Information processing apparatus, system, method, and program

Abstract

To provide an information processor capable of improving accuracy of a meteorological radar observation amount.SOLUTION: A general architecture that implements the various features of the embodiments will now be described with reference to the drawings. The processor is configured to calculate a first two-dimension between a number of first coordinates and a number of second coordinates, the first coordinates being coordinates at which a first meteorological radar observation amount at a first azimuth angle satisfies a first condition, the second coordinates being coordinates at which the first meteorological radar observation amount at each of one or more second azimuth angles within a first range from the first azimuth angle satisfies the first condition. The processing unit determines, based on the first difference, whether a plurality of the first weather radar observation amounts corresponding to a plurality of first coordinates including the first azimuth angle are affected by interference.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD Embodiments of the present invention relate to an information processing device, a system, a method, and a program. [Background technology]

[0002] In recent years, damage caused by localized weather phenomena such as sudden downpours has been increasing, and there is a demand for more accurate data obtained by weather radars in order to detect localized weather phenomena early. Weather radar is a meteorological observation device that measures weather-related information (hereinafter also referred to as weather radar observables) by emitting radio waves from an antenna, which are reflected by raindrops and then received by the antenna. An example of a weather radar observable is precipitation intensity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5607428 Summary of the Invention [Problem to be solved by the invention]

[0004] Weather radars sometimes receive radio waves (signals) emitted by other systems that use a similar frequency. In such cases, the accuracy of the weather radar observations can be reduced due to interference between the radio waves of the other systems and the radio waves that should be received.

[0005] The problem to be solved by the present invention is to provide an information processing device, system, method, and program that can improve the accuracy of weather radar observation quantities. [Means for solving the problem]

[0006] According to an embodiment, an information processing device includes a processing unit. The processing unit uses first weather radar observation quantities corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance to calculate a first difference between the number of first coordinates at which the first weather radar observation quantity at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation quantity at each of one or more second azimuth angles within a first range relative to the first azimuth angle satisfies the first condition. The processing unit determines whether the multiple first weather radar observation quantities corresponding to multiple first coordinates including the first azimuth angle are affected by interference based on the first difference. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a block diagram showing an example of the arrangement of an information processing system including an information processing apparatus according to a first embodiment. [Figure 2] FIG. 1 is a block diagram showing an example of the hardware arrangement of an information processing apparatus according to a first embodiment. [Figure 3] FIG. 1 is a block diagram showing an example of the functional arrangement of an information processing apparatus according to a first embodiment. [Figure 4] 4A and 4B are diagrams showing examples of weather radar observation amounts that are determined to be affected by interference in the information processing device according to the first embodiment. [Figure 5] 5 is a flowchart showing an example of the procedure of a collision detection process executed in the information processing device according to the first embodiment. [Figure 6] FIG. 10 is a diagram showing another example of a weather radar observable determined to be affected by interference in the information processing device according to the first embodiment. [Figure 7] 10A and 10B are diagrams showing weather radar observation amounts determined to be unaffected by interference in an information processing device according to a comparative example. [Figure 8] 10A and 10B are diagrams showing examples of weather radar observation amounts determined to be affected by interference and weather radar observation amounts determined to be not affected by interference, respectively, in an information processing device according to a second embodiment. [Figure 9] 10 is a flowchart showing an example of the procedure of a collision detection process executed in an information processing device according to a second embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of the functional arrangement of an information processing device according to a third embodiment. [Figure 11] 11A and 11B are diagrams showing examples of weather radar observation amounts and weather radar observation amounts from which interference has been removed, in an information processing device according to a third embodiment. [Figure 12] 10 is a flowchart showing an example of the procedure of a first interference detection and removal process executed in an information processing device according to a third embodiment. [Figure 13] FIG. 10 is a block diagram showing an example of the functional arrangement of an information processing device according to a fourth embodiment. [Figure 14] 10A and 10B are diagrams showing examples of (a) weather radar observation amounts, (b) weather radar observation amounts with interference removed, and (c) weather radar observation amounts with interference further removed, in an information processing device according to a fourth embodiment. [Figure 15] 10 is a flowchart showing an example of the procedure of a second interference detection and removal process executed in an information processing device according to a fourth embodiment. [Figure 16] FIG. 13 is a block diagram showing an example of the functional arrangement of an information processing device according to a fifth embodiment. [Figure 17] FIG. 13 is a diagram showing an example of weather radar observation amounts that are determined to be affected by interference in the information processing device according to the fifth embodiment. [Figure 18] 10A and 10B are diagrams showing examples of (a) weather radar observation amounts, (b) weather radar observation amounts with interference removed, and (c) weather radar observation amounts with interference further removed, in an information processing device according to a fifth embodiment. [Figure 19] 13 is a flowchart showing an example of the procedure of a third interference detection and removal process executed in the information processing device according to the fifth embodiment. [Figure 20] FIG. 13 is a block diagram showing an example of the functional arrangement of an information processing device according to a sixth embodiment. [Figure 21] 13 is a flowchart showing an example of the procedure of interference removal execution determination processing executed in an information processing device according to a sixth embodiment. [Figure 22] 13 is a flowchart showing an example of the procedure of a fourth interference detection and removal process executed in the information processing device according to the sixth embodiment. [Figure 23] FIG. 13 is a block diagram showing an example of the configuration of a weather radar device including an information processing device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings.

[0009] (First embodiment) First, a configuration example of an information processing system including an information processing device according to the first embodiment will be described with reference to Fig. 1. The information processing system 1 is a system that observes and processes weather-related information (weather radar observation amounts) 41. The information processing system 1 includes, for example, a weather radar device 2A and an information processing device 3.

[0010] The weather radar device 2A is a meteorological observation device that observes weather radar observables 41. Specifically, the weather radar device 2A measures (generates) the weather radar observables 41 by reflecting radio waves emitted from an antenna (transmitter) off raindrops and receiving the reflected radio waves with an antenna (receiver). The raindrops from which the radio waves are reflected are also called raindrops. The emitted radio waves may also be reflected by snow, ice crystals, graupel, or hailstones, or a combination of these, instead of raindrops. The weather radar device 2A performs full-circle observations, for example, by mechanically rotating the antenna to change the azimuth angle.

[0011] The weather radar device 2A is realized, for example, as a single-polarized radar or a dual-polarized radar (multi-parameter radar). A single-polarized radar is a weather radar device that emits a single radio wave having a horizontal vibration component (i.e., horizontally polarized wave). A dual-polarized radar is a weather radar device that emits two types of radio waves having horizontal and vertical vibration components (i.e., horizontally polarized wave and vertically polarized wave). The radio waves emitted by the weather radar device 2A are also called radar waves.

[0012] The weather radar observation amount 41 is, for example, information about weather observed at each coordinate in a three-dimensional coordinate system. The three-dimensional coordinate system corresponds to a specific space observable by the weather radar device 2A. The three-dimensional coordinate system is, for example, a polar coordinate system specified by an elevation angle, an azimuth angle, and a distance (range) from the weather radar device 2A. Hereinafter, the distance from the weather radar device 2A will also be simply referred to as distance. The coordinates correspond to lattice points obtained by dividing the specific space observable by the weather radar device 2A into a lattice shape. For example, multiple lattice points (i.e., multiple coordinates) are defined by dividing the specific space by specific units for each coordinate axis.

[0013] The weather radar observation amount 41 may be information about weather observed at each coordinate in a two-dimensional coordinate system. The two-dimensional coordinate system corresponds to a specific plane observable by the weather radar device 2A. The two-dimensional coordinate system is, for example, a polar coordinate system specified by azimuth angle and distance. The coordinates correspond to lattice points obtained by dividing the specific plane observable by the weather radar device 2A into a lattice. For example, multiple lattice points (i.e., multiple coordinates) are defined by dividing the specific plane by specific units for each coordinate axis.

[0014] The weather radar observation quantity 41 is, for example, the precipitation intensity at each coordinate. Specifically, if the weather radar device 2A is a single-polarization radar, the weather radar observation quantity 41 includes, for example, the received power, reflectivity factor, Doppler velocity, and Doppler velocity width at each coordinate. If the weather radar device 2A is a dual-polarization radar, the weather radar observation quantity 41 includes, for example, the reflectivity factor difference, inter-polarization correlation coefficient, inter-polarization phase difference, and inter-polarization phase difference change rate in addition to the received power, reflectivity factor, Doppler velocity, and Doppler velocity width at each coordinate.

[0015] The received power indicates the strength (intensity) of the radio waves received by the antenna after being reflected by raindrops. The reflection factor Z is a value that reflects the amount of raindrops and is calculated from the received power P.

[0016] The Doppler velocity is a velocity measured using the Doppler effect of radio waves reflected by raindrops. More specifically, the Doppler velocity includes, for example, the velocity of wind components moving away from the weather radar device 2A and the velocity of wind components moving toward the weather radar device 2A. The Doppler velocity range is the variation in the Doppler velocity.

[0017] The differential reflectance factor is the difference in the intensity of the reflectance factor depending on two types of emitted radio waves (for example, horizontally polarized waves and vertically polarized waves). The differential reflectance factor represents the aspect ratio of raindrops, etc.

[0018] The cross-polarization correlation coefficient is the correlation coefficient between signals received in horizontal and vertical polarizations. The cross-polarization correlation coefficient represents the uniformity of precipitation particles such as raindrops (e.g., rain, snow, ice crystals, graupel, hail, etc.).

[0019] The inter-polarization phase difference is the difference in phase between the signals received in horizontal and vertical polarization. The inter-polarization phase difference represents the distance integrated value of the amount of raindrops between the radar and each distance. The inter-polarization phase difference change rate is the rate of change in the inter-polarization phase difference in the distance direction. The inter-polarization phase difference change rate is a value that reflects the amount of raindrops.

[0020] The weather radar device 2A transmits the measured weather radar observation amount 41 to the information processing device 3 directly or indirectly.

[0021] The information processing device 3 is a device that processes the weather radar observation quantity 41 measured (generated) by the weather radar device 2A. The information processing device 3 is realized, for example, as a server computer, a personal computer, or a dedicated processing device. Alternatively, the information processing device 3 (or the function of the information processing device 3) may be provided on a cloud system. The information processing device 3 has, for example, a function to determine whether the measured weather radar observation quantity 41 has been affected by external interference (hereinafter also referred to as an interference determination function).

[0022] The information processing system 1 may further include a storage 4.

[0023] The storage 4 is a storage device capable of storing data. The storage 4 may be provided in any server computer (storage server) or in a cloud system. The storage 4 may store weather radar observation quantities 41 measured by the weather radar device 2A. When the storage 4 is provided, the weather radar observation quantities 41 may be transmitted directly from the weather radar device 2A to the information processing device 3, or may be stored in the storage 4 by the weather radar device 2A and then transmitted from the storage 4 to the information processing device 3.

[0024] Here, an example of the internal configuration of the weather radar device 2A will be described.

[0025] The weather radar device 2A includes, for example, a transmitter / receiver 21, a radar information processor 22, and a radar observation quantity transmitter .

[0026] The transmitting / receiving unit 21 transmits and receives radio waves used to measure the weather radar observation quantities 41. The transmitting / receiving unit 21 includes, for example, a transmitter and a receiver. The transmitter emits radio waves from an antenna. The emitted radio waves are reflected by, for example, raindrops. The receiver receives the reflected radio waves (reflected waves) from an antenna.

[0027] The radar information processing unit 22 performs specific processing on signals based on reflected waves received by the transmitter / receiver unit 21 (more specifically, the receiver) to generate data indicating weather radar observation quantities 41 at each coordinate in a three-dimensional coordinate system or a two-dimensional coordinate system. The specific processing includes signal processing such as RF / IF processing and AD conversion. Hereinafter, the data indicating the weather radar observation quantities 41 will also be referred to as observation data 41. The radar information processing unit 22 sends the generated observation data 41 to the radar observation quantity transmission unit 23.

[0028] The radar observation quantity transmission unit 23 is a communication device that transmits the observation data 41 to the outside. The communication by the radar observation quantity transmission unit 23 may be either wired communication or wireless communication. The radar observation quantity transmission unit 23 transmits the observation data 41 to, for example, the information processing device 3. The transmitted observation data 41 is stored, for example, in any storage area within the information processing device 3. Alternatively, the radar observation quantity transmission unit 23 may transmit the observation data 41 to the storage 4. In this case, the transmitted observation data 41 may be stored in a storage area of ​​the storage 4 and then transmitted from the storage 4 to the information processing device 3. The storage 4 transmits the observation data 41 to the information processing device 3, for example, in response to a request from the information processing device 3.

[0029] With the above configuration, the weather radar device 2A can transmit the observation data (weather radar observation amount) 41 to the information processing device 3 directly or indirectly.

[0030] The weather radar observation quantity 41 measured by the weather radar device 2A may be interfered with by radio waves (also called interference waves or interference signals) emitted from an external interference signal source 5 using a similar frequency. The interference signal source 5 may be, for example, another nearby weather radar device, a radar device other than the weather radar device, or communication equipment. When the weather radar device 2A receives an interference signal, the accuracy of the weather radar observation quantity 41 decreases.

[0031] Specifically, for example, if the interfering signal source 5 radiates (transmits) an interfering signal for a long time or at a high frequency relative to the antenna rotation speed of the weather radar device 2A, the interfering signals will be concentrated at an azimuth angle corresponding to the direction of the interfering signal source 5 as seen from the weather radar device 2A and will be distributed linearly in the distance direction. Furthermore, if the antenna of the interfering signal source 5 is also rotating, when the antenna of the interfering signal source 5 is facing an azimuth angle corresponding to the direction of the weather radar device 2A as seen from the interfering signal source 5, the weather radar device 2A may receive the interfering signal due to a side lobe even if the antenna on the weather radar device 2A is not facing the interfering signal source 5. In such a case, if the interfering signal source 5 radiates an interfering signal for a long time or at a high frequency relative to the antenna rotation speed of the weather radar device 2A and the interfering signal source 5, the interfering signals will be concentrated at a specific azimuth angle and distributed linearly in the distance direction. Such interfering signals distributed linearly in the distance direction have a significant adverse effect on the data accuracy of the weather radar observation quantities 41 and the visual quality when the weather radar observation quantities 41 are plotted on a map.

[0032] The power of the interference signal and the coordinates corresponding to how many azimuth angles the interference affects vary depending on the orientation and rotation speed of both antennas, the signal transmission sequence used at that time, and the transmission waveform of the radio waves from the interference signal source 5. For this reason, depending on the time, an interference signal with very strong power may be distributed linearly across a wide range of azimuth angles, while an interference signal with relatively weak power may be distributed linearly in the distance direction. Therefore, for example, when determining whether or not there is interference based on received power, it may be difficult to distinguish between an interference signal with relatively weak power and the desired signal.

[0033] In this way, the radio waves received by the transmitter / receiver 21 of the weather radar device 2A may be radio waves affected by interference waves. If the radio waves received by the transmitter / receiver 21 are affected by interference waves, the accuracy of the weather radar observation amount 41 obtained by processing these radio waves may be reduced due to the influence of the interference waves.

[0034] Therefore, the information processing device 3 according to this embodiment has a function of determining whether or not the weather radar observation amount 41 has been affected by interference (interference determination function). The interference determination function includes, for example, a function of determining whether or not the weather radar observation amount 41 has been affected by interference that is linearly distributed in the distance direction for a specific azimuth angle. This enables the information processing device 3 to improve the accuracy of the weather radar observation amount 41. The configuration and processing of the information processing device 3 for realizing the interference determination function will be described below.

[0035] FIG. 2 is a block diagram showing an example of the hardware configuration of the information processing device 3.

[0036] The information processing device 3 includes, for example, a central processing unit (CPU) 11, a storage 12, a random access memory (RAM) 13, and a communication device 14. The CPU 11, the storage 12, the RAM 13, and the communication device 14 are connected via, for example, a bus 10.

[0037] The CPU 11 is, for example, at least one processor. The CPU 11 controls the operations of various components in the information processing device 3. The CPU 11 executes various programs loaded from the storage 12 to the RAM 13. These programs include, for example, an operating system (OS) and various application programs. The application programs include a collision detection program 131. The collision detection program 131 is a program having a collision detection function. The collision detection function is realized, for example, by the CPU 11 executing the collision detection program 131. Note that the collision detection function may be realized by dedicated hardware (circuitry) provided in the information processing device 3.

[0038] The storage 12 is a storage device including a non-volatile storage medium, and is realized as, for example, a solid-state drive (SSD) or a hard disk drive (HDD).

[0039] The RAM 13 is, for example, a volatile memory, and is realized as, for example, a dynamic random access memory (DRAM) or a static random access memory (SRAM).

[0040] The communication device 14 is a device configured to perform wired or wireless communication with an external device (e.g., the weather radar device 2A or the storage 4). The communication device 14 includes, for example, a transmitter that transmits data and a receiver that receives data. The receiver can receive weather radar observations 41 (observation data 41) from, for example, the radar observation transmitter 23 of the weather radar device 2A or the storage 4.

[0041] FIG. 3 is a block diagram showing an example of the functional configuration of the information processing device 3.

[0042] The information processing device 3 includes a processing unit 31 having an interference determination function. The processing unit 31 processes the input weather radar observation amount 41 and outputs an interference determination result 42 indicating whether or not the weather radar observation amount 41 has been interfered with by an interfering wave (i.e., whether or not the weather radar observation amount 41 has been affected by interference). The processing unit 31 processes the weather radar observation amount 41 observed at each coordinate in a three-dimensional coordinate system specified by, for example, an elevation angle, an azimuth angle, and a distance from the weather radar device 2A.

[0043] In the following, it is assumed that the processing unit 31 processes the weather radar observation quantity 41 observed at each coordinate in a two-dimensional coordinate system specified by the azimuth angle and the distance from the weather radar device 2A for each elevation angle of the observation target. Also, the case where the weather radar observation quantity 41 input to the processing unit 31 is a reflectivity factor Z will be mainly illustrated. Note that the weather radar observation quantity 41 input to the processing unit 31 may be another type of weather radar observation quantity 41 such as received power P. The processing unit 31 determines whether or not the weather radar observation quantity 41 is affected by, for example, interference distributed linearly in the distance direction.

[0044] The processing unit 31 includes, for example, a coordinate number calculation unit 311, a difference calculation unit 312, and an interference determination unit 313. Each of these units may be, for example, a functional configuration that is processed by the processing unit 31. The processing unit 31 is realized by at least one processing device and executes the processing of the information processing device 3. This processing device includes, for example, a control device and an arithmetic unit, and is realized by analog or digital circuits, etc. The processing device may be a central processing unit (CPU), a general-purpose processor, a microprocessor, a digital signal processor (DSP), an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or a combination thereof. As an example, the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 may be functional configurations that are realized when the CPU 11 executes the interference determination program 131.

[0045] The coordinate number calculation unit 311 and the difference calculation unit 312 use the weather radar observation amount 41 corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance to calculate the difference between the number of first coordinates at which the weather radar observation amount 41 at a target azimuth angle (hereinafter also referred to as a target azimuth angle) for which the influence of interference is to be determined satisfies a first condition and the number of second coordinates at each of one or more azimuth angles (hereinafter also referred to as first peripheral azimuth angles) within a first range relative to the target azimuth angle at which the weather radar observation amount 41 satisfies the first condition. The first range is a range in which at least one or more azimuth angles ahead of the target azimuth angle and one or more azimuth angles after the target azimuth angle can be identified. Specifically, the one or more azimuth angles within the first range relative to the target azimuth angle (i.e., the first peripheral azimuth angles) are, for example, two azimuth angles adjacent to both sides of the target azimuth angle. The operations of the coordinate number calculation unit 311 and the difference calculation unit 312 will be specifically described below.

[0046] The coordinate number calculation unit 311 calculates, for each azimuth angle, the number C of coordinates at which the weather radar observation quantity 41 satisfies a first condition, using the weather radar observation quantity 41 corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance. Specifically, the coordinate number calculation unit 311 calculates (counts), for each azimuth angle, the number C of coordinates at which the reflectivity factor Z satisfies the first condition. The first condition is, for example, a condition that the reflectivity factor Z is equal to or greater than a first threshold value. The first threshold value is, for example, 10 dBZ. Hereinafter, the number C of coordinates calculated for a certain azimuth angle will also be referred to as the number C of coordinates corresponding to that azimuth angle.

[0047] The coordinate number calculation unit 311 may calculate the number C of coordinates at which the weather radar observation quantity 41 satisfies the first condition for each azimuth angle within a certain range of the weather radar observation quantity 41 corresponding to each coordinate in the two-dimensional coordinate system of azimuth angle and distance. For example, the coordinate number calculation unit 311 calculates the number of first coordinates at which the weather radar observation quantity 41 at the target azimuth angle satisfies the first condition. Then, the coordinate number calculation unit 311 calculates the number of second coordinates at which the weather radar observation quantity 41 at each of the first surrounding azimuth angles satisfies the first condition.

[0048] The difference calculation unit 312 calculates a difference value D using the coordinate number C corresponding to the target azimuth angle and the coordinate numbers C corresponding to each of the first peripheral azimuth angles. Specifically, the difference calculation unit 312 calculates the difference by subtracting the coordinate numbers C corresponding to each of one or more azimuth angles within a first range with respect to the target azimuth angle from the coordinate number C corresponding to the target azimuth angle.

[0049] For example, when the target azimuth angle is the kth azimuth angle, the difference calculation unit 312 calculates the difference value D k is calculated using the following formula 1. D k =MAX(C k -C k-1 ,C k -C k+1 ) Equation 1 C k is the coordinate number corresponding to the kth azimuth angle. C k-1 is the coordinate number corresponding to the (k-1)th azimuth angle. Ck+1 is the coordinate number corresponding to the (k+1)th azimuth angle. The (k-1)th azimuth angle and the (k+1)th azimuth angle are the azimuth angles adjacent to the kth azimuth angle on either side.

[0050] According to Equation 1, the difference value D corresponding to the kth azimuth angle k When calculating the k-th azimuth angle, the difference calculation unit 312 calculates the coordinate number C k From the coordinate number C corresponding to the (k-1)th azimuth angle k-1 The difference calculation unit 312 calculates a difference (first difference) by subtracting the coordinate number C corresponding to the k-th azimuth angle. k From the coordinate number C corresponding to the (k+1)th azimuth angle k+1 Then, the difference calculation unit 312 calculates the difference (second difference) by subtracting the maximum value of the first difference and the second difference from the k-th azimuth angle. k Therefore, the difference value D k is the coordinate number C corresponding to the kth azimuth angle k are the coordinate numbers C corresponding to the (k-1)th and (k+1)th azimuth angles adjacent to each other. k-1 and the number of coordinates C k+1 This value indicates how much larger it is compared to the smaller number of coordinates.

[0051] Note that, if the total number of azimuth angles defined in the two-dimensional coordinate system is N, k is an integer between 1 and N. The number k, which identifies one of the N azimuth angles, indicates one of the 1st to Nth azimuth angles. The 1st to Nth azimuth angles are cyclically identified using the number k. Specifically, the 1st azimuth angle is treated as the azimuth angle after the Nth azimuth angle. In other words, the Nth azimuth angle is treated as the azimuth angle before the 1st azimuth angle. Therefore, when k is 1, N is used as (k-1). When k is N, 1 is used as (k+1). The same applies to other azimuth angles represented using the number k.

[0052] Furthermore, the first peripheral azimuth angle of the target azimuth angle may be an azimuth angle that is not adjacent to the target azimuth angle. Specifically, for example, if the target azimuth angle is the kth azimuth angle, the first peripheral azimuth angles of the kth azimuth angle may be the (k-2)th azimuth angle and the (k+2)th azimuth angle. In this case, in the above-mentioned formula 1, the coordinate number C k-1 is the number of coordinates C k-2 and the coordinate number C k+1 is the number of coordinates C k+2 can be replaced by

[0053] Furthermore, the first peripheral azimuth angle of the target azimuth angle may be one azimuth angle. For example, if the target azimuth angle is the kth azimuth angle, the first peripheral azimuth angle of the kth azimuth angle may be any one of the (k-1)th azimuth angle, the (k-2)th azimuth angle, the (k+1)th azimuth angle, and the (k+2)th azimuth angle that are included within the first range with respect to the kth azimuth angle. In this case, the difference calculation unit 312 calculates the coordinate number C corresponding to the kth azimuth angle. k The difference obtained by subtracting the coordinate number C corresponding to that one azimuth angle from the kth azimuth angle is called the difference value D k It is calculated as follows.

[0054] The interference determination unit 313 determines whether or not the multiple weather radar observation quantities 41 corresponding to the multiple coordinates including the target azimuth angle are affected by interference, based on the difference (specifically, the difference value D) calculated by the difference calculation unit 312. The multiple coordinates including the target azimuth angle are, for example, all coordinates (polar coordinates) specified by the target azimuth angle and each of the multiple distances defined in a two-dimensional coordinate system. The interference determination unit 313 determines whether or not the multiple weather radar observation quantities 41 corresponding to the multiple coordinates including the target azimuth angle are affected by interference, for example, depending on whether or not the difference value D satisfies a second condition. The second condition is, for example, a condition that the difference value D is equal to or greater than a second threshold. The second threshold is set to an arbitrary value, such as 30. More specifically, the second threshold can be set, for example, based on the coordinate interval in the distance direction or empirically. For example, when the coordinate interval in the distance direction is 150 m and the target azimuth angle is to be determined to be affected by interference (linearly distributed) that differs from the first surrounding azimuth angle over a distance of 6000 m or more, the second threshold is set to 40 (= 6000 / 150). Note that if the second threshold is set too small, a desired signal that is a wave reflected from a rain cloud may be mistakenly determined to be an interference signal. Therefore, the second threshold can be determined by dividing a linear distribution of a length that can be clearly determined to be affected by interference (6000 m in the above example) by the coordinate interval in the distance direction.

[0055] For example, when the target azimuth angle is the k-th azimuth angle, the interference determination unit 313 determines whether or not the plurality of weather radar observation amounts 41 corresponding to the plurality of coordinates including the k-th azimuth angle have been affected by interference, based on the difference value Dk. Specifically, for example, when the difference value Dk satisfies the second condition (for example, when it is equal to or greater than the second threshold), the interference determination unit 313 determines that the plurality of weather radar observation amounts 41 corresponding to the plurality of coordinates including the k-th azimuth angle have been affected by interference. On the other hand, when the difference value Dk k does not satisfy the second condition (for example, is less than the second threshold), the interference determination unit 313 determines that the multiple weather radar observations 41 corresponding to the multiple coordinates including the k-th azimuth angle are not affected by interference.

[0056] The interference determination unit 313 outputs, for example, an interference determination result 42 indicating, for each azimuth angle, whether or not the corresponding plurality of weather radar observation amounts 41 are affected by interference. Note that the interference determination result 42 may indicate the azimuth angle at which the corresponding plurality of weather radar observation amounts 41 are affected by interference.

[0057] With the above configuration, the information processing device 3 can determine whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle, and obtain the interference determination result 42.

[0058] 4 shows an example of a weather radar observation quantity 41 that is determined to be affected by interference in the information processing device 3. Here, an example is shown in which the processing unit 31 of the information processing device 3 determines whether or not the weather radar observation quantity 41 is affected by interference, using the weather radar observation quantity 41 measured for each coordinate (grid point) in a two-dimensional coordinate system of azimuth angle and distance.

[0059] 4 shows an example of weather radar observation quantities 41 measured at each coordinate in a two-dimensional coordinate system in which the horizontal axis indicates azimuth angle and the vertical axis indicates distance. Specifically, the weather radar observation quantities 41 measured at each of (3×T) coordinates specified by all combinations of three consecutive azimuth angles (k−1), k, and (k+1) and T distances are shown. The T distances are, for example, consecutive distances spaced at regular intervals and arranged in order of proximity to the weather radar device 2A. In FIG. 4 and the following figures, the case where T is 10 is mainly illustrated.

[0060] Each of the T coordinates corresponding to the (k-1)th azimuth angle is specified by the (k-1)th azimuth angle and each of the T distances. Each of the T coordinates corresponding to the kth azimuth angle is specified by the kth azimuth angle and each of the T distances. Each of the T coordinates corresponding to the (k+1)th azimuth angle is specified by the (k+1)th azimuth angle and each of the T distances.

[0061] Hereinafter, the T weather radar observations 41 corresponding to the T coordinates corresponding to the (k-1)th azimuth angle will also be referred to as the T weather radar observations 41 corresponding to the (k-1)th azimuth angle. The T weather radar observations 41 corresponding to the T coordinates corresponding to the kth azimuth angle will also be referred to as the T weather radar observations 41 corresponding to the kth azimuth angle. The T weather radar observations 41 corresponding to the T coordinates corresponding to the (k+1)th azimuth angle will also be referred to as the T weather radar observations 41 corresponding to the (k+1)th azimuth angle. It is also assumed that the weather radar observations 41 are reflectivity factors Z.

[0062] In the example shown in Figure 4, the 10 reflectance factors Z corresponding to the (k-1)th azimuth angle are all 0. The T reflectance factors Z corresponding to the kth azimuth angle are all 1. The T reflectance factors Z corresponding to the (k+1)th azimuth angle are all 0. In Figure 4, the coordinates where the reflectance factor Z is 1 are indicated by a diagonal line pattern.

[0063] The following describes the operation of determining whether or not T reflection factors Z corresponding to the kth azimuth angle are affected by interference distributed linearly in the distance direction, using the reflection factors Z shown in Fig. 4. Here, the first threshold is set to 1 and the second threshold is set to 10.

[0064] First, the coordinate number calculation unit 311 calculates the number C of coordinates for which the reflectivity factor Z is equal to or greater than the first threshold value at the (k-1)th azimuth angle using T reflectivity factors Z corresponding to the (k-1)th azimuth angle. k-1 The coordinate number calculation unit 311 calculates 0 by using T reflectance factors Z corresponding to the k-th azimuth angle. k The coordinate number calculation unit 311 calculates 10 by using T reflectance factors Z corresponding to the (k+1)th azimuth angle. k+1 and calculate 0.

[0065] Next, the difference calculation unit 312 calculates the coordinate number C corresponding to the k-th azimuth angle. kCoordinate number C corresponding to the (k-1)th azimuth angle from k-1 The difference calculation unit 312 calculates 10 as the difference (first difference) obtained by subtracting the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k+1)th azimuth angle from k+1 The difference calculation unit 312 calculates 10 as the difference (second difference) obtained by subtracting k Then, the maximum value of the first difference and the second difference, 10, is calculated.

[0066] Then, the interference determination unit 313 calculates the calculated difference value D k is equal to or greater than the second threshold, it is determined that the T reflectivity factors Z corresponding to the k-th azimuth angle have been affected by interference that is distributed linearly in the distance direction.

[0067] In this way, the information processing device 3 can use the weather radar observation quantity 41 (reflection factor Z) corresponding to the kth azimuth angle and the azimuth angles in the first range relative to the kth azimuth angle (in FIG. 4, the (k-1)th azimuth angle and the (k+1)th azimuth angle) to determine that the weather radar observation quantity 41 corresponding to the kth azimuth angle has been affected by interference that is distributed linearly in the distance direction.

[0068] 5 is a flowchart showing an example of the procedure of the interference determination process executed in the information processing device 3. The interference determination process is a process for determining whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle. The processing unit 31 of the information processing device 3 executes the interference determination process in response to receiving the weather radar observation amount 41 from, for example, the weather radar device 2A or the storage 4. Here, an example is shown in which the weather radar observation amount 41 used in the interference determination process is the reflectivity factor Z, the first condition is that it is equal to or greater than a first threshold, and the second condition is that it is equal to or greater than a second threshold.

[0069] First, the processing unit 31 calculates the number C of coordinates where the reflectivity factor Z is equal to or greater than the first threshold for each azimuth angle (step S101). Specifically, for each of a plurality of coordinates including each azimuth angle, the processing unit 31 counts the number of reflectivity factors Z that are equal to or greater than the first threshold among the plurality of reflectivity factors Z corresponding to the plurality of coordinates (i.e., the plurality of reflectivity factors Z measured at the plurality of coordinates).

[0070] Next, the processing unit 31 sets a variable k to 1 (step S102). The variable k is used to identify one of all azimuth angles at which the weather radar observation quantity 41 is measured. The total number of azimuth angles at which the weather radar observation quantity 41 is measured is set to N. In other words, the N azimuth angles at which the weather radar observation quantity 41 is measured include the first to Nth azimuth angles. In step S101, the coordinate number C calculated for the kth azimuth angle is set to the coordinate number C corresponding to the kth azimuth angle. k It is called.

[0071] The processing unit 31 calculates the difference value D corresponding to the k-th azimuth angle using the above-mentioned equation 1. k (Step S103). Then, the processing unit 31 calculates the calculated difference value D k It is determined whether or not is equal to or greater than the second threshold value (step S104).

[0072] Difference value D k If k is equal to or greater than the second threshold (Yes in step S104), the processing unit 31 outputs an interference determination result 42 indicating that the weather radar observation amount 41 corresponding to the k-th azimuth angle has been affected by interference (step S105), and proceeds to step S107.

[0073] Difference value D k If k is less than the second threshold (No in step S104), the processing unit 31 outputs an interference determination result 42 indicating that the weather radar observation quantity 41 corresponding to the k-th azimuth angle is not affected by interference (step S106), and proceeds to step S107.

[0074] Next, the processing unit 31 sets the variable k to k+1 (step S107). That is, the processing unit 31 adds 1 to the variable k. Then, the processing unit 31 determines whether the variable k is greater than the total number N of azimuth angles (step S108).

[0075] If the variable k is equal to or less than the total number N of azimuth angles (No in step S108), the processing unit 31 returns to step S103. As a result, the processing unit 31 performs processing to determine whether or not the weather radar observation quantity 41 corresponding to the k-th azimuth angle has been affected by interference, based on the newly set variable k.

[0076] If the variable k is greater than the total number N of azimuth angles (Yes in step S108), the processing unit 31 ends the interference determination process. That is, the processing unit 31 ends the interference determination process because the processing for determining whether or not the weather radar observation amount 41 has been affected by interference for each of the N azimuth angles has been completed.

[0077] By the above interference determination process, the information processing device 3 can determine whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle. As a result, the information processing device 3 can improve the accuracy of the entire weather radar observation amount 41 by, for example, not using the weather radar observation amount 41 at an azimuth angle affected by interference. Therefore, the information processing device 3 can improve the accuracy of detecting local weather phenomena using the weather radar observation amount 41, for example.

[0078] Here, with reference to Figures 6 and 7, it will be explained that the information processing device 3 according to the first embodiment can more accurately determine whether the weather radar observation quantity 41 has been affected by interference than the information processing device according to the comparative example.

[0079] Fig. 6 shows another example of the weather radar observation quantity 41 that is determined to be affected by interference in the information processing device 3 according to the first embodiment. Similar to Fig. 4, Fig. 6 shows an example of the weather radar observation quantity 41 (reflectivity factor Z) measured at each coordinate in a two-dimensional coordinate system in which the horizontal axis indicates the azimuth angle and the vertical axis indicates the distance.

[0080] In the example shown in FIG. 6, among the T reflectivity factors Z corresponding to the (k-1)th azimuth angle, the fifth reflectivity factor Z in order of proximity to the weather radar device 2A is 10, and the remaining (T-1) reflectivity factors Z are all 0. The T reflectivity factors Z corresponding to the kth azimuth angle are all 1. Among the T reflectivity factors Z corresponding to the (k+1)th azimuth angle, the fifth reflectivity factor Z in order of proximity to the weather radar device 2A is 10, and the remaining (T-1) reflectivity factors Z are all 0. A coordinate where the reflectivity factor Z is 10 indicates a localized area of ​​heavy rain. In FIG. 6, coordinates where the reflectivity factor Z is 1 are indicated by a diagonal line pattern, and coordinates where the reflectivity factor Z is 10 are indicated by a dotted pattern.

[0081] The following describes the operation of determining whether or not T reflection factors Z corresponding to the kth azimuth angle are affected by interference distributed linearly in the distance direction, using the reflection factors Z shown in Fig. 6. Here, the first threshold is set to 1, and the second threshold is set to 5.

[0082] First, the coordinate number calculation unit 311 calculates the number C of coordinates for which the reflectivity factor Z is equal to or greater than the first threshold value at the (k-1)th azimuth angle using T reflectivity factors Z corresponding to the (k-1)th azimuth angle. k-1 The coordinate number calculation unit 311 calculates 1 by using T reflectance factors Z corresponding to the k-th azimuth angle. k The coordinate number calculation unit 311 calculates 10 by using T reflectance factors Z corresponding to the (k+1)th azimuth angle. k+1 and calculate 1.

[0083] Next, the difference calculation unit 312 calculates the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k-1)th azimuth angle from k-1 The difference calculation unit 312 calculates 9 as the difference (first difference) obtained by subtracting the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k+1)th azimuth angle from k+1The difference calculation unit 312 calculates 9 as the difference (second difference) obtained by subtracting k The maximum value of the first difference and the second difference, 9, is calculated as follows:

[0084] Then, the interference determination unit 313 calculates the difference value D k is equal to or greater than the second threshold, it is determined that the T reflectivity factors Z corresponding to the k-th azimuth angle have been affected by interference that is distributed linearly in the distance direction.

[0085] In this way, the information processing device 3 according to the first embodiment can determine that the weather radar observation 41 corresponding to the kth azimuth angle is affected by interference even when the weather radar observation 41 corresponding to the first surrounding azimuth angle (in FIG. 6, the weather radar observation 41 corresponding to the (k-1)th azimuth angle and the weather radar observation 41 corresponding to the (k+1)th azimuth angle) includes a weather radar observation 41 indicating a localized heavy rain area. The information processing device 3 according to the first embodiment can accurately determine whether the weather radar observation 41 corresponding to each azimuth angle is affected by interference by using the coordinate number C for each azimuth angle and the difference value D calculated based on the coordinate number C.

[0086] In contrast, the information processing device according to the comparative example determines whether or not the weather radar observation amount 41 corresponding to the k-th azimuth angle is affected by interference using the average value of the weather radar observation amount for each azimuth angle.

[0087] Fig. 7 shows weather radar observation quantities determined to be affected by interference in an information processing device according to a comparative example. Similar to Fig. 6, Fig. 7 shows weather radar observation quantities 41C (reflectivity factor Z) measured at each coordinate in a two-dimensional coordinate system in which the horizontal axis indicates azimuth angle and the vertical axis indicates distance. The weather radar observation quantities 41C shown in Fig. 7 are the same as the weather radar observation quantities 41 shown in Fig. 6.

[0088] The operation of the information processing device of the comparative example will be described below, in which the information processing device uses the reflection factors Z shown in FIG. 7 to determine whether or not T reflection factors Z corresponding to the kth azimuth angle are affected by interference distributed linearly in the distance direction.

[0089] First, the average value of the reflectivity factor Z is calculated for each azimuth angle. Specifically, the average value A of the T reflectivity factors Z corresponding to the (k-1)th azimuth angle is calculated as follows: k-1 The average value A of the T reflectance factors Z corresponding to the kth azimuth angle is calculated as 1 (= 10 / 10). k The average value A of the T reflectance factors Z corresponding to the (k+1)th azimuth angle is calculated as 1. k+1 Therefore, although the distribution of the reflectivity factor Z values ​​differs at each of the three azimuth angles from (k-1)th to (k+1), the average value A is the same.

[0090] Then, the average value A corresponding to the kth azimuth angle k The average value A corresponding to the (k-1)th azimuth angle from k-1 The difference (third difference) obtained by subtracting 0 (= 1 - 1) is calculated. The average value A corresponding to the kth azimuth angle k The average value A corresponding to the (k+1)th azimuth angle from k+1 The difference (fourth difference) obtained by subtracting 0 is calculated.

[0091] If the threshold value is 5, the information processing device of the comparative example determines that the T reflection factors Z corresponding to the kth azimuth angle are not affected by interference because the third difference and the fourth difference are both less than the threshold value.

[0092] In this way, the information processing device of the comparative example uses the average value of the weather radar observation amount 41C for each azimuth angle, and therefore cannot properly determine whether the weather radar observation amount 41C corresponding to the kth azimuth angle is affected by interference. Furthermore, when localized rainfall in which the power changes suddenly in the azimuth angle direction is observed, the information processing device of the comparative example may erroneously determine that the desired signal is a signal affected by interference.

[0093] Therefore, the information processing device 3 according to the first embodiment can determine whether the weather radar observation quantity 41 is affected by interference with higher accuracy than the information processing device according to the comparative example. Specifically, the information processing device 3 can determine, for example, interference that is distributed linearly in the distance direction with higher accuracy than the information processing device according to the comparative example. Furthermore, because the information processing device 3 uses the weather radar observation quantity 41 generated (transmitted) by the weather radar device 2A, it can determine whether the weather radar observation quantity 41 is affected by interference without changing the internal configuration of the weather radar device 2A.

[0094] (Second embodiment) The information processing device 3 according to the first embodiment calculates, for each azimuth angle, the coordinate number C at which the weather radar observation quantity 41 satisfies a first condition, and determines that the weather radar observation quantity 41 corresponding to the target azimuth angle has been affected by interference if a difference value D calculated using the coordinate number corresponding to the target azimuth angle and the coordinate number C corresponding to a peripheral azimuth angle (first peripheral azimuth angle) within a first range of the target azimuth angle satisfies a second condition.

[0095] In contrast, the information processing device 3 according to the second embodiment determines that the weather radar observation quantity 41 corresponding to the target azimuth angle is affected by interference if the difference value D corresponding to the target azimuth angle satisfies the second condition and the coordinate number C corresponding to at least one of one or more azimuth angles within a second range relative to the target azimuth angle satisfies the third condition.

[0096] The configuration of the information processing system 1 including the information processing device 3 according to the second embodiment is similar to that of the information processing system 1 including the information processing device 3 according to the first embodiment. The second embodiment differs from the first embodiment in that, in determining whether the weather radar observation quantity 41 corresponding to the target azimuth angle is affected by interference, it is further determined whether the coordinate number C corresponding to at least one of the surrounding azimuth angles satisfies a third condition. Below, the differences from the first embodiment will be mainly described.

[0097] In the information processing device 3 of the second embodiment, the interference determination unit 313 of the processing unit 31 determines whether a condition (first combination condition) is satisfied in which the difference value D corresponding to the target azimuth angle satisfies the second condition and the coordinate number C corresponding to at least one of one or more azimuth angles (second peripheral azimuth angles) within a second range with respect to the target azimuth angle satisfies the third condition. The interference determination unit 313 determines that the coordinate number C corresponding to at least one of the second peripheral azimuth angles satisfies the third condition as indicating that a weather radar observation amount 41 indicating clear weather is present at the second peripheral azimuth angle. The third condition is, for example, a condition in which the coordinate number C is equal to or less than a third threshold. The third threshold is set to an arbitrary value, for example, 3.

[0098] The second range may be at least partially the same as or different from the first range described in the first embodiment. In other words, the second peripheral azimuth angle may be at least partially the same as or different from one or more azimuth angles (first peripheral azimuth angles) that are within the first range with respect to the target azimuth angle.

[0099] For example, a case will be described in which the target azimuth angle is the k-th azimuth angle, the first peripheral azimuth angles are the (k-1)th azimuth angle and the (k+1)th azimuth angle, and the second peripheral azimuth angles are the (k-2)th azimuth angle, the (k-1)th azimuth angle, the (k+1)th azimuth angle, and the (k+2)th azimuth angle. In this case, the interference determination unit 313 calculates the coordinate numbers C corresponding to the five azimuth angles from the (k-2)th to the (k+2)th azimuth angles, respectively. k-2 , C k-1 , C k , C k+1 , and C k+2 is used to determine whether the weather radar observation 41 corresponding to the k-th azimuth angle is affected by interference.

[0100] Specifically, the interference determination unit 313 calculates, for example, a difference value D corresponding to the k-th azimuth angle. k is equal to or greater than the second threshold, and the coordinate number C corresponding to the second peripheral azimuth angle k-2 , C k-1 , C k+1 , and C k+2is equal to or less than the third threshold. k-2 , C k-1 , C k+1 , and C k+2 is equal to or less than the third threshold, the difference value D corresponding to the k-th azimuth angle k If the first combination condition is not satisfied, the interference determination unit 313 determines that the weather radar observation quantity 41 corresponding to the k-th azimuth angle is not affected by interference.

[0101] 8 shows examples of (a) weather radar observation quantities 41 determined to be affected by interference and (b) weather radar observation quantities 41 determined to be not affected by interference in the information processing device 3 according to the second embodiment. Similar to FIG. 4, FIGS. 8(a) and 8(b) show examples of weather radar observation quantities 41 (e.g., reflectivity factor Z) measured at each coordinate in a two-dimensional coordinate system in which the horizontal axis indicates the azimuth angle and the vertical axis indicates the distance.

[0102] In the example shown in FIG. 8(a), all of the T weather radar observation amounts 41 corresponding to the (k-1)th azimuth angle are 0. All of the T weather radar observation amounts 41 corresponding to the kth azimuth angle are 1. Of the T weather radar observation amounts 41 corresponding to the (k+1)th azimuth angle, the first, third, and fifth weather radar observation amounts 41 in order of proximity to the weather radar device 2A are 1, the second and fourth weather radar observation amounts 41 are 2, and the remaining (T-5) weather radar observation amounts 41 (i.e., the sixth to tenth weather radar observation amounts 41) are all 0. In FIG. 8, coordinates where the weather radar observation amounts 41 are 1 or greater are indicated by a diagonal line pattern.

[0103] The operation of determining whether or not T weather radar observations 41 corresponding to the k-th azimuth angle are affected by interference using the weather radar observations 41 shown in Fig. 8(a) above will be described. In the example shown in Fig. 8, the first threshold is 1, the second threshold is 5, and the third threshold is 1.

[0104] First, the coordinate number calculation unit 311 calculates the number C of coordinates where the weather radar observation amount 41 at the (k-1)th azimuth angle is equal to or greater than the first threshold value using T weather radar observation amounts 41 corresponding to the (k-1)th azimuth angle. k-1 The coordinate number calculation unit 311 calculates 0 by using T weather radar observation amounts 41 corresponding to the k-th azimuth angle, and calculates the number C of coordinates where the weather radar observation amount 41 is equal to or greater than the first threshold value at the k-th azimuth angle. k The coordinate number calculation unit 311 calculates 10 by using T weather radar observation amounts 41 corresponding to the (k+1)th azimuth angle, and calculates the number C of coordinates where the weather radar observation amount 41 is equal to or greater than the first threshold value at the (k+1)th azimuth angle. k+1 As a result, 5 is calculated.

[0105] Next, the difference calculation unit 312 calculates the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k-1)th azimuth angle from k-1 The difference calculation unit 312 calculates 10 as the difference (first difference) obtained by subtracting the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k+1)th azimuth angle from k+1 The difference calculation unit 312 calculates 5 as the difference (second difference) obtained by subtracting k Then, the maximum value of the first difference and the second difference, 10, is calculated.

[0106] Then, the interference determination unit 313 calculates the difference value D k is equal to or greater than the second threshold, and the coordinate number C corresponding to the (k-1)th azimuth angle k-1Since (=0) is equal to or less than the third threshold, it is determined that T weather radar observation amounts 41 corresponding to the k-th azimuth angle are affected by interference. In other words, the interference determination unit 313 determines that, in the weather radar observation amounts 41 shown in FIG. 8(a), a weather radar observation amount 41 indicating clear weather exists at the (k-1)-th azimuth angle, and therefore, the difference value D k is equal to or greater than the second threshold, it is determined that T weather radar observations 41 corresponding to the k-th azimuth angle are affected by interference.

[0107] 8(b), among the T weather radar observation amounts 41 corresponding to the (k-1)th azimuth angle, the eighth and tenth weather radar observation amounts 41 in order of proximity to the weather radar device 2A are 1, the ninth weather radar observation amount 41 is 2, and the remaining (T-3) weather radar observation amounts 41 (i.e., the first to seventh weather radar observation amounts 41) are all 0. All of the T weather radar observation amounts 41 corresponding to the kth azimuth angle are 1. Among the T weather radar observation amounts 41 corresponding to the (k+1)th azimuth angle, the first, third, and fifth weather radar observation amounts 41 in order of proximity to the weather radar device 2A are 1, the second and fourth weather radar observation amounts 41 are 2, and the remaining (T-5) weather radar observation amounts 41 are all 0.

[0108] The operation of determining whether or not T weather radar observations 41 corresponding to the k-th azimuth angle are affected by interference using the weather radar observations 41 shown in FIG. 8(b) above will be described.

[0109] First, the coordinate number calculation unit 311 calculates the number C of coordinates where the weather radar observation amount 41 at the (k-1)th azimuth angle is equal to or greater than the first threshold value using T weather radar observation amounts 41 corresponding to the (k-1)th azimuth angle. k-1 The coordinate number calculation unit 311 calculates 3 by using T weather radar observation amounts 41 corresponding to the k-th azimuth angle, and calculates the number C of coordinates where the weather radar observation amount 41 is equal to or greater than the first threshold value at the k-th azimuth angle. kThe coordinate number calculation unit 311 calculates 10 by using T weather radar observation amounts 41 corresponding to the (k+1)th azimuth angle, and calculates the number C of coordinates where the weather radar observation amount 41 is equal to or greater than the first threshold value at the (k+1)th azimuth angle. k+1 As a result, 5 is calculated.

[0110] Next, the difference calculation unit 312 calculates the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k-1)th azimuth angle from k-1 The difference calculation unit 312 calculates 7 as the difference (first difference) obtained by subtracting the coordinate number C corresponding to the k-th azimuth angle. k Coordinate number C corresponding to the (k+1)th azimuth angle from k+1 The difference calculation unit 312 calculates 5 as the difference (second difference) obtained by subtracting k Then, the maximum value of the first difference and the second difference, 7, is calculated.

[0111] Then, the interference determination unit 313 calculates the difference value D k is equal to or greater than the second threshold, but the coordinate number C corresponding to the (k-1)th azimuth angle k-1 (=3) and the coordinate number C corresponding to the (k+1)th azimuth angle k+1 Since none of the (k-1)th and (k+1)th azimuth angles is equal to or less than the third threshold, the interference determination unit 313 determines that the T weather radar observations 41 corresponding to the k-th azimuth angle are not affected by interference. In other words, in the weather radar observations 41 shown in FIG. 8(b), there are no weather radar observations 41 indicating clear weather at either the (k-1)th or (k+1)th azimuth angle, so the interference determination unit 313 determines that the difference value D k is equal to or greater than the second threshold, it is determined that the T weather radar observations 41 corresponding to the k-th azimuth angle are not affected by interference.

[0112] In this way, the information processing device 3 can determine for each azimuth angle whether the weather radar observation amount 41 has been affected by interference by further considering whether the coordinate number C corresponding to at least any of the second peripheral azimuth angles is equal to or less than the third threshold value (i.e., whether the weather radar observation amount 41 corresponding to at least any of the second peripheral azimuth angles is a weather radar observation amount 41 indicating clear weather). This allows the information processing device 3 to improve the accuracy of the weather radar observation amount 41, for example, by not using the weather radar observation amount 41 for an azimuth angle affected by interference.

[0113] 9 is a flowchart showing an example of the procedure of the collision detection process executed in the information processing device 3 according to the second embodiment. This collision detection process is the collision detection process described above with reference to FIG. 5 in the first embodiment, with the procedure of step S205 added. The procedures of steps S201 to S204 and steps S206 to S209 are the same as the procedures of steps S101 to S108 of the collision detection process shown in FIG. 5. Therefore, the following mainly describes the process related to the added step S205. Here, an example is shown in which the first condition is a condition that the value is equal to or greater than a first threshold, the second condition is a condition that the value is equal to or greater than a second threshold, and the third condition is a condition that the value is equal to or less than a third threshold.

[0114] The processing unit 31 calculates the difference value D corresponding to the k-th azimuth angle. k is equal to or greater than the second threshold (Yes in step S204), the processing unit 31 determines whether the coordinate number C corresponding to at least one of the surrounding azimuth angles (second surrounding azimuth angles) of the kth azimuth angle is equal to or less than the third threshold (step S205). That is, the processing unit 31 determines whether the weather radar observation amount 41 corresponding to at least one of the surrounding azimuth angles is a weather radar observation amount 41 indicating clear weather.

[0115] If the coordinate number C corresponding to at least one of the surrounding azimuth angles of the k-th azimuth angle is equal to or less than the third threshold (Yes in step S205), the processing unit 31 outputs an interference determination result 42 indicating that the weather radar observation amount 41 corresponding to the k-th azimuth angle has been affected by interference (step S206), and proceeds to step S208. In other words, the processing unit 31 determines that the weather radar observation amount 41 corresponding to the surrounding azimuth angles indicates clear weather, and therefore determines that the difference value D is equal to or greater than the second threshold. k It is determined that the weather radar observation 41 at the k-th azimuth angle corresponding to the k-th azimuth angle is affected by interference.

[0116] On the other hand, if the coordinate number C corresponding to any of the surrounding azimuth angles of the k-th azimuth angle is greater than the third threshold (Yes in step S205), the processing unit 31 outputs an interference determination result 42 indicating that the weather radar observation amount 41 corresponding to the k-th azimuth angle is not affected by interference (step S207), and proceeds to step S208. In other words, the processing unit 31 determines that the weather radar observation amount 41 corresponding to the surrounding azimuth angles indicates rain (rainfall), and therefore the difference value D k Even if the weather radar observation value 41 at the k-th azimuth angle corresponding to the k-th azimuth angle is not affected by interference, it is determined that the weather radar observation value 41 is not affected by interference.

[0117] By the above interference determination process, the information processing device 3 can determine, for each azimuth angle, whether or not the weather radar observation amount 41 is affected by interference in clear weather. This allows the information processing device 3 to determine with high accuracy whether or not the weather radar observation amount 41 in clear weather is affected by interference, and can also prevent the information processing device 3 from erroneously determining that the weather radar observation amount 41 is affected by interference during rainfall. Note that, although an example is shown in FIG. 9 in which the determination in step S205 is performed after the determination in step S204, the determination in step S204 may also be performed after the determination in step S205.

[0118] (Third embodiment) The information processing device 3 according to the first and second embodiments determines for each azimuth angle whether the weather radar observation quantity 41 is affected by interference. The information processing device 3 according to the third embodiment further removes the weather radar observation quantity 41 that has been determined to be affected by interference.

[0119] The configuration of the information processing system 1 including the information processing device 3 according to the third embodiment is similar to that of the information processing system 1 including the information processing device 3 according to the first and second embodiments. The third embodiment differs from the first and second embodiments in that the weather radar observation amount 41 affected by interference is further removed. The following mainly describes the differences from the first and second embodiments.

[0120] 10 is a block diagram showing an example of the functional configuration of an information processing device 3 according to the third embodiment. A processing unit 31 of the information processing device 3 processes the input weather radar observation amount 41 and outputs a weather radar observation amount 43 from which the weather radar observation amount 41 affected by interference has been removed. The weather radar observation amount 41 is, for example, a reflectivity factor Z. In this case, the weather radar observation amount 43 is expressed as a reflectivity factor Z'.

[0121] The processing unit 31 includes, for example, a coordinate number calculation unit 311, a difference calculation unit 312, an interference determination unit 313, and an interference removal unit 314. These units may be functional components processed by the processing unit 31, or may be functional components realized by the CPU 11 executing the interference determination program 131, for example. The functions of the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 are as described above with reference to FIG. 3 etc.

[0122] The interference removal unit 314 removes weather radar observation quantities 41 affected by interference from the input weather radar observation quantities 41 based on the interference determination result 42 output by the interference determination unit 313. Specifically, when the interference determination unit 313 determines that multiple weather radar observation quantities 41 corresponding to the target azimuth angle (more specifically, multiple weather radar observation quantities 41 corresponding to multiple coordinates including the target azimuth angle) are affected by interference, the interference removal unit 314 sets the multiple weather radar observation quantities 41 to invalid values. That is, the interference removal unit 314 replaces each of the multiple weather radar observation quantities 41 with an invalid value. For example, when the target azimuth angle is the kth azimuth angle, the interference removal unit 314 sets the multiple weather radar observation quantities 41 corresponding to the kth azimuth angle to invalid values. An invalid value is, for example, a value that is predefined to be treated as an invalid value or not to be treated as a weather radar observation quantity. Alternatively, the use of a certain value (for example, −1, 0, etc.) as an invalid value may be specified in a system (for example, the information processing system 1) that uses the weather radar observation amount 41.

[0123] If the interference determination unit 313 determines that the plurality of weather radar observation amounts 41 corresponding to the target azimuth angle are affected by interference, the interference removal unit 314 may set the plurality of weather radar observation amounts 41 and the plurality of weather radar observation amounts 41 corresponding to one or more azimuth angles (third peripheral azimuth angles) within a third range with respect to the target azimuth angle to invalid values. More specifically, the plurality of weather radar observation amounts 41 corresponding to one or more azimuth angles within the third range with respect to the target azimuth angle are the plurality of weather radar observation amounts 41 corresponding to a plurality of coordinates including one or more azimuth angles within the third range with respect to the target azimuth angle. The plurality of coordinates including one or more azimuth angles are, for example, all coordinates specified by one or more azimuth angles and one or more distances defined in a two-dimensional coordinate system.

[0124] The third range indicates a range of azimuth angles within which the corresponding weather radar observations 41 are removed. The third range is, for example, the same as the second range described in the second embodiment. In this case, the third peripheral azimuth angles are the same as one or more azimuth angles (second peripheral azimuth angles) that are within the second range relative to the target azimuth angle. Alternatively, the third range may be at least partially the same as or different from the second range.

[0125] For example, assume that the target azimuth angle is the kth azimuth angle, the first peripheral azimuth angles are the (k-1)th and (k+1)th azimuth angles, and the third peripheral azimuth angles are the (k-2)th, (k-1)th, (k+1)th, and (k+2)th azimuth angles. In this case, the interference removal unit 314 sets the multiple weather radar observation amounts 41 corresponding to each of the five azimuth angles from the (k-2)th to the (k+2)th to invalid values.

[0126] Hereinafter, the processing by the interference removal unit 314 to remove the weather radar observation amount 41 affected by interference (that is, to set it to an invalid value) will also be referred to as interference removal processing.

[0127] 11 shows an example of (a) a weather radar observation amount 41 and (b) a weather radar observation amount 43 from which interference has been removed in the information processing device 3. Figures 11(a) and 11(b) respectively show the distribution (Plan Position Indication: PPI) of the weather radar observation amounts 41 and 43 at each coordinate (polar coordinate) specified by the azimuth angle and the distance from the weather radar device 2A on a plane (Cartesian coordinate system) in which the horizontal axis indicates the east-west direction and the vertical axis indicates the north-south direction. The origin O on the plane (i.e., coordinate (0,0) on the horizontal and vertical axes) corresponds to the location where the weather radar device 2A is installed.

[0128] 11(a) shows the weather radar observation quantity 41 (reflection factor Z) input to the information processing device 3. In the information processing device 3, the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 determine that the weather radar observation quantity 41 corresponding to the azimuth angle α has been affected by interference that is distributed linearly in the distance direction.

[0129] 11(b) shows a weather radar observation amount 43 from which the weather radar observation amount 41 determined to be affected by interference has been removed. The interference removal unit 314 removes the weather radar observation amount 41 determined to be affected by interference. Specifically, the interference removal unit 314 generates the weather radar observation amount 43 by setting the weather radar observation amount 41 corresponding to the azimuth angle α to an invalid value.

[0130] In this way, the information processing device 3 according to the third embodiment can remove the weather radar observation amount 41 that is determined to be affected by interference. Therefore, the information processing device 3 can acquire the weather radar observation amount 43 that does not include the influence of interference, and can improve the accuracy of the weather radar observation amount 43.

[0131] 12 is a flowchart showing an example of the procedure of the first interference determination and removal process executed in the information processing device 3. The first interference determination and removal process is a process of determining whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle, and removing the weather radar observation amount 41 affected by the interference. The processing unit 31 of the information processing device 3 executes the first interference determination and removal process in response to receiving the weather radar observation amount 41 from, for example, the weather radar device 2A or the storage 4. Here, an example will be shown in which the first condition is a condition that the value is equal to or greater than a first threshold value, and the second condition is a condition that the value is equal to or greater than a second threshold value.

[0132] The first collision detection and removal process is a process in which the procedure of step S306 is added to the collision detection process described above with reference to Fig. 5 in the first embodiment. The procedures of steps S301 to S305 and steps S307 to S309 are the same as the procedures of steps S101 to S108 of the collision detection process shown in Fig. 5. Therefore, the process related to the added step S306 will be described below.

[0133] In step S305, the processing unit 31 outputs the interference determination result 42 indicating that the weather radar observation quantity 41 corresponding to the k-th azimuth angle has been affected by interference, and then sets the weather radar observation quantity 41 corresponding to the k-th azimuth angle to an invalid value (step S306), and proceeds to step S308. Specifically, the processing unit 31 sets the weather radar observation quantity 41 (e.g., reflectivity factor Z, received power P) of each of the multiple coordinates corresponding to the k-th azimuth angle to an invalid value.

[0134] By the above-described first interference determination and removal process, the information processing device 3 can remove the weather radar observation amount 41 that is affected by interference. Therefore, the information processing device 3 can acquire the weather radar observation amount 43 that does not include the influence of interference, and can improve the accuracy of the weather radar observation amount 43.

[0135] The first interference determination and removal process may be a process in which the procedure of step S306 is added to the interference determination process described above with reference to Fig. 9 in the second embodiment. In this case, the procedure of step S306 is added immediately after step S206 of the interference determination process shown in Fig. 9. This first interference determination and removal process can determine with high accuracy whether or not the weather radar observation amount 41 in fine weather is affected by interference, and can acquire the weather radar observation amount 43 that does not include the influence of interference in a state in which it is possible to prevent the weather radar observation amount 41 from being erroneously determined to be affected by interference during rainfall.

[0136] Furthermore, the first interference determination / removal process may be a process of removing weather radar observation amounts 41 affected by interference from input weather radar observation amounts 41, using the interference determination result 42 obtained by the interference determination process, after the interference determination process shown in Fig. 5 or 9 is completed. In this case, the processing unit 31 determines, for each azimuth angle, whether the weather radar observation amount 41 is affected by interference, using the interference determination result 42. Then, when the processing unit 31 determines that the weather radar observation amount 41 corresponding to a certain azimuth angle is affected by interference, it removes the weather radar observation amount 41 corresponding to that azimuth angle.

[0137] (Fourth embodiment) The information processing device 3 according to the third embodiment determines whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle, and removes the weather radar observation amount 41 that has been determined to be affected by interference.

[0138] In the information processing device 3 according to the first to third embodiments, when the weather radar observation quantity 41 is affected by continuous interference across multiple azimuth angles (for example, a wide range of azimuth angles), the weather radar observation quantity 41 corresponding to the azimuth angle at the end of the multiple azimuth angles is determined to be affected by the interference. Therefore, in the information processing device 3, it is conceivable to set a parameter indicating a wide third range (a range of azimuth angles to be removed) so as to remove the weather radar observation quantity 41 corresponding to a range centered on the azimuth angle at the end and including the multiple azimuth angles affected by the interference.

[0139] As a result, for example, if the weather radar observation quantity 41 is affected by continuous interference across five azimuth angles, and the azimuth angle at the end of the five azimuth angles is set as a target azimuth angle and it is determined that the corresponding weather radar observation quantity 41 is affected by the interference, the information processing device 3 removes the weather radar observation quantity 41 corresponding to the range that includes the five azimuth angles with the target azimuth angle as the center. Specifically, the information processing device 3 removes, for example, the weather radar observation quantity 41 that corresponds to the range of azimuth angles from four angles before to four angles after the target azimuth angle (azimuth angles in the range of ±4 angles from the target azimuth angle). Therefore, the information processing device 3 can remove the weather radar observation quantity 41 that is affected by continuous interference across five azimuth angles.

[0140] However, if the parameter (third range) is set to remove the weather radar observation amounts 41 corresponding to a wide range of azimuth angles centered on the target azimuth angle, not only the weather radar observation amounts 41 corresponding to azimuth angles on the side of the target azimuth angle that are continuously affected by interference (for example, azimuth angles in a range of target azimuth angle +4) but also the weather radar observation amounts 41 corresponding to azimuth angles on the side that are not affected by interference (for example, azimuth angles in a range of target azimuth angle -4) will be removed. Furthermore, even if only the weather radar observation amounts 41 corresponding to the target azimuth angle are affected by interference, the weather radar observation amounts 41 corresponding to a wide range of azimuth angles centered on the target azimuth angle (for example, azimuth angles in a range of target azimuth angle ±4) will be removed. Therefore, in the information processing device 3 according to the third embodiment, if the parameter indicating the wide third range is set, there is a possibility that the weather radar observation amounts 41, which are desired signals not affected by interference (i.e., the weather radar observation amounts 41 that should be observed), will be excessively removed.

[0141] In contrast, when a weather radar observation quantity 41 is affected by continuous interference spanning multiple azimuth angles, the information processing device 3 according to the fourth embodiment removes the weather radar observation quantity 41 affected by the interference without excessively removing the weather radar observation quantity 41 that is not affected by the interference.

[0142] The configuration of the information processing system 1 including the information processing device 3 according to the fourth embodiment is similar to that of the information processing system 1 including the information processing device 3 according to the first to third embodiments. The first to third embodiments differ from the fourth embodiment in that the weather radar observation amounts 41 affected by continuous interference across multiple azimuth angles are removed without excessively removing weather radar observation amounts 41 not affected by interference. Below, the differences from the first to third embodiments will be mainly described.

[0143] Fig. 13 is a block diagram showing an example of the functional configuration of an information processing device 3 according to the fourth embodiment. The processing unit 31 of the information processing device 3 processes the input weather radar observation amount 41 and outputs a weather radar observation amount 44 from which the weather radar observation amount 41 affected by interference has been removed. The processing unit 31 is configured to repeatedly execute the processes (interference detection and removal process) by the coordinate number calculation unit 311, difference calculation unit 312, interference determination unit 313, and interference removal unit 314 described above with reference to Figs. 3 and 10 a plurality of times. Fig. 13 illustrates a configuration in which the interference detection and removal process is repeatedly executed twice. Note that the interference detection and removal process may be repeatedly executed three or more times.

[0144] The processing unit 31 includes, for example, a coordinate number calculation unit 311-2, a difference calculation unit 312-2, an interference determination unit 313-2, and an interference removal unit 314-2 in addition to a coordinate number calculation unit 311, a difference calculation unit 312, an interference determination unit 313, and an interference removal unit 314. These units may be functional components processed by the processing unit 31, and are functional components realized, for example, by the CPU 11 executing the interference detection program 131. The functions of the coordinate number calculation unit 311, the difference calculation unit 312, the interference determination unit 313, and the interference removal unit 314 are as described above with reference to FIGS. 3 and 10, etc.

[0145] The coordinate number calculation unit 311-2, the difference calculation unit 312-2, the interference determination unit 313-2, and the interference removal unit 314-2 have the same functions as the coordinate number calculation unit 311, the difference calculation unit 312, the interference determination unit 313, and the interference removal unit 314, respectively. Note that the coordinate number calculation unit 311-2 uses the weather radar observation amount 43 (reflection factor Z') sent by the interference removal unit 314 to calculate, for each azimuth angle, the coordinate number C at which the weather radar observation amount 43 satisfies a first condition (for example, is equal to or greater than a first threshold value). The subsequent operations of the difference calculation unit 312-2, the interference determination unit 313-2, and the interference removal unit 314-2 are the same as those of the difference calculation unit 312, the interference determination unit 313, and the interference removal unit 314.

[0146] 14 shows examples of (a) weather radar observation amounts, (b) weather radar observation amounts with interference removed, and (c) weather radar observation amounts with interference further removed, in the information processing device 3. 14(a), (b), and (c) show distributions (PPI) of weather radar observation amounts 41, 43, and 44 at coordinates specified by the azimuth angle and the distance from the weather radar device 2A, respectively, on a plane in which the horizontal axis indicates the east-west direction and the vertical axis indicates the north-south direction.

[0147] 14(a) shows the weather radar observation amount 41 (reflection factor Z) input to the information processing device 3. The coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 determine that the weather radar observation amount 41 has been affected by interference. Specifically, the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 determine that the weather radar observation amount 41 corresponding to the azimuth angles at both ends of a plurality of azimuth angles centered around the azimuth angle β (hereinafter referred to as first target azimuth angles) has been affected by interference that is distributed linearly in the distance direction.

[0148] 14(b) shows a weather radar observation amount 43 from which the weather radar observation amount 41 determined to be affected by interference has been removed. The interference removal unit 314 removes the weather radar observation amount 41 determined to be affected by interference. Specifically, the interference removal unit 314 generates the weather radar observation amount 43 by setting the weather radar observation amount 41 corresponding to the first target azimuth angle to an invalid value.

[0149] 14(c) shows a weather radar observation quantity 44 obtained by further removing the weather radar observation quantity 43 determined to be affected by interference. Specifically, the coordinate number calculation unit 311-2, the difference calculation unit 312-2, and the interference determination unit 313-2 determine that the weather radar observation quantities 43 corresponding to one or more azimuth angles (hereinafter referred to as second target azimuth angles) obtained by excluding the first target azimuth angle from multiple azimuth angles centered on the azimuth angle β are affected by interference distributed linearly in the distance direction. Then, the interference removal unit 314-2 generates the weather radar observation quantity 44 by setting the weather radar observation quantity 43 corresponding to the second target azimuth angle to an invalid value.

[0150] In this way, the information processing device 3 according to the fourth embodiment can remove weather radar observation amounts 41 that are affected by interference continuously at multiple azimuth angles, without excessively removing weather radar observation amounts 41 that are not affected by interference, by repeatedly performing interference determination and removal processing on the input weather radar observation amounts 41. Therefore, the information processing device 3 can acquire weather radar observation amounts 44 that do not include the influence of interference, and improve the accuracy of the weather radar observation amounts 44.

[0151] FIG. 15 is a flowchart showing an example of the procedure of the second interference determination and removal process executed in the information processing device 3 according to the fourth embodiment. The second interference determination and removal process is a process of determining whether or not the weather radar observation amount 41 is affected by interference for each azimuth angle, and removing the weather radar observation amount 41 affected by the interference. More specifically, the second interference determination and removal process is a process of repeating the first interference determination and removal process described above with reference to FIG. 12 in the third embodiment a specific number of times. Here, the specific number is set to B times, and is referred to as the number of repetitions B. B is, for example, an integer equal to or greater than 2. The processing unit 31 of the information processing device 3 executes the second interference determination and removal process in response to receiving the weather radar observation amount 41 from the weather radar device 2A or the storage 4, for example.

[0152] First, the processing unit 31 sets a variable i to 1 (step S41). The variable i indicates that the first interference detection and removal process is being performed for the i-th time out of the number of repetitions B.

[0153] Next, the processing unit 31 performs the i-th first interference detection and removal process (step S42). The specific procedure of the first interference detection and removal process is as described above with reference to the flowchart in FIG.

[0154] After the i-th iteration of the first interference detection and removal process is completed, the processing unit 31 sets the variable i to i+1 (step S43). Then, the processing unit 31 determines whether the variable i is equal to or less than the number of iterations B (step S44).

[0155] If the variable i is equal to or smaller than the number of repetitions B (Yes in step S44), the processing unit 31 returns to step S42. As a result, the i-th iteration of the first interference detection and removal process is performed based on the newly set variable i.

[0156] If the variable i is greater than the number of repetitions B (No in step S44), the processing unit 31 ends the second interference detection and removal process.

[0157] By the above-described second interference determination and removal process, when the weather radar observation quantities 41 corresponding to a wide range of continuous azimuth angles are affected by interference, the information processing device 3 can remove the weather radar observation quantities 41 corresponding to the wide range of azimuth angles without excessively removing the weather radar observation quantities 41 corresponding to azimuth angles that are not affected by interference.

[0158] (Fifth embodiment) When a weather radar observation quantity 41 is affected by continuous interference across multiple azimuth angles, the information processing device 3 according to the fourth embodiment removes the weather radar observation quantity 41 affected by the interference without excessively removing the weather radar observation quantity 41 that is not affected by the interference.

[0159] Like the information processing device 3 according to the fourth embodiment, when a weather radar observation quantity 41 is affected by continuous interference across multiple azimuth angles, the information processing device 3 according to the fifth embodiment removes the weather radar observation quantity 41 affected by the interference without excessively removing the weather radar observation quantity 41 that is not affected by the interference, but the method for doing so is different from that according to the fourth embodiment.

[0160] The configuration of the information processing system 1 including the information processing device 3 according to the fifth embodiment is similar to that of the information processing system 1 including the information processing device 3 according to the first to third embodiments. The first to third embodiments differ from the fifth embodiment in that the weather radar observation amounts 41 affected by continuous interference across multiple azimuth angles are removed without excessively removing weather radar observation amounts 41 not affected by interference. Below, the differences from the first to third embodiments will be mainly described.

[0161] 16 is a block diagram showing an example of the functional configuration of an information processing device 3 according to a fifth embodiment. In addition to a weather radar observation 41, a second weather radar observation 45 is input to a processing unit 31 of the information processing device 3. The second weather radar observation 45 is, for example, a reflectivity factor difference ZDR. The second weather radar observation 45 may be a Doppler velocity width W. When the reflectivity factor difference ZDR is used as the second weather radar observation 45, the weather radar device 2A that generates the weather radar observation 41 and the second weather radar observation 45 is, for example, a dual-polarization radar. The processing unit 31 processes the input weather radar observation 41 and the second weather radar observation 45 and outputs a weather radar observation 47 from which the weather radar observation 41 affected by interference has been removed.

[0162] The processing unit 31 includes, for example, a coordinate number calculation unit 311, a difference calculation unit 312, an interference determination unit 313, and an interference removal unit 314, as well as a statistics calculation unit 321, a second interference determination unit 322, and a second interference removal unit 323.

[0163] The statistics calculation unit 321 receives as input second weather radar observation values ​​45 corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance. The statistics calculation unit 321 calculates statistics S for each azimuth angle using the second weather radar observation values ​​45. Specifically, the statistics calculation unit 321 calculates, for example, the maximum absolute value of the reflectivity factor difference ZDR for each azimuth angle as the statistics S. Note that the statistics calculation unit 321 may also use the second weather radar observation values ​​45 to calculate statistics S at a target azimuth angle (target azimuth angle) for determining whether or not there has been an effect of interference. For example, the statistics calculation unit 321 may calculate, as the statistics S, the maximum absolute value of the reflectivity factor difference ZDR at the target azimuth angle.

[0164] Note that other combinations may be used as the combination of the type of second weather radar observation quantity 45 used by the statistics calculation unit 321 and the calculated statistics S according to the characteristics of the influencing interference signal. For example, if there is a characteristic that the Doppler velocity width W increases when influenced by an interference signal, the statistics calculation unit 321 calculates the average value of the Doppler velocity width W for each azimuth angle as the statistics S.

[0165] The second interference determination unit 322 determines whether or not the plurality of second weather radar observation quantities 45 corresponding to the target azimuth angle (more specifically, the plurality of second weather radar observation quantities 45 corresponding to the plurality of coordinates including the target azimuth angle) have been affected by interference, based on the statistic S calculated by the statistic calculation unit 321. The second interference determination unit 322 determines whether or not the plurality of second weather radar observation quantities 45 corresponding to the target azimuth angle have been affected by interference, for example, depending on whether or not the statistic S satisfies a fourth condition. The fourth condition is, for example, that the statistic S is equal to or greater than a fourth threshold. When the second weather radar observation quantity 45 is a reflectivity factor difference ZDR, the fourth threshold is set to, for example, 10 dB.

[0166] For example, when the target azimuth angle is the kth azimuth angle, the second interference determination unit 322 calculates the statistic S k Based on the statistic S k is equal to or greater than the fourth threshold, the second interference determination unit 322 determines that the plurality of second weather radar observation amounts 45 corresponding to the k-th azimuth angle are affected by interference. k is less than the fourth threshold, the second interference determination unit 322 determines that the plurality of second weather radar observation amounts 45 corresponding to the k-th azimuth angle are not affected by interference.

[0167] The second interference determination unit 322 sends, for example, second interference determination results 48 indicating for each azimuth angle whether the corresponding plurality of second weather radar observation amounts 45 have been affected by interference to the second interference removal unit 323. Note that the second interference determination results 48 may indicate the azimuth angles at which the corresponding plurality of second weather radar observation amounts 45 have been affected by interference.

[0168] The second interference removal unit 323 receives the second interference determination result 48 and the weather radar observation amount 41. Based on the second interference determination result 48, the second interference removal unit 323 removes the weather radar observation amount 41 affected by interference from the input weather radar observation amount 41.

[0169] Specifically, when the second interference determination unit 322 determines that the plurality of second weather radar observation amounts 45 corresponding to the target azimuth angle are affected by interference, the second interference removal unit 323 sets the plurality of weather radar observation amounts 41 corresponding to the target azimuth angle (more specifically, the plurality of weather radar observation amounts 41 corresponding to the plurality of coordinates including the target azimuth angle) to invalid values. For example, when the target azimuth angle is the kth azimuth angle, the second interference removal unit 323 sets the plurality of weather radar observation amounts 41 corresponding to the kth azimuth angle to invalid values.

[0170] In addition, when the second interference determination unit 322 determines that the plurality of second weather radar observation amounts 45 corresponding to the target azimuth angle are affected by interference, the second interference removal unit 323 may set the plurality of weather radar observation amounts 41 corresponding to the target azimuth angle and the plurality of weather radar observation amounts 41 corresponding to one or more azimuth angles (third surrounding azimuth angles) within a third range with respect to the target azimuth angle to invalid values.

[0171] The second interference removal unit 323 sends to the coordinate number calculation unit 311 a weather radar observation amount 46 (reflection factor Z′) obtained by removing the weather radar observation amount 41 affected by interference.

[0172] The coordinate number calculation unit 311 calculates, for each azimuth angle, the coordinate number C at which the weather radar observation amount 46 satisfies a first condition (for example, is equal to or greater than a first threshold value) using the weather radar observation amount 46 sent by the second interference removal unit 323. The operations of the coordinate number calculation unit 311, the difference calculation unit 312, the interference determination unit 313, and the interference removal unit 314 are the same as those described in the first to third embodiments, except that the weather radar observation amount 41 input to the information processing device 3 from the outside is not input directly to the coordinate number calculation unit 311, but the weather radar observation amount 46 from which interference has been removed by the second interference removal unit 323 from the weather radar observation amount 41 is input to the coordinate number calculation unit 311. That is, the coordinate number calculation unit 311, difference calculation unit 312, interference determination unit 313, and interference removal unit 314 receive as input the weather radar observation amount 46 from which interference has been removed by the second interference removal unit 323, and further perform interference determination and removal processing on the weather radar observation amount 46. This makes it possible to remove weather radar observation amounts 41 that are affected by interference continuously at multiple azimuth angles.

[0173] Fig. 17 shows an example of a second weather radar observation quantity that is determined to be affected by interference by the information processing device 3. Similar to Fig. 4, Fig. 17 shows an example of a second weather radar observation quantity 45 measured at each coordinate in a two-dimensional coordinate system in which the horizontal axis indicates the azimuth angle and the vertical axis indicates the distance. Here, it is assumed that the second weather radar observation quantity 45 is the reflectivity factor difference ZDR.

[0174] In the example shown in Fig. 17, of the T reflectivity factor differences ZDR corresponding to the (k-1)th azimuth angle, the fifth reflectivity factor difference ZDR in order of proximity to the weather radar device 2A is 3, and the remaining (T-1) reflectivity factor differences ZDR are all 0. Of the T reflectivity factor differences ZDR corresponding to the kth azimuth angle, the fifth reflectivity factor difference ZDR in order of proximity to the weather radar device 2A is 15, and the remaining (T-1) reflectivity factor differences ZDR are all 1. Of the T reflectivity factor differences ZDR corresponding to the (k+1)th azimuth angle, the fifth reflectivity factor difference ZDR in order of proximity to the weather radar device 2A is 5, and the remaining (T-1) reflectivity factor differences ZDR are all 0. In Fig. 17, coordinates where the reflectivity factor difference ZDR is greater than 1 are indicated by a diagonal line pattern.

[0175] The following describes the operation of determining whether or not T reflectivity factor differences ZDR corresponding to the kth azimuth angle are affected by interference distributed linearly in the distance direction, using the reflectivity factor differences ZDR (second weather radar observation quantity 45) shown in Fig. 17. Here, the fourth threshold is set to 10.

[0176] First, the statistics calculation unit 321 uses T reflectivity factor differences ZDR corresponding to the (k-1)th azimuth angle to calculate 3 as the maximum absolute value of the reflectivity factor difference ZDR at the (k-1)th azimuth angle. The statistics calculation unit 321 uses T reflectivity factor differences ZDR corresponding to the (k)th azimuth angle to calculate 15 as the maximum absolute value of the reflectivity factor difference ZDR at the kth azimuth angle. The statistics calculation unit 321 uses T reflectivity factor differences ZDR corresponding to the (k+1)th azimuth angle to calculate 5 as the maximum absolute value of the reflectivity factor difference ZDR at the (k+1)th azimuth angle.

[0177] Next, the second interference determination unit 322 determines that the T weather radar observation amounts 44 corresponding to the kth azimuth angle, for which the calculated maximum value is equal to or greater than the fourth threshold, are affected by interference linearly distributed in the distance direction. The second interference determination unit 322 also determines that the T weather radar observation amounts 44 corresponding to the (k-1)th azimuth angle and the (k+1)th azimuth angle, for which the calculated maximum value is less than the fourth threshold, are not affected by interference linearly distributed in the distance direction. The second interference determination unit 322 then sends a second interference determination result 48 indicating that the second weather radar observation amount 45 corresponding to the kth azimuth angle is affected by interference to the second interference removal unit 323.

[0178] In this case, the second interference removal unit 323 removes, for example, the weather radar observation 41 corresponding to the k-th azimuth angle from the weather radar observation 41 including the reflectivity factor Z, based on the second interference determination result 48 indicating that the second weather radar observation 45 corresponding to the k-th azimuth angle has been affected by interference. That is, the second interference removal unit 323 removes the interference received by the weather radar observation 41 (for example, the reflectivity factor Z) based on the second interference determination result 48 determined using the second weather radar observation 45 (for example, the reflectivity factor difference ZDR). The second interference removal unit 323 sends the weather radar observation 46 obtained by removing the interference to the coordinate number calculation unit 311.

[0179] 18 shows examples of (a) weather radar observation quantities, (b) weather radar observation quantities with the effects of interference removed, and (c) weather radar observation quantities with the effects of interference further removed, in the information processing device 3. Figures 18(a), (b), and (c) show distributions (PPI) of weather radar observation quantities 41, 46, and 47 at each coordinate specified by the azimuth angle and the distance from the weather radar device 2A on a plane in which the horizontal axis indicates the east-west direction and the vertical axis indicates the north-south direction, respectively.

[0180] 18(a) shows the weather radar observation amount 41 (reflection factor Z) input to the information processing device 3. The statistics calculation unit 321 and the second interference determination unit 322 determine that the weather radar observation amount 41 has been affected by interference. Specifically, the statistics calculation unit 321 and the second interference determination unit 322 determine that, for example, among a plurality of azimuth angles centered on the azimuth angle γ, the weather radar observation amount 41 corresponding to one or more azimuth angles (hereinafter referred to as third target azimuth angles) at which the maximum absolute value of the reflectivity factor difference ZDR is equal to or greater than a fourth threshold value has been affected by interference distributed in the distance direction.

[0181] 18(b) shows a weather radar observation quantity 46 from which the weather radar observation quantity 41 determined to be affected by interference has been removed. The second interference removal unit 323 removes the weather radar observation quantity 41 corresponding to the third target azimuth angle. Specifically, the second interference removal unit 323 generates the weather radar observation quantity 46 by setting the weather radar observation quantity 41 corresponding to the third target azimuth angle to an invalid value. Note that the second interference removal unit 323 may remove the weather radar observation quantity 41 corresponding to the third target azimuth angle and the weather radar observation quantities 41 corresponding to azimuth angles surrounding the third target azimuth angle.

[0182] 18(c) shows a weather radar observation quantity 47 obtained by further removing the weather radar observation quantity 46 determined to be affected by interference. Specifically, the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 determine that the weather radar observation quantities 46 corresponding to one or more azimuth angles (hereinafter referred to as fourth target azimuth angles) obtained by excluding the third target azimuth angle from the multiple azimuth angles centered on the azimuth angle γ are affected by interference distributed in the distance direction. Then, the interference removal unit 314 removes the weather radar observation quantity 46 corresponding to the fourth target azimuth angle to generate the weather radar observation quantity 47. Note that the interference removal unit 314 may remove the weather radar observation quantity 46 corresponding to the fourth target azimuth angle and the weather radar observation quantities 46 corresponding to azimuth angles surrounding the fourth target azimuth angle.

[0183] In this way, the information processing device 3 according to the fifth embodiment generates a weather radar observation 46 from which the influence of interference on the input weather radar observation 41 (e.g., the reflectivity factor Z) has been removed, for example, based on the second interference determination result 48 determined using the reflectivity factor difference ZDR, and then acquires a weather radar observation 47 from which the influence of interference on the weather radar observation 46 has been further removed, based on the interference determination result 42 determined using the difference value D for each azimuth angle based on the reflectivity factor Z. This makes it possible to remove the weather radar observation 41 that has been affected by interference continuously at multiple azimuth angles. Therefore, the information processing device 3 can acquire the weather radar observation 47 that does not include the influence of interference, thereby improving the accuracy of the weather radar observation.

[0184] 19 is a flowchart showing an example of the procedure of the third interference determination and removal process executed in the information processing device 3 according to the fifth embodiment. The third interference determination and removal process is a process of determining whether the second weather radar observation quantity 45 is affected by interference for each azimuth angle and removing the weather radar observation quantity 41 affected by the interference. More specifically, the third interference determination and removal process is a process of determining whether the second weather radar observation quantity 45 is affected by interference for each azimuth angle using the statistic S based on the second weather radar observation quantity 45, removing the weather radar observation quantity 41 affected by the interference, and then performing the first interference determination and removal process described above with reference to FIG. 12 in the third embodiment. Here, the statistic S based on the reflectivity factor difference ZDR is used as the statistic S based on the second weather radar observation quantity 45, and the fourth condition is a condition that the statistic S is equal to or greater than a fourth threshold value. The processing unit 31 of the information processing device 3 executes the third interference determination and removal process in response to receiving the weather radar observation amount 41 and the second weather radar observation amount 45 from the weather radar device 2A or the storage 4, for example.

[0185] First, the processing unit 31 calculates the statistic S of the reflectivity factor difference ZDR for each azimuth angle (step S501). Specifically, for each of a plurality of coordinates corresponding to each azimuth angle, the processing unit 31 calculates the maximum absolute value of the plurality of reflectivity factor differences ZDR corresponding to each of the plurality of coordinates (i.e., the plurality of reflectivity factor differences ZDR measured at each of the plurality of coordinates) as the statistic S of the reflectivity factor difference ZDR.

[0186] Next, the processing unit 31 sets a variable k to 1 (step S502). The variable k is used to identify one of all azimuth angles (i.e., N azimuth angles) at which the weather radar observation 41 and the second weather radar observation 45 are measured. In the following, the statistic S of the reflectivity factor difference ZDR calculated for the k-th azimuth angle in step S501 is referred to as the statistic S corresponding to the k-th azimuth angle. k It is also called.

[0187] The processing unit 31 calculates the statistics S corresponding to the k-th azimuth angle. k It is determined whether or not is equal to or greater than the fourth threshold value (step S503).

[0188] Statistics S k is equal to or greater than the fourth threshold (Yes in step S503), the processing unit 31 outputs an interference determination result 48 indicating that the second weather radar observation quantity 45 corresponding to the k-th azimuth angle has been affected by interference (step S504). The processing unit 31 sets the weather radar observation quantity 41 (e.g., reflectivity factor Z) corresponding to the k-th azimuth angle to an invalid value (step S505), and proceeds to step S507. Note that the processing unit 31 may also set multiple weather radar observation quantities 41 corresponding to multiple azimuth angles centered around the k-th azimuth angle to invalid values.

[0189] Statistics S k If the kth azimuth angle is less than the fourth threshold value (No in step S503), the processing unit 31 outputs an interference determination result 48 indicating that the second weather radar observation amount 45 corresponding to the kth azimuth angle is not affected by interference (step S506), and proceeds to step S507.

[0190] Next, the processing unit 31 sets the variable k to k+1 (step S507), and then the processing unit 31 determines whether the variable k is greater than the total number N of azimuth angles (step S508).

[0191] If the variable k is equal to or less than the total number N of azimuth angles (No in step S508), the processing unit 31 returns to step S503. As a result, the processing unit 31 determines whether or not the second weather radar observation quantity 45 corresponding to the k-th azimuth angle has been affected by interference, based on the newly set variable k, and if it is determined that the second weather radar observation quantity 45 corresponding to the k-th azimuth angle has been affected by interference, performs processing to set the weather radar observation quantity 41 corresponding to the k-th azimuth angle to an invalid value.

[0192] If the variable k is larger than the total number N of azimuth angles (Yes in step S508), the processing unit 31 performs the first interference determination and removal process (step S509) and ends the third interference determination and removal process. That is, the processing unit 31 determines whether or not the second weather radar observation value 45 has been affected by interference for each of the N azimuth angles based on the statistics S, and if it determines that the second weather radar observation value 45 corresponding to a certain azimuth angle has been affected by interference, the processing unit 31 performs the first interference determination and removal process after completing the process of setting the weather radar observation value 41 corresponding to that azimuth angle to an invalid value. The first interference determination and removal process has been described above with reference to the flowchart in FIG. 12.

[0193] By the above-described third interference determination and removal process, when the weather radar observation quantity 41 corresponding to a wide continuous azimuth angle is affected by interference, the information processing device 3 can remove the weather radar observation quantity 41 corresponding to the wide continuous azimuth angle.

[0194] (Sixth embodiment) The information processing device 3 according to the third embodiment determines for each azimuth angle whether the weather radar observation quantity 41 is affected by interference, and removes the determined weather radar observation quantity 41 affected by interference. The information processing device 3 according to the sixth embodiment further determines, using the weather radar observation quantity 41, whether to execute processing to remove the weather radar observation quantity 41 affected by interference.

[0195] The configuration of the information processing system 1 including the information processing device 3 according to the sixth embodiment is similar to that of the information processing system 1 including the information processing device 3 according to the first to third embodiments. The first to third embodiments and the sixth embodiment differ in that a determination is further made as to whether or not to execute processing to remove weather radar observation amounts 41 affected by interference. The following mainly describes the differences from the first to third embodiments.

[0196] 20 is a block diagram showing an example of the functional configuration of an information processing device 3 according to the sixth embodiment. A processing unit 31 of the information processing device 3 processes an input weather radar observation amount 41 (e.g., a reflectivity factor Z) and outputs a weather radar observation amount 43 (e.g., a reflectivity factor Z′) from which the weather radar observation amount 41 affected by interference has been removed.

[0197] The processing unit 31 includes, for example, a coordinate number calculation unit 311, a difference calculation unit 312, an interference determination unit 313, and an interference removal unit 314, as well as a second coordinate number calculation unit 331 and an interference removal execution determination unit 332. These units may be functional components processed by the processing unit 31, or may be functional components realized by, for example, the CPU 11 executing the interference detection program 131. The functions of the coordinate number calculation unit 311, the difference calculation unit 312, and the interference determination unit 313 are as described above with reference to FIG. 3 etc.

[0198] The second coordinate number calculation unit 331 receives as input weather radar observation quantities 41 corresponding to each coordinate in a two-dimensional coordinate system of azimuth and distance. The weather radar observation quantities 41 input to the second coordinate number calculation unit 331 are, for example, the same as the weather radar observation quantities 41 input to the coordinate number calculation unit 311. The second coordinate number calculation unit 331 calculates the number L of coordinates (hereinafter referred to as the number of coordinates L) at which the weather radar observation quantities 41 satisfy a fifth condition, among the multiple weather radar observation quantities 41 corresponding to multiple coordinates within a specific range in the two-dimensional coordinate system. The specific range may be the entire range defined in the two-dimensional coordinate system (the range observable by the weather radar device 2A), or a specified portion of the range defined in the two-dimensional coordinate system. The fifth condition is, for example, that the value is equal to or greater than a fifth threshold. The fifth threshold may be the same as or different from the first threshold.

[0199] The interference removal execution determination unit 332 determines whether or not to execute interference removal processing by the interference removal unit 314, based on the number of coordinates L calculated by the second coordinate number calculation unit 331. In other words, the interference removal execution determination unit 332 and the interference removal unit 314 execute interference removal processing by the interference removal unit 314, based on the number of coordinates L. Specifically, the interference removal execution determination unit 332 calculates, for example, a value (hereinafter referred to as a first value) indicating the relationship between the total number of coordinates M included in a specific range and the number of coordinates L. The first value is, for example, the ratio R of the number of coordinates L to the total number of coordinates M (i.e., R=L / M). The interference removal execution determination unit 332 determines whether or not the first value satisfies a sixth condition. The sixth condition is, for example, a condition that the first value is less than a sixth threshold. The sixth threshold is, for example, 10%.

[0200] If the first value does not satisfy the sixth condition (for example, the ratio R is equal to or greater than the sixth threshold), it means that there is a high possibility that the weather radar observation amount 41 includes a desired signal during rainy weather (rainfall). In other words, if the first value does not satisfy the sixth condition and the weather radar observation amount 41 at a certain coordinate is a value indicating rainfall, there is a low possibility that the weather radar observation amount 41 has been affected by interference.

[0201] On the other hand, if the first value satisfies the sixth condition (for example, the ratio R is less than the sixth threshold), it means that there is a high possibility that the weather radar observation amount 41 includes a signal (observation amount) in clear weather. In other words, if the first value satisfies the sixth condition and the weather radar observation amount 41 at a certain coordinate is a value indicating rainfall, there is a possibility that the weather radar observation amount 41 has been affected by interference.

[0202] Therefore, if the first value does not satisfy the sixth condition (for example, if the ratio R is equal to or greater than the sixth threshold), the interference removal execution determination unit 332 determines not to execute the interference removal process. If the first value satisfies the sixth condition (for example, if the ratio R is less than the sixth threshold), the interference removal execution determination unit 332 determines to execute the interference removal process. The interference removal execution determination unit 332 sends a determination result 49 indicating whether or not to execute the interference removal process (on or off) to the interference removal unit 314.

[0203] The interference removal unit 314 controls the execution of the interference removal process using the interference determination result 42 by the interference determination unit 313 based on the determination result 49 by the interference removal execution determination unit 332 .

[0204] Specifically, when the determination result 49 indicates that interference removal processing is to be performed (ON), the interference removal unit 314 performs interference removal processing using the interference determination result 42. That is, when the condition (second combined condition) that the first value satisfies the sixth condition (for example, the ratio R is less than a sixth threshold) and the plurality of weather radar observation amounts 41 corresponding to the target azimuth angle are determined to be affected by interference is satisfied, the interference removal unit 314 removes the plurality of weather radar observation amounts 41 corresponding to the target azimuth angle (that is, performs the interference removal processing). When the first value satisfies the sixth condition, the interference removal unit 314 performs interference removal processing for each azimuth angle for which the interference determination result 42 indicates that the corresponding plurality of weather radar observation amounts 41 are affected by interference.

[0205] On the other hand, if the determination result 49 indicates that the interference removal process is not to be performed (OFF), the interference removal unit 314 does not perform the interference removal process using the interference determination result 42. In other words, if the second combination condition is not satisfied, the interference removal unit 314 does not remove the multiple weather radar observation amounts 41 corresponding to the target azimuth angle (i.e., does not perform the interference removal process). If the first value does not satisfy the sixth condition (for example, if the ratio R is equal to or greater than the sixth threshold), the interference removal unit 314 does not perform the interference removal process for any azimuth angle for which the interference determination result 42 indicates that the corresponding multiple weather radar observation amounts 41 are affected by interference.

[0206] The interference removal unit 314 outputs the execution result of the interference removal process for the weather radar observation amount 41 using the interference determination result 42, the execution of which is controlled based on the determination result 49, as a weather radar observation amount 43.

[0207] With the above configuration, the information processing device 3 can prevent excessive removal of desired signals from the weather radar observation amount 41 during rainfall, in which the desired signals are obtained at a rate equal to or greater than a certain level. Also, for the weather radar observation amount 41 during clear weather, the information processing device 3 can obtain the weather radar observation amount 43 that does not include the influence of interference.

[0208] 21 is a flowchart showing an example of the procedure of interference removal execution determination processing executed in the information processing device 3 according to the sixth embodiment. The interference removal execution determination processing is processing for determining whether or not to execute interference removal processing. The processing unit 31 of the information processing device 3 executes the interference removal execution determination processing in response to receiving weather radar observation amounts 41 from the weather radar device 2A or the storage 4, for example. Here, a case where the sixth condition is a condition that the value is less than a sixth threshold will be illustrated.

[0209] First, the processing unit 31 calculates the number L of coordinates in the weather radar observation amount 41 within a specific range where the reflectivity factor Z is equal to or greater than a fifth threshold (step S61). The processing unit 31 calculates the ratio R of the number L of coordinates to the total number M of coordinates within the specific range (step S62). Then, the processing unit 31 determines whether the calculated ratio R is less than a sixth threshold (step S63). The sixth threshold is, for example, 10%.

[0210] If the ratio R is equal to or greater than the sixth threshold (No in step S63), the processing unit 31 outputs a determination result 49 indicating that the interference removal process will not be executed (OFF) (step S64), and ends the interference removal execution determination process. Specifically, if the ratio R is equal to or greater than the sixth threshold, the processing unit 31 determines that the weather radar observation amount 41 in that specific range is the weather radar observation amount 41 during rainfall in which the desired signal (desired observation amount) is obtained at a rate equal to or greater than a certain rate. Therefore, the processing unit 31 outputs a determination result 49 indicating that the interference removal process will not be executed.

[0211] If the ratio R is less than the sixth threshold (Yes in step S63), the processing unit 31 outputs a determination result 49 indicating that the interference removal process should be executed (ON) (step S65), and ends the interference removal execution determination process. Specifically, if the ratio R is less than the sixth threshold, the processing unit 31 determines that the weather radar observation amount 41 in the specific range is, for example, a weather radar observation amount 41 in clear weather (i.e., a weather radar observation amount 41 that may be affected by interference). Therefore, the processing unit 31 outputs a determination result 49 indicating that the interference removal process should be executed.

[0212] By the above-described interference removal execution determination process, the processing unit 31 can output a determination result 49 indicating whether or not to execute interference removal processing.

[0213] 22 is a flowchart showing an example of the procedure of the fourth interference determination and removal process executed in the information processing device 3 according to the sixth embodiment. The fourth interference determination and removal process is a process of determining for each azimuth angle whether or not the weather radar observation quantity 41 is affected by interference, and then removing the weather radar observation quantity 41 affected by interference when a determination result 49 indicating that interference removal should be executed is output in the interference removal execution determination process. The processing unit 31 of the information processing device 3 executes the fourth interference determination and removal process, for example, after the execution of the interference removal execution determination process is completed (i.e., after the determination result 49 indicating whether or not to execute the interference removal process is output).

[0214] Steps S701 to S705 and steps S707 to S710 of the fourth collision detection and removal processing are the same as steps S301 to S309 of the first collision detection and removal processing described above with reference to Fig. 12. The fourth collision detection and removal processing corresponds to processing in which step S706 is added between steps S305 and S306 of the first collision detection and removal processing. Therefore, the following description will mainly focus on the processing related to the added step S706.

[0215] In step S705, the processing unit 31 outputs the interference determination result 42 indicating that the weather radar observation quantity 41 corresponding to the k-th azimuth angle has been affected by interference, and then determines whether or not to execute the interference removal process (step S706). Specifically, the processing unit 31 determines whether or not to execute the interference removal process based on the determination result 49 output by the interference removal execution determination process described above with reference to Fig. 21. That is, if the determination result 49 indicates that the interference removal process should be executed, the processing unit 31 determines that the interference removal process should be executed. On the other hand, if the determination result 49 indicates that the interference removal process should not be executed, the processing unit 31 determines that the interference removal process should not be executed.

[0216] If the interference removal process is to be executed (Yes in step S706), the processing unit 31 sets the weather radar observation amount 41 corresponding to the k-th azimuth angle to an invalid value (step S707), and the process proceeds to step S709.

[0217] If the interference removal process is not to be executed (No in step S706), the processing unit 31 proceeds to step S709 without executing the interference removal process.

[0218] By the above-described fourth interference determination and removal process, when the determination result 49 output by the interference removal execution determination process indicates that the interference removal process should be executed and an interference determination result 42 indicating that the weather radar observation amount 41 corresponding to the kth azimuth angle is affected by interference is output in step S705, the information processing device 3 can remove the weather radar observation amount 41 affected by interference. Specifically, by the interference removal execution determination process and the fourth interference determination and removal process, the information processing device 3 does not execute the interference removal process for the weather radar observation amount 41 during rainfall in which the desired signal is obtained at a rate equal to or higher than a certain rate, but executes the interference removal process for the weather radar observation amount 41 during clear weather.

[0219] This allows the information processing device 3 to prevent excessive removal of desired signals from the weather radar observation amount 41 during rainfall, in which the desired signals are obtained at a rate equal to or greater than a certain level. Also, for the weather radar observation amount 41 during clear weather, the information processing device 3 can obtain weather radar observation amount 43 that does not include the influence of interference.

[0220] The processing unit 31 may execute the interference removal execution determination process and part of the fourth interference determination and removal process in parallel in response to receiving the weather radar observation amount 41 from the weather radar device 2A or the storage 4. In this case, the processing unit 31 executes these two processes so as to complete the interference removal execution determination process before executing step S706 of the fourth interference determination and removal process (i.e., before determining whether or not to execute interference removal).

[0221] 5 or 9 are completed, the fourth interference detection / removal process may be a process for controlling the execution of interference removal process based on the interference detection result 42 obtained by the interference detection process, using the determination result 49 obtained by the interference removal execution determination process. In this case, when the determination result 49 indicates that the interference removal process should be executed, the processing unit 31 executes the interference removal process based on the interference detection result 42.

[0222] (Seventh embodiment) In the first to sixth embodiments, the information processing device 3 is a device separate from the weather radar device 2A. In contrast, in the seventh embodiment, the information processing device 3 is built into the weather radar device. The configuration of the weather radar device including the information processing device 3 according to the seventh embodiment is similar to the weather radar device 2A according to the first to sixth embodiments. The seventh embodiment differs from the first to sixth embodiments in that the information processing device 3 is incorporated into the weather radar device. Below, the differences from the first to sixth embodiments will be mainly described.

[0223] 23 is a block diagram showing an example of the configuration of a weather radar device including an information processing device 3 according to the seventh embodiment. The weather radar device 2B includes, for example, a transmitter / receiver 21, a radar information processing unit 22, and the information processing device 3.

[0224] The transmitting / receiving unit 21 of the weather radar device 2B is similar to the transmitting / receiving unit 21 of the weather radar device 2A described above with reference to FIG.

[0225] The radar information processing unit 22 of the weather radar device 2B is similar to the radar information processing unit 22 of the weather radar device 2A described above with reference to Figure 1, except that it sends the weather radar observation quantity 41 to the information processing device 3 instead of the radar observation quantity transmission unit 23.

[0226] The information processing device 3 of the weather radar device 2B is similar to the information processing device 3 of any of the first to sixth embodiments, except that it receives the weather radar observation amount 41 from the radar information processing unit 22 instead of the radar observation amount transmission unit 23.

[0227] With the above configuration, the information processing device 3 according to the seventh embodiment (or the weather radar device 2B including the information processing device 3) can achieve the same effects as the information processing devices 3 according to the first to sixth embodiments.

[0228] As described above, according to the first to sixth embodiments, the accuracy of weather radar observations can be improved. Using the weather radar observations 41 corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, the processing unit 31 calculates the difference between the number of first coordinates at which the weather radar observations 41 at a first azimuth angle satisfy a first condition and the number of second coordinates at which the weather radar observations 41 at one or more second azimuth angles within a first range relative to the first azimuth angle satisfy the first condition. Based on the calculated difference, the processing unit 31 determines whether the multiple weather radar observations 41 corresponding to the multiple first coordinates including the first azimuth angle have been affected by interference.

[0229] This allows the information processing device 3 to accurately determine whether or not a specific azimuth angle is affected by interference that is linearly distributed in the distance direction.The information processing device 3 can improve the data accuracy of the weather radar observation amounts 41 by, for example, not using the weather radar observation amounts 41 that correspond to the azimuth angle affected by interference.Therefore, the information processing device 3 can improve the accuracy of detecting local weather phenomena using the weather radar observation amounts 41, for example.

[0230] The various processes of these embodiments can be realized by a computer program, and therefore, effects similar to those of these embodiments can be easily achieved simply by installing and executing the computer program on a computer via a computer-readable storage medium that stores the computer program.

[0231] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0232] The following additional notes are provided regarding the above-described embodiment. <1> using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculating a first difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; a processing unit that determines whether or not the plurality of first weather radar observation amounts corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference based on the first difference; An information processing device comprising: <2> the one or more second azimuth angles are azimuth angles adjacent to the first azimuth angle; <1> The information processing device described in <3> The first weather radar observable is a received power or a reflectivity factor. <1> or <2> The information processing device described in <4> the processing unit determines that the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates are affected by interference when the first difference satisfies a second condition; <1> ~ <3> 10. The information processing device according to claim 9, wherein: <5> the processing unit determines whether or not the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates have been affected by interference based on the first difference when the number of third coordinates at which the first weather radar observation quantities at each of one or more third azimuth angles within a second range with respect to the first azimuth angle satisfy the third condition at at least any of the third azimuth angles satisfies the third condition; <1> ~ <4> 10. The information processing device according to claim 9, wherein: <6> When the processing unit determines that the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates are affected by interference, the processing unit sets the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates to invalid values, or sets the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates and the plurality of first weather radar observation quantities respectively corresponding to a plurality of fourth coordinates including any one or more fourth azimuth angles within a third range with respect to the first azimuth angle to the invalid values. <1> ~ <5> 10. The information processing device according to claim 9, wherein: <7> The processing unit using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of first coordinates set to the invalid values, or using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of first coordinates set to the invalid values ​​and the plurality of first weather radar observation amounts corresponding to the plurality of fourth coordinates set to the invalid values, to calculate a second difference between the number of fifth coordinates at which the first weather radar observation amount at a fifth azimuth angle satisfies the first condition and the number of sixth coordinates at which the first weather radar observation amount at each of one or more sixth azimuth angles within the first range with respect to the fifth azimuth angle satisfies the first condition; determining whether or not the plurality of first weather radar observation amounts respectively corresponding to a plurality of fifth coordinates including the fifth azimuth angle are affected by interference based on the second difference; When it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates are affected by interference, the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates are set to invalid values, or the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates and the plurality of first weather radar observation quantities respectively corresponding to a plurality of seventh coordinates including any one or more seventh azimuth angles within the third range with respect to the fifth azimuth angle are set to the invalid values. <6> The information processing device described in <8> The processing unit calculating a first statistic at a fifth azimuth angle using a second weather radar observation amount corresponding to each coordinate in the two-dimensional coordinate system; determining whether or not a plurality of the second weather radar observation quantities corresponding to a plurality of fifth coordinates including the fifth azimuth angle are affected by interference based on the first statistics; when it is determined that the second weather radar observation quantities respectively corresponding to the fifth coordinates are affected by interference, setting the first weather radar observation quantities respectively corresponding to the fifth coordinates to the invalid values, or setting the first weather radar observation quantities respectively corresponding to the fifth coordinates and the first weather radar observation quantities respectively corresponding to a plurality of sixth coordinates including any one or more sixth azimuth angles within the third range with respect to the fifth azimuth angle to the invalid values, calculating the first difference between the number of first coordinates and the number of second coordinates using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of fifth coordinates that are set to the invalid values, or using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of fifth coordinates that are set to the invalid values ​​and the plurality of first weather radar observation amounts corresponding to the plurality of sixth coordinates that are set to the invalid values; determining whether the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates are affected by interference based on the first differences; <6> The information processing device described in <9> the second weather radar observable is a reflectivity factor difference, the processing unit calculates, as the first statistic, a maximum value of the absolute value of the second weather radar observation quantity at the fifth azimuth angle. <8> The information processing device described in <10> the processing unit determines that the plurality of first weather radar observation quantities corresponding to the plurality of fifth coordinates, respectively, are affected by interference when the first statistics satisfy a fourth condition; <8> or <9> The information processing device described in <11> The processing unit calculating the number of third coordinates at which the first weather radar observations satisfy a fifth condition using a plurality of the first weather radar observations corresponding to a plurality of coordinates within a specific range in the two-dimensional coordinate system; when it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates are affected by interference, the process of setting the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates to the invalid values, or setting the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates and the plurality of first weather radar observation quantities respectively corresponding to the plurality of fourth coordinates to the invalid values ​​is performed based on the number of the third coordinates. <6> The information processing device described in <12> the processing unit executes the processing when a first value indicating a relationship between the number of the plurality of coordinates and the number of the third coordinates satisfies a sixth condition and when it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates are affected by interference. <11> The information processing device described in <13> the processing unit calculates, as the first value, a ratio of the number of the third coordinates to the number of the plurality of coordinates; <12> The information processing device described in <14> <1> ~ <13> an information processing device according to any one of the preceding claims; Emitting radio waves and receiving reflected waves from the radio waves; a weather radar device that generates data of the first weather radar observation amount corresponding to each coordinate in the two-dimensional coordinate system using a signal based on the reflected wave; A system including: <15> The weather radar device emits the radio waves including horizontally polarized waves and vertically polarized waves. <14> The system described in <16> The weather radar device has the information processing device built in. <14> or <15> The system described in <17> using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculating a difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; Based on the difference, it is determined whether or not the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference. method. <18> using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculating a difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; and determining whether or not the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference based on the difference. program. [Explanation of symbols]

[0233] 1...information processing system, 2A, 2B...weather radar device, 3...information processing device, 4...storage, 5...interference signal source, 11...CPU, 12...storage, 13...RAM, 131...interference determination program, 14...communication device, 21...transmitter / receiver, 22...radar information processing unit, 23...radar observation quantity transmission unit, 31...processing unit, 311, 311-2...coordinate number calculation unit, 312, 312-2...difference calculation unit, 313, 313-2...interference determination determination unit, 314, 314-2... interference removal unit, 321... statistical quantity calculation unit, 322... second interference determination unit, 323... second interference removal unit, 331... second coordinate number calculation unit, 332... interference removal execution determination unit, 41... weather radar observation amount (reflection factor Z), 42... interference determination result, 43, 44, 46, 47... weather radar observation amount (reflection factor Z'), 45... second weather radar observation amount (reflection factor difference ZDR), 48... second interference determination result, 49... determination result.

Claims

1. using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculating a first difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; a processing unit that determines whether or not the plurality of first weather radar observation amounts corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference based on the first difference; An information processing device comprising:

2. the one or more second azimuth angles are azimuth angles adjacent to the first azimuth angle; The information processing device according to claim 1 .

3. the first weather radar observable is a received power or a reflectivity factor; The information processing device according to claim 1 .

4. the processing unit determines that the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates, respectively, are affected by interference when the first difference satisfies a second condition; The information processing device according to claim 1 .

5. the processing unit determines, based on the first difference, whether or not the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates have been affected by interference when the number of third coordinates at which the first weather radar observation quantities at each of one or more third azimuth angles within a second range with respect to the first azimuth angle satisfy the third condition at at least any of the third azimuth angles. The information processing device according to claim 1 .

6. When the processing unit determines that the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates, respectively, are affected by interference, the processing unit sets the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates, respectively, to invalid values, or sets the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates, respectively, and the plurality of first weather radar observation quantities corresponding to a plurality of fourth coordinates, each including one or more fourth azimuth angles within a third range with respect to the first azimuth angle, to the invalid values. The information processing device according to claim 1 .

7. The processing unit using the first weather radar observation quantities corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates set to the invalid values, or using the first weather radar observation quantities corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation quantities corresponding to the plurality of first coordinates set to the invalid values ​​and the plurality of first weather radar observation quantities corresponding to the plurality of fourth coordinates set to the invalid values, to calculate a second difference between the number of fifth coordinates at which the first weather radar observation quantity at a fifth azimuth angle satisfies the first condition and the number of sixth coordinates at which the first weather radar observation quantity at each of one or more sixth azimuth angles within the first range with respect to the fifth azimuth angle satisfies the first condition; determining whether or not the plurality of first weather radar observation amounts respectively corresponding to a plurality of fifth coordinates including the fifth azimuth angle are affected by interference based on the second difference; When it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates are affected by interference, the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates are set to invalid values, or the plurality of first weather radar observation quantities respectively corresponding to the plurality of fifth coordinates and the plurality of first weather radar observation quantities respectively corresponding to a plurality of seventh coordinates including any one or more seventh azimuth angles within the third range with respect to the fifth azimuth angle are set to the invalid values. The information processing device according to claim 6 .

8. The processing unit calculating a first statistic at a fifth azimuth angle using a second weather radar observation amount corresponding to each coordinate in the two-dimensional coordinate system; determining whether or not a plurality of the second weather radar observation quantities corresponding to a plurality of fifth coordinates including the fifth azimuth angle are affected by interference based on the first statistics; when it is determined that the second weather radar observation quantities respectively corresponding to the fifth coordinates are affected by interference, setting the first weather radar observation quantities respectively corresponding to the fifth coordinates to the invalid values, or setting the first weather radar observation quantities respectively corresponding to the fifth coordinates and the first weather radar observation quantities respectively corresponding to a plurality of sixth coordinates including any one or more sixth azimuth angles within the third range with respect to the fifth azimuth angle to the invalid values, calculating the first difference between the number of first coordinates and the number of second coordinates using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of fifth coordinates that have been set to the invalid values, or using the first weather radar observation amounts corresponding to each coordinate in the two-dimensional coordinate system, including the plurality of first weather radar observation amounts corresponding to the plurality of fifth coordinates that have been set to the invalid values ​​and the plurality of first weather radar observation amounts corresponding to the plurality of sixth coordinates that have been set to the invalid values; determining whether the plurality of first weather radar observation amounts corresponding to the plurality of first coordinates, respectively, are affected by interference based on the first differences; The information processing device according to claim 6 .

9. the second weather radar observable is a reflectivity factor difference, the processing unit calculates, as the first statistic, a maximum value of the absolute value of the second weather radar observation quantity at the fifth azimuth angle. The information processing device according to claim 8 .

10. the processing unit determines that the plurality of first weather radar observation quantities corresponding to the plurality of fifth coordinates, respectively, are affected by interference when the first statistics satisfy a fourth condition; The information processing device according to claim 8 .

11. The processing unit calculating the number of third coordinates at which the first weather radar observations satisfy a fifth condition using a plurality of the first weather radar observations corresponding to a plurality of coordinates within a specific range in the two-dimensional coordinate system; When it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates are affected by interference, a process of setting the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates to the invalid values, or setting the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates and the plurality of first weather radar observation quantities respectively corresponding to the plurality of fourth coordinates to the invalid values ​​is executed based on the number of the third coordinates. The information processing device according to claim 6 .

12. the processing unit executes the processing when a first value indicating a relationship between the number of the plurality of coordinates and the number of the third coordinates satisfies a sixth condition and when it is determined that the plurality of first weather radar observation quantities respectively corresponding to the plurality of first coordinates are affected by interference. The information processing device according to claim 11.

13. the processing unit calculates, as the first value, a ratio of the number of the third coordinates to the number of the plurality of coordinates; The information processing device according to claim 12.

14. An information processing device according to any one of claims 1 to 13; Emitting radio waves and receiving reflected waves from the radio waves; a weather radar device that generates data of the first weather radar observation amount corresponding to each coordinate in the two-dimensional coordinate system using a signal based on the reflected wave; A system including:

15. The weather radar device emits the radio waves including horizontally polarized waves and vertically polarized waves. The system of claim 14.

16. The weather radar device has the information processing device built in. The system of claim 14.

17. using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculating a difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; Based on the difference, it is determined whether or not the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference. method.

18. using a first weather radar observation corresponding to each coordinate in a two-dimensional coordinate system of azimuth angle and distance, calculate a difference between the number of first coordinates at which the first weather radar observation at a first azimuth angle satisfies a first condition and the number of second coordinates at which the first weather radar observation at each of one or more second azimuth angles within a first range with respect to the first azimuth angle satisfies the first condition; and determining whether or not the plurality of first weather radar observation amounts respectively corresponding to the plurality of first coordinates including the first azimuth angle are affected by interference based on the difference. program.

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