimensional position of each of the transmitter and the receiver is known and the measurement position (horizontal position and altitude) for the wind direction and the wind speed is given. Therefore, those skilled in the art can easily understand the contents. With such a configuration, the degree of freedom of the arrangement of the transducer and the receiver in the phased array type Doppler soda system is increased, the installation of this system is simplified, and the radiated acoustic beam and each received beam are in the sky. The certainty of crossing is improved.

100 CPU
110 Transmitter / receiver unit 111 Transmitter / receiver (TR)
112 Transmission control unit 113 RAM
114 phase difference signal generator 115, 121 filter 116 transmission wave matrix switching unit 117 transmission amplifier 118 separation circuit 119 reception amplifier 120 reception wave matrix switching unit 122 analog / digital converter 123 phase synthesis unit 124 reception control unit 130a, 130b Unit 131 Receiver (R)
140 Position Information Supply Unit 141 Temperature Information Supply Unit 150 Acoustic Element

Claims (4)

A transducer configured to arrange a plurality of first acoustic elements for transmission and reception as a phased array, radiate acoustic beams of two or more different frequencies to the sky, and receive scattered waves from the acoustic beam;
A plurality of second acoustic elements for receiving waves are arranged and configured as a phased array to receive scattered waves from the acoustic beam, and are arranged at locations different from the transducer. Waver,
Drive signal generation means for generating a drive signal to each of the plurality of first acoustic elements with a phase difference for each of the first acoustic elements;
First phase synthesis means for synthesizing signals received by the plurality of first acoustic elements with a phase difference for each of the first acoustic elements;
A second phase synthesizing unit that is provided for each of the receivers and synthesizes the signals received by the plurality of second acoustic elements of the corresponding receiver with a phase difference for each of the second acoustic elements; ,
By controlling the phase difference in the drive signal generating means, the first phase synthesizing means, and each of the second phase synthesizing means, the direction of emission of the acoustic beam is controlled, and the incoming scattered wave is received. Control the direction, extract only the received signal based on the scattered wave from any measurement position above the sky, extract the Doppler shift component in the extracted received signal, and extract the measurement position based on the extracted Doppler shift component Control means for calculating the wind direction and wind speed at
Have
By controlling the launch direction and the incoming direction while sweeping the frequency of the acoustic beam, only the first frequency is used to calculate the wind direction and wind speed at the first altitude, A phased array type Doppler soda system that uses only the second frequency lower than the first frequency for calculating the wind direction and the wind speed at the second altitude higher than the altitude.
A plurality of the first group of receivers whose distance from the transducer is equal to or less than a first distance, and a plurality of second group of the second group whose distance from the transceiver exceeds the first distance The receiver,
The wind direction and wind speed at an altitude less than or equal to a threshold altitude are calculated using received signals obtained by the plurality of receivers of the first group, and the wind direction at an altitude exceeding the threshold altitude. 2. The Doppler soda system according to claim 1, wherein reception signals obtained by a plurality of receivers of the second group are used for calculating the wind speed. The phase difference in the drive signal generating means is controlled so that the acoustic beam converges at the observation position, and the first wave so as to synthesize the scattered waves from the convergence point in phase with the observation position as a convergence point. 3. The Doppler soda system according to claim 1, wherein the phase difference in the phase synthesizing unit and each of the second phase synthesizing units is controlled. A position information supply means for supplying data relating to the arrangement position of each of the transmitter / receiver and each receiver to the control means, and a temperature information supply means for supplying data representing temperature information to the control means, the control means on the basis of the data input from the position information supply means and said temperature information supply means executes the correction calculation in the alignment and the calculation of the wind direction and wind speed of the acoustic beam, of claims 1 to 3 The Doppler soda system according to any one of the above.

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