JP2022097116A - Wave amplitude estimation method, wave amplitude estimation device, and program - Google Patents

Abstract

To estimate the amplitude of a wave without performing integration for acceleration time series data indicating a change over time of a measured value of the acceleration in the vertical direction applied to a floating matter floating on the water due to a vertical motion of the water surface.SOLUTION: Acceleration acquisition means 111 acquires acceleration time series data from a terminal 2 through an interface 13. Smoothing means 112 reads out the acceleration time series data acquired by the acceleration acquisition means 111 and stored in a memory 12 and smooths a change over time in a predetermined period of the acceleration indicated by the acceleration time series data. Period specification means 113 specifies, by using the acceleration time series data, a period of a change over time of the acceleration in the vertical direction applied to a floating matter J floating on the water due to a vertical motion of the water surface. Amplitude estimation means 114 estimates the amplitude of a wave according to the period specified by the period specification means 113, in accordance with the relationship between the amplitude of the wave and the period of the change over time of the acceleration.SELECTED DRAWING: Figure 4

Description

The present invention relates to a wave amplitude estimation method, an amplitude estimation device, and a program.

The wave height meter is used to grasp the water level fluctuation in real time in the sea area of the construction site. There are various types of wave height gauges such as seafloor-mounted type, aerial radiation type, and buoy type.

The seafloor-mounted wave height meter is a wave height meter that captures water level fluctuations from the seabed using an ultrasonic irradiation device, a water pressure sensor, or the like. It is difficult to install a seafloor-mounted wave height gauge at deep water because a diver is required to install it. In addition, since the ultrasonic irradiation device and water pressure sensor are located on the seabed, they need to be connected by cables in order to transmit observation data to work vessels at sea.

The aerial radiation type wave height meter emits ultrasonic waves from the air toward the water surface and captures the water surface fluctuation from the reflection. However, if the work vessel is upset, it is necessary to consider the upset. In addition, since it is necessary to radiate at a right angle toward the water surface, it is difficult to keep the ultrasonic wave radiation angle at a right angle due to the shaking of the ship.

A buoy-type wave height meter is a type of wave height meter that captures water level fluctuations using a buoy (also called a buoy) suspended on the water surface. Buoy-type wave height gauges include those using a Global Navigation Satellite System (GNSS) and those using an acceleration sensor.

A buoy-type wave height meter using GNSS can acquire elevation information by GNSS, but the equipment and materials tend to be large depending on the required accuracy.

A buoy-type accelerometer that uses an accelerometer measures acceleration in the vertical direction with an accelerometer attached to the buoy, and estimates water level fluctuations by double-integrating this acceleration over time.

For example, in Patent Document 1, the velocity extracted in a wave observation device or the like configured to integrate the output of an acceleration sensor to obtain a velocity component, or to obtain a displacement component by further integrating the velocity component. A wave observation device using an acceleration sensor is described in which a trend component superimposed on the component or displacement component is removed by passing the component or displacement component through a high frequency filter having a required passing region. ing.

Japanese Unexamined Patent Publication No. 61-212716

However, in order to estimate the water level fluctuation by the method of double integrating the acceleration with time, a relatively high-precision accelerometer is required.

One of the objects of the present invention is the wave height, so-called wave, without integrating the acceleration time series data showing the change over time of the measured value of the vertical acceleration received by the floating substance floating on the water due to the vertical movement of the water surface. Is to estimate the amplitude of.

The amplitude estimation method according to claim 1 of the present invention includes an acceleration acquisition step of acquiring acceleration time-series data indicating a change over time in the measured value of the vertical acceleration received by the floating matter floating on the water due to the vertical movement of the water surface, and the above-mentioned. A cycle specifying step that specifies the cycle of the acceleration over time indicated by the acceleration time series data, and an amplitude estimation step that estimates the wave amplitude according to the cycle specified in the cycle specifying step according to the relationship between the wave amplitude and the cycle. It is a method of estimating the amplitude of a wave including.

The amplitude estimation method according to claim 2 of the present invention is the timing according to claim 1, wherein in the cycle specifying step, the acceleration that changes with time indicated by the acceleration time series data changes from a negative value to a positive value. Amplitude having a time interval calculation step of calculating the time interval of the above, and a statistical value calculation step of calculating the statistical value of a predetermined number of continuous time intervals on the time axis calculated in the time interval calculation step as the cycle. It is an estimation method.

The amplitude estimation method according to claim 3 of the present invention is the timing according to claim 1, wherein in the cycle specifying step, the acceleration that changes with time indicated by the acceleration time series data changes from a positive value to a negative value. Amplitude having a time interval calculation step of calculating the time interval of the above, and a statistical value calculation step of calculating the statistical value of a predetermined number of continuous time intervals on the time axis calculated in the time interval calculation step as the cycle. It is an estimation method.

The amplitude estimation method according to claim 4 of the present invention is the embodiment according to any one of claims 1 to 3, wherein the wave amplitude is the square of the acceleration period multiplied by the acceleration amplitude. This is an amplitude estimation method using the relationship of multiplying and dividing by 4 times the square of the pi.

The amplitude estimation method according to claim 5 of the present invention is the aspect according to any one of claims 1 to 4, smoothing that smoothes the change over time of the acceleration indicated by the acceleration time series data. The cycle specifying step is an amplitude estimation method for specifying the cycle from the change over time of the acceleration smoothed in the smoothing step.

The amplitude estimation device according to claim 6 of the present invention includes an acceleration acquisition means for acquiring acceleration time-series data indicating a change over time in the measured value of the vertical acceleration received by a floating substance floating on the water due to the vertical movement of the water surface. A cycle specifying means for specifying the period of change in acceleration with time indicated by acceleration time series data, and an amplitude estimating means for estimating the wave amplitude according to the period specified by the period specifying means according to the relationship between the wave amplitude and the period. It is a wave amplitude estimation device including.

The program according to claim 7 of the present invention includes a process of acquiring acceleration time-series data indicating a change over time in a measured value of vertical acceleration received by a floating substance floating on water due to vertical movement of the water surface, and the acceleration. The process of specifying the cycle of the acceleration over time indicated by the time-series data and the process of estimating the wave amplitude according to the specified cycle in the process of specifying the cycle according to the relationship between the wave amplitude and the cycle are executed. It is a program to make it.

According to the present invention, the amplitude of a wave is estimated without integrating the acceleration time-series data showing the change over time of the measured value of the vertical acceleration received by the floating substance floating on the water due to the vertical movement of the water surface. Can be done.

The schematic diagram which shows an example of the whole structure of the amplitude estimation system 9. The figure which shows an example of the structure of the amplitude estimation apparatus 1. The figure which shows an example of the structure of the terminal 2. The figure which shows an example of the functional structure of the amplitude estimation apparatus 1. The flow diagram which shows an example of the operation flow of the amplitude estimation apparatus 1. The figure which shows the example of the time series data acquired or calculated by the amplitude estimator.

<Overall configuration of amplitude estimation system>
FIG. 1 is a schematic diagram showing an example of the overall configuration of the amplitude estimation system 9. The amplitude estimation system 9 includes an amplitude estimation device 1 and a terminal 2. Further, the amplitude estimation system 9 shown in FIG. 1 has a communication line 3.

The water surface Lv is the water surface of the sea or lake, and moves up and down in the vertical direction by the action of waves. The floating substance J is a structure such as a buoy that floats on the water. The suspended matter J moves in the vertical direction as the water surface Lv moves up and down.

The terminal 2 is attached to the floating object J. Therefore, the terminal 2 receives a vertical force due to the vertical movement of the water surface Lv together with the floating object J. The terminal 2 has a function of measuring at least the acceleration in the vertical direction, generates acceleration time-series data indicating a change over time in the measured value of the acceleration, and supplies the data to the amplitude estimation device 1.

The amplitude estimation device 1 is an information processing device that estimates the amplitude of a wave generated on the water surface Lv, and is, for example, a computer. The amplitude estimation device 1 acquires the above-mentioned acceleration time series data from the terminal 2. Then, the amplitude estimation device 1 specifies the cycle of the change with time of the acceleration indicated by the acquired acceleration time series data, and estimates the amplitude of the wave using the specified cycle according to a predetermined relationship.

The communication line 3 is a line that wirelessly connects the amplitude estimation device 1 and the terminal 2 so as to be able to communicate with each other. The terminal 2 transmits the acceleration time series data generated by the terminal 2 to the amplitude estimation device 1 via the communication line 3. The communication line 3 may be, for example, a line using an LPWA (Low Power Wide Area).

Examples of this LPWA include "ELTRES (registered trademark)", "LoRa (registered trademark)", "LoRaWAN (registered trademark)", "RPMA (registered trademark)", "SIGFOX (registered trademark)", and "EnOcean (enOcean). Registered Trademarks) Long Range ”,“ NB-IoT ”,“ NB-Fi Protocol ”,“ GreenOFDM ”,“ DASH7 ”,“ Wi-SUN ”,“ Weightless-P ”,“ LTE-MTC ”,“ LTE Cat. 0 ”,“ LTE Cat.M1 ”and the like.

<Amplitude estimation device configuration>
FIG. 2 is a diagram showing an example of the configuration of the amplitude estimation device 1. The amplitude estimation device 1 includes a processor 11, a memory 12, and an interface 13. The processor 11 controls the amplitude estimation device 1 by executing a computer program (hereinafter, simply referred to as a program) stored in the memory 12. The processor 11 is, for example, a CPU (Central Processing Unit).

The interface 13 is an interface for the processor 11 to exchange information with the communication line 3 and other external devices.

The processor 11 connects to the communication line 3 via the interface 13 and acquires the acceleration time series data generated by the terminal 2 from the communication line 3.

Further, the amplitude estimation device 1 is connected to, for example, an external display device via the interface 13 and causes the user to display the determined information.

The memory 12 is a storage means for, for example, a RAM (Random Access Memory), a ROM (Read Only Memory), a solid state drive, a hard disk drive, etc., and stores an operating system, various programs, data, and the like to be read by the processor 11.

<Terminal configuration>
FIG. 3 is a diagram showing an example of the configuration of the terminal 2. The terminal 2 has a processor 21, a memory 22, an interface 23, and an acceleration sensor 26.

The processor 21 controls the terminal 2 by executing a program stored in the memory 22. The processor 21 is, for example, a CPU.

The interface 23 is an interface for the processor 21 to exchange information with the communication line 3 and other external devices.

The processor 21 connects to the communication line 3 via the interface 23, and transmits acceleration time series data to the amplitude estimation device 1 via the communication line 3.

Further, the terminal 2 may be connected to an external storage device such as a flash memory via the interface 23, and the acceleration time series data or the like may be stored in this storage device.

The memory 22 is a storage means for, for example, a RAM, a ROM, a solid state drive, a hard disk drive, etc., and stores an operating system, various programs, data, and the like to be read by the processor 21.

The acceleration sensor 26 is, for example, a sensor that measures acceleration by a MEMS (Micro Electro Mechanical Systems) method. The acceleration sensor 26 measures at least the vertical acceleration received by itself and sequentially stores it in the memory 22. As a result, acceleration time series data indicating the time course of the measured vertical acceleration is generated in the memory 22. The generated acceleration time series data is transmitted to the amplitude estimation device 1 as described above. Since the terminal 2 is attached to the floating object J, the acceleration measured by the processor 21 is not only the acceleration received by the terminal 2 but also the acceleration received by the floating object J.

<Functional configuration of amplitude estimation device>
FIG. 4 is a diagram showing an example of the functional configuration of the amplitude estimation device 1. The processor 11 of the amplitude estimation device 1 functions as an acceleration acquisition means 111, a smoothing means 112, a period specifying means 113, an amplitude estimating means 114, and a reference position specifying means 115 by executing the above-mentioned program.

The acceleration acquisition means 111 acquires the above-mentioned acceleration time series data from the terminal 2 via the interface 13. That is, the processor 11 functioning as the acceleration acquisition means 111 is an example of an acceleration acquisition means for acquiring acceleration time-series data indicating a change over time in the measured value of the vertical acceleration received by the floating object floating on the water due to the vertical movement of the water surface. Is.

The reference position specifying means 115 shown in FIG. 4 is transmitted from the terminal 2, and is based on a position that changes with time based on the acceleration time series data acquired by the acceleration acquiring means 111, for example, about the latest 100 waves (for example, 100.3). Calculate the average value of acceleration over a relatively long predetermined period (hereinafter referred to as the first period) such as a period corresponding to a wave or a non-integer wave such as 97.8 waves, and use this average value as the average value. By using it, etc., the reference position (referred to as the reference position) of the water surface in the vertical direction is specified. That is, the processor 11 functioning as the reference position specifying means 115 calculates the average value of the acceleration that changes with time indicated by the acceleration time series data for a predetermined period, and based on the average value, determines the reference position of the water surface in the vertical direction. This is an example of a processor that executes a specified reference position specifying process.

The smoothing means 112 reads out the acceleration time-series data acquired by the acceleration acquisition means 111 and stored in the memory 12, and smoothes the time-dependent change of the acceleration indicated by the acceleration time-series data for a predetermined period. This predetermined period is a relatively short period (hereinafter referred to as a second period), for example, 2 seconds. In this case, the smoothing means 112 smoothes the acceleration data actually measured by the terminal 2 by calculating the moving average value of the acceleration for 2 seconds. Although the above-mentioned second period is set to 2 seconds, the second period may be a cycle Ta or less, which will be described later, and is not limited to 2 seconds.

The cycle specifying means 113 uses the acceleration time series data to specify the cycle of the vertical acceleration of the floating substance J floating on the water due to the vertical movement of the water surface. That is, the processor 11 functioning as the cycle specifying means 113 is an example of the cycle specifying means for specifying the cycle of the change with time of the acceleration indicated by the acceleration time series data. The cycle specifying means 113 shown in FIG. 4 identifies the cycle of the change over time of the acceleration smoothed by the smoothing means 112.

The cycle specifying means 113 shown in FIG. 4 includes a time interval calculating means 113a and a statistical value calculating means 113b.

The time interval calculation means 113a shown in FIG. 4 specifies the timing when the acceleration smoothed by the smoothing means 112 changes a predetermined time, and calculates the time interval between the timings.

For example, the time interval calculating means 113a uses the zero point of the acceleration corresponding to the reference position specified by the reference position specifying means 115 (the average value of the accelerations in the first period), so that the acceleration changes from plus to minus, that is, so-called. Using the zero-down cross points, the time interval for each wave sandwiched between two adjacent zero-down cross points is calculated. That is, the processor 11 that functions as the time interval calculation means 113a is a processor that executes a time interval calculation step of calculating the time interval of the timing at which the acceleration that changes with time indicated by the acceleration time series data changes from a positive value to a negative value. This is an example.

The statistical value calculating means 113b shown in FIG. 4 calculates statistical values of a predetermined number of consecutive time intervals calculated by the time interval calculating means 113a as a cycle of the change with time of acceleration. The statistical value calculating means 113b calculates, for example, the average value of the latest three times among the time intervals calculated in the past as the cycle of the change with time of the current acceleration.

The amplitude estimating means 114 estimates the amplitude of the wave according to the period specified by the period specifying means 113 according to the relationship between the wave amplitude and the period of the change of acceleration with time. For example, the relationship between the wave amplitude and the period of change in acceleration over time is that the wave amplitude is the value obtained by multiplying the amplitude of the acceleration by the square of the period of this acceleration and dividing by four times the square of the pi. There is a relationship.

The amplitude estimation means 114 transmits the estimated wave amplitude information to, for example, an external display device via the interface 13 and displays the information.

<Operation of amplitude estimator>
FIG. 5 is a flow chart showing an example of the operation flow of the amplitude estimation device 1. The processor 11 of the amplitude estimation device 1 acquires the acceleration time-series data (step S101), and smoothes the time-dependent change of the acceleration indicated by the acquired acceleration time-series data in the second period (for example, 2 seconds or the like). .. This smoothing is performed, for example, by calculating the arithmetic mean value of the accelerations measured over the second period (step S102).

The above-mentioned step S101 is an example of an acceleration acquisition step for acquiring acceleration time-series data indicating a change over time in the measured value of the vertical acceleration received by the floating substance floating on the water due to the vertical movement of the water surface.

Further, the above-mentioned step S102 is an example of a smoothing step for smoothing the change with time of the acceleration indicated by the acceleration time series data in a predetermined period.

FIG. 6 is a diagram showing an example of time series data acquired or calculated by the amplitude estimation device. The measured acceleration a ₀ shown in FIG. 6A is a curve showing the change over time of the acceleration measured by the acceleration sensor 26 of the terminal 2. The horizontal axis of the graph shown in FIG. 6A is time, and the vertical axis is the acceleration value. The actually measured acceleration a ₀ is obtained by multiplying the measured acceleration by -1, and the positive and negative directions are reversed.

The smoothing acceleration a _ave shown in FIG. 6 (a) is a value obtained by arithmetically averaging the above-mentioned values of a ₀ for 2 seconds, and is a so-called moving average. That is, the smoothing acceleration a _ave shown in FIG. 6A is a smoothing of the actually measured acceleration a ₀ during a predetermined period.

On the other hand, the processor 11 executes the following steps S103 and S104 in parallel with the execution of the process of step S102 in order to determine the period for estimating the wave amplitude. That is, the processor 11 calculates an average value of the acceleration indicated by the acceleration time series data acquired in step S101 over the first period (for example, the latest 100 waves) (step S103), and uses this average value at the time of position. The reference position of the water surface indicated by the series data is specified (step S104).

Next, as shown in FIG. 5, the processor 11 calculates the time interval of the timing at which the smoothed acceleration changes a predetermined time (step S105). The predetermined change includes, for example, the timing of the zero down cross point described above.

The processor 11 calculates (specifies) the statistical value of a predetermined number of continuous time intervals among the calculated time intervals as the cycle of the change with time of the acceleration (step S106). This step S106 is an example of a cycle specifying step for specifying the cycle of the change with time of the acceleration indicated by the acceleration time series data.

For example, in the graph displayed in FIG. 6A, the positive and negative values are reversed, so that the above-mentioned smoothing acceleration a _ave values are changed from positive to time t0, t1, t2, t3, and t4. It is the time when it changed to negative.

Here, the period T1 is the time interval from the time t0 to the time t1, and the period T2 is the time interval from the time t1 to the time t2. Further, the period T3 is a time interval from time t2 to time t3, and the period T4 is a time interval from time t3 to time t4. When the time t1, the time t2, the time t3, and the time t4 are reached, the processor 11 calculates the period T1, the period T2, the period T3, and the period T4, respectively.

That is, this step S106 is an example of a cycle specifying step including a time interval calculation step for calculating the time interval of the timing at which the acceleration that changes with time indicated by the acceleration time series data changes from a positive value to a negative value.

Next, in the period T4, the processor 11 calculates the period Ta, which is the period of the change over time of the acceleration corresponding to the period T1 to the period T3, before the time t4. Then, the processor 11 uses this period Ta to predict the wave generated in the period T4 in real time. Similarly, the processor 11 calculates the arithmetic mean value of the latest three periods even after the time t4, and predicts the swing width of the wave generated in the period until the next zero down cross point.

Although the arithmetic mean value is calculated for the latest three periods in the time interval process, it is not limited to the latest three periods and may be one or more of the latest periods.

The period Ta is calculated by the period T1, the period T2, and the period T3 as the arithmetic mean value of the period T1, the period T2, and the period T3 as shown in the following equation (1). That is, this step S106 is an example of a cycle specifying step having a statistical value calculation step of calculating a statistical value of a predetermined number of continuous time intervals continuously on the time axis calculated in the time interval calculation step as a cycle of aging of acceleration. Is.

[Number 1]
Ta = (T1 + T2 + T3) / 3 ... (1)

Then, the processor 11 estimates the amplitude of the wave according to the calculated period Ta (step S107). The estimated displacement z _est shown in FIG. 6B is a value obtained by estimating the actual displacement z from the smoothing acceleration a _ave . For example, the estimated displacement z _est is calculated by multiplying the smoothing acceleration a _ave by the square of the acceleration period Ta and dividing by four times the square of the pi. In this case, the estimated displacement z _est is calculated by the smoothing acceleration a _ave , the period Ta, and the pi as shown in the following equation (2). As described above, since the measured acceleration a ₀ is calculated in advance to reverse the positive and negative of the measured value, there is no negative sign in the equation (2).

[Number 2]
z _est = (Ta ² / 4π ² ) × a _ave … (2)

This step S107 is an example of an amplitude estimation step for estimating the amplitude of the wave according to the cycle specified in the cycle specifying step.

By executing the processes of steps S101 to S107 described above, the processor 11 estimates the amplitude of the wave generated on the water surface that changes with time. That is, the amplitude estimation device 1 is a device that performs a wave amplitude estimation method including the steps from step S101 to step S107 described above.

By the above operation, the amplitude estimation device 1 can calculate the period of the three immediately preceding accelerations with time change from the acceleration time series data, and can estimate the time change of the displacement of the water surface from the time change of the acceleration. In particular, high waves that threaten the safety of work at sea are known to invade to some extent continuously. The amplitude estimation device 1 described above makes it possible to estimate the amplitude of a wave that contributes to work safety by considering the characteristics of the immediately preceding wave.

<Modification example>
The above is the description of the embodiment, but the content of this embodiment can be modified as follows. Further, the following modification examples may be combined.

<1>
In the above-described embodiment, when the processor 11 functions as the time interval calculation means 113a, the processor 11 identifies a so-called zero down cross point in which the acceleration changes from plus to minus, and sandwiches it between two adjacent zero down cross points. Although the time interval for each wave is calculated, the time interval may be calculated by specifying the timing of other changes.

For example, the processor 11 may specify a so-called zero-up cross point where the acceleration changes from negative to positive when functioning as the time interval calculating means 113a. In this case, the processor 11 may calculate the time interval for each wave sandwiched between two adjacent zero-up cross points. In this case, the processor 11 is an example of a processor that executes a time interval calculation step of calculating the time interval of the timing at which the acceleration that changes with time indicated by the acceleration time series data changes from a negative value to a positive value.

<2>
In the above-described embodiment, when the processor 11 functions as the smoothing means 112, the acceleration measured by the terminal 2 is calculated by calculating the moving average value of the acceleration measured over a predetermined period such as 2 seconds. The data was smoothed, but it is not necessary to perform smoothing. In this case, the cycle specifying means 113 may specify the cycle of the change with time of the acceleration measured by the terminal 2.

<3>
In the above-described embodiment, the terminal 2 has the acceleration sensor 26, but it is not necessary to have the acceleration sensor 26 as long as the acceleration in the linear direction of the water surface Lv can be measured along the time axis. Further, although the terminal 2 is attached to the floating object J, the terminal 2 itself may be configured to float on the water.

<4>
In the above-described embodiment, the amplitude estimation device 1 and the terminal 2 are connected to each other via the communication line 3 to exchange information, but even if the information is exchanged without going through the communication line 3. good. For example, the interface 13 of the amplitude estimation device 1 and the interface 23 of the terminal 2 both have a function of short-range wireless communication, and the short-range wireless communication allows the amplitude estimation device 1 and the terminal 2 to obtain information. You may exchange.

Further, the amplitude estimation device 1 does not have to acquire acceleration time series data from the terminal 2 in real time. For example, the amplitude estimation device 1 may acquire the acceleration time series data stored in the memory 22 of the terminal 2 via a wired cable connecting the interface 23 and the interface 13. Further, the terminal 2 may copy the acceleration time series data stored in the memory 22 to an external flash memory or the like via the interface 23. In this case, the amplitude estimation device 1 may acquire a copy of the acceleration time series data described above from a flash memory or the like.

<5>
The program executed by the processor 11 described above is stored in a recording medium readable by a computer device, such as a magnetic recording medium such as a magnetic tape and a magnetic disk, an optical recording medium such as an optical disk, an optical magnetic recording medium, and a semiconductor memory. Can be provided in a state of being. Further, this program may be downloaded via a communication line such as the Internet. That is, this program shows the process of acquiring acceleration time-series data indicating the change over time of the measured value of the vertical acceleration received by the floating matter floating on the water due to the vertical movement of the water surface, and the acceleration time-series data. It is a program to execute the process of specifying the cycle of acceleration over time and the process of estimating the wave amplitude according to the specified cycle in the process of specifying the cycle according to the relationship between the wave amplitude and the cycle. be. As the control means exemplified by the above-mentioned amplitude estimation device, various devices other than the CPU may be applied, and for example, a dedicated processor or the like is used.

1 ... Amplitude estimation device, 11 ... Processor, 111 ... Acceleration acquisition means, 112 ... Smoothing means, 113 ... Period specifying means, 113a ... Time interval calculation means, 113b ... Statistical value calculation means, 114 ... Amplitude estimation means, 115 ... Reference position specifying means, 12 ... memory, 13 ... interface, 2 ... terminal, 21 ... processor, 22 ... memory, 23 ... interface, 26 ... acceleration sensor, 3 ... communication line, 9 ... amplitude estimation system, Lv ... water surface, J ... floating matter, T1 to T4 ... period, t0 to t4 ... time.

Claims (7)

Acceleration acquisition process to acquire acceleration time series data showing the change over time of the measured value of vertical acceleration received by the floating matter floating on the water due to the vertical movement of the water surface, and the acceleration acquisition process.
A cycle specifying step for specifying the cycle of the acceleration over time indicated by the acceleration time series data, and
An amplitude estimation step that estimates the wave amplitude according to the period specified in the period specifying step according to the relationship between the wave amplitude and the period, and
Wave amplitude estimation method. The cycle specifying step includes a time interval calculation step of calculating the time interval of the timing at which the acceleration that changes with time indicated by the acceleration time series data changes from a negative value to a positive value.
The amplitude estimation method according to claim 1, further comprising a statistical value calculation step of calculating a predetermined number of continuous statistical values of time intervals on a time axis calculated in the time interval calculation step as the cycle. The cycle specifying step includes a time interval calculation step of calculating the time interval of the timing at which the acceleration that changes with time indicated by the acceleration time series data changes from a positive value to a negative value.
The amplitude estimation method according to claim 1, further comprising a statistical value calculation step of calculating a predetermined number of continuous statistical values of time intervals on a time axis calculated in the time interval calculation step as the cycle. As the above relationship, any one of claims 1 to 3 using the relationship that the amplitude of the wave is a value obtained by multiplying the amplitude of the acceleration by the square of the period of the acceleration and dividing by 4 times the square of the pi. The amplitude estimation method according to item 1. It is provided with a smoothing step for smoothing the change over time of the acceleration indicated by the acceleration time series data for a predetermined period.
The amplitude estimation method according to any one of claims 1 to 4, wherein the cycle specifying step specifies the cycle from the change over time of the acceleration smoothed in the smoothing step. Acceleration acquisition means for acquiring acceleration time-series data showing changes over time in measured values of vertical acceleration received by floating objects floating on the water due to vertical movement of the water surface.
A cycle specifying means for specifying the cycle of the acceleration with time indicated by the acceleration time series data, and
An amplitude estimation means that estimates the wave amplitude according to the period specified by the period specifying means according to the relationship between the wave amplitude and the period.
A wave amplitude estimator equipped with. On the computer
The process of acquiring acceleration time-series data showing the change over time in the measured value of the vertical acceleration received by the floating matter floating on the water due to the vertical movement of the water surface.
The process of specifying the cycle of the acceleration over time indicated by the acceleration time series data, and
According to the relationship between the wave amplitude and the period, the process of estimating the wave amplitude according to the specified period in the process of specifying the period, and the process of estimating the wave amplitude according to the specified period.
A program to execute.

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