Weather radar device and computer program

Abstract

To provide a weather radar system and a computer program that can suppress an erroneous removal of a precipitation echo even when a rotational structure is present in a radar coverage.SOLUTION: A weather radar system of an embodiment of the present invention observes the weather based on the reflection echo of a pulse signal directed into an observation coverage. The weather radar system comprises a position acquisition unit, a precipitation determination unit, and a reduction processing unit. The position acquisition unit acquires a piece of positional information that is a verification target necessary or unnecessary for clutter reduction processing for reducing clutter in the observation coverage. The precipitation determination unit determines the presence or absence of precipitation based on the observation result in the vicinity of the informed position acquired by the position acquisition unit. The reduction processing unit performs relatively stronger clutter reduction processing to the observation result of the position of the verification target when the precipitation determination unit determines that the precipitation is absent compared to when it determines that the precipitation is present.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a weather radar device and a computer program. [Background technology]

[0002] In recent years, with the increase in demand for renewable energy, wind turbines have been installed all over the country. On the other hand, weather radars are installed in places with good visibility in order to expand their observation range, so wind turbines, which are installed in places with good ventilation, may be installed within the observation coverage area.

[0003] Weather radar devices detect moving targets based on Doppler information, but they can detect rotating structures such as rotor blades on wind power generation facilities installed on land or offshore, which can cause confusion in the display device, for example.

[0004] In the past, a process was applied to forcibly invalidate observed values ​​in the direction of structures that cause false alarms. However, this simple process of invalidating values ​​also applies to clutter that has a large effect only on clear days and a small effect on rainy days, so there is a risk of erroneously removing necessary precipitation echoes. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Kong, F., Y. Zhang, R. Palmer, "Wind Turbine Clutter Mitigation for Weather Radar by Adaptive Spectrum Processing," 2012 IEEE Radar Conference, Atlanta, GA, 2012. Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a weather radar device and a computer program capable of suppressing erroneous removal of precipitation echoes even when a rotating structure is present in the radar coverage area. [Means for solving the problem]

[0007] A weather radar device according to an embodiment observes weather based on reflected echoes of a pulse signal transmitted toward an observation coverage area. The weather radar device includes a position acquisition unit, a precipitation determination unit, and a reduction processing unit. The position acquisition unit acquires information on a position within the observation coverage area that is to be verified as to whether clutter reduction processing is required to reduce clutter. The precipitation determination unit determines the presence or absence of precipitation based on observation results for a vicinity of the position from which the position acquisition unit acquired information. When the precipitation determination unit determines that there is no precipitation, the reduction processing unit applies a relatively stronger clutter reduction processing to the observation results for the verification position than when it determines that there is precipitation. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a weather radar device according to the present invention. [Diagram 2] 2 is a flowchart of an analysis process of the weather radar device shown in FIG. 1. [Diagram 3] FIG. 2 is a diagram for explaining the positional relationship between a bin requiring verification and surrounding bins within a radar coverage area. [Figure 4] FIG. 4 is a diagram for explaining the positional relationship between the surrounding bins and the precipitation area shown in FIG. 3 . [Diagram 5] FIG. 2 is a diagram showing an example of echoes from wind turbines standing in a radar coverage area. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 shows the configuration of a weather radar device 10 according to an embodiment.

[0010] This weather radar device 10 is used to observe weather conditions within a radar coverage area (observation coverage area), and observes the location and density of rain and snow, wind speed and direction, etc. by emitting (transmitting) electromagnetic waves (pulse signals) from an antenna and receiving and analyzing the electromagnetic waves (reflected echoes) that are reflected back from the observation target.

[0011] As shown in FIG. 1, a weather radar device 10 includes at least a weather radar 11, a radar signal processing unit 12, a communication interface (I / F) 13, a RAW data processing unit 14, a RAW data storage unit 15, and a radar data analysis unit 16.

[0012] The weather radar 11 uses an antenna to radiate electromagnetic waves toward the radar coverage area at a predetermined cycle, and receives electromagnetic waves (reflected wave signals) reflected by, for example, rain or snow in the atmosphere. If buildings, mountains, oceans, rivers, wind turbines of wind power generation facilities, etc. are present within the radar coverage area, reflected waves from these objects will also be received as clutter.

[0013] The radar signal processing unit 12 performs signal processing such as amplification, demodulation, and pulse compression on the reflected wave signal received by the weather radar 11, and further performs A / D conversion to obtain a radar signal.

[0014] The communication I / F 13 transmits the radar signal obtained by the radar signal processing unit 12 to the RAW data processing unit 14. In other words, the radar signal processing unit 12 and the RAW data processing unit 14 are provided at separate locations, and information transmission is performed via the communication I / F 13.

[0015] The RAW data processing unit 14 generates three-dimensional observation data (RAW data) about the radar coverage area based on the radar signal from the radar signal processing unit 12. Note that this three-dimensional observation data is generated in units of one period of scanning the radar coverage area.

[0016] The RAW data storage unit 15 stores the three-dimensional observation data generated by the RAW data processing unit 14 for each period (for example, 30 seconds).

[0017] The radar data analysis unit 16 extracts the three-dimensional observation data from the raw data storage unit 15, performs analysis processing on the data, and obtains weather data 100 for the radar coverage area. That is, the radar data analysis unit 16 is an example of a position acquisition unit, a precipitation determination unit, and a reduction processing unit. The radar data analysis unit 16 can be realized by a processor (computer) executing software (programs) stored in a memory.

[0018] The weather data 100 obtained in the above manner is output to a display device (not shown) at a subsequent stage. The display device visually displays, for example, the precipitation conditions within the radar coverage area centered on the weather radar 11 in two or three dimensions.

[0019] Next, the analysis process by the radar data analysis unit 16 will be described with reference to Fig. 2. Fig. 2 is a flowchart for explaining this analysis process. Note that in the following description, for simplicity, an example will be described in which processing is performed in units of bins, but, for example, the radar coverage area may be divided into meshes of a size equal to or smaller than the size of a bin, and similar processing may be performed in units of the meshes.

[0020] In step S201, the radar data analysis unit 16 reads out and analyzes the three-dimensional observation data from the raw data storage unit 15, measures and obtains the observation values ​​(received power level, phase difference, etc.) for each bin regarding the radar coverage, and proceeds to step S202.

[0021] Specifically, the radar data analysis unit 16 obtains the observation value by treating an observation bin (observation mesh) obtained by meshing the radar coverage in the sector direction and range direction as one observation area. Note that the sector direction is the rotation direction around the center of the polar coordinate system, with the weather radar 11 as the center, while the range direction is the distance direction from the center.

[0022] That is, the radar data analysis unit 16 defines the position of the observation bin by a sector and a range, and obtains the observation value in each observation bin by averaging three-dimensional observation data of a plurality of periods for each observation bin.

[0023] Prior to measuring the observed values, the radar data analysis unit 16 appropriately performs MTI (Moving Target Indicator) processing, pulse compression processing, pulse Doppler processing, CFAR (Constant False Alarm Rate) detection processing, and the like.

[0024] In step S202, the radar data analysis unit 16 detects the position of an observation bin (hereinafter referred to as a bin requiring verification) where the presence of a wind turbine is suspected, for example, because the observation value is higher than a preset threshold value, or because an observation value above the threshold value occurs for a predetermined period of time or more (a Doppler velocity component above the threshold value is observed for a predetermined period of time or more), and then proceeds to step S203.

[0025] In this example, the radar data analysis unit 16 detects observation bins where the presence of wind turbines is suspected based on the observation values, but the operator may specify (teach) the observation bins (or their positions) where the presence of wind turbines is suspected through a human interface (not shown). Alternatively, the corresponding observation bins may be detected based on map data showing the positions of wind turbines.

[0026] In step S203, the radar data analysis unit 16 detects surrounding observation bins (hereinafter referred to as surrounding bins) adjacent to the verification bin detected in step S202, calculates observation values ​​for these surrounding bins based on multiple periods of three-dimensional observation data, and proceeds to step S204.

[0027] Here, the specific positional relationship between the to-be-verified bin and the surrounding bins will be described with reference to Fig. 3. Fig. 3 shows the radar coverage area R, in the center of which the antenna of the weather radar 11 is located. Area A indicates the to-be-verified bin, and hatched area B indicates the surrounding bins. In step S203, the radar data analysis unit 16 calculates an observation value (e.g., an average observation value) for the surrounding bin, i.e., area B, based on three-dimensional observation data of multiple periods.

[0028] In step S204, the radar data analysis unit 16 compares the observation value calculated in step S203 with a preset threshold value to determine the presence or absence of precipitation in the surrounding bins. That is, the threshold value is set to a value for determining the presence or absence of precipitation echoes.

[0029] Specifically, the radar data analysis unit 16 compares the observation value of the area B in Fig. 3 with a threshold value for determining whether or not it is a precipitation echo, and determines whether or not there is a precipitation echo. If the observation value is equal to or greater than the threshold value, it is considered to be a precipitation echo (precipitation is present) and the process proceeds to step S205, whereas if the observation value is less than the threshold value, it is considered to be no precipitation echo (no precipitation) and the process proceeds to step S206.

[0030] The determination of the presence or absence of precipitation may be based on whether or not precipitation is occurring over the entire periphery (whole circumference) of region A. That is, for example, if precipitation is occurring over at least a portion of the periphery of region A, it may be determined that precipitation is occurring.

[0031] In step S205, since no precipitation echoes were detected from the surrounding bins around the bin to be verified, the radar data analysis unit 16 determines that the surrounding bins are not within the precipitation area P, as shown in Figure 4(a), and applies wind turbine clutter reduction processing to the observation value of the bin to be verified, and then terminates the processing.

[0032] As an example of the wind turbine clutter reduction process, the observed values ​​of the verification-required bins are forcibly invalidated by a process such as replacing the values ​​so that the Doppler velocity component becomes zero, thereby removing the clutter.

[0033] On the other hand, in step S206, since precipitation echoes have been detected from the surrounding bins around the verification bin, the radar data analysis unit 16 determines that some of the surrounding bins are within the precipitation area P, as shown in FIG. 4(b), or that all of the surrounding bins are within the precipitation area P, as shown in FIG. 4(c), and terminates the process without applying wind turbine clutter reduction processing to the observation values ​​of the verification bin (or applying low-strength wind turbine clutter reduction processing).

[0034] That is, it is also possible to interpret that step S206 performs a relatively weak wind turbine clutter reduction process compared to step S205.

[0035] As described above, the weather radar device having the above configuration judges the presence or absence of precipitation echoes for bins surrounding a verification bin where the presence of a wind turbine is suspected. If a precipitation echo is not detected, wind turbine clutter reduction processing is applied to the observation value of the verification bin, and if a precipitation echo is detected, wind turbine clutter reduction processing with a relatively lower intensity is applied compared to when a precipitation echo is not detected.

[0036] Therefore, according to the weather radar device of the above configuration, it is possible to reduce the observation value only for the observation bins in which the presence of rotating structures is strongly suspected among the radar analysis data used for meteorological observation, thereby suppressing the erroneous removal of precipitation echoes.

[0037] For example, as shown in Fig. 5, when many wind turbines stand along a coastline, the effect of wind turbine clutter appears on the display device and makes it very difficult to see (parts pointed to by arrows in Fig. 5), but if no precipitation echo is detected, wind turbine clutter reduction processing can be applied to prevent the display from being confused with precipitation. If a precipitation echo is detected, erroneous removal can be suppressed.

[0038] Furthermore, for example, mirror echoes may occur due to the presence of a large tower or building near the weather radar 11. Even in such cases, clutter reduction processing is performed when there is no rainfall, so the mirror echoes can be reduced.

[0039] It should be noted that the present invention is not limited to the above-described embodiment as it is, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining multiple components disclosed in the above-described embodiment. For example, a configuration in which some components are deleted from all the components shown in the embodiment can also be considered. Furthermore, the components described in different embodiments may be appropriately combined. [Explanation of symbols]

[0040] 10...weather radar device, 11...weather radar, 12...radar signal processing unit, 13...communication interface, 14...raw data processing unit, 15...raw data storage unit, 16...radar data analysis unit, 100...weather data.

Claims

1. A weather radar device that observes weather based on reflected echoes of a pulse signal transmitted toward an observation coverage area, a position acquisition unit that acquires information on a position within the observation coverage area that is a target for verifying whether or not clutter reduction processing is required to reduce clutter; a precipitation determination unit that determines whether or not precipitation is present in the vicinity of the position where the position acquisition unit acquires information based on an observation result; a reduction processing unit that, when the precipitation determination unit determines that there is no precipitation, applies the clutter reduction processing to the observation result of the position to be verified in a stronger manner than when the precipitation determination unit determines that there is precipitation; A weather radar device comprising:

2. The weather radar device according to claim 1 , wherein the position acquisition unit acquires the position information based on an instruction from an operator.

3. The weather radar device according to claim 1 , wherein the position acquisition unit acquires the position information based on past observation results.

4. The weather radar device according to claim 1 , wherein the position acquisition unit acquires information on a position where a Doppler velocity component equal to or greater than a preset threshold is continuously observed based on past observation results.

5. The weather radar device according to claim 1 , wherein the precipitation determining unit determines the presence or absence of precipitation based on a comparison between an observation result in the vicinity of the position and a preset threshold value.

6. The weather radar device according to claim 1 , wherein the precipitation determining unit determines that precipitation is occurring when precipitation is present over an entire periphery of the position.

7. The weather radar device according to claim 1 , wherein the precipitation determining unit determines that precipitation is occurring when precipitation is present on at least a portion of an outer periphery of the position.

8. A computer program used in a weather radar device that observes weather based on a reflected echo of a pulse signal transmitted toward an observation coverage area, comprising: Computer, a position acquisition unit that acquires information on a position within the observation coverage area that is a target for verifying whether or not clutter reduction processing is required to reduce clutter; a precipitation determination unit that determines whether or not precipitation is present in the vicinity of the position where the position acquisition unit acquires information based on an observation result; a reduction processing unit that, when the precipitation determination unit determines that there is no precipitation, applies the clutter reduction processing to the observation result of the position to be verified in a stronger manner than when the precipitation determination unit determines that there is precipitation; A program to make it function as such.

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