JP2007170859A - Radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable measurement accuracy of wind speed vector to be improved, without having to install two or more radar systems, even in location where there is no uniformity of space. <P>SOLUTION: A radar system is provided with a beam-emitting section 2 for emitting a laser beam which is generated by a transmitting/receiving section 1, in the atmosphere, while changing the beam direction of the laser beam; and mirror reflectors 3a, 3b and 3c disposed in directions in which the laser beam is emitted by the beam emitting section 2, and for changing the beam direction of the laser beam into a direction in which an observation point 4 exists. The Doppler velocities of laser beams A', B' and C' reflected by the observation point 4 in different beam directions are analyzed, and the wind speed vector is calculated by combining two or more Doppler velocities. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radar apparatus that observes the wind speed and direction of an arbitrary observation point.

The conventional radar apparatus observes the wind speed by measuring the atmospheric Doppler velocity. In particular, in a laser radar that uses laser light as a transmission wave, aerosol in the atmosphere becomes a scatterer, and thus the wind velocity is observed by measuring the Doppler velocity of the aerosol.
It is the Doppler velocity that is directly measured by the radar apparatus, and the Doppler velocity is a visual line direction component of the wind velocity.
The wind has a wind direction component in addition to the wind speed, but if the same wind is measured from multiple line-of-sight directions, wind speed components in multiple line-of-sight directions can be obtained. Vector (wind speed, wind direction) can be obtained.

As one method for observing the same wind from a plurality of line-of-sight directions, it is conceivable that radar devices are arranged at mutually different positions and a plurality of radar devices measure the Doppler velocity of the aerosol.
However, in this case, it is necessary to secure a place for installing a plurality of radar devices, which is not suitable when the installation place is limited.

On the other hand, as a method of observing the same wind from a plurality of line-of-sight directions with a single radar apparatus, there is one that assumes the spatial uniformity of the wind (for example, see Non-Patent Document 1).
Although the actual wind spatial distribution is non-uniform, the radar apparatus disclosed in Non-Patent Document 1 includes the Doppler velocity in each beam direction by time averaging, so that it is included in the wind velocity in the line-of-sight direction. The wind speed vector is calculated by suppressing the spatial non-uniform component.
However, since the wind near the ground is affected by the ground structure and the spatial uniformity becomes low, the spatial nonuniformity may not be sufficiently suppressed only by the time average. Therefore, it may not be possible to use a wind speed measurement method that assumes spatial uniformity.

H. Sauvaget, “Radar Metalogy”, Arttech House, 1992, P210-212.

Since the conventional radar device is configured as described above, there is a problem that the measurement accuracy of the wind speed vector may be deteriorated in a place where the uniformity of the wind is disturbed by the influence of the topography or the ground structure. It was.
In addition, even when the wind is relatively spatially uniform, the measurement accuracy of the wind speed vector may deteriorate due to slight spatial non-uniformity. Need to be suppressed. For this reason, there is a problem that it is not possible to measure the wind speed vector with high time resolution.

  The present invention has been made to solve the above-described problems, and provides a radar device capable of improving the measurement accuracy of a wind speed vector without installing a plurality of radar devices even in a place where there is no spatial uniformity. The purpose is to obtain.

  The radar apparatus according to the present invention is installed in an electromagnetic wave radiating means for radiating the electromagnetic wave into the atmosphere while switching the beam direction of the electromagnetic wave generated by the electromagnetic wave generating means, and in the direction in which the electromagnetic wave is radiated by the electromagnetic wave radiating means. And a beam direction switching means for switching the beam direction of the electromagnetic wave to the direction in which the observation point exists, analyzing the Doppler velocity of the electromagnetic waves having different beam directions reflected by the observation point, and Are used to calculate the wind speed vector.

  According to this invention, the electromagnetic wave radiating means for radiating the electromagnetic wave into the atmosphere while switching the beam direction of the electromagnetic wave generated by the electromagnetic wave generating means, and the electromagnetic wave radiating means are installed in the direction in which the electromagnetic wave is radiated. A beam direction switching unit that switches the beam direction of the electromagnetic wave to the direction in which the observation point exists is provided, and the Doppler velocities of multiple electromagnetic waves with different beam directions reflected by the observation point are analyzed, and the multiple Doppler velocities are synthesized. Thus, the wind velocity vector is calculated, so that there is an effect that the measurement accuracy of the wind velocity vector can be improved without installing a plurality of radar devices even in a place where there is no spatial uniformity.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a radar apparatus according to Embodiment 1 of the present invention. In the figure, a transmission / reception unit 1 generates a laser beam as an electromagnetic wave and outputs the laser beam to a beam radiating unit 2. Reception processing such as frequency conversion processing and amplification processing is performed on the laser light received by the beam emitting unit 2 (laser light reflected by the observation point 4). In addition, the transmission / reception part 1 comprises the electromagnetic wave production | generation means.

The beam emitting unit 2 emits the laser beams A, B, and C into the atmosphere while switching the beam direction of the laser beam generated by the transmission / reception unit 1, while the laser beams A ′ and B reflected by the observation point 4. ', C' is received sequentially. In other words, the beam radiating unit 2 switches the direction of the laser beam generated by the transmitting / receiving unit 1 and sequentially reflects the laser beams A, B, C so that the laser beams A, B, C are focused on the observation point 4. The laser beams A ′, B ′, C ′ reflected by the observation point 4 are sequentially received via the reflecting mirrors 3a, 3b, 3c.
The beam radiating unit 2 constitutes electromagnetic wave radiating means and electromagnetic wave receiving means.

The reflecting mirrors 3a, 3b, and 3c are installed in the direction in which the laser beams A, B, and C are emitted by the beam emitting unit 2, and the reflecting mirrors 3a, 3b, and 3c are the laser beams A emitted from the beam emitting unit 2. , B, and C are reflected, and the beam directions of the laser beams A, B, and C are switched to the direction in which the observation point 4 exists. The reflecting mirrors 3a, 3b, 3c constitute beam direction switching means.
The signal processing unit 5 analyzes the Doppler velocities of the laser beams A ′, B ′, and C ′ after the reception processing by the transmission / reception unit 1, synthesizes a plurality of Doppler velocities, and calculates a wind speed vector. The signal processing unit 5 constitutes a wind speed vector calculating unit.

Next, the operation will be described.
The transmission / reception unit 1 generates laser light that is a continuous wave of a single frequency, and outputs the laser light to the beam emission unit 2.
When receiving the laser beam from the transmission / reception unit 1, the beam emitting unit 2 emits the laser beam A toward the reflecting mirror 3a.
The reflecting mirror 3 a reflects the laser beam A emitted from the beam emitting unit 2, but the mirror installation angle is adjusted so that the beam direction of the reflected laser beam A faces the observation point 4. .
The beam radiating unit 2 adjusts the focal length of the laser light A so that the laser light A is condensed at the observation point 4 when the laser light A is emitted.

When the beam radiating unit 2 emits the laser beam A toward the reflecting mirror 3a as described above, the laser beam B is transmitted to the reflecting mirror 3b within a time period (for example, within several seconds) in which the time change of the wind can be regarded as small. Radiates toward
The reflecting mirror 3 b reflects the laser beam B emitted from the beam emitting unit 2, but the mirror installation angle is adjusted so that the beam direction of the reflected laser beam B faces the observation point 4. .
The beam radiating unit 2 adjusts the focal length of the laser beam B so that the laser beam B is condensed at the observation point 4 when the laser beam B is emitted.

When the beam radiating unit 2 emits the laser beam B toward the reflecting mirror 3b as described above, the laser beam C is reflected within the reflecting mirror 3c within a time period (for example, within several seconds) in which the time change of the wind can be considered small. Radiates toward
The reflecting mirror 3 c reflects the laser light C emitted from the beam emitting unit 2, but the mirror installation angle is adjusted so that the beam direction of the reflected laser light C faces the observation point 4. .
The beam radiating unit 2 adjusts the focal length of the laser light C so that the laser light C is condensed at the observation point 4 when the laser light C is emitted.
Thereby, the laser beams A, B, and C reflected by the reflecting mirrors 3a, 3b, and 3c are condensed so as to intersect at one point of the observation point 4.

The laser beams A, B, and C collected at the observation point 4 are reflected at the observation point 4, and the laser beams A ′, B ′, and C ′ that are reflected waves at the observation point 4 are laser beams A, B, and C, respectively. It returns to the beam radiation part 2 by the reverse path | route.
That is, the laser beam A ′, which is a reflected wave at the observation point 4, is reflected by the reflecting mirror 3a and returns to the beam emitting unit 2, and the laser beam B ′, which is the reflected wave at the observation point 4, is reflected by the reflecting mirror 3b. Then, returning to the beam radiating unit 2, the laser beam C ′ that is a reflected wave at the observation point 4 is reflected by the reflecting mirror 3 c and returns to the beam radiating unit 2.
That is, since the laser beams A, B, and C emitted from the beam emitting unit 2 are collected at the observation point 4, the reflected wave from the aerosol (reflector) in the atmosphere existing near the observation point 4 is reflected. It comes to return to the beam radiation part 2 excellently.

The beam emitting unit 2 sequentially receives the laser beams A ′, B ′, and C ′ reflected by the observation point 4 and outputs the laser beams A ′, B ′, and C ′ to the transmitting / receiving unit 1 in order.
When the transmission / reception unit 1 receives the laser beams A ′, B ′, and C ′ from the beam emission unit 2, the transmission / reception unit 1 performs reception processing on the laser beams A ′, B ′, and C ′.
Specifically, in order to facilitate signal processing in the signal processing unit 5 at the subsequent stage, frequency conversion processing for converting the laser beams A ′, B ′, and C ′ into low-frequency signals, and amplification for increasing the signal intensity Implement processing.

When the signal processing unit 5 receives the laser beams A ′, B ′, and C ′ after receiving processing from the transmission / reception unit 1, the signal processing unit 5 analyzes the Doppler velocities of the laser beams A ′, B ′, and C ′ to obtain a plurality of Doppler velocities. To calculate the wind speed vector.
Specifically, it is as follows.

The signal processing unit 5 performs frequency analysis of the laser beams A ′, B ′, and C ′ because the frequencies of the received laser beams A ′, B ′, and C ′ are shifted by the Doppler effect. Then, the Doppler frequencies of the laser beams A ′, B ′, and C ′ are respectively calculated.
The frequency analysis of the laser beams A ′, B ′, and C ′ may be performed using, for example, Fourier transform, and the atmospheric Doppler spectrum can be calculated by performing Fourier transform on the received signal.
In the Doppler spectrum, a spectral peak is obtained with excellent signal intensity at the frequency point of the atmospheric Doppler frequency.
When this spectral peak is detected and the frequency of that peak is extracted, this peak frequency becomes the measured value of the Doppler frequency of the atmosphere.

When the signal processing unit 5 calculates the Doppler frequencies Fd of the laser beams A ′, B ′, and C ′, the laser beams A ′, B ′, and C ′ are calculated from the Doppler frequencies Fd of the laser beams A ′, B ′, and C ′. The Doppler speed Vd is calculated respectively.
Vd = λ · Fd / 2
Where λ is the wavelength of the laser beams A ′, B ′, and C ′.

When the signal processing unit 5 calculates the Doppler velocities Vd of the laser beams A ′, B ′, and C ′, respectively, by combining the Doppler velocities Vd, the wind speed that is the Doppler velocities of the atmosphere (the Doppler velocities after synthesis). A vector (a beam direction component of wind speed) is calculated.
Since the wind speed vector is defined in three dimensions, if there are Doppler velocities obtained by observing the observation point 4 from three independent directions, they can be calculated from those Doppler velocities. Here, the three independent directions mean that the beam directions parallel to each other are not included in the three beam directions.

In the example of FIG. 1, the Doppler velocity at the observation point 4 is measured from three independent directions using three reflecting mirrors 3 a, 3 b, and 3 c, but independent using four or more reflecting mirrors. The wind speed vector may be calculated by measuring the Doppler speed from four or more directions.
In this case, since there is redundancy in the measurement of the Doppler speed, for example, the wind speed vector is calculated by an optimization method such as a least square method.

In general, since the wind speed component in the vertical direction is smaller than the wind speed component in the horizontal direction, the wind speed in the vertical direction can often be regarded as almost zero.
In such a case, the horizontal wind speed may be obtained by measuring the Doppler speed from two independent directions using two reflecting mirrors.

In the example of FIG. 1, the installation angles of the reflecting mirrors 3a, 3b, and 3c are adjusted so that the laser beams A, B, and C intersect at the observation point 4, but the wind is spatially uniform. If the adjustment is made so that the laser beams A, B, and C pass through the range that can be considered, it is not always necessary that the three laser beams A, B, and C intersect at the observation point 4 accurately.
Further, the condensing points for each beam may be spatially shifted as long as the distance at which the laser beams A, B, and C are collected is within a range where the wind can be regarded as being spatially uniform.
In the example of FIG. 1, an example is shown in which observations from three independent directions are switched in terms of time, but three transmitters / receivers 1 may be prepared to measure the three directions simultaneously.

As is apparent from the above, according to the first embodiment, the beam radiation unit 2 that emits the laser light into the atmosphere while switching the beam direction of the laser light generated by the transmission / reception unit 1, and the beam radiation Reflecting mirrors 3a, 3b, and 3c that are installed in the direction in which the laser beam is emitted by the unit 2 and switch the beam direction of the laser beam to the direction in which the observation point 4 exists are reflected by the observation point 4 Since the Doppler velocities of the laser beams A ′, B ′, and C ′ having different beam directions are analyzed and a plurality of Doppler velocities are combined to calculate the wind velocity vector, a plurality of even in a place where there is no spatial uniformity There is an effect that the measurement accuracy of the wind speed vector can be improved without installing a radar device.
In addition, in order to ensure space uniformity, it is not necessary to perform a time averaging process, so that it is possible to measure a wind speed vector with high time resolution. Therefore, the radar apparatus according to the first embodiment is suitable for measuring, for example, a gust of wind.

Embodiment 2. FIG.
In the first embodiment, the laser beam generated by the transmission / reception unit 1 is collected at the observation point 4 to obtain the distance resolution, and the wind velocity vector at the observation point 4 is measured. Modulates the laser light and the beam radiating unit 2 emits a pulse signal that is the modulated laser light toward the reflecting mirrors 3a, 3b, and 3c to obtain distance resolution, and the wind velocity vector at the observation point 4 is obtained. You may make it measure.
Specifically, it is as follows.

When the beam radiating unit 2 emits the laser light pulse-modulated by the transmission / reception unit 1 into the atmosphere, the reflected wave of the laser light has a delay time proportional to the propagation distance to the observation point 4 where the laser light is reflected. Is received by the beam radiating unit 2.
Therefore, the measurement results obtained from the reflected waves of the laser light received at different timings by the beam radiating unit 2 correspond to the wind speed vectors at different distances.
That is, wind speed vectors at a plurality of points located at different distances from the beam radiating unit 2 are measured.
However, at a point far away from the observation point 4, the laser beam passage position is spatially separated, which may not satisfy the spatial uniformity. Therefore, even when wind speeds at a plurality of points are measured, the measurement is limited to points that are relatively close to the observation point 4.

FIG. 2 is an explanatory view showing an example of wind speed measurement of the radar apparatus according to Embodiment 2 of the present invention.
However, in FIG. 2, for simplification of description, the laser beam A and B (pulse-modulated laser beam) that emits two laser beams is shown. However, as in the first embodiment, three laser beams are used. A, B, and C may be emitted.
In the figure, reference numerals 11a, 12a, and 13a are observation points at which the wind velocity vector is measured by receiving the laser beam A reflected by the reflecting mirror 3a. The observation points 11a, 12a, and 13a are The distance is different from each other.
Further, 11b, 12b, and 13b are observation points at which the wind speed vector is measured by receiving the laser beam B reflected by the reflecting mirror 3b, and the observation points 11b, 12b, and 13b are distances from the beam emitting unit 2. Are different from each other.

Among these observation points 11a, 12a, 13a, 11b, 12b, and 13b, the observation point 12a and the observation point 12b exist at positions where the two laser beams A and B intersect, and the other observation points 11a, 13a, and 11b and 13b do not exist at the position where the two laser beams A and B intersect.
However, since the observation points 11a, 13a, 11b, and 13b exist at positions spatially close to the observation points 12a and 12b where the laser beams A and B intersect, the spatial uniformity of the wind is satisfied.
Therefore, the wind speed vector can be measured not only at the observation points 12a and 12b but also at the observation points 11a, 13a, 11b, and 13b.

According to the second embodiment, since laser light that has been pulse-modulated is radiated in order to obtain distance resolution, the beam condensing function with respect to the observation point 4 in the beam radiating unit 2 becomes unnecessary. can get.
Moreover, there exists an effect which can measure the wind speed vector of several observation point 11a, 12a, 13a, 11b, 12b, 13b.

  In the second embodiment, the transmission / reception unit 1 performs pulse modulation on the laser beam. However, the modulation method is not limited to pulse modulation as long as the distance resolution can be obtained. You may make it modulate a laser beam with other modulation systems, such as a pulse compression system.

Embodiment 3 FIG.
FIG. 3 is a block diagram showing a radar apparatus according to Embodiment 3 of the present invention. In the figure, the same reference numerals as those in FIG.
In the first embodiment, reflection mirrors 3a, 3b, and 3c are installed by the number of laser beams A, B, and C emitted from the beam irradiation unit 2 (the number of laser beams is N (N is a natural number of 2 or more)). In this case, it is shown that N reflectors are provided). However, as shown in FIG. 3, the number of laser beams A, B, and C emitted from the beam irradiation unit 2 is one less than the number of the laser beams. The reflecting mirrors 3a and 3b may be installed (if the number of laser beams is N (N is a natural number of 2 or more), N-1 reflecting mirrors are installed).

In this case, the laser beams A and B emitted from the beam irradiation unit 2 are emitted to the observation point 4 via the reflecting mirrors 3a and 3b, while the remaining laser beam C is directly observed from the beam emission unit 2 to the observation point. 4 to radiate.
However, since the propagation distance of the laser beam C from the beam radiating unit 2 to the observation point 4 is shorter than the propagation distance of the laser beams A and B from the beam radiating unit 2 to the observation point 4, the same as in the first embodiment. In addition, when the beam radiating unit 2 collects the laser beams A, B, and C at the observation point 4 by the beam condensing function, the focal length needs to be changed according to the beam direction.
On the other hand, as in the second embodiment, when the distance resolution is obtained by pulse-modulating the laser beams A, B, and C, the distance corresponds to the delay time of the reflected waves of the laser beams A, B, and C. Therefore, if the time for receiving and sampling the reflected waves of the laser beams A, B, and C is set for each beam direction, the wind velocity vector at the observation point 4 can be measured with all the laser beams A, B, and C. .

  According to the third embodiment, since the reflecting mirror 3c in one beam direction is not required, the space required for installing the reflecting mirror is reduced, and the effort required for installing and adjusting the reflecting mirror is reduced. It is done.

Embodiment 4 FIG.
4 is a block diagram showing a radar apparatus according to Embodiment 4 of the present invention. In the figure, the same reference numerals as those in FIG.
The beam shift detector 6 compares temporal variations in the Doppler velocities of the laser beams A ′, B ′, and C ′ analyzed by the signal processor 5, and the beam direction is the observation point 4 by referring to the comparison result. The laser beams A, B, and C deviated from the above are detected. The beam shift detector 6 constitutes a beam shift detector.

In the first embodiment, the orientations of the reflecting mirrors 3a, 3b, and 3c need to be set so that the laser beams A, B, and C emitted from the beam emitting unit 2 pass through the observation point 4.
However, if the direction of the reflecting mirrors 3a, 3b, 3c is shifted with time (for example, when an earthquake or the like occurs, the direction of the reflecting mirrors 3a, 3b, 3c may be shifted), the laser beams A, B , C pass through a position distant from the observation point 4, so that the measurement accuracy of the wind speed vector is deteriorated.
Therefore, in the fourth embodiment, the beam shift caused by the shift in the direction of the reflecting mirrors 3a, 3b, 3c is automatically detected.
Specifically, it is as follows. FIG. 5 is a flowchart showing the processing contents of the radar apparatus according to Embodiment 4 of the present invention.

When the signal processing unit 5 calculates the Doppler speeds of the laser beams A ′, B ′, and C ′ in the same manner as in the first to third embodiments, the beam deviation detection unit 6 outputs the laser beam A ′ from the signal processing unit 5. , B ′ and C ′ are input for a plurality of times.
Then, the beam shift detector 6 selects any two laser beams from the laser beams A ′, B ′, and C ′ (step ST1). Here, for convenience of explanation, it is assumed that the laser beams A ′ and B ′ are selected.
When the beam deviation detector 6 selects two arbitrary laser beams A ′ and B ′, the beam shift detector 6 calculates a cross-correlation coefficient between the Doppler velocity of the laser beam A ′ and the Doppler velocity of the laser beam B ′ (step ST2). .
K = ΣV _{1, i} × V _{2, i} / (ΣV _{1, i} ² × ΣV _{2, i} ² ) ^1/2
Here, K is a cross-correlation coefficient, V _{1, i} is the Doppler velocity of the i-th observed laser beam A ′, and V _{2, i} is the Doppler velocity of the i-th observed laser beam B ′.
Further, Σ is a symbol that means the Doppler speed from i = 1 to N or the sum of squares of the Doppler speed. N is the number of data of each Doppler speed.

Here, Doppler velocities having different beam directions are obtained by projecting the same wind in different directions, and both have different values. However, when the wind speed is high, the projection component in any direction increases, and conversely, when the wind speed is low, the projection component in any direction also decreases. Even in the beam direction, the same characteristics are obtained.
Therefore, when the time variation patterns of the two Doppler velocities are similar, it can be considered that the two Doppler velocities are measured at the same spatial position. Conversely, if the time variation patterns of the two Doppler velocities are not similar, it can be considered that the two Doppler velocities are measured at different spatial positions. For this reason, when the similarity of the time variation pattern is low, the occurrence of the beam shift can be recognized.

When the beam shift detector 6 selects the laser beams A ′ and B ′ and calculates the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′ as described above, the laser beam A ′. , B ′, and C ′, a combination other than the laser beams A ′ and B ′ is also selected, and similarly, a cross-correlation coefficient K related to the Doppler velocity is calculated (step ST3).
That is, the laser beams B ′ and C ′ are selected, the cross-correlation coefficient K related to the Doppler velocity of the laser beams B ′ and C ′ is calculated, and the laser beams C ′ and A ′ are selected and the laser The cross-correlation coefficient K of the Doppler velocity related to the lights C ′ and A ′ is calculated.

  When the beam shift detection unit 6 calculates the cross-correlation coefficients K of the Doppler velocities of the respective combinations as described above, the beam shift detection unit 6 compares these cross-correlation coefficients K with a preset threshold value, and compares these cross-correlation relationships. If there is a cross-correlation coefficient K that is smaller than a preset threshold in the number K (step ST4), the presence of the laser beam whose beam direction is deviated from the observation point 4 is recognized, and the occurrence of beam deviation is detected. In order to notify the user, for example, processing such as turning on the lamp of the radar device is performed (step ST5). Further, when the wind speed vector is automatically recorded, a flag indicating that there is a possibility of beam deviation may be written.

Here, the beam deviation detection unit 6 has been shown to recognize the presence of laser light whose beam direction is deviated from the observation point 4. However, as shown below, the beam deviation detection unit 6 generates a beam deviation. The laser beam may be detected.
For example, when the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′ and the cross-correlation coefficient K of the Doppler velocities related to the laser beams C ′ and A ′ are smaller than the threshold value, the mutual correlation between both. A beam shift of the laser beam A related to the number K is detected.
Further, when the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′ and the cross-correlation coefficient K of the Doppler velocities related to the laser beams B ′ and C ′ are smaller than the threshold value, the mutual correlation between both. A beam shift of the laser beam B related to the number K is detected.
Further, when the cross-correlation coefficient K related to the Doppler velocities of the laser beams B ′ and C ′ and the cross-correlation coefficient K of the Doppler velocities related to the laser beams C ′ and A ′ are smaller than the threshold value, the mutual correlation between both. A beam shift of the laser beam C related to the number K is detected.

  As is apparent from the above, according to the fourth embodiment, the temporal variations in the Doppler velocities of the laser beams A ′, B ′, and C ′ analyzed by the signal processing unit 5 are compared with each other, and the comparison result is obtained. Referring to the configuration, the laser beams A, B, and C whose beam directions are deviated from the observation point 4 are detected, so that the user can eliminate the beam deviation and improve the measurement accuracy of the wind speed vector. There is an effect.

In the fourth embodiment, the calculation of the cross-correlation coefficient is shown as the similarity of the temporal variation of the two Doppler velocities, but the temporal variation of the two Doppler velocities is emphasized in order to emphasize the temporal variation component. You may make it calculate the cross correlation coefficient in a component.
That is, the beam shift detection unit 6 calculates the average value (component that does not vary in time) of the laser beams A ′, B ′, and C ′, and calculates the Doppler velocity of the laser beams A ′, B ′, and C ′. The average values of the Doppler velocities of the laser beams A ′, B ′, and C ′ are respectively subtracted.
A ″ = Doppler velocity of laser beam A′−Average value of Doppler velocity of laser beam A ′ B ″ = Doppler velocity of laser beam B′−Average value of Doppler velocity of laser beam B ′ C ″ = Laser beam C ′ Doppler speed—average value of Doppler speed of laser light C ′ Then, the beam shift detector 6 detects the cross-correlation coefficient K related to the subtracted Doppler speeds A ″ and B ″, and the subtracted Doppler speeds B ″ and C ″. And the cross-correlation coefficient K related to the subtracted Doppler velocities C ″ and A ″.

  In the fourth embodiment, the beam shift detector 6 calculates the cross-correlation coefficient. However, the cross-correlation coefficient is not limited to the cross-correlation coefficient as long as it represents the degree of temporal variation. An amount other than the number of relationships may be calculated as the evaluation value.

Embodiment 5 FIG.
6 is a block diagram showing a radar apparatus according to Embodiment 5 of the present invention. In the figure, the same reference numerals as those in FIG.
When the beam deviation detecting unit 6 detects the laser beam whose beam direction is deviated from the observation point 4, the reflecting mirror control unit 7 controls the reflecting mirror adjusting units 8a, 8b, and 8c, and the beam direction of the laser beam. Adjust.
The reflecting mirror adjusting units 8a, 8b, and 8c are configured by a gantry capable of changing two axes (reflecting mirror axes) of the azimuth angle and the elevation angle of the mirror surface normal in the reflecting mirrors 3a, 3b, and 3c. Under the instruction of the unit 7, the beam direction of the laser beam whose beam direction is deviated from the observation point 4 is adjusted.
The reflecting mirror control unit 7 and the reflecting mirror adjusting units 8a, 8b, and 8c constitute beam direction adjusting means.
FIG. 7 is a flowchart showing the processing contents of the radar apparatus according to Embodiment 5 of the present invention.

Next, the operation will be described.
When the beam deviation detection unit 6 detects the laser beam whose beam direction is deviated from the observation point 4 in the same manner as in the fourth embodiment, the reflection mirror control unit 7 controls the reflection mirror adjustment units 8a, 8b, and 8c. Control the beam direction of the laser light.
Specifically, it is as follows.

  The reflector control unit 7 specifies the lowest cross-correlation coefficient K among the cross-correlation coefficients K calculated by the beam shift detection unit 6, and determines the combination of laser beams related to the cross-correlation coefficient K. Extract (step ST11). Here, for convenience of explanation, it is assumed that the cross-correlation coefficient K related to the Doppler velocity of the laser beams A ′ and B ′ is the lowest and the combination of the laser beams A ′ and B ′ is extracted.

When the combination of the laser beams A ′ and B ′ is extracted, the reflector control unit 7 calculates an average value of the cross-correlation coefficient K with the other laser beams for the laser beam A ′ (step ST12).
In the example of FIG. 6, since the laser beams B ′ and C ′ exist in addition to the laser beam A ′, the cross-correlation coefficient K related to the Doppler velocity of the laser beams A ′ and B ′ and the laser beam C The average value of the cross-correlation coefficient related to the Doppler velocity of “, A” is calculated.

Next, the reflecting mirror control unit 7 calculates the average value of the cross-correlation coefficient K with the other laser light for the laser light B ′ (step ST13).
In the example of FIG. 6, since the laser beams C ′ and A ′ exist in addition to the laser beam B ′, the cross-correlation coefficient K related to the Doppler velocity of the laser beams A ′ and B ′ and the laser beam B The average value with the cross-correlation coefficient relating to the Doppler velocity of ', C' is calculated.

The reflecting mirror control unit 7 compares the average value of the cross-correlation coefficient K for the laser beam A ′ with the average value of the cross-correlation coefficient K for the laser beam B ′, and the laser beam having the smaller average value. Is selected (step ST14).
For example, when the laser beam A ′ is selected, the reflecting mirror control unit 7 controls the reflecting mirror adjusting unit 8a to change the direction of the reflecting mirror 3a so that the cross-correlation coefficient K for the laser beam A ′ increases. Adjust (step ST15).
When the laser beam B ′ is selected, the reflecting mirror adjusting unit 8b is controlled to adjust the direction of the reflecting mirror 3b so that the cross-correlation coefficient K for the laser beam B ′ is increased (step ST15).

Specifically, the direction of the reflecting mirror is adjusted as follows.
The direction of the reflecting mirror is defined by a normal vector of the reflecting surface, and the normal vector can be expressed in two dimensions, for example, an elevation angle and an azimuth angle. Therefore, the correction of the direction of the reflecting mirror can be adjusted by two axes (for example, an elevation angle and an azimuth angle). Here, the description will be made assuming that the axis of the reflecting mirror is adjusted by the two axes of the reflecting mirror axis (1) and the reflecting mirror axis (2).

For example, when adjusting the direction of the reflecting mirror 3a that reflects the laser beam A, the reflecting mirror adjusting unit 8a corrects the reflecting mirror axis (1) of the reflecting mirror 3a in the positive direction under the instruction of the reflecting mirror control unit 7. The beam shift detector 6 measures the Doppler velocities of the laser beams A ′ and B ′ a plurality of times, and calculates the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′.
The reflector control unit 7 determines that the beam correction direction is appropriate if the cross-correlation coefficient K related to the Doppler velocity of the laser beams A ′ and B ′ is larger than that before the correction of the beam direction. Maintain beam direction correction in this direction.
Conversely, if the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′ is smaller than that before the correction of the beam direction, it is determined that the beam correction direction is reverse, and the beam correction direction. Is changed to the opposite direction (the beam correction direction is changed to the negative direction of the reflector axis (1)).

Next, the reflecting mirror adjusting unit 8a corrects the reflecting mirror axis (2) of the reflecting mirror 3a in the positive direction under the instruction of the reflecting mirror control unit 7, and the beam deviation detecting unit 6 detects the laser beams A ′ and B ′. Are measured a plurality of times, and a cross-correlation coefficient K related to the Doppler speeds of the laser beams A ′ and B ′ is calculated.
The reflector control unit 7 determines that the beam correction direction is appropriate if the cross-correlation coefficient K related to the Doppler velocity of the laser beams A ′ and B ′ is larger than that before the correction of the beam direction. Maintain beam direction correction in this direction.
Conversely, if the cross-correlation coefficient K related to the Doppler velocities of the laser beams A ′ and B ′ is smaller than that before the correction of the beam direction, it is determined that the beam correction direction is reverse, and the beam correction direction. Is changed in the opposite direction (the beam correction direction is changed in the negative direction of the reflector axis (2)).

  The reflecting mirror adjustment unit 8a repeats the beam direction correction of the reflecting mirror axis (1) and the reflecting mirror axis (2) alternately under the instruction of the reflecting mirror control unit 7, and the cross-correlation coefficient K becomes sufficiently large. Or until the cross-correlation coefficient K does not change.

  As apparent from the above, according to the fifth embodiment, when the laser beam whose beam direction is deviated from the observation point 4 is detected by the beam deviation detecting unit 6, the reflecting mirror adjusting units 8a, 8b, and 8c are operated. Since it is configured to control and adjust the beam direction of the laser beam, even if a beam deviation occurs, the beam deviation is automatically eliminated, and the measurement accuracy of the wind speed vector can be improved. .

  In the fifth embodiment, only the beam direction of one laser beam is adjusted. However, when there are a plurality of laser beams whose beam shifts are detected by the beam shift detector 6, a plurality of laser beams are detected. Adjust the beam direction.

  In the first to fifth embodiments described above, the radar apparatus using laser light as the transmission wave has been described. However, the radar apparatus may use radio waves as the transmission wave, and similar effects can be obtained.

It is a block diagram which shows the radar apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the example of a wind speed measurement of the radar apparatus by Embodiment 2 of this invention. It is a block diagram which shows the radar apparatus by Embodiment 3 of this invention. It is a block diagram which shows the radar apparatus by Embodiment 4 of this invention. It is a flowchart which shows the processing content of the radar apparatus by Embodiment 4 of this invention. It is a block diagram which shows the radar apparatus by Embodiment 5 of this invention. It is a flowchart which shows the processing content of the radar apparatus by Embodiment 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transmission / reception part (electromagnetic wave production | generation means), 2 Beam emission part (electromagnetic wave emission means, electromagnetic wave reception means), 3a, 3b, 3c Reflective mirror (beam direction switching means), 4 observation points, 5 Signal processing part (wind velocity vector calculation means) ), 6 Beam deviation detector (beam deviation detector), 7 Reflector controller (beam direction adjuster), 8a, 8b, 8c Reflector adjuster (beam direction adjuster).

Claims (9)

  An electromagnetic wave generating means for generating an electromagnetic wave, an electromagnetic wave emitting means for radiating the electromagnetic wave into the atmosphere while switching a beam direction of the electromagnetic wave generated by the electromagnetic wave generating means, and a direction in which the electromagnetic wave is emitted by the electromagnetic wave emitting means. A beam direction switching unit that is installed and switches the beam direction of the electromagnetic wave to a direction in which the observation point exists, an electromagnetic wave reception unit that receives a plurality of electromagnetic waves having different beam directions reflected by the observation point, and the electromagnetic wave reception A radar apparatus comprising: a wind speed vector calculating means for analyzing a Doppler speed of a plurality of electromagnetic waves received by the means and calculating a wind speed vector by combining the plurality of Doppler speeds.   2. The radar apparatus according to claim 1, wherein the electromagnetic wave radiating means has a condensing function for condensing the electromagnetic wave radiated into the atmosphere at an observation point.   2. The radar apparatus according to claim 1, wherein the electromagnetic wave generating means modulates the electromagnetic wave by a modulation method capable of obtaining a distance resolution, and outputs the modulated electromagnetic wave to the electromagnetic wave radiating means.   When the number of beam directions switched by the electromagnetic wave radiating means is N, N beam direction switching means are installed, and the electromagnetic waves radiated from the electromagnetic wave radiating means are reflected by the N beam direction switching means and observed. The radar device according to any one of claims 1 to 3, wherein the radar device is radiated to a point.   When the number of beam directions switched by the electromagnetic wave radiating means is N, N-1 beam direction switching means are installed, and the electromagnetic waves radiated from the electromagnetic wave radiating means are transmitted to the N-1 beam direction switching means. The radar according to any one of claims 1 to 3, wherein the electromagnetic wave radiated from the electromagnetic wave radiation means is directly radiated to the observation point while being reflected and radiated to the observation point. apparatus.   A beam deviation detection means is provided for detecting electromagnetic waves whose beam direction is deviated from the observation point by comparing the time fluctuations in the Doppler velocities of a plurality of electromagnetic waves analyzed by the wind speed vector calculation means and referring to the comparison result. The radar device according to any one of claims 1 to 5, wherein   The beam shift detection means calculates the cross-correlation coefficient at the Doppler velocity of multiple electromagnetic waves, and if the cross-correlation coefficient is smaller than a preset threshold, the presence of the electromagnetic wave whose beam direction is shifted from the observation point is recognized. The radar apparatus according to claim 6.   The beam shift detection means calculates a cross-correlation coefficient in the fluctuation component of the Doppler velocity of a plurality of electromagnetic waves, and if the cross-correlation coefficient is smaller than a preset threshold, the beam direction is shifted from the observation point. 7. The radar apparatus according to claim 6, wherein existence is recognized. 7. A beam direction adjusting means for adjusting a beam direction of the electromagnetic wave switched by the beam direction switching means when an electromagnetic wave whose beam direction is deviated from the observation point is detected by the beam deviation detecting means. The radar apparatus described.

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