JP2004037474A - Laser radar device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a more downsized laser radar device having a function for measuring visibility distance near a corresponding device in addition to a function for measuring a distance to a target. <P>SOLUTION: The device comprises a scanning means for scanning a laser beam, a photodetector for detecting the reflected light of the laser beam to convert to a received signal, a calculation circuit for atmosphere attenuation for calculating the atmosphere attenuation based on the reflected light of the laser beam reflected from a reference target, an integration-processing circuit for integration-processing by the number of integration-processing times corresponding to the calculated atmospheric attenuation, an azimuth/distance-measuring circuit for measuring the distance to the target from data after integration-processing the reflected light of the laser beam reflected by the target and the scanning angle of the laser beam, and a conversion circuit for determining the visibility distance from the atmospheric attenuation by the reflected light of the laser beam, which is calculated by the scanning angle of the laser beam scanned by the target and a calculation means for the atmospheric attenuation, and a conversion table. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a laser radar device that suppresses the influence of noise under rainfall conditions and prevents the detection performance of a target from deteriorating.

In recent years, laser radar devices that detect a target using a laser have been actively researched. For example, Japanese Patent Laid-Open No. 50-137762 discloses that two types of beams having different divergence angles are used. A laser radar device that changes the divergence angle of a laser beam by focusing on capturing a target is described. Further, Japanese Patent Application Laid-Open No. 1-280272 discloses a weather radar that further considers an attenuation rate of a beam light in the atmosphere. A laser radar is described in which a laser beam angle of a laser beam is determined according to an atmospheric attenuation rate of a light beam that changes depending on conditions.

Further, according to the laser radar device described in Japanese Patent Application Laid-Open No. 1-280272, a constant detection distance is always obtained even if the attenuation rate of laser light in the atmosphere fluctuates, and laser radar detection due to changes in weather conditions. It states that the performance can be prevented from deteriorating.

Japanese Patent Laid-Open Publication No. Sho 50-137762 (Pages 1 to 2; FIGS. 1 to 2)

JP-A-1-280272 (Pages 3-7, FIGS. 1, 4 and 10 etc.)

However, since the conventional laser radar device is configured as described above, in any case, there is a problem that a variable mechanism of a laser beam angle is required, and it is difficult to reduce the size of the device configuration. . For example, in a laser radar device to be mounted on an aircraft or the like, the mounting range is greatly limited, and thus there is a strong demand for downsizing.

The present invention has been made in order to solve the above-described problems, and can suppress the influence of noise even when weather conditions change, thereby maintaining the target object detection performance at a certain level or more, and It is another object of the present invention to obtain a laser radar device having a novel configuration which does not require a laser beam angle changing mechanism and is suitable for miniaturization.

A laser radar device according to the present invention includes a laser light source, scanning means for scanning a laser beam of laser light generated by the laser light source, and a reflected signal of the laser beam scanned by the scanning means for detecting a received signal. A photodetector for converting to a reference target, an atmospheric attenuation rate calculating circuit for calculating an atmospheric attenuation rate from a reception signal by a reflected light of the laser beam reflected from the reference target and output from the photodetector, and the calculated atmospheric attenuation rate An integration number instruction circuit for instructing the number of integration processing times corresponding to (i), and a reception signal by the reflected light of the laser beam reflected from the target object and output from the photodetector at the integration processing number instruction from the integration number instruction circuit. An integration processing circuit for performing integration processing, a distance from the data after the integration processing and a scanning angle of the laser beam detected by the scanning unit to the target object; The azimuth / distance measuring circuit to be measured, and the scanning angle of the laser beam scanned on the target and the atmospheric attenuation rate and the atmospheric attenuation rate by the reflected light of the laser beam calculated by the atmospheric attenuation rate calculating means, which are the visibility distance or And a conversion circuit for obtaining the visibility distance or the rainfall from the conversion table for converting the rainfall.

According to another aspect of the present invention, there is provided a laser radar device, comprising: a laser light source; a scanning unit that scans a laser beam of a laser beam generated by the laser light source; and a reflected light of the laser beam scanned by the scanning unit. A photodetector that converts the received light into a received signal; an atmospheric attenuation rate calculation circuit that calculates an atmospheric attenuation rate from a received signal that is reflected by a laser beam reflected from a reference target and output from the photodetector; An integration number instruction circuit for instructing the number of integration processes corresponding to the atmospheric attenuation rate, and a reception signal by the reflected light of the laser beam reflected from the target object and output from the photodetector, from the integration number instruction circuit. An integration circuit for performing integration by the number of integration processes, a change amount of a frequency of data after the integration process, and a scanning angle of the laser beam detected by the scanning unit; An azimuth / wind speed measurement circuit for measuring the wind speed of the azimuth of the target object from the target, and the atmospheric attenuation by the reflected light of the laser beam calculated by the scanning angle of the laser beam scanned on the target object and the atmospheric decay rate calculating means. A conversion circuit for obtaining the visibility distance or the rainfall from a conversion table for converting the rate and the atmospheric attenuation rate into the visibility distance or the rainfall is provided.

As described above, according to the present invention, conversion for determining a visibility distance or rainfall from the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculating means, the scanning angle of the laser beam detected by the scanning means, and the conversion table. Since the circuit is provided, in addition to the function of measuring the distance from the laser radar device to the target, a more compact laser radar having a function of measuring either the visibility distance or the rainfall near the laser radar device. A device can be obtained.

Further, according to another invention, in addition to the function of measuring the wind speed in the direction of the target from the laser radar device, a smaller size having a function of measuring either the visibility distance or the rainfall near the laser radar device is further combined. Thus, a laser radar device having a simplified structure can be obtained.

The conversion circuit according to the present invention is configured to convert the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculating means, the scanning angle of the laser beam detected by the scanning means, and the atmospheric attenuation rate into a visibility distance or a rainfall amount from a conversion table. Find rainfall.

Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a laser radar device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a laser light source for a laser beam, 2 denotes a beam splitter, 3 denotes a scanning mirror that scans the transmission direction of the laser beam, and 4 denotes reflected light from a target guided by the beam splitter 2 to an electric signal. A photodetector 5 for converting and outputting as a received signal is an azimuth / distance measuring circuit for measuring the azimuth or distance of the target based on the output of the photodetector 4 and the scanning angle of the scanning mirror 3.

Reference numeral 6 denotes a transmission laser beam (hereinafter, simply referred to as a laser beam) scanned by the scanning mirror 3, reference numeral 7 denotes reflected light of the laser beam 6 reflected by a target or the like, and reference numeral 8 denotes reflected light reflected by a reference target. An atmospheric attenuation rate calculating circuit, which is an atmospheric attenuation rate calculating means for calculating an atmospheric attenuation rate in the atmosphere by the following, gives an instruction to an integration processing circuit to be described later based on the atmospheric attenuation rate in the atmosphere calculated by the atmospheric attenuation rate calculating circuit. The integration number instruction circuit 10 for calculating the number of integration processes is an integration processing circuit for integrating the received signal output from the photodetector circuit 4 with the integration number specified by the integration number instruction circuit 9. Note that the atmospheric attenuation rate calculation circuit 8 and the integration number instruction circuit 9 may be configured as a single circuit like a visibility integration number instruction circuit described later.

Next, the operation will be described. The laser light generated by the laser light source 1 is output to the scanning mirror 3 via the beam splitter 2, and the scanning mirror 3 scans the scanning area as a laser beam 6. In the laser radar device according to the present embodiment, first, the laser beam 6 is transmitted in the direction of the reference target, and the reflected light 7 from the reference target is transmitted to the photodetector 4 via the scanning mirror 3 and the beam splitter 2. To detect. The photodetector 4 converts the reflected light from the reference target into an electric signal and outputs it as a received signal to the atmospheric attenuation rate calculation circuit 8 and the integration circuit 10, respectively.

The atmospheric attenuation rate calculation circuit 8 detects that the laser beam 6 is being scanned with respect to the reference target from the scanning azimuth signal instructed to the scanning mirror 3 by the azimuth / distance measurement circuit 5 and transmits the laser beam 6 to the reference target. The atmospheric attenuation rate in the atmosphere is calculated from the reflected light of the laser beam 6 thus obtained.
This atmospheric attenuation rate can be obtained from the following laser radar equation (1). In the laser radar equation (1), Pr is the intensity of the signal received by the laser radar, P ₀ is the laser output, K is the efficiency of the optical system, Ar is the effective area of the receiving optical system, Y is the geometric efficiency, T Indicates the atmospheric attenuation rate, S ₀ indicates the target scattering coefficient, and R indicates the distance to the target.

Further, from the laser radar equation (1), the atmospheric attenuation rate is calculated by the following equation (2). Note that P ₀ , K, Ar, Y, S _0, and R are constant even when weather conditions such as rainfall change.

The integration number instructing circuit 9 receives the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculating circuit 8, and compares the input atmospheric attenuation rate with the atmospheric attenuation rate when the weather is fine to give the integration processing circuit 10. The instructed integration processing count is calculated. Then, the integration processing circuit 10 is instructed by the integration processing number calculated by the integration number designating circuit 9, and thereafter performs integration processing on the reflected light reflected from the target object according to the instructed integration processing number. .

Specifically, as described above, if the number of integration processes corresponding to the atmospheric attenuation rate in the atmosphere calculated from the reflected light from the reference target is ten, the integration processing circuit 10 determines the reflected light reflected from the target. That is, the received signal converted by the photodetector 4 is integrated 10 times and output to the azimuth / distance measuring circuit.

The azimuth / distance measurement circuit 5 generates a scanning azimuth signal and detects the angle of the target based on the scanning angle. The detected angle of the target and the integration processing output from the integration processing circuit 10 are performed. And the distance from the laser radar device to the target.

効果 Here, the effect of the integration process will be described. When the atmospheric attenuation of the laser light increases due to rainfall or the like, the ratio of the noise included in the received signal from the target to the received signal from the other than the target decreases. Therefore, when the above-described integration processing is performed, noise included in the received signal is suppressed in accordance with the number of times of integration, and the noise ratio included in the received signal from the target and the received signal from a signal other than the target is reduced. It is greatly improved.

For example, if the number of integration processes is M, noise noise included in a received signal is suppressed to 1 / √M, and it becomes relatively easy to detect a target from a received signal having much noise such as rainfall.

FIG. 2 is an explanatory diagram of the operation of the laser radar device according to the present embodiment. In the operation of the present device, first, the laser beam 6 is transmitted to the reference target 11 and the number of times of integration processing instructed to the integration processing circuit 10 is determined. calculate. After the number of integration processes is determined, the laser beam 6 is transmitted to the desired target, and the integration process is performed based on the calculated number of integration processes to measure the distance to the target.

If the weather condition in the direction of the desired target is different, for example, if the rainfall condition is different from the weather condition in the direction of the reference target, the atmospheric attenuation rate in the atmosphere will be different. It is desirable to select a building or the like under the same weather conditions as the direction of the target to be performed.

As described above, according to the laser radar device of the first embodiment, the noise included in the received signal can be suppressed by integrating the received signal from the target with the integration number according to the weather condition. Thus, the target object detection performance can be maintained at a certain level or more without adjusting the laser beam angle of the laser beam.

The atmospheric attenuation rate calculation circuit 8, the integration number instruction circuit 9, and the integration processing circuit 10 can be configured and processed by using a terminal device such as a personal computer or a workstation, so that they are mounted on an aircraft or the like. A laser radar device suitable for miniaturization can be easily obtained.

Next, a second embodiment of the present invention will be described. The laser radar device according to the first embodiment obtains the required number of integration processes from the atmospheric attenuation rate calculated from the reflected light from the reference target and performs the integration process based on the number of integration processes to thereby perform the integration process from the laser radar device to the target. Although the distance was measured, the atmospheric attenuation rate may be calculated using visibility information from a visibility sensor, and the laser radar device according to the present embodiment requires the atmospheric attenuation rate based on the visibility information based on the visibility information. The number of integration processes is determined, and the integration process is performed based on the number of integration processes.

FIG. 3 is a block diagram showing a laser radar apparatus according to Embodiment 2 of the present invention. In FIG. 3, reference numeral 12 denotes a visibility measuring means for measuring the visibility around a desired target, and 13 denotes visibility information, an atmospheric attenuation rate, and the like. And converts the visibility information measured by the visibility measuring means 12 into an atmospheric decay rate using the data table, and converts the converted atmospheric decay rate with the atmospheric decay rate in fine weather. This is a visibility integration number instruction circuit that calculates the number of integrations of the integration processing circuit 10 by comparison. In addition, the visibility integration number instruction circuit 9 is the same as that of the above embodiment. As shown in FIG. 1, a circuit for calculating the atmospheric attenuation rate and a circuit for calculating the number of times of integration may be configured separately. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted.

Next, the operation will be described. The laser light generated by the laser light source 1 is output to the scanning mirror 3 via the beam splitter 2, and the scanning mirror 3 scans the scanning area as a laser beam 6. Here, in the laser radar device according to the present embodiment, it is not necessary to calculate the atmospheric attenuation rate in the atmosphere from the reference target, and the laser light output from the laser light source 1 is directed toward the target via the scanning mirror 3. Is scanned.
The reflected light 7 from the target is guided to the photodetector 4 via the scanning mirror 3 and the beam splitter 2, converted into an electric signal by the photodetector 4, and output to the integration processing circuit 10 as a reception signal. You.

On the other hand, the visibility integration number instruction circuit 13 receives the visibility information measured by the visibility measurement means 12, and the visibility integration frequency instruction circuit 13 first uses the conversion table shown in FIG. The conversion rate is converted into the atmospheric attenuation rate, and then the converted atmospheric attenuation rate is compared with the atmospheric attenuation rate in fine weather to calculate the number of integration processes performed by the integration processing circuit 10. As described above, in the laser radar device according to the present embodiment, the atmospheric attenuation rate in the atmosphere is obtained using the measurement result of the visibility measuring unit 12 and the conversion table as shown in FIG.

FIG. 4 is a data table showing the relationship between visibility information and the atmospheric attenuation rate, and is a conversion table explanatory diagram showing an example of a conversion table provided in the visibility integration number instruction circuit 13 as shown in FIG.

Then, the integration processing circuit 10 performs an integration process on the received signal from the target output from the photodetector 4 according to the integration processing number instructed from the visibility integration number instruction circuit 13, and outputs the integration processing result in the azimuth / distance. Output to the measurement circuit. The azimuth / distance measurement circuit 5 generates a scanning azimuth signal and detects the angle of the target based on the scanning angle. The detected angle of the target and the data after the integration processing output from the integration processing circuit 10 are output. Then, the distance from the laser radar device to the target is measured.

As described above, according to the laser radar device of the present embodiment, noise included in the received signal can be suppressed by integrating the received signal from the target with the number of integrations according to the weather conditions. Thus, the target object detection performance can be maintained at a certain level or more without adjusting the laser beam angle of the laser beam.

Further, since the visibility integration number instruction circuit 13 and the integration processing circuit 10 can be configured and processed using a terminal device such as a personal computer or a workstation, a laser suitable for miniaturization such as mounted on an aircraft or the like can be used. A radar device can be easily obtained.

Next, another embodiment of the present invention will be described. Embodiment above. 2, the atmospheric attenuation rate is obtained from the visibility information obtained from the visibility measuring means 12 and the conversion table shown in FIG. 4, but the atmospheric attenuation rate is obtained using the rainfall information from the rainfall measuring means. The rate may be obtained, and the laser radar device according to the present embodiment obtains the number of necessary integration processes from the atmospheric attenuation rate based on the rainfall information and performs the integration process based on the number of integration processes.

FIG. 5 is a block diagram showing a laser radar apparatus according to another embodiment of the present invention. In FIG. 5, reference numeral 14 denotes rainfall measuring means for measuring the rainfall around a desired target, and 15 denotes rainfall information and atmospheric attenuation. It has a data table indicating the relationship with the rate, and converts rainfall information measured by the rainfall measuring means 14 into an atmospheric decay rate using the above data table, and converts the converted atmospheric decay rate into an atmospheric decay rate in fine weather. This is a rainfall integration number instruction circuit that calculates the number of integrations of the integration processing circuit 10 by comparing the ratio with the rate. Also, the rainfall integration number instruction circuit 15 is provided in the above-described embodiment. Similarly to the visibility integration number instructing circuit 13 shown in FIG. 2, the circuit may be configured to be divided into a circuit for calculating the atmospheric attenuation rate and a circuit for calculating the number of integration processes. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted.

The rainfall integration number instructing circuit 15 receives the rainfall information measured by the rainfall measuring means 14, first converts the input rainfall information into an atmospheric decay rate using a conversion table shown in FIG. By comparing the converted atmospheric decay rate with the atmospheric decay rate in fine weather, the number of times of integration processing of the integration processing circuit 10 is calculated. As described above, in the laser radar device according to the present embodiment, the atmospheric attenuation rate in the atmosphere is obtained by using the measurement result of the rainfall measuring unit 14 and the conversion table as shown in FIG.

FIG. 6 is a data table showing the relationship between rainfall information and atmospheric decay rate, and is a conversion table explanatory diagram showing an example of a conversion table provided in the rainfall integration number instruction circuit 15 as shown in FIG.

{And the above embodiment. Similarly to the laser radar device shown in FIG. 2, the integration processing circuit 10 performs an integration process on the reception signal from the target output from the photodetector 4 according to the integration processing number specified by the rainfall integration number instruction circuit 15, The result of the integration process is output to the azimuth / distance measurement circuit. The azimuth / distance measurement circuit 5 generates a scanning azimuth signal and detects the angle of the target based on the scanning angle. The detected angle of the target and the data after the integration processing output from the integration processing circuit 10 are output. Then, the distance from the laser radar device to the target is measured.

As described above, according to the laser radar device of the present embodiment, noise included in the received signal can be suppressed by integrating the received signal from the target with the number of integrations according to the weather conditions. Thus, the target object detection performance can be maintained at a certain level or more without adjusting the laser beam angle of the laser beam.

In addition, since the rainfall integration number instruction circuit 13 and the integration processing circuit 10 can be configured and processed by using a terminal device such as a personal computer or a workstation, a laser suitable for miniaturization such as mounted on an aircraft or the like is provided. A radar device can be easily obtained.

Next, another embodiment of the present invention will be described. Embodiment above. Prior to measuring the distance to a target, the laser radar apparatus according to No. 1 calculates an atmospheric attenuation rate based on reflected light from a reference target, and performs integration processing based on the number of integration processes based on the atmospheric attenuation rate. However, the visibility distance or the rainfall may be obtained from the calculated atmospheric attenuation rate. The laser radar device according to the present embodiment not only calculates the number of integration processes of the integration processing circuit 10 from the atmospheric attenuation rate calculated from the reflected light from the reference target, but also further uses the calculated atmospheric attenuation rate to further increase the visibility. It also determines the distance or rainfall.

FIG. 7 is a block diagram showing a laser radar apparatus according to another embodiment of the present invention, which is capable of obtaining a visibility distance. In FIG. 7, reference numeral 16 denotes a data table indicating the relationship between visibility information and the atmospheric attenuation rate. The visibility distance converts the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculation circuit 8 into the visibility distance using the data table. This is a conversion circuit, and as the data table, for example, a conversion table as shown in FIG. 4 is used. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted.

As shown in FIG. 7, according to the laser radar device of the present embodiment, the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculation circuit 8 is input to the visibility distance conversion circuit 16, and the conversion is performed, for example, as shown in FIG. Since the visibility distance is obtained from the atmospheric attenuation rate using the table, in addition to the function of measuring the distance from the laser radar device to the target, it also has a function of measuring the visibility distance near the laser radar device. A laser radar device can be obtained. The conversion table is set in the visibility distance conversion circuit 16 in advance, and the converted visibility distance is output to the outside.

FIG. 8 is a block diagram showing a laser radar device according to another embodiment of the present invention, which is capable of obtaining a visibility distance. In FIG. 8, reference numeral 17 denotes a data table indicating a relationship between the rainfall information and the atmospheric decay rate, and a rainfall conversion for converting the atmospheric decay rate calculated by the atmospheric decay rate calculation circuit 8 into a rainfall value using the data table. It is a circuit, and a conversion table as shown in FIG. 6, for example, is used as the data table. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted.

As shown in FIG. 8, according to the laser radar device of the present embodiment, the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculating circuit 8 is input to the rainfall conversion circuit 17 and, for example, a conversion table as shown in FIG. Is used to calculate the rainfall value from the atmospheric attenuation rate, so that in addition to the function of measuring the distance from the laser radar device to the target, the laser also has the function of measuring the rainfall value near the laser radar device. A radar device can be obtained. The conversion table is set in the rainfall conversion circuit 17 in advance, and the converted rainfall value is output to the outside.

Next, another embodiment of the present invention will be described. Embodiment above. The laser radar device according to the fourth embodiment calculates the visibility distance or the rainfall using the atmospheric attenuation ratio calculated by the atmospheric attenuation ratio calculation circuit 8, but the laser radar device according to the present embodiment uses the atmospheric attenuation ratio from the atmospheric attenuation ratio. It seeks both visibility distance and rainfall. FIG. 9 is a block diagram showing a laser radar device according to another embodiment of the present invention. As shown in FIG. 9, in the laser radar device according to the present embodiment, the relationship between visibility information and atmospheric attenuation rate is shown. And a rainfall conversion circuit having a data table indicating the relationship between the rainfall information and the atmospheric decay rate. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted. In addition, the integration number instruction circuit 9, the integration processing circuit 10, and the azimuth / distance measurement circuit 5 are not shown for convenience.

As shown in FIG. 9, according to the laser radar device of the present embodiment, the atmospheric attenuation rate calculated by the atmospheric attenuation rate calculation circuit 8 is input to the visibility distance conversion circuit 16 and the rainfall conversion circuit 17, respectively. 4 and 6 are used to determine the visibility distance and the rainfall value from the atmospheric attenuation rate, respectively. In addition to the function of measuring the distance from the laser radar device to the target, the laser radar is used. A laser radar device having a function of measuring the visibility distance and the rainfall value near the device can be obtained. The conversion tables are set in advance in the visibility distance conversion circuit 16 and the rainfall amount conversion circuit 18, respectively, and the converted visibility distance and rainfall value are output to the outside.

Next, another embodiment of the present invention will be described. The laser radar device according to the above embodiment measures the distance from the laser radar device to the target by performing integration processing based on the number of integration processes calculated based on the atmospheric attenuation rate. It is also possible to calculate the number of integration processes required to secure the wind speed measurement performance during rainfall from the atmospheric attenuation rate, and measure the wind speed near the laser radar device by the calculated number of integration processes. The laser radar device according to the present embodiment measures the wind speed near the laser radar device by performing the integration process based on the number of integration processes calculated from the atmospheric attenuation rate.

FIG. 10 is a block diagram showing a laser radar device according to another embodiment of the present invention. In FIG. 10, reference numeral 18 denotes a wind direction detected by a scanning angle, and a transmission laser frequency of the laser beam 6 and a photodetector. 4 is an azimuth / wind speed measurement circuit for detecting a wind speed value from an amount of change (a so-called Doppler shift amount) of the frequency of the received signal converted by the step 4. In the drawings, the same reference numerals indicate the same or corresponding portions, and a detailed description thereof will be omitted.

Next, the operation will be described. In FIG. 10, the atmospheric attenuation rate calculation circuit 8 is the same as that of the above embodiment. As in the case of 1, the atmospheric attenuation rate when the laser beam 6 is transmitted to the reference target is calculated. The calculation method is the same as in the first embodiment. Same as 1. The integration number instructing circuit 9 compares the atmospheric attenuation rate obtained by the atmospheric attenuation amount calculating circuit 8 with the atmospheric attenuation rate in fine weather to calculate the number of integration processes required to secure the wind speed measurement performance during rainfall. . Then, the integration processing circuit 10 performs an integration process on the received signal from the target input from the photodetector 4 according to the number of integration processes instructed by the integration number instructing circuit 9, and the azimuth / wind speed measurement circuit 18 uses the scanning angle to determine the wind. And the wind speed value is detected from the amount of change (the so-called Doppler shift amount) between the transmission laser frequency of the laser beam 6 and the frequency of the reception signal converted by the photodetector 4.

As described above, according to the laser radar device of the present embodiment, the number of integration processes required to secure the wind speed measurement performance during rainfall is calculated, and the received signal is integrated by the calculated integration process times. By processing, it is possible to integrate the received signal about the wind speed with the number of integrations according to the weather conditions, suppress the noise included in the received signal, and adjust the wind speed without adjusting the laser beam angle of the laser beam. The value detection performance can be maintained at or above a certain level.

The atmospheric attenuation rate calculation circuit 8, the integration number instruction circuit 9, and the integration processing circuit 10 can be configured and processed by using a terminal device such as a personal computer or a workstation, so that they are mounted on an aircraft or the like. A laser radar device suitable for miniaturization can be easily obtained.

FIG. 1 is a block diagram illustrating a laser radar device according to an embodiment of the present invention. FIG. 2 is an operation explanatory diagram showing an operation state of the laser radar device shown in FIG. 1. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention. FIG. 4 is a conversion table provided in the visibility integration number instruction circuit 13 shown in FIG. 3 and is a conversion table explanatory diagram showing a relationship between visibility information and an atmospheric attenuation rate. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention. FIG. 6 is a conversion table provided in the visibility integration number instruction circuit 15 shown in FIG. 5 and is an explanatory diagram of a conversion table showing a relationship between rainfall information and an atmospheric attenuation rate. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention. FIG. 13 is a block diagram showing a laser radar device according to another embodiment of the present invention.

Explanation of reference numerals

1 laser light source, 2 beam splitter, 3 scanning mirror, 4 photodetector,
5 azimuth / distance measurement circuit, 6 laser beam, 7 reflected light,
8 atmospheric attenuation rate calculation circuit, 9 integration number instruction circuit, 10 integration processing circuit,
11 reference target, 12 visibility measurement means, 13 visibility integration number instruction circuit,
14 rainfall measuring means, 15 rainfall integration number indication circuit,
16 Visibility distance conversion circuit, 17 Rainfall conversion circuit, 18 Direction / wind speed measurement circuit.

Claims (3)

A laser light source; scanning means for scanning a laser beam of laser light generated by the laser light source; a photodetector for detecting reflected light of the laser beam scanned by the scanning means and converting the reflected light into a received signal; An atmospheric attenuation rate calculation circuit that calculates an atmospheric attenuation rate from a reception signal by a reflected light of the laser beam reflected from the target and output from the photodetector, and instructs the number of integration processes corresponding to the calculated atmospheric attenuation rate. An integration number instruction circuit, an integration processing circuit that integrates a reception signal by reflected light of a laser beam reflected from a target object and output from the photodetector at an integration processing number instructed by the integration number instruction circuit; An azimuth / distance measuring circuit for measuring the distance to the target from the data after the integration process and the scanning angle of the laser beam detected by the scanning means; The scanning angle of the laser beam scanned on the target, the atmospheric attenuation rate due to the reflected light of the laser beam calculated by the atmospheric attenuation rate calculating means, and the conversion table for converting the atmospheric attenuation rate to the visibility distance or rainfall, and the visibility distance. A laser radar device comprising a conversion circuit for obtaining rainfall. A laser light source; scanning means for scanning a laser beam of laser light generated by the laser light source; a photodetector for detecting reflected light of the laser beam scanned by the scanning means and converting the reflected light into a received signal; An atmospheric attenuation rate calculation circuit that calculates an atmospheric attenuation rate from a reception signal by a reflected light of the laser beam reflected from the target and output from the photodetector, and instructs the number of integration processes corresponding to the calculated atmospheric attenuation rate. An integration number instruction circuit, an integration processing circuit that integrates a reception signal by reflected light of a laser beam reflected from a target object and output from the photodetector at an integration processing number instructed by the integration number instruction circuit; A heading / wind measuring the wind speed in the heading of the target from the amount of change in the frequency of the data after the integration processing and the scanning angle of the laser beam detected by the scanning means. A measuring circuit for converting the scanning angle of the laser beam scanned on the target and the atmospheric attenuation rate and the atmospheric attenuation rate by the reflected light of the laser beam calculated by the atmospheric attenuation rate calculating means into a visibility distance or rainfall. A conversion circuit for obtaining a visibility distance or a rainfall amount from a table and a laser radar device. 3. The laser radar device according to claim 1, wherein the conversion tables for converting the atmospheric attenuation rate into one of a visibility distance and a rainfall amount are provided, and both the visibility distance and the rainfall amount are obtained. .

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