JP2020169884A - Wave measuring device, wave measuring method, and wave measuring program - Google Patents

Abstract

To measure wave data with high accuracy by a simple structure and process.SOLUTION: A wave measuring device 10 comprises a motion data calculation unit 20, a wave spectrum estimation unit 31, a unique frequency estimation unit 40, and a ship response function setting unit 50. The motion data calculation unit 20 calculates the motion data of the ship. The wave spectrum estimation unit 31 estimates a wave spectrum using the motion data and a ship response function. The unique frequency estimation unit 40 estimates the unique frequency of the ship from the wave spectrum or motion data. The ship response function setting unit 50 sets a ship response function using the unique frequency.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wave measurement technique for measuring wave data such as wave height, wave direction, and wave period.

Conventionally, a wave measuring device attached to a ship as shown in Patent Document 1 is known.

Japanese Unexamined Patent Publication No. 2017-181413

However, in the conventional wave measuring device, the wave data is measured by using the detection results and settings of a plurality of components, so that the system tends to be complicated.

Therefore, an object of the present invention is to provide a wave measurement technique for measuring wave data with high accuracy with a simple configuration and processing.

The wave measuring device of the present invention includes a sway data calculation unit, a wave spectrum estimation unit, a natural frequency estimation unit, and a hull response function setting unit. The sway data calculation unit calculates the sway data of the hull. The wave spectrum estimation unit estimates the wave spectrum using the sway data and the hull response function. The natural frequency estimation unit estimates the natural frequency of the hull from the wave spectrum. The hull response function setting unit sets the hull response function using the natural frequency.

In this configuration, the natural frequency is estimated from the hull sway data due to waves and applied to the hull response function. Therefore, the hull response function is set to a value suitable for the hull.

According to the present invention, wave data can be measured with high accuracy with a simple configuration and processing.

It is a functional block diagram of the wave measuring apparatus which concerns on embodiment of this invention. (A) is a diagram showing the orientation characteristics of the roll response function, (B) is a diagram showing the frequency characteristics of the roll response function, and (C) shows the orientation characteristics of the heave response function. It is a figure, (D) is a figure which shows the frequency characteristic of the response function for a heave, (E) is a figure which shows the orientation characteristic of the response function for pitch, (F) is a figure which shows the response function for pitch. It is a figure which shows the frequency characteristic. FIG. 3A is a diagram showing the relationship between the amplitude ratio of the wave component and the phase difference, and FIG. 3B is a diagram showing the relationship between the amplitude ratio of the tuning component and the phase difference. It is a figure which shows the concept for estimating a natural frequency. It is a figure which shows the frequency characteristic of the determination value α. (A) is a diagram showing an example of a wave detection screen when the processing of the present embodiment is performed, and (B) is an example of a wave detection screen when the processing of the present embodiment is not performed. It is a figure which shows. It is a flowchart of the main process of the wave measurement method which concerns on embodiment of this invention. It is a flowchart of the estimation process of a natural frequency. It is a more detailed flowchart of a part of the estimation process of a natural frequency. It is a flowchart of the calculation process of the wave data after the estimation of the natural frequency is completed. It is a functional block diagram of the wave measuring apparatus which concerns on another embodiment of this invention. (A), (B), and (C) are functional block diagrams showing a configuration example of the sway data calculation unit, respectively.

The wave measurement technique according to the embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram of the wave measuring device according to the embodiment of the present invention.

As shown in FIG. 1, the wave measuring device 10 includes a sway data calculation unit 20, a calculation unit 30, a natural frequency estimation unit 40, and a hull response function setting unit 50. The calculation unit 30 includes a wave spectrum estimation unit 31 and a wave data calculation unit 32. The sway data calculation unit 20, the arithmetic unit 30, the natural frequency estimation unit 40, and the hull response function setting unit 50 each have a program that realizes processing of each functional unit, a storage medium that stores this program, and this program. It is realized by an arithmetic unit such as a CPU that executes the above. The natural frequency estimation unit 40 and the hull response function setting unit 50 may be included in the calculation unit 30.

The sway data calculation unit 20 is attached to the hull of the ship and detects, for example, changes in the posture of the hull including roll, pitch, and heave. The sway data calculation unit 20 generates sway data including a roll component, a pitch component, and a heave component from a change in the attitude of the hull. The sway data calculation unit 20 generates sway data at a predetermined cycle. The specific configuration of the sway data calculation unit 20 will be described later. The sway data calculation unit 20 outputs the sway data to the calculation unit 30.

The hull response function setting unit 50 sets the hull response function and outputs it to the wave spectrum estimation unit 31 of the calculation unit 30. The hull response function is generally a function showing the relationship between the waves reaching the hull and the sway of the hull due to the waves. The hull response function is composed of a roll response function, a pitch response function, and a heave response function.

The hull response function setting unit 50 outputs the initial hull response function to the wave spectrum estimation unit 31 until the estimation of the eigenfrequency by the eigenfrequency estimation unit 40 is completed.

If the hull response function setting unit 50 has completed the estimation of the eigenfrequency by the eigenfrequency estimation unit 40, the hull response function setting unit 50 applies the estimated eigenfrequency to set the hull response function. Then, the hull response function setting unit 50 outputs the hull response function set based on the natural frequency to the wave spectrum estimation unit 31.

Specifically, the hull response function setting unit 50 sets the hull response function, for example, as shown below.

FIG. 2A is a diagram showing the orientation characteristics of the roll response function, and FIG. 2B is a diagram showing the frequency characteristics of the roll response function. FIG. 2C is a diagram showing the orientation characteristics of the heave response function, and FIG. 2D is a diagram showing the frequency characteristics of the heave response function. FIG. 2 (E) is a diagram showing the orientation characteristics of the pitch response function, and FIG. 2 (F) is a diagram showing the frequency characteristics of the pitch response function.

As shown in FIG. 2A, the roll response function has higher azimuth characteristics in the starboard (90 °) and port (270 °) directions (1.0), stern (0 °) and bow (0 °). Lower in the 180 °) direction (0.0). Depending on the orientation, as shown in FIG. 2B, the roll response function has a maximum at the natural frequency ω0 as a frequency characteristic. In this way, the hull response function setting unit 50 applies the natural frequency to the roll response function. This is because ships generally have a vertically elongated shape and are susceptible to shaking due to lateral waves. And this sway depends on the shape of the ship, and this shape has a natural frequency.

The hull response function setting unit 50 sets the hull sway function using the natural frequency after the estimation of the natural frequency is completed. Specifically, as shown in FIG. 2B, the hull response function setting unit 50 may perform the same as the heave response function and the pitch response function, which will be described later, before the completion of the estimation of the natural frequency. A roll response function consisting of a constant value (for example, 1.0) that is the same value for all frequency components is used. That is, before the completion of the estimation of the natural frequency, all the frequency components of the roll response function are set to be the same.

It is preferable that all frequency components are the same, but substantially all frequency components may have substantially the same value. For example, when almost all frequency components are 1.0, some frequency components may be about 1.1 or about 0.9. In this case, the variation range of the value of the frequency component can be appropriately set according to the estimation accuracy of the natural frequency and the like. Further, the constant value is not limited to 1.0, and may be another value.

The setting of these frequency components is not limited to the application to the roll response function before the completion of the estimation of the natural frequency, and can also be applied to the heave response function and the pitch response function shown below.

As shown in FIG. 2C, the heave response function has the same azimuth characteristic in all directions (for example, 1.0). As shown in FIG. 2D, the heave response function has the same frequency characteristics at all frequencies (for example, 1.0). The hull response function setting unit 50 uses this heave response function, which is involved before and after the completion of estimation of the natural frequency. That is, the response function for heave is set so that the amplitude of the sway data and the amplitude of the wave spectrum are the same as the azimuth characteristic and the frequency characteristic.

As shown in FIG. 2 (E), the pitch response function is low in the starboard (90 °) and port (270 °) directions (for example, 0.0), and in the stern (0 °) direction and as azimuth characteristics. High in the bow (180 °) direction (eg 1.0). As shown in FIG. 2F, the pitch response function has the same frequency characteristics at all frequencies (for example, 1.0). The hull response function setting unit 50 uses this pitch response function, which is involved before and after the completion of the estimation of the natural frequency. That is, the pitch response function is set so that the amplitude of the sway data and the amplitude of the wave spectrum are the same as the frequency characteristics.

The wave spectrum estimation unit 31 estimates the wave spectrum in each direction with respect to the hull by using the sway data and the hull response function. For example, the wave spectrum estimation unit 31 estimates the wave spectrum by inputting a plurality of sway data arranged in a time series and executing a state estimation operation such as a Kalman filter or Bayesian estimation. The wave spectrum has an amplitude component, a phase component, and a frequency component. At this time, the wave spectrum estimation unit 31 applies the hull response function from the hull response function setting unit 50 to the state estimation calculation.

Then, as described above, the hull response function is appropriately set according to the shape of the hull after the estimation of the natural frequency is completed. Therefore, the wave spectrum estimation unit 31 can estimate the wave spectrum with high accuracy by using the hull response function updated (set) after the estimation of the natural frequency is completed.

The wave spectrum estimation unit 31 outputs the wave spectrum to the wave data calculation unit 32 and the natural frequency estimation unit 40. After the estimation of the natural frequency is completed, the wave spectrum estimation unit 31 does not have to output the wave spectrum to the natural frequency estimation unit 40. On the other hand, before estimating the natural frequency, the wave spectrum estimation unit 31 does not have to output the wave spectrum to the wave data calculation unit 32.

The wave data calculation unit 32 calculates wave data including the peak wave direction, wave height, and frequency from the wave spectrum after the estimation of the natural frequency is completed by using a known method. At this time, by using the hull response function based on the natural frequency, the tuning component according to the shape of the hull is suppressed. Therefore, the wave data calculation unit 32 can calculate the wave data with high accuracy.

The eigenfrequency estimation unit 40 estimates the eigenfrequency from the wave spectrum. More specifically, the eigenfrequency estimation unit 40 estimates the eigenfrequency from the wave spectrum estimated using the initial hull response function. The eigenfrequency estimation unit 40 outputs the estimated eigenfrequency to the hull response function setting unit 50.

(Estimation method of natural frequency)
Next, a specific method for estimating the natural frequency by the natural frequency estimation unit 40 will be described. FIG. 3A is a diagram showing the relationship between the amplitude ratio of the wave component and the phase difference, and FIG. 3B is a diagram showing the relationship between the amplitude ratio of the tuning component and the phase difference. Each point shown in FIGS. 3A and 3B corresponds to each shaking data.

The wave component is a component that appears by the wave itself, and the tuning component is a component that appears by the shape of the hull when it receives waves. The amplitude ratio is the ratio of the amplitude of the port side wave spectrum to the amplitude of the starboard wave spectrum. The phase difference is the difference between the phase of the port side wave spectrum and the phase of the starboard wave spectrum.

As shown in FIGS. 3 (A) and 3 (B), in the wave component, the amplitude ratio and the phase difference are dispersed. On the other hand, in the tuning component, the amplitude ratio is concentrated near 1.0 and the phase difference is concentrated near π.

Thus, in the wave component, there is no correlation between the amplitude of the port-side wave spectrum and the amplitude of the starboard-side wave spectrum. In the wave component, there is no correlation between the phase of the port side wave spectrum and the phase of the starboard wave spectrum.

On the other hand, in the tuning component, the amplitude of the port-side wave spectrum and the amplitude of the starboard-side wave spectrum have substantially the same magnitude. Further, in the tuning component, the phase of the port side wave spectrum and the phase of the starboard wave spectrum are substantially opposite phases.

FIG. 4 is a diagram showing a concept for estimating a natural frequency. FIG. 4 shows an example. In FIG. 4, the port wave vector vL is represented by the amplitude and phase of the port wave spectrum. The starboard wave vector vR is represented by the amplitude and phase of the starboard wave spectrum. The vector sum vsS is the sum of the vectors of the port wave vector vL and the starboard wave vector vR.

As described above, if it is a tuning component, the amplitude of the port side wave vector vL and the amplitude of the starboard wave vector vR are substantially the same, and the phase of the port side wave vector vL and the phase of the starboard wave vector vR are substantially opposite in phase. is there. Therefore, as shown in FIG. 4, the magnitude of the vector sum vs. is smaller than the magnitude of the port wave vector vL and the magnitude of the starboard wave vector vR.

Utilizing this, the eigenfrequency estimation unit 40 estimates the eigenfrequency, which is the frequency of the tuning component.

The eigenfrequency estimation unit 40 calculates the magnitude DvL of the port side wave vector vL, the magnitude DvR of the starboard wave vector vR, and the magnitude DvS of the vector sum vs. The eigenfrequency estimation unit 40 adds the magnitude of the port wave vector vL and the magnitude of the starboard wave vector vR to calculate a reference value SVN (= DvL + DvR) for normalization. The natural frequency estimation unit 40 divides the magnitude DvS of the vector sum vs. the reference value SVN for normalization to calculate the normalized determination value α (= DvS / SVN). The intrinsic frequency estimation unit 40 calculates the determination value α for each frequency.

FIG. 5 is a diagram showing the frequency characteristics of the determination value α. As shown in FIG. 5, the determination value α has a minimum value at the angular frequency ω. The minimum value in the present application may be the minimum value of the actual data or the minimum value of the function obtained by performing a predetermined fitting on the actual data. As described above, since the magnitude DvS of the vector sum vs. is small in the tuning component, the angular frequency ω at which the determination value α is the minimum value is the frequency of the tuning component, that is, the natural frequency ω0.

Utilizing this, the intrinsic frequency estimation unit 40 detects the minimum value from the frequency function of the determination value α. The eigenfrequency estimation unit 40 detects a frequency at which the determination value α is the minimum value, and sets the eigen frequency ω0. As a result, the eigenfrequency estimation unit 40 can estimate the eigenfrequency ω0.

Since the wave spectrum contains many error components, it is preferable that the eigenfrequency estimation unit 40 estimates the eigenfrequency ω0 by using a weighted averaging calculation. The weighted average calculation is, for example, an operation (calculation of a weighted average value) in which a value obtained by subtracting a determination value αω of each angular frequency ω from 1.0 is weighted by each angular frequency ω to calculate an average value. By using such a weighted averaging calculation, the eigenfrequency estimation unit 40 can reduce the influence of the error component and estimate the eigenfrequency ω0 with higher accuracy.

Then, in this way, the eigenfrequency estimation unit 40 estimates the eigenfrequency ω0 according to the hull, and the hull response function setting unit 50 uses the eigenfrequency ω0 to obtain a hull response function suitable for the hull. Can be set. Then, by using this hull response function, the wave spectrum estimation unit 31 can estimate the wave spectrum with high accuracy, and the wave data calculation unit 32 can calculate the wave data with high accuracy.

FIG. 6A is a diagram showing an example of a wave detection screen when the processing of the present embodiment is performed. FIG. 6B is a diagram showing an example of a wave detection screen when the processing of the present embodiment is not performed.

When the wave component is present in the port side direction of the hull, the tuning component appears together with the wave component as shown in FIG. 6 (B) unless the processing of the present embodiment is performed. On the other hand, by using the process of the present embodiment, as shown in FIG. 6 (A), the tuning component does not appear, and only the wave component appears.

In this way, the wave measuring device 10 can suppress and remove the tuning component and output only the wave component.

(Explanation of wave measurement method and wave measurement program)
In the above description, an embodiment in which each process is realized by a different functional unit is shown, but the above process may be programmed and stored, and may be executed by an arithmetic processing unit such as a CPU. In this case, the arithmetic processing unit may execute the following processing. The specific description of each process has been described above, and below, only necessary parts will be added and described.

(Main processing flow)
FIG. 7 is a flowchart of the main process of the wave measurement method according to the embodiment of the present invention. As shown in FIG. 7, the arithmetic processing unit estimates the natural frequency ω0 using the sway data of the hull (S11). The arithmetic processing unit estimates the wave spectrum and calculates the wave data by using the hull response function using the natural frequency ω0 (S12).

(Flow of estimation processing of natural frequency)
FIG. 8 is a flowchart of the natural frequency estimation process. As shown in FIG. 8, the arithmetic processing unit sets an initial hull response function (S101). The initial hull response function does not depend on the natural frequency ω0, and the frequency characteristic is a constant value.

The arithmetic processing unit acquires the sway data (S102). The arithmetic processing unit estimates the wave spectrum using the initial hull response function (S103). The arithmetic processing unit estimates the natural frequency ω0 using the wave spectrum (S104).

If the estimation of the eigenfrequency ω0 is completed (S105: YES), the arithmetic processing unit ends the estimation of the eigenfrequency ω0. If the estimation of the eigenfrequency ω0 is not completed (S105: NO), the arithmetic processing unit acquires the sway data and continues the estimation of the eigenfrequency ω0. The completion of the estimation of the eigenfrequency ω0 is detected, for example, by obtaining a predetermined number of sway data, that is, a predetermined time has elapsed from the start of the estimation of the eigenfrequency ω0. Further, the completion of the estimation of the natural frequency ω0 is detected when the natural frequency ω0 is estimated at predetermined time intervals and the statistical values such as the variance of the estimated values and the standard deviation are equal to or less than the end threshold value.

(More detailed flow of part of the natural frequency estimation process)
FIG. 9 is a more detailed flowchart of a part of the natural frequency estimation process. As shown in FIG. 9, the arithmetic processing apparatus acquires the port side wave vector vL, which is the port side wave spectrum of the hull, and the starboard wave vector vR, which is the starboard side wave spectrum of the hull, from the wave spectrum (S401). The arithmetic processing unit calculates the vector sum vs of the port wave vector vL and the starboard wave vector vR (S402).

The arithmetic processing unit calculates the determination value α from the magnitude of the port wave vector vL, the magnitude of the starboard wave vector vR, and the magnitude of the vector sum vs. (S403). The arithmetic processing unit calculates the frequency characteristic of the determination value α (S404). The arithmetic processing unit estimates the natural frequency ω0 from the frequency characteristic of the determination value α (S405).

(Calculation processing of wave data after completion of estimation of natural frequency)
FIG. 10 is a flowchart of the wave data calculation process after the estimation of the natural frequency is completed. As shown in FIG. 10, the hull response function is set using the natural frequency ω0 estimated by the processes of FIGS. 9 and 10 (S201). The arithmetic processing unit acquires the sway data (S202).

The arithmetic processing unit estimates the wave spectrum using the hull response function using the natural frequency and the sway data (S203). The arithmetic processing unit calculates wave data including wave direction, frequency, and wave height from the wave spectrum (S204).

(Another embodiment of the wave measuring device)
FIG. 11 is a functional block diagram of the wave measuring device according to another embodiment of the present invention. As shown in FIG. 11, the wave measuring device 10A is different from the wave measuring device 10 in the natural frequency estimation unit 40A. The other configuration of the wave measuring device 10A is the same as that of the wave measuring device 10, and the description of the same parts will be omitted.

The sway data is input to the intrinsic frequency estimation unit 40A. The intrinsic frequency estimation unit 40A detects the tuning component from the shaking data. For example, the natural frequency estimation unit 40A extracts the frequency spectrum of the sway data and detects the tuning component from the frequency spectrum.

The intrinsic frequency estimation unit 40A estimates the intrinsic frequency from the tuning component. The eigenfrequency estimation unit 40A outputs the eigenfrequency to the hull response function setting unit 50.

In this way, the natural frequency can also be detected directly from the sway data.

(Structure example of the sway data calculation unit)
In the above description, a specific configuration example of the sway data calculation unit 20 has not been shown, but for example, various configurations as shown below can be applied. 12 (A), 12 (B), and 12 (C) are functional block diagrams showing a configuration example of the sway data calculation unit, respectively.

(Structure example 1 of the sway data calculation unit)
As shown in FIG. 12A, the sway data calculation unit 20 includes an antenna 211, an antenna 212, a GNSS receiving unit 221 and a GNSS receiving unit 222, an IMU 23, and a calculation unit 24. The GNSS receiving unit 221 and the GNSS receiving unit 222, and the arithmetic unit 24 are realized by an electronic circuit, a storage medium for programming and storing the processing executed by these functional units, and an arithmetic processing unit that executes the program. Will be done.

The antenna 211 and the antenna 212 are installed on the hull. The antenna 211 receives the positioning signal from the GNSS satellite and outputs it to the GNSS receiving unit 221. The antenna 212 receives the positioning signal from the GNSS satellite and outputs it to the GNSS receiving unit 222.

The GNSS receiving unit 221 captures and tracks the GNSS signal received by the antenna 211, and outputs positioning data based on the tracking result. The positioning data includes, for example, a carrier phase integrated value, a pseudo distance, and the like. The positioning data may include a single positioning result using a pseudo distance. The GNSS receiving unit 221 outputs the positioning data to the calculation unit 24.

The GNSS receiving unit 222 captures and tracks the GNSS signal received by the antenna 212, and outputs positioning data based on the tracking result. The positioning data includes, for example, a carrier phase integrated value, a pseudo distance, and the like. The positioning data may include a single positioning result using a pseudo distance. The GNSS receiving unit 222 outputs the positioning data to the calculation unit 24.

The IMU 23 is a so-called inertial sensor, and includes an acceleration sensor and an angular velocity sensor. The IMU 23 is fixed to the hull in a predetermined posture. The IMU 23 measures inertial data such as acceleration and angular velocity. The IMU 23 outputs inertial data to the calculation unit 24.

The calculation unit 24 calculates the attitude angle of the hull from the positioning data and the inertial data using a known method, and outputs it as sway data.

In this configuration, by using the positioning data based on the positioning signal and the inertial data based on the inertial force, the shaking data calculation unit 20 can calculate the shaking data with high accuracy. In addition, the agitation data calculation unit 20 has high robustness.

(Structure example 2 of the sway data calculation unit)
As shown in FIG. 12B, the sway data calculation unit 20A includes an antenna 211, an antenna 212, an antenna 213, a GNSS receiving unit 221, a GNSS receiving unit 222, a GNSS receiving unit 223, and a calculation unit 24. The GNSS receiving unit 221 and the GNSS receiving unit 222, the GNSS receiving unit 223, and the arithmetic unit 24 are a storage medium for programming and storing an electronic circuit and processing executed by these functional units, and an operation for executing the program. It is realized by the processing device.

The antenna 211, the antenna 212, and the antenna 213 are installed on the hull. The antenna 211 receives the positioning signal from the GNSS satellite and outputs it to the GNSS receiving unit 221. The antenna 212 receives the positioning signal from the GNSS satellite and outputs it to the GNSS receiving unit 222. The antenna 213 receives the positioning signal from the GNSS satellite and outputs it to the GNSS receiving unit 223.

The GNSS receiving unit 221 captures and tracks the GNSS signal received by the antenna 211, and outputs positioning data based on the tracking result. The positioning data includes, for example, a carrier phase integrated value, a pseudo distance, and the like. The positioning data may include a single positioning result using a pseudo distance. The GNSS receiving unit 221 outputs the positioning data to the calculation unit 24.

The GNSS receiving unit 222 captures and tracks the GNSS signal received by the antenna 212, and outputs positioning data based on the tracking result. The positioning data includes, for example, a carrier phase integrated value, a pseudo distance, and the like. The positioning data may include a single positioning result using a pseudo distance. The GNSS receiving unit 222 outputs the positioning data to the calculation unit 24.

The GNSS receiving unit 223 captures and tracks the GNSS signal received by the antenna 213, and outputs positioning data based on the tracking result. The positioning data includes, for example, a carrier phase integrated value, a pseudo distance, and the like. The positioning data may include a single positioning result using a pseudo distance. The GNSS receiving unit 223 outputs the positioning data to the calculation unit 24.

The calculation unit 24 calculates the attitude angle of the hull from a plurality of positioning data using a known method, and outputs it as sway data.

In this configuration, the sway data calculation unit 20A can calculate the sway data with high accuracy without using the IMU.

The number of antennas and GNSS receiving units of the above-mentioned shaking data calculation unit 20 and the shaking data calculation unit 20A indicates the minimum number, and may be larger than this number.

(Structure example 3 of the sway data calculation unit)
As shown in FIG. 12C, the sway data calculation unit 20B includes an IMU 23 and a calculation unit 24. The arithmetic unit 24 is realized by an electronic circuit, a storage medium for programming and storing processes executed by these functional units, and an arithmetic processing unit that executes the program.

The IMU 23 is a so-called inertial sensor, and includes an acceleration sensor and an angular velocity sensor. The IMU 23 is fixed to the hull in a predetermined posture. The IMU 23 measures inertial data such as acceleration and angular velocity. The IMU 23 outputs inertial data to the calculation unit 24.

The calculation unit 24 calculates the attitude angle of the hull from the inertial data using a known method, and outputs it as sway data.

With this configuration, sway data can be output even in an environment where positioning signals cannot be received.

In the above description, the determination value α uses a normalized value, but it is also possible to use a value that is not normalized. However, by using the normalized value, the wave measuring device can obtain a frequency characteristic that is not affected by the magnitude of the wave spectrum. Therefore, by using the normalized determination value α, the wave measuring device can estimate the natural frequency with higher accuracy.

10, 10A: Wave measuring device 20, 20A, 20B: Sway data calculation unit 23: IMU
24: Calculation unit 30 of the sway data calculation unit 30: Calculation unit 31: Wave spectrum estimation unit 32: Wave data calculation unit 40, 40A: Natural frequency estimation unit 50: Hull response function setting unit 211, 212, 213: Antennas 221 and 222: Antennas 221, 222 , 223: GNSS receiver

Claims (14)

The sway data calculation unit that calculates the sway data of the hull,
A wave spectrum estimation unit that estimates the wave spectrum using the sway data and the hull response function,
A wave data calculation unit that calculates wave data from the wave spectrum,
An intrinsic frequency estimation unit that estimates the intrinsic frequency of the hull from the wave spectrum or the shaking data,
A hull response function setting unit that sets the hull response function using the natural frequency,
Wave measuring device equipped with. The wave measuring device according to claim 1.
The wave spectrum has an amplitude component and a phase component as well as a frequency component.
The natural frequency estimation unit
The amplitude component of the wave spectrum on the port side of the hull and
The amplitude component of the starboard side wave spectrum of the hull and
The vector sum of the port-side wave spectrum and the starboard-side wave spectrum composed of the amplitude component and the phase component,
To estimate the intrinsic frequency,
Wave measuring device. The wave measuring device according to claim 2.
The natural frequency estimation unit
The intrinsic frequency is estimated using a determination value obtained by dividing the magnitude of the vector sum by the magnitude of the port-side wave spectrum and the magnitude of the starboard wave spectrum.
Wave measuring device. The wave measuring device according to claim 3.
The natural frequency estimation unit
The frequency at which the determination value is the minimum value is defined as the natural frequency.
Wave measuring device. The wave measuring device according to claim 3 or 4.
The natural frequency estimation unit
The intrinsic frequency is estimated using the weighted average value of the determination value.
Wave measuring device. The wave measuring device according to any one of claims 1 to 5.
The hull response function setting unit
The hull response function is composed of at least a roll response function.
Applying the natural frequency to the roll response function,
Wave measuring device. The wave measuring device according to any one of claims 1 to 6.
The natural frequency estimation unit
The natural frequency is estimated from the wave spectrum using the initial hull response function before applying the estimated natural frequency.
Wave measuring device. The wave measuring device according to any one of claims 1 to 7.
The hull response function before the completion of the estimation of the natural frequency sets the amplitude of the sway data and the amplitude of the wave spectrum to be the same.
Wave measuring device. The sway data calculation unit that calculates the sway data of the hull,
A wave spectrum estimation unit that estimates the wave spectrum using a hull response function in which substantially all frequency components are set to substantially the same value and the sway data.
A wave data calculation unit that calculates wave data from the wave spectrum,
Wave measuring device equipped with. The wave measuring device according to claim 9.
The wave spectrum estimation unit sets the amplitude of the sway data and the amplitude of the wave spectrum to be substantially the same.
Wave measuring device. Calculate the hull sway data and
The wave spectrum is estimated using the sway data and the hull response function.
Wave data is calculated from the wave spectrum,
The natural frequency of the hull is estimated from the wave spectrum or the sway data, and
The hull response function is set using the natural frequency.
Wave measurement method. The wave measurement method according to claim 11.
The wave spectrum has an amplitude component and a phase component as well as a frequency component.
Vector of the amplitude component of the port side wave spectrum of the hull, the amplitude component of the starboard side wave spectrum of the hull, the port side wave spectrum composed of the amplitude component and the phase component, and the starboard side wave spectrum. Estimate the natural frequency using the sum and
Wave measurement method. Calculate the hull sway data and
The wave spectrum is estimated using the sway data and the hull response function.
Wave data is calculated from the wave spectrum,
The natural frequency of the hull is estimated from the wave spectrum or the sway data, and
The hull response function is set using the natural frequency.
A wave measurement program that causes an arithmetic processing unit to execute processing. The wave measurement program according to claim 13.
The wave spectrum has an amplitude component and a phase component as well as a frequency component.
Vector of the amplitude component of the port side wave spectrum of the hull, the amplitude component of the starboard side wave spectrum of the hull, the port side wave spectrum composed of the amplitude component and the phase component, and the starboard side wave spectrum. Estimate the natural frequency using the sum and
A wave measurement program that causes an arithmetic processing unit to execute processing.

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