Radar ocean wave analysis device, radar ocean wave analysis program, and radar ocean wave analysis drone

Abstract

To calculate at least one of an ocean wave height, an ocean wave wavelength, an ocean wave direction, and an ocean wave velocity with high accuracy and reduce a calculation load of at least one of the ocean wave height, the ocean wave wavelength, the ocean wave direction, and the ocean wave velocity, even if the ocean wave wavelength is a short wavelength or a long wavelength.SOLUTION: A radar ocean wave analysis device 2 performs an ocean wave analysis using a radar. The radar ocean wave analysis device 2 includes: an analysis area size setting section 24 that sets a depth length and a width length of a rectangular analysis area in which the ocean wave analysis is performed to a length twice or more a desired wavelength and sets the length to a variable length according to the desired wavelength; and a radar ocean wave analysis section 21 that performs an ocean wave analysis of at least one of an ocean wave height, an ocean wave wavelength, an ocean wave direction, and an ocean wave velocity on the basis of a radar scan image in the analysis area set by the analysis area size setting section 24.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a technique for performing ocean wave analysis using radar. [Background technology]

[0002] Techniques for performing wave analysis using radar are disclosed in Patent Documents 1 to 3, etc. In Patent Documents 1 to 3, a rectangular analysis area for performing wave analysis is set, and wave analysis of wave height, wave wavelength, wave direction, and wave speed is performed based on a radar scan image within the analysis area. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-094995 [Patent Document 2] Japanese Patent Application Publication No. 2020-094996 [Patent Document 3] Japanese Patent Application Publication No. 2020-094997 Summary of the Invention [Problem to be solved by the invention]

[0004] The issues with radar wave analysis processing using conventional technology are shown in Figure 1. In Figure 1, an analysis area A of approximately 2000 m x 2000 m is set to a fixed size, and wave analysis is performed based on a radar scan image R within analysis area A. The wave wavelengths in the left and right columns of Figure 1 are different.

[0005] In the left column of Figure 1, the wave wavelength is short, and the fixed size of the analysis area A is significantly larger than the short wave wavelength. Therefore, according to the Nyquist theorem, the short wave wavelength can be calculated with high accuracy in the radar scan image R within the analysis area A. However, when the radar wave analysis device is mounted on a drone or aircraft rather than a ship, the calculation load for the wave height, wave wavelength, wave direction, and wave speed cannot be reduced.

[0006] In the right column of Figure 1, the wave wavelength is long, and the fixed size of the analysis area A is almost the same as that of the long wave wavelength. Therefore, according to the Nyquist theorem, it is impossible to calculate the long wave wavelength in the radar scan image R within the analysis area A. Furthermore, when the radar wave analysis device is mounted on a drone or aircraft rather than on a ship, the calculation load for the wave height, wave wavelength, wave direction, and wave speed cannot be reduced.

[0007] Therefore, in order to solve the above problem, the present disclosure aims to calculate at least one of the wave height, wave wavelength, wave direction, and wave speed with high accuracy, regardless of whether the wave wavelength is short or long, and to reduce the calculation load of at least one of the wave height, wave wavelength, wave direction, and wave speed. [Means for solving the problem]

[0008] In order to solve the above problem, the "depth length" and "width length" of the analysis region are set to "lengths at least twice the desired wavelength" and are set to "variable lengths" depending on the desired wavelength.

[0009] Here, when the desired wavelength is a long wavelength, setting the "depth" and "width" of the analysis region to "lengths at least twice the long wavelength" makes it possible to achieve both the minimum high accuracy of the wave wavelength and the maximum reduction in the load of wave analysis under conditions that minimally satisfy the Nyquist theorem. Setting the "depth" and "width" of the analysis region to "lengths at most 5 or 10 times the long wavelength" makes it possible to optimize the trade-off between the high accuracy of the wave wavelength and the reduction in the load of wave analysis under conditions that fully satisfy the Nyquist theorem.

[0010] On the other hand, when the desired wavelength is a short wavelength, setting the "depth" and "width" of the analysis region to "lengths at least twice the short wavelength" makes it possible to achieve both a minimum increase in the accuracy of the wave wavelength and a further reduction in the load of wave analysis under conditions that minimally satisfy the Nyquist theorem. Furthermore, setting the "depth" and "width" of the analysis region to "lengths at most 5 or 10 times the short wavelength" makes it possible to optimize the trade-off between a high accuracy of the wave wavelength and a reduction in the load of wave analysis under conditions that fully satisfy the Nyquist theorem.

[0011] Specifically, the present disclosure is a radar wave analysis device that performs wave analysis using a radar, characterized by comprising: an analysis area size setting unit that sets the depth and width of a rectangular analysis area in which wave analysis is performed to lengths that are at least twice the desired wavelength and that are variable depending on the desired wavelength; and a radar wave analysis unit that performs wave analysis of at least one of wave height, wave wavelength, wave direction, and wave speed based on a radar scan image within the analysis area set by the analysis area size setting unit.

[0012] With this configuration, regardless of whether the wave wavelength is short or long, at least one of the wave height, wave wavelength, wave direction, and wave speed can be calculated with high accuracy within an analysis area of ​​a size corresponding to the desired wavelength, and the calculation load of at least one of the wave height, wave wavelength, wave direction, and wave speed can be reduced.

[0013] The present disclosure also provides a radar wave analysis device that further includes a wave spectrum calculation unit that initially sets an initial analysis area as the analysis area and calculates a wave spectrum based on a radar scan image within the initial analysis area, and the analysis area size setting unit sets the depth and width of the analysis area to lengths that are at least twice the maximum wavelength or peak wavelength of the wave spectrum calculated by the wave spectrum calculation unit, and sets the lengths to be variable depending on the maximum wavelength or the peak wavelength.

[0014] With this configuration, since the intensity of the ocean wave spectrum is concentrated around a specific wave number, it is possible to set an analysis region of a size according to the maximum wavelength or peak wavelength of the ocean wave spectrum.

[0015] The present disclosure also provides a radar wave analysis device further comprising a hull length information acquisition unit that acquires hull length information for a ship that is the subject of a determination of whether it will be damaged by waves, and wherein the analysis area size setting unit sets the depth and width of the analysis area to lengths that are at least twice the desired wavelength, which is equal to the hull length for which the hull length information acquisition unit acquired information, and sets the lengths to variable lengths depending on the desired wavelength, which is equal to the hull length.

[0016] With this configuration, waves with a wavelength equal to the length of the hull can damage the hull, and it is possible to set an analysis region of a size according to a desired wavelength equal to the length of the hull.

[0017] The present disclosure also provides a radar wave analysis program for causing a computer to execute the processing steps performed by the processing units included in the above-described radar wave analysis device.

[0018] According to this configuration, it is possible to provide a program having the above-described effects.

[0019] The present disclosure also provides a radar wave analysis drone that is characterized by comprising the above-described radar wave analysis device and a radar transmitter / receiver device for performing wave analysis.

[0020] With this configuration, a drone having the effects described above can be provided. [Effects of the Invention]

[0021] In this way, the present disclosure can calculate at least one of the wave height, wave wavelength, wave direction, and wave speed with high accuracy, regardless of whether the wave wavelength is short or long, and can reduce the calculation load of at least one of the wave height, wave wavelength, wave direction, and wave speed. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 is a diagram illustrating a problem with radar wave analysis processing in the prior art. [Figure 2] FIG. 1 is a diagram illustrating the principle of radar wave analysis processing according to the present disclosure. [Figure 3] 1 is a diagram illustrating a configuration of a radar ocean wave analysis system according to the present disclosure. [Figure 4] FIG. 2 is a diagram showing a procedure of radar wave analysis processing according to the present disclosure. [Figure 5] FIG. 10 is a diagram showing a specific example of radar wave analysis processing according to the present disclosure. [Figure 6] FIG. 10 is a diagram showing a specific example of radar wave analysis processing according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0023]

[0023] The following embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of implementation of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0024] (Principle of radar wave analysis processing disclosed herein) The principle of the radar wave analysis process of the present disclosure is shown in Figure 2. In Figure 2, wave analysis is performed based on a radar scan image R (see Figure 1) within an analysis area A. The upper and lower sections of Figure 2 differ in whether the wave wavelength is long or short. The left and right columns of Figure 2 differ in whether the directional relationship between the depth or width direction of the analysis area A and the extension direction of the wave crest W is parallel or oblique.

[0025] Here, the present disclosure sets the "depth length" and "width length" of the analysis area A to "lengths at least twice the desired wavelength" and to "variable lengths" according to the desired wavelength. Therefore, the present disclosure can calculate at least one of the wave height, wave wavelength, wave direction, and wave speed with high accuracy within the analysis area A of a size according to the desired wavelength, regardless of whether the wave wavelength is short or long, and can reduce the calculation load of at least one of the wave height, wave wavelength, wave direction, and wave speed.

[0026] In the lower part of Figure 2, when the desired wavelength is a long wavelength, setting the "depth length" and "width length" of analysis area A to "lengths at least twice the long wavelength" can achieve both minimal accuracy in the wave wavelength and maximum reduction in the load of wave analysis under conditions that minimally satisfy the Nyquist theorem. Furthermore, setting the "depth length" and "width length" of analysis area A to "lengths at most 5 or 10 times the long wavelength" can optimize the trade-off between high accuracy in the wave wavelength and reduced load in wave analysis under conditions that fully satisfy the Nyquist theorem. Furthermore, the above-mentioned setting conditions for the "depth length" and "width length" of analysis area A are satisfied when the extension direction of the wave crest W is parallel to the depth or width direction of analysis area A, as shown in the lower left column of Figure 2, and are also satisfied when the extension direction of the wave crest W is oblique to the depth or width direction of analysis area A, as shown in the lower right column of Figure 2.

[0027] In the upper part of Figure 2, when the desired wavelength is a short wavelength, setting the "depth length" and "width length" of analysis area A to "lengths at least twice the short wavelength" can achieve both minimally high accuracy of the wave wavelength and further reduce the load of wave analysis under conditions that minimally satisfy the Nyquist theorem. Furthermore, setting the "depth length" and "width length" of analysis area A to "lengths at most 5 or 10 times the short wavelength" can optimize the trade-off between high accuracy of the wave wavelength and reduced load of wave analysis under conditions that fully satisfy the Nyquist theorem. Furthermore, the above-mentioned setting conditions for the "depth length" and "width length" of analysis area A are satisfied when the extension direction of the wave crest W is parallel to the depth or width direction of analysis area A, as shown in the upper left column of Figure 2, and are also satisfied when the extension direction of the wave crest W is oblique to the depth or width direction of analysis area A, as shown in the upper right column of Figure 2.

[0028] (Configuration of the radar wave analysis system of the present disclosure) The configuration of the radar wave analysis system of the present disclosure is shown in Fig. 3. The radar wave analysis system S includes a radar transceiver 1, a radar wave analysis device 2, and a radar display device 3. The radar transceiver 1 includes a radar transmitter 11, a transmission / reception switch 12, a radar antenna 13, and a radar receiver 14, and transmits radar irradiated waves and receives radar reflected waves. The radar wave analysis device 2 includes a radar wave analyzer 21, a wave spectrum calculator 22, a ship length information acquirer 23, an analysis region size setting unit 24, and an analysis region calculator 25 (including one of the wave spectrum calculator 22 and the ship length information acquirer 23), and is realized by installing the radar wave analysis program shown in Fig. 4 on a computer. The radar display device 3 displays the radar wave analysis results.

[0029] Here, when a radar wave analysis system S equipped with a large radar transceiver 1 is mounted on a ship or the like, the device scale for radar wave analysis processing is large and the calculation performance is high. On the other hand, when a radar wave analysis system S equipped with a small radar transceiver 1 is mounted on a drone D or an aircraft or the like, the device scale for radar wave analysis processing is small and the calculation performance is low. The present disclosure is more effective when the device scale for radar wave analysis processing is small and the calculation performance is low, but it can also be applied when the device scale for radar wave analysis processing is large and the calculation performance is high.

[0030] (Procedure of radar wave analysis processing according to the present disclosure) The procedure for the radar wave analysis processing of the present disclosure is shown in Fig. 4. Specific examples of the radar wave analysis processing of the present disclosure are shown in Figs. 5 and 6. First, an overview will be given. The analysis area size setting unit 24 sets the "depth length" and "width length" of the rectangular analysis area A in which wave analysis is performed to "a length that is at least twice the desired wavelength (preferably not more than five or ten times)" and sets them to "variable lengths" according to the desired wavelength (steps S2 and S4). The radar wave analysis unit 21 performs wave analysis of at least one of the wave height, wave wavelength, wave direction, and wave speed of the waves based on the radar scan image R (see Fig. 1) within the analysis area A set by the analysis area size setting unit 24 (step S5).

[0031] Here, the swell wavelength (see FIG. 5) or the hull length (see FIG. 6) as the desired wavelength is several hundred meters, whereas in the prior art the fixed size of the analysis area A is set to approximately 2000 m x approximately 2000 m, and in the present disclosure the variable size of the analysis area A is set to approximately 1000 m x approximately 1000 m or approximately 2000 m x approximately 2000 m, etc. In other words, in the present disclosure, the variable size of the analysis area A is set to a length that is "more than twice (preferably not more than five or not more than ten times)" the swell wavelength or the hull length as the desired wavelength.

[0032] Next, Fig. 5 will be described. The ocean wave spectrum calculation unit 22 initially sets an initial analysis area as an analysis area A, and calculates the ocean wave spectrum based on the radar scan image R within the initial analysis area (step S1). In the left column of Fig. 5, the analysis area calculation unit 25 initially sets the initial analysis area to a predetermined direction, predetermined distance, and predetermined size as seen from the radar ocean wave analysis system S. Here, the predetermined direction and predetermined distance may be any direction and any distance as long as the ocean wave crests are displayed, and the predetermined size may be approximately 2000 m x approximately 2000 m (the same size as in the prior art), considering that the wavelength of the swell (several hundred meters) is unknown.

[0033] In the left column of Figure 5, the ocean wave spectrum is calculated with high precision based on the radar scan image R within the initial analysis area, but it may also be estimated simply based on information such as wind speed and direction (such as a ocean wave spectrum model).The maximum wavelength of the ocean wave spectrum is calculated as 2π / minimum wavenumber based on the minimum wavenumber among the wavenumbers at which the intensity of the ocean wave spectrum is higher than a fixed threshold.Alternatively, the peak wavelength of the ocean wave spectrum is calculated as 2π / peak wavenumber based on the peak wavenumber at which the intensity of the ocean wave spectrum peaks.

[0034] The analysis area size setting unit 24 sets the "depth length" and "width length" of the analysis area A to "at least twice (preferably not more than five or not more than ten times)" the maximum wavelength or peak wavelength of the ocean wave spectrum calculated by the ocean wave spectrum calculation unit 22, and sets a "variable length" according to the maximum wavelength or peak wavelength (step S2). In the right column of Figure 5, the analysis area calculation unit 25 sets the analysis area A in a predetermined direction, a predetermined distance, and a variable size as viewed from the radar ocean wave analysis system S. Here, the variable size may be approximately 1000 m x approximately 1000 m (a smaller size than in conventional technology), taking into account the wavelength of swells (several hundred meters).

[0035] Next, Fig. 6 will be described. The vessel length information acquisition unit 23 acquires hull length information for the vessel V that is the subject of a determination of whether it will be damaged by the effects of waves (step S3). In the left column of Fig. 6, information on the length of the vessel V from bow to stern is acquired as hull length information in order to verify the possibility that the vessel V will resonate with waves and be damaged, but information on the width of the vessel V from port to starboard may also be acquired in order to verify the possibility that the vessel V will roll.

[0036] The analysis domain size setting unit 24 sets the "depth length" and "width length" of the analysis domain A to "a length at least twice (preferably not more than five or not more than ten times)" the desired wavelength equal to the hull length for which the ship length information acquisition unit 23 has acquired information, and sets the length to a "variable length" according to the desired wavelength equal to the hull length (step S4). In the right column of Figure 6, the analysis domain calculation unit 25 sets the analysis domain A to a predetermined direction, a predetermined distance, and a variable size as viewed from the radar wave analysis system S. Here, the variable size may be approximately 1000 m x approximately 1000 m (a smaller size than in conventional technology), taking into account the hull length (several hundred meters, etc.).

[0037] 5 and 6, the radar wave analysis unit 21 performs wave analysis of at least one of the wave height, wave wavelength, wave direction, and wave speed based on the radar scan image R within the analysis area A set by the analysis area size setting unit 24 (step S5). The radar display device 3 displays the radar wave analysis results (step S6). Steps S5 and S6 are repeated until the radar wave analysis is completed (step S7), and at least one of the wave height, wave wavelength, wave direction, and wave speed is calculated and displayed.

[0038] In this way, since the intensity of the wave spectrum is concentrated near a specific wave number, the analysis area A can be set to a size corresponding to the maximum wavelength or peak wavelength of the wave spectrum. Alternatively, since waves with a wavelength equal to the length of the hull can damage the hull, the analysis area A can be set to a size corresponding to a desired wavelength equal to the length of the hull. In a modified example, the analysis area A can also be set to a size corresponding to a desired wavelength other than the maximum wavelength or peak wavelength of the wave spectrum and the desired wavelength equal to the length of the hull. [Industrial Applicability]

[0039] The radar wave analysis device, radar wave analysis program, and radar wave analysis drone disclosed herein can calculate at least one of wave height, wave wavelength, wave direction, and wave speed with high accuracy, regardless of whether the wave wavelength is short or long, and can reduce the calculation load of at least one of wave height, wave wavelength, wave direction, and wave speed (particularly when the radar is mounted on a drone, aircraft, etc.). [Explanation of symbols]

[0040] R: Radar scan image A:Analysis area W: wave crest V: Ship S: Radar wave analysis system D: Radar wave analysis drone 1: Radar transmitter and receiver 2: Radar wave analyzer 3: Radar display device 11: Radar transmitter 12: Transmission / reception switching unit 13: Radar antenna 14: Radar receiver 21: Radar wave analysis section 22: Wave spectrum calculation section 23: Ship length information acquisition unit 24: Analysis area size setting section 25:Analysis area calculation section

Claims

1. A radar wave analysis device that performs wave analysis using a radar, an analysis area size setting unit that sets the depth and width of a rectangular analysis area in which wave analysis is performed to lengths that are at least twice the desired wavelength and that are variable depending on the desired wavelength; a radar wave analysis unit that performs wave analysis of at least one of wave height, wave wavelength, wave direction, and wave speed based on a radar scan image within the analysis area set by the analysis area size setting unit; A radar wave analysis device comprising:

2. a wave spectrum calculation unit that initially sets an initial analysis area as the analysis area and calculates a wave spectrum based on a radar scan image within the initial analysis area, The analysis area size setting unit sets the depth and width of the analysis area to lengths that are at least twice the maximum wavelength or peak wavelength of the ocean wave spectrum calculated by the ocean wave spectrum calculation unit, and sets the lengths to be variable depending on the maximum wavelength or the peak wavelength.

2. The radar wave analysis device according to claim 1, wherein:

3. a hull length information acquisition unit for acquiring hull length information of a ship to be determined as to whether it will be damaged by the influence of waves; The analysis region size setting unit sets the depth and width of the analysis region to lengths that are at least twice the desired wavelength, which is equal to the hull length for which the hull length information acquisition unit has acquired information, and sets the lengths to be variable depending on the desired wavelength, which is equal to the hull length.

2. The radar wave analysis device according to claim 1, wherein:

4. 4. A radar wave analysis program for causing a computer to execute each processing step performed by each processing unit included in the radar wave analysis device according to claim 1.

5. A radar wave analysis drone comprising the radar wave analysis device according to any one of claims 1 to 3 and a radar transmitting and receiving device for performing wave analysis.

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