JP3322214B2 - Airflow detection method and laser radar device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airflow detection method and a laser radar device for detecting wind and turbulence for, for example, weather observation and air traffic control, and more particularly to a method of detecting wind conditions (wind direction and speed) in rain. The present invention relates to an airflow detection method for detecting a turbulent airflow in a predetermined space and a laser radar device.

[0002]

2. Description of the Related Art As a conventional laser radar apparatus, there is, for example, a laser radar apparatus described in "Applied Measurement of Plasma and Gas Laser" (Katsunori Muraoka and Mitsuo Maeda: Sangyo Tosho) shown in FIG. The device shown in FIG.
The receiving telescope 115 fixed to 50 and the signal processor 10
3 and the receiving telescope 115 includes the laser transmitter 11
3, collimator 114, photodetector 116, optical filter 1
Seventeen. The signal processor 103 has a signal processing unit 103a and a control unit 103b.
From the computer 118 built in the display 104
Is output to the recorder 105.

Next, the operation of the conventional laser radar device will be described. The laser transmitter 113 of the laser radar device shown in FIG.
After being collimated at 14 and sent out to the atmosphere, and the backscattered light from the atmosphere is received by the receiving telescope 115, the optical signal is converted by the photodetector 116 into an electric signal. Assuming that the speed of the light is c, the power of the light returned from the point at the distance R is given by the following lidar equation.

P (R) = PoK (cτ / 2) Aβ (R) Y (R) To (R) 2 / R2 (1) where Po is the transmission power, K is the efficiency of the receiving optical system, A
Is the effective area of the telescope, β (R) is the differential backscattering cross section,
Y (R) is the overlap factor between the transmitted beam and the telescope field of view, and To (R) is the transmittance per way.

[0005] The received signal is subjected to a Doppler shift of a frequency corresponding to the wind speed represented by the following equation. Δf = 2V / λ (2) where V is the wind speed, and λ is the wavelength of light (transmitted laser light). The above-described laser radar device includes a signal processing unit 103a
Then, the shift amount of this frequency is detected, and it is
After analysis by the computer 118 in 3b, the wind speed obtained from the analysis is displayed on the display 104.

[0006]

However, the conventional laser radar device has the following problems.
In other words, a laser radar device that detects wind uses an aerosol as a tracer, so it is a very effective means for observation in fine weather.However, in rainy weather, raindrops with a much larger particle size than aerosols use Receive scattering.
Therefore, the aerosol echo is much weaker than the raindrop echo, and it is very difficult to detect it.

On the other hand, an air traffic control radar apparatus employs a technique of canceling echoes from rainfall by switching the polarization (making it circularly polarized). However, in a meteorological application, a raindrop which is an object (target) is used. And aerosols are spherical and cannot be distinguished.

In the distance measuring device disclosed in Japanese Patent Application Laid-Open No. Hei 6-308234, a raindrop sensor for detecting rainfall is provided, and based on rainfall information from the raindrop sensor, that is, the intensity of the light pulse according to the amount of rainfall, It is configured to control the gain of the receiver to prevent a decrease in the measurement distance due to rainfall. On the other hand, in a laser radar device that detects wind, control of the signal intensity alone only enhances the echo of raindrops and cannot separate and detect the wind.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to detect an airflow which captures the movement of a wind or a characteristic backward turbulence without being affected by raindrops even during rainfall. It is to provide a method and a laser radar device.

[0010]

In order to achieve the above object, the present invention provides a step of irradiating a laser beam to a measurement target space and receiving a scattering signal of the laser light by a raindrop in the measurement target space. A first calculating step of obtaining a motion vector of the raindrop based on the received scattered signal; a step of irradiating the raindrop with a radio wave of a predetermined wavelength upward from below vertically; Receiving the reflected wave of the radio wave from the first and second, based on the received reflected wave, a second calculation step of calculating the vertical drop velocity component of the raindrop,
A third calculation step for obtaining a wind speed from a vector calculation of the motion vector and the vertical drop velocity component is provided.

Preferably, a microwave radar is used for the irradiation of the radio waves. Further, the microwave radar is a dual-polarization radar, and the second operation step switches the vertical polarization and the horizontal polarization of the dual-polarization radar to obtain a vertical drop velocity component of the raindrop. . Furthermore, the vertical drop velocity component of the raindrop, the particle size of the raindrop based on the flatness of the raindrop obtained by the polarization switching of the dual polarization radar, and,
The fall velocity estimated from the air resistance is corrected.

[0012] Preferably, a sound wave radar is used for the irradiation of the radio wave.

According to another aspect of the present invention, a step of irradiating a measurement target space including a wake turbulence with a laser beam, a step of detecting a Doppler component of the scattered signal of the laser beam due to raindrops in the measurement target space, From the Doppler radar, irradiating the raindrops with a radio wave of a predetermined wavelength, and irradiating the radio waves, obtaining Doppler data for the raindrops, from the Doppler component and Doppler data,
Calculating a motion component of the wake turbulence, and providing an airflow detection method for obtaining a wind speed based on the motion component of the wake turbulence.

According to another aspect of the present invention, the first irradiation step of irradiating the rear turbulence generation space with the laser beam, and the laser light is irradiated to the rear turbulence non-generation space separated from the rear turbulence generation space by a predetermined distance. A second irradiating step; a step of detecting a first Doppler component of the scattered signal of the laser light by the raindrops in the space where the wake turbulence is generated; and Detecting a second Doppler component of the scattered signal of the laser light; and calculating a motion component of the wake turbulence from the first Doppler component and the second Doppler component. Provided is an airflow detection method for obtaining a wind speed based on a motion component.

According to another aspect of the present invention, the first and second irradiation steps of irradiating a laser beam to the space where the wake turbulence occurs, and the first and second irradiation steps of the laser light due to raindrops in the space where the wake turbulence occurs. Detecting the Doppler echo, and calculating the motion component of the wake turbulence from the first Doppler echo and the second Doppler echo, wherein the laser transceiver according to the detection of the first Doppler echo An airflow detection method is provided in which the distance resolution is set higher than the distance resolution of the laser transceiver for detecting the second Doppler echo, and the wind speed is obtained based on the motion component of the wake turbulence.

Preferably, the laser transceiver for detecting the first Doppler echo and the laser transceiver for detecting the second Doppler echo are physically symmetrical with the space where the wake turbulence is generated therebetween. It is arranged in a suitable position.

According to another aspect of the present invention, there is provided a laser radar apparatus for determining a wind speed by using the above-described airflow detecting method.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Embodiment 1 FIG. Hereinafter, Embodiment 1 according to the present invention will be described. FIG. 1 is a block diagram showing a configuration of a laser radar device according to an embodiment of the present invention. FIG.
FIG. 3 is a flowchart showing a processing procedure in the present laser radar device. Laser radar device 10 shown in FIG.
Is a laser transceiver 1 that irradiates a target with a laser beam and receives a scattered signal therefrom (here, a device having a single transmission / reception optical system), a microwave radar device 2, a signal processor 3 and a display 4. The operation of the present apparatus will be described later.

FIG. 2 shows the force (wind) acting on raindrops from outside.
Shows the relationship between and exercise. As shown in FIG.
Moves in the direction (the direction indicated by “motion vector of raindrop” in the figure) in which the drop motion due to gravity and the action of the wind are combined. In the movement of the raindrop by the action of the wind on a large scale, which is the movement of the atmosphere, the velocity component of the raindrop in the wind direction can be considered to be equal to the wind velocity. Therefore, if the vertical falling velocity component due to gravity is removed from the speed and direction of the raindrop detected by the laser radar device, the speed and direction of the wind can be obtained.

It is known that the vertical falling speed of rain is not constant at a constant speed, as it is known that the speed of vertical rain is large in heavy rain such as showers and low in small rain such as drizzle. It can be considered as follows. That is,
The raindrops grown by the condensation of water vapor begin to fall under the influence of gravity and are gradually accelerated. The upward resistance of the accelerated raindrop increases due to the air resistance, and the raindrop eventually falls at a speed at which the upward force and the downward force balance.

The speed at which particles fall at a constant speed is called the terminal speed, which is expressed by the following equation (Stokes' law). V = 2ρLIQr2g / 9η (3) where V is the terminal velocity, ρLIQ is the density of rain, r is the radius of the raindrop, g is the acceleration of gravity, and η is the viscosity coefficient of air. As shown in the above equation (3), the falling speed of the raindrop is proportional to the square of its radius, but the radius of the raindrop and other coefficients differ depending on the rainfall situation at each time.
The falling speed is not uniform either. Therefore, in the laser radar device according to the present embodiment, the falling speed of rain is detected by the microwave radar device 2 in FIG.

The microwave radar device 2 shown in FIG. 1 does not require a long-distance detection capability unlike a general large-sized radar device because the measurement target is rainfall. Therefore, the microwave radar device 2 itself can be realized as a low-power device.

In the present embodiment, the beam of the microwave radar device 2 is fixed vertically upward so that the observation target space (target volume) is
Position so that it is directly above. Thus, the speed information obtained from the microwave radar device 2 does not include a horizontal speed component. Therefore, assuming that the wind is blowing horizontally with respect to raindrops as shown in FIG. 2, the speed information obtained from the microwave radar device 2 indicates the vertical falling speed of rain. Can be.

However, the wind does not always blow only in the horizontal direction, but generally, as shown in FIG.
It has a vertical velocity component. Therefore, the speed simply detected by the above method includes an error. In order to reduce the measurement error, analysis of the altitude distribution of the measurement results (at a measurement point sufficiently close to the ground surface, the wind speed in the vertical direction is close to 0), averaging processing, or installation at an appropriate distance It is necessary to improve the measurement accuracy by analyzing the measurement results by a plurality of rain rate detectors.

Therefore, a method of obtaining wind speed information from which the influence of rain has been removed from the rainfall speed detected by the microwave radar device 2 and the reception signal obtained from the laser transceiver 1 by the above method. explain.

The following processing is performed in the signal processor 3 of the laser radar device 10 according to the present embodiment in order to obtain wind speed information from which the influence of rain has been removed.

Now, as shown in FIG.
The obtained raindrop velocity (for simplicity of explanation, the direction of movement of the raindrop is assumed to be straight toward the direction of the laser transceiver) is obtained from V1 and the microwave radar device 2 by the above-described method. The vertical drop velocity of the raindrop is V2, and the angle between the vertical drop and the beam is θ. In this case, the component V1cos θ indicated by the dotted line in the figure is an apparent falling speed component detected by the radar device 2, and therefore, the wind speed Vx can be calculated by the following equation.

Vx = {(V1 sin θ) 2+ (V1cosθ−V2) 2} = {(V12 + V22-2V1V2cosθ) (4)

As described above, the present laser radar device irradiates a laser beam from a laser transceiver toward a target and receives a scattered signal from the laser beam (step S in FIG. 13).
1). Then, after obtaining the motion vector of the raindrop (step S2), the vertical drop speed is detected (step S2).
3) An operation for removing the obtained velocity component from the received signal of the laser radar device is executed (step S4), thereby obtaining a wind speed from which the influence of rain has been removed.

That is, the raindrop has a motion that combines the velocity component under the influence of the wind and the vertical drop component under the influence of the gravity, and the motion of the raindrop cannot be the wind motion. And the wind speed Vx is obtained based on the wind speed information from which the influence of rain has been removed. In addition,
The result is visually displayed on the display 4 (step S
5).

The display form and expression method on the display 4 are not particularly limited here. Therefore, the obtained result is used, for example, as information for preparing an information sentence that can be transmitted to an air traffic controller, and the obtained raw information is used as ancillary information for the controller on the display 4. May be visually displayed.

As described above, according to the present embodiment, the scattered echo due to raindrops is measured during rainfall, focusing on the fact that the reflected echoes from raindrops are much stronger than the echoes reflected from aerosols during rainfall. The vertical drop velocity component of the raindrop at this time is removed from the reception signal of the laser radar device, thereby enabling observation of the wind in rainy weather.

In the laser radar device according to the first embodiment, the microwave radar device is used for detecting the vertical falling velocity component of rainfall. However, the present invention is not limited to this. For example, a sound wave radar device may be used. Is also good. That is, by using the acoustic wave radar, the measurement range can be widened, and there is an effect that the averaging process of the received signal in the measurement range can be performed.

Embodiment 2 Hereinafter, Embodiment 2 of the present invention will be described. FIG. 4 is a block diagram showing a configuration of the laser radar device according to the present embodiment. In the laser radar device 20 shown in FIG.
The same components as those of the laser radar device according to the first embodiment are denoted by the same reference numerals, and the description thereof will not be repeated.

In the laser radar device 20 shown in FIG. 4, a dual polarization radar device 5 is used instead of the microwave radar device 2 according to the first embodiment. As shown in FIG. 4, the dual-polarization radar device 5 is disposed obliquely below the observation target space, and performs measurement by switching between vertical polarization and horizontal polarization. Along with the measurement, the flatness of raindrops is measured.

Raindrops are generally not perfectly spherical, but are in the form of whiskers due to the air resistance of the grains. Therefore, the degree of flatness is known, and the falling velocity is estimated from the particle diameter of the raindrop and the air resistance. It is a known technique to know the flatness and the particle size of raindrops by switching between vertically polarized waves and horizontally polarized waves by using a dual-polarization radar, and a description thereof will be omitted here.

As described above, in the present embodiment, the measurement result of the rainfall speed based on the Doppler signal is corrected by knowing the flatness of the raindrop, and estimating the falling speed from the particle size and the air resistance. The wind speed Vx can be obtained more accurately based on the wind speed information from which the influence of the wind has been removed.

Embodiment 3 Hereinafter, a third embodiment according to the present invention will be described. FIG. 5 is a block diagram showing a configuration of the laser radar device according to the present embodiment. In the laser radar device 30 shown in the figure, the same components as those of the laser radar device according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted here.

Laser radar device 30 according to the present embodiment
As shown in FIG. 5, rainfall Doppler information from the weather Doppler radar device 6 of the airport meteorological observatory arranged obliquely below the observation target space is taken into the signal processor 3 via the interface device 7. I have.

FIG. 6 is a diagram showing the state of wake turbulence generated on the wake of an aircraft. As shown in the figure, the wake turbulence generated in the wake creates vortices 62 and 63 in opposite directions on the left and right main wings of the aircraft 61, respectively. The size of the vortex is
Depending on the size of the aircraft, for example, jumbo
Jets have a diameter of a few hundred meters and are said to last for a few minutes.

The meteorological Doppler radar device 6 cannot detect the wake turbulence even if the measurement is performed in the vicinity of the wake of the aircraft because the range resolution is not suitable for the wake turbulence detection. Since the motion of the wake turbulence is averaged within the above range, the Doppler data at the time of rainfall is based on the wind motion in the sky, which is not affected by the wake turbulence.

Here, the Doppler component of the scattered signal of the laser beam due to raindrops in the measurement target space is detected. The Doppler component is a signal in which the backscatter from the atmosphere is received by the laser receiver and the frequency component is shifted from the received signal. The above Doppler data is quantized information relating to wind, and is data sent as communication information from another device, for example, a Doppler radar device.

The data from the measurement volume obtained by the laser transceiver 1 of the laser radar device shown in FIG. 5 is obtained by synthesizing the motion of the wake turbulence and the flow of the air above the air (including the rainfall velocity). . For this reason, the signal processor 3 extracts only the motion component of the wake turbulence by removing the flow component of the air in the sky provided by the meteorological Doppler radar device 6 from the composite signal by arithmetic processing.

As described above, according to the present embodiment, the above-mentioned turbulence motion and the above-mentioned atmospheric air flow given by the meteorological Doppler radar device are obtained from the combined measurement data of the above-mentioned atmospheric air flow. By removing the component, only the motion component of the wake turbulence is extracted, and the characteristic wake turbulence motion can be captured even during rainfall.

Embodiment 4 Hereinafter, a fourth embodiment according to the present invention will be described. FIG. 7 is a block diagram showing a configuration of the laser radar device according to the present embodiment. In the laser radar device 40 shown in the figure, the same components as those of the laser radar device according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted here.

The laser radar device 40 shown in FIG. 7 is a laser transmitter / receiver 1 directly directed to the wake turbulence generating space.
(8) and a laser transceiver 2 directed to a space (space in which no wake turbulence occurs) slightly away from the measurement target space
(9) Two laser transceivers are provided. Of these laser transceivers, the laser transceiver 1 (8) measures the combined motion of the wake turbulence motion and the raindrop motion affected by the airflow above. Further, only the movement of the raindrop affected by the airflow in the sky is measured by the laser transceiver 2 (9) directed to the space where no turbulence is generated.

Then, in an arithmetic processing unit (not shown) in the signal processor 3, a difference between the signals obtained from the two laser transceivers is obtained, and only the motion component of the wake turbulence is extracted from the result.

As described above, according to the present embodiment, the signals from the wake turbulence generating space and the wake turbulence non-generating space are obtained by the two laser transceivers, and the turbulence of the wake turbulence is obtained based on the difference between them. The motion component can be extracted.

In the above-described fourth embodiment, an example of a laser radar device composed of two laser transceivers is shown. However, the function of the two laser transceivers is realized only by a single laser transceiver. May be configured. That is, one laser transceiver performs two-cycle beam scanning, performs measurement in the wake turbulence space in one cycle, and performs measurement in the non-wake turbulence space in the other cycle. The same effect as when using a machine can be obtained.

FIG. 8 shows another method for realizing the functions of two laser transceivers using only a single laser transceiver. That is, as shown in the figure, the transmission beam from the laser transceiver 1 is transmitted to the beam splitter 80.
And one is directly input to the beam expander 82a. The other beam is reflected by a mirror 81 and then input to a beam expander 82b.

With such a configuration, the beam expander 8
The beam 1 is output from the beam expander 2a, and the beam 2 is output from the beam expander 82b while keeping a certain distance in each measurement space. Then, the difference between the received signals obtained from the respective measurement spaces is calculated, and the motion component of the wake turbulence can be extracted as described above.

Embodiment 5 FIG. Hereinafter, a fifth embodiment according to the present invention will be described. FIG. 9 is a block diagram showing a configuration of the laser radar device according to the present embodiment. In the laser radar device 50 shown in the figure, the same components as those of the laser radar device according to the fourth embodiment shown in FIG. 7 are denoted by the same reference numerals, and the description thereof is omitted here.

The laser radar device 50 shown in FIG. 9 is a device for extracting the motion component of the wake turbulence, and the vortex of the wake turbulence has a diameter of about one hundred and several tens m.
Here, the range resolution of the laser transceiver 1 (8) is set to several tens of meters, and the range resolution of the laser transceiver 2 (9) is set to several hundred meters.

Since the wake turbulence generated by the aircraft makes a swirling motion within a limited range, the vector and intensity of the wind become zero on average within that range. As mentioned above,
Since the laser transceiver 2 (9) is set to have a sufficiently large range resolution with respect to the magnitude of the wake turbulence, the movement of the wake turbulence can be ignored for the received echo, and the obtained result is , Can be regarded as background airflow.

Then, the data received from the laser transceiver 2 (9) and the data containing the wake turbulence obtained by the laser transceiver 1 (8) are processed by an arithmetic processing (not shown) in the signal processor 3. The comparison processing is performed by the device, and based on the result, only the motion component of the wake turbulence is extracted. Here, the above-mentioned reception echo (Doppler echo) refers to a raw signal that is obtained by outputting a laser from a laser transmitter and receiving the backscatter from the atmosphere by the laser receiver.

As described above, according to the present embodiment, a difference is provided between the resolutions of the two laser transceivers, and for one of them, a sufficiently large range resolution is set with respect to the magnitude of the wake turbulence. Thus, by comparing the received data obtained from both, it is possible to extract only the motion component of the wake turbulence.

Although the fifth embodiment shows an example of a configuration using two laser transceivers having different range resolutions, the present invention is not limited to this. For example, a single laser transceiver may be used. A similar effect can be obtained by transmitting transmission pulses having two types of widths in a time-division manner, separating and comparing each echo.

Embodiment 6 FIG. Hereinafter, a sixth embodiment according to the present invention will be described. FIG. 10 is a block diagram showing a configuration of the laser radar device according to the present embodiment. In the laser radar device 60 shown in the figure, the same components as those of the laser radar device according to the fifth embodiment shown in FIG. 9 are denoted by the same reference numerals, and description thereof is omitted here.

[0059] Laser radar device 60 according to the present embodiment.
Then, as shown in FIG. 10, the laser transceiver 1 (8) and the laser transceiver 2 are located at positions symmetrical with respect to the measurement range.
(9) is arranged, and the beam scanning angles are synchronized with each other,
Measure the target volume. Specifically, the laser transceivers 1 and 2 as sensors are disposed at symmetrical positions with respect to the space where the wake turbulence (vortices 202 and 203 in opposite directions) generated in the wake of the aircraft 201 is generated. .

FIG. 14 is a diagram for explaining the position of observation of the wake turbulence in the apparatus according to the present embodiment, and the beam scanning method from the laser transceiver. The beam scanning method shown in FIG. 3 uses the vertical beam scanning in which the characteristics of the wake turbulence of the aircraft 201 are most easily captured as the basic scanning, and is called SRHI scanning.

That is, FIG. 14A shows a state in which the main beam scanning is viewed from the lateral direction. A beam is emitted from the laser transceiver 9 in a direction crossing the wake 90 of the aircraft 201. The measurement of the wake turbulence is performed in a predetermined measurement range, that is, the aircraft 20 indicated by hatching in FIG.
1 in the rear area 95. FIG. 14B shows this beam scanning viewed from directly above. The rear area 95, which is the measurement range, has a distance of 500 m in the horizontal direction around the wake 90. Within the range.

FIG. 11 and FIG. 12 are diagrams for explaining the direction of movement of the raindrop in the present embodiment. FIG.
When the raindrop has a horizontal velocity component, FIG.
Shows the difference between the signals received by the laser transceivers 1 and 2 when the raindrops only make vertical movements.

As shown in FIG. 11, when the raindrop has a horizontal motion component, the speed component V1 of the raindrop detected by the laser transceiver 1 and the speed component V2 of the raindrop detected by the laser transceiver 2 Have different sizes (|
V1 | ≠ | V2 |), the received signals of the respective laser transceivers are also different.

On the other hand, when the raindrop is falling only in the vertical direction, | V1 | = | V, as shown in FIG.
2 |, and the reception signals of the laser transceivers 1 and 2 become equal. Therefore, in the present embodiment, by utilizing the difference between the velocity components, the received signals of the respective laser transceivers are compared and processed by the arithmetic processing unit, thereby reducing the effect of rainfall and reducing the motion of the wake turbulence. Catch.

As described above, in the present embodiment, two laser transceivers are arranged at symmetrical positions with respect to the space where the wake turbulence is generated, and the respective received signals are compared.
By performing the processing, it is possible to capture a characteristic wake turbulence motion even during rainfall.

[0066]

As described above, according to the present invention,
The motion vector of the raindrop is obtained based on the received scattered signal,
By calculating the vertical drop speed from the reflection of the radiated radio wave and performing a vector operation on these motion vectors and the vertical drop speed, it becomes possible to observe the wind speed without being affected by raindrops in rainy weather.

Further, by using a microwave radar for the irradiation of the radio waves, the power consumption of the apparatus can be reduced. The microwave radar is a dual-polarization radar, and the second operation step switches the vertical polarization and the horizontal polarization of the dual-polarization radar to obtain a vertical drop velocity component of the raindrop, Furthermore, by applying the vertical drop velocity component of the raindrop to the raindrop particle size based on the flatness of the raindrop obtained by the polarization switching of the dual-polarization radar and the correction of the drop velocity estimated from the air resistance, The wind speed can be determined accurately.

Also, by using a sound wave radar for radiating radio waves, the measurement range can be widened, and the received signal in the measurement range can be averaged.

The weather Doppler radar emits radio waves of a predetermined wavelength to raindrops to obtain Doppler data for the raindrops, and calculates a Doppler component based on a scattered signal of laser light and a motion component of the wake turbulence from the Doppler data. Thus, a desired wind speed can be obtained based on the motion component of the wake turbulence.

According to another aspect of the invention, the first Doppler component of the laser light scattered signal by the raindrop in the space where the wake turbulence is generated and the second Doppler component of the laser light scattered signal by the raindrop in the space where no wake turbulence is generated By detecting the Doppler components of the above, and by comparing these Doppler components, it is possible to capture the characteristic wake turbulence motion even during rainfall.

According to another aspect of the present invention, the distance resolution of the laser transceiver for detecting the first Doppler echo is set to be higher than the distance resolution of the laser transceiver for detecting the second Doppler echo. By calculating the motion component of the wake turbulence from the first and second Doppler echoes of the laser light caused by the raindrops in the space where the turbulence occurs, the characteristic wake turbulence motion during rainfall can be captured.

Then, the laser transceiver for detecting the first Doppler echo and the laser transceiver for detecting the second Doppler echo are arranged at physically symmetric positions with a space for generating the wake turbulence interposed therebetween. Thus, the received signals can be compared and processed, and the characteristic wake turbulence motion can be captured even during rainfall.

According to another aspect of the present invention, in the laser radar device, by using the above-described airflow detection method, not only the wind speed can be observed in rainy weather, but also the characteristic rearward direction during rainfall. The motion of the turbulence can be captured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a laser radar device according to Embodiment 1 of the present invention.

FIG. 2 is a diagram illustrating a relationship between a force acting on a raindrop from the outside and a motion.

FIG. 3 is a diagram showing a relationship between a force acting externally on a raindrop and a movement.

FIG. 4 is a block diagram showing a configuration of a laser radar device according to a second embodiment.

FIG. 5 is a block diagram showing a configuration of a laser radar device according to a third embodiment.

FIG. 6 is a diagram illustrating a state of wake turbulence generated in a wake of an aircraft.

FIG. 7 is a block diagram showing a configuration of a laser radar device according to a fourth embodiment.

FIG. 8 shows Embodiment 4 using only a single laser transceiver.
FIG. 13 is a block diagram showing another configuration example for realizing the function according to FIG.

FIG. 9 is a block diagram showing a configuration of a laser radar device according to a fifth embodiment.

FIG. 10 is a block diagram showing a configuration of a laser radar device according to a sixth embodiment.

FIG. 11 is a diagram for explaining a moving direction of a raindrop according to the sixth embodiment.

FIG. 12 is a diagram for explaining a direction of movement of a raindrop according to a sixth embodiment.

FIG. 13 is a flowchart showing a processing procedure in the laser radar device according to the first embodiment.

FIG. 14 is a diagram showing a wake turbulence observation position in the device according to the sixth embodiment.

FIG. 15 is a block diagram showing a basic configuration of a conventional laser radar device.

[Explanation of symbols]

1, 8, 9 laser transceiver, 2 microwave radar device, 3 signal processor, 4 display device, 5 dual polarization radar device, 6 weather Doppler radar device, 7 interface device, 10 , 20, 30, 40, 50, 60: laser radar device, 21: raindrop, 61, 201: aircraft, 80
... beam splitters, 82a and 82b ... beam expanders,
90: track, 95: measurement range (rear area)

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-10-39022 (JP, A) JP-A-1-187479 (JP, A) JP-A-4-269685 (JP, A) JP-A-10-108 104255 (JP, A) JP-A-6-214024 (JP, A) JP-A-3-252586 (JP, A) JP-A-11-183615 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S ^7/ 00-17/88 G01W 1/00-1/18 G01P 5/00

Claims (10)

(57) [Claims] A step of irradiating the measurement target space with laser light; a step of receiving a scattered signal of the laser light due to raindrops in the measurement target space; and a step of irradiating the raindrop based on the received scattered signal. A first calculation step of obtaining a motion vector; a step of irradiating a radio wave of a predetermined wavelength to the raindrop upward from below vertically; a step of receiving a reflected wave of the radio wave from the raindrop; A second calculating step of calculating a vertical falling velocity component of the raindrop based on the reflected wave; and a third calculating step of calculating a wind velocity from a vector calculation of the motion vector and the vertical falling velocity component. Airflow detection method. 2. The airflow detection method according to claim 1, wherein a microwave radar is used for irradiating the radio wave. 3. The microwave radar is a dual-polarization radar, and in the second operation step, the vertical polarization and the horizontal polarization of the dual-polarization radar are switched, and the vertical drop velocity of the raindrop is changed. 3. The method according to claim 2, wherein a component is obtained. 4. The vertical drop velocity component of the raindrop is corrected for a raindrop particle diameter based on the flatness of the raindrop obtained by the polarization switching of the dual-polarization radar and a fall velocity estimated from air resistance. 4. The method according to claim 3, wherein
Airflow detection method as described. 5. The airflow detection method according to claim 1, wherein a sound wave radar is used for irradiating the radio wave. 6. A step of irradiating a laser beam to a measurement target space including a wake turbulence; a step of detecting a Doppler component of a scattered signal of the laser light due to raindrops in the measurement target space; Irradiating a radio wave of a predetermined wavelength to the raindrop; irradiating the radio wave to obtain Doppler data for the raindrop; and calculating a motion component of the wake turbulence from the Doppler component and the Doppler data. An airflow detection method comprising: obtaining a wind speed based on a motion component of the wake turbulence. 7. A first irradiation step of irradiating a laser beam onto a space where wake turbulence is generated, and a second irradiation irradiating laser light onto a space where no wake turbulence is generated at a predetermined distance from the space where the wake turbulence is generated. Detecting a first Doppler component of the scattered signal of the laser light due to the raindrops in the space where the wake turbulence is generated, and detecting the first Doppler component of the scattered signal of the laser light due to the raindrops in the space where the wake turbulence is not generated. Detecting two Doppler components; and from the first Doppler component and the second Doppler component,
Calculating a motion component of the wake turbulence; and calculating a wind speed based on the motion component of the wake turbulence. 8. A first and a second irradiation step of irradiating a laser beam to a wake turbulence generating space, and detecting first and second Doppler echoes of the laser light due to raindrops in the wake turbulence generating space. And calculating a motion component of the wake turbulence from the first Doppler echo and the second Doppler echo. The distance resolution of the laser transceiver according to the detection of the first Doppler echo is An airflow detecting method, wherein the wind speed is determined based on the motion component of the wake turbulence by setting the distance higher than the distance resolution of the laser transceiver for detecting the second Doppler echo. 9. A laser transceiver for detecting the first Doppler echo and a laser transceiver for detecting the second Doppler echo are located at physically symmetric positions with the wake turbulence generation space interposed therebetween. The airflow detection method according to claim 8, wherein: 10. A laser radar device, wherein a wind speed is obtained by using the airflow detection method according to claim 1.