Wave characteristic value measuring device and method based on motion reference unit

Abstract

The invention provides a wave characteristic value measuring device and method based on a motion reference unit. Firstly, vertical acceleration output by a motion reference unit is subjected to spectral analysis and square root unscented Kalman filtering, and vertical displacement information of a carrier moving along with waves is obtained. Secondly, identifying time information and relative height of each wave crest and each wave trough of the sea waves through an improved zero-crossing variable baseline algorithm according to the vertical displacement information, and further obtaining the wave height and the wave period of the sea waves through a statistical method; and the direction of the wave is obtained by using attitude angle information output by the motion reference unit. The method effectively solves the problem that the motion reference unit cannot be directly applied to wave characteristic value measurement, expands the application scene of the motion reference unit, has real-time performance, and can provide wave characteristic value information as reference for marine surveying and mapping, marine development, marine monitoring and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of inertial measurement, and in particular relates to a wave characteristic value measurement device and method based on a motion reference unit. Background Art

[0002] The ocean contains more abundant resources than the land, so the development and exploitation of the ocean has become a strategic choice for many countries today. Since the 21st century, my country has actively carried out the development of ocean monitoring technology. Ocean monitoring technology plays a vital role in the development, utilization and research of the ocean. It not only helps to develop and utilize marine resources, protect the marine environment and warn of marine disasters, but also plays an important role in monitoring marine climate, ensuring maritime military activities and other fields. Reference "History, Current Situation and Development of Wave Buoys in my country's Offshore" (Mao Zusong. Journal of Marine Technology, 2007, 26 (2): 23-27) points out that the commonly used ocean monitoring method in my country is to use ocean wave buoys to measure wave characteristic values ​​such as wave height, wave direction and wave period. Wang Juncheng et al. pointed out in "Research Status and Development Trend of Attitude Information Measurement Technology of Marine Data Buoys" published in "Oceans and Lakes" that inertial sensors and GNSS receiver antennas are usually installed on wave buoys to measure wave parameters. As a type of inertial sensor, the Motion Reference Unit (MRU) is often used as a backup to measure the vertical displacement parameters of the carrier and cannot be directly applied to the field of ocean monitoring. In the patent application number 202010342197.2, entitled “Method for determining wave parameters using a GNSS altimetry buoy”, a method combining GNSS and wave buoys is used to measure wave parameters, but since GNSS is easily interfered by external information, this method requires the use of complex filtering methods to retain wave information. In the patent application number 202210083198.9, entitled “A method for calculating the main wave direction of a wave buoy based on wave energy weighting”, the attitude angle information of the carrier motion is processed and the method of crossing the zero point is used. However, since the carrier attitude changes little and the attitude angle is not easy to measure when crossing the zero point, it requires a more cumbersome data processing method to obtain the wave direction. Therefore, in order to expand the application scenarios of MRU, give full play to the advantages of MRU's low cost and high precision, apply MRU to ocean measurement, and design a method to measure wave eigenvalues ​​based on the carrier motion parameters output by MRU, it is very meaningful. Summary of the invention

[0003] The object of the present invention is to provide a wave characteristic value measurement device and method based on a motion reference unit, which can provide a method for measuring wave height, wave period and wave direction with higher accuracy.

[0004] Technical solution of the present invention: In order to achieve the above-mentioned invention object, according to the first aspect of the present invention, a wave characteristic value measuring device based on a motion reference unit is proposed, including a floating carrier, a magnetic sensor arranged in the floating carrier, a motion reference unit, a collection unit, and a data processing unit; the collection unit is communicatively connected with the motion reference unit and the magnetic sensor, and is used to collect vertical acceleration information and attitude information output by the motion reference unit, and heading angle information of the floating carrier output by the magnetic sensor in real time; the data processing unit is communicatively connected with the collection unit, and is used to obtain vertical acceleration information, attitude information, and heading angle information, and use the vertical acceleration information to obtain vertical displacement information of the carrier moving with the wave, and the vertical displacement information is used to identify the time information and relative height of each wave crest and trough of the wave through the wave dynamic baseline algorithm that crosses the zero point, and then the wave height and wave period of the wave are obtained through a statistical method; and the direction of the wave is calculated using the attitude angle information and the heading angle information.

[0005] In a possible embodiment, the floating carrier is a spherical buoy.

[0006] According to a second aspect of the present invention, a wave characteristic value measurement method based on a motion reference unit is proposed, using the above-mentioned wave characteristic value measurement device based on a motion reference unit, comprising the following steps:

[0007] Step 1. Start the MRU built into the floating carrier to perform initialization work such as alignment. After the initialization is completed, start collecting the vertical acceleration information and attitude information of the floating carrier;

[0008] Step 2. According to the random wave theory, the waves are regarded as the superposition of multiple cosine waves with different amplitudes and frequencies under the premise of a stationary random process; the vertical motion of the floating carrier excited by the waves has the same form; the wave spectrum frequency band of the research object is selected to be 0.05-0.2Hz, and the wave energy in this frequency band accounts for more than 99% of the total energy. The vertical acceleration information output by the MRU is spectrally analyzed to identify the cosine wave components that constitute the vertical motion of the floating carrier under the multi-frequency state; and the identified frequency components are used as the initial input of the state space model;

[0009] Step 3. In order to obtain the vertical displacement of the floating carrier, the displacement and velocity of each cosine wave component of the vertical motion are selected as the state quantity and the MRU output is used as the quantity measurement according to the vertical motion expression of the carrier based on the random wave model, and the state space model is established; the displacement and velocity information of each cosine wave component is obtained through square root unscented Kalman filtering, and the vertical displacement information h of the floating carrier in the motion time period t is obtained after vector superposition. z , and the vertical displacement information h of the floating carrier movement zAs the vertical information h of the wave heaving motion, the vertical displacement curve of the wave in the time period t is plotted;

[0010] Step 4. Select the sliding average window length according to the actual sampling frequency, total number of sampling points and data processing period of the device; when the number of sampling points in the window is determined, take the mean of all sampling points in the window as the value of the middle sampling point in the window; slide the window in the direction of increasing time until the window slides through the entire sampling period to obtain all the calculated sampling points in the sampling period t; smoothly connect all the calculated sampling points to obtain the wave dynamic baseline in the carrier motion time period t;

[0011] Step 5. Define the upper zero point as the intersection point where the wave vertical displacement curve passes through the baseline upward, and take the intersection point where the wave vertical displacement curve passes through the dynamic baseline upward as the upper zero point s 0 (n), the vertical distance between the maximum wave crest sampling value and the maximum wave trough sampling value between two adjacent upper zero crossing points is taken as the wave height of the wave at that moment, and the time difference between the two adjacent upper zero crossing points is taken as the wave period of the wave;

[0012] Step 6. The navigation coordinate system selected is the north-east-ground coordinate system, and the carrier coordinate system is taken vertically downward as the positive longitudinal axis; when the carrier is located at the upper crossing zero point, the attitude angles of the carrier motion output by the MRU at this time are the pitch angle θ and the roll angle γ, and the upper crossing zero point wave direction is calculated according to the attitude angles;

[0013] Step 7. Due to the large number of uncertainties in the changes of waves on the ocean, the wave direction at a certain moment obtained in step 6 cannot be used as the main direction of the waves during this period. Divide the horizontal azimuth in the navigation coordinate system into 16 azimuth intervals on average, and each interval is 22.5 degrees. Then determine the wave direction during each wave cycle, and count the number of times each direction appears within the sampling period t of the equipment when the floating carrier moves. If the frequency of wave direction in a certain direction within the determined time period is the highest, then this direction can be considered to be the main direction of the wave direction. As shown in the following formula:

[0014]

[0015] Where: R i is the frequency of the wave direction in the i-th direction interval; n i is the number of times the wave direction appears in the i-th direction interval; N is the number of wave cycles in the ocean data.

[0016] In a possible embodiment, the floating carrier is a spherical buoy.

[0017] In a possible embodiment, in step 2, the vertical motion of the floating carrier under wave excitation is first regarded as a superposition of several cosine waves with different amplitudes and periods, and is expressed as a function of time t:

[0018]

[0019] In the formula, A j ,ω j as well as Respectively represent the amplitude, characteristic frequency and initial phase of the jth cosine wave component. m Represents the number of cosine wave components in the vertical motion fitting process. The relationship between the position and acceleration of each cosine wave component is:

[0020]

[0021] From formula 5, it can be seen that the cosine wave components that make up the vertical motion of the floating carrier all satisfy the following expression:

[0022]

[0023] They represent the jth cosine wave component (j=1,...,N m )’s displacement, velocity and acceleration;

[0024] The state quantity of each cosine wave component is established:

[0025]

[0026] Here x k,j Represents the state quantity x j The kth state component of (k=1,2,3); ω j represents the characteristic frequency of the jth cosine wave component; They represent the jth cosine wave component (j=1,...,N m )’s displacement and velocity.

[0027] At the same time, the acceleration output of each cosine wave component is measured as:

[0028]

[0029] This gives the state space model of the system:

[0030]

[0031] The output of the system is z That is, the actual accelerometer output result is theoretically the superposition of the acceleration outputs of each cosine wave component; however, the actual measurement result contains several error terms that need to be compensated:

[0032]

[0033] Where g is the gravitational acceleration constant; θ and γ represent the pitch angle and roll angle respectively; b z and z represents the accelerometer zero bias and some noise interference terms;

[0034] Vertical motion state equation:

[0035]

[0036] w k is the system noise, v k represents the measurement noise; the vertical motion of the floating carrier is composed of the cosine wave components x j Jointly inspire:

[0037]

[0038] State transition matrix:

[0039]

[0040] In the formula

[0041]

[0042] Δt is the sampling period; measurement matrix:

[0043]

[0044] The vertical displacement and velocity of the floating carrier are taken as the state variables of the system, and the accelerometer output projected by the geographic coordinate system is taken as the quantity measurement; at the same time, the power spectrum analysis of the accelerometer output is performed, and its frequency identification result ω j Input as initial parameters of the system model.

[0045] In one possible embodiment, in step 3, the SRUKF algorithm process covariance matrix Q is selected k , measurement noise matrix R k And the initial error matrix P 0 And set the rest of the initial model parameters. According to the initial error matrix initial value P 0 The sigma point used to capture the mean and covariance of the state distribution is selected based on the information, and the sigma point is nonlinearly transferred; the time update and measurement update steps are completed according to the sampling points obtained after the transformation; the state one-step prediction, measurement prediction, error covariance matrix and other related parameters obtained after the above two steps are filtered and updated, and the displacement z of multiple cosine wave components is calculated through continuous iterative calculation. j and speed The estimated results are output and the results will be stored in X kThe displacement of the ship's heave motion is given by X k The corresponding displacement component estimation results are vector-superimposed to obtain the actual velocity of the heave motion; similarly, the actual velocity of the heave motion is obtained by superimposing the estimation results of each velocity component.

[0046] In a possible embodiment, in step 5, (s 0 (n+1)-s 0 (n)) Maximum peak h nm With the maximum trough h nl The vertical distance between nm -h nl ) as the wave height h at that moment n ,but As the wave period of the wave at this time;

[0047] Where n is the number of sampling point sequence points; s 0 (n) is the nth zero crossing point; h nm and h nl h are the absolute heights of the maximum peak and maximum trough of the wave curve relative to the baseline from n to (n+1); n That is, the wave height from n to (n+1); is the time when the nth zero crossing occurs; Δt n It is the difference between the time when the (n+1)th zero crossing occurs and the time when the nth zero crossing occurs.

[0048] In a possible embodiment, in step 6, the direction of the longitudinal axis of the floating carrier projected onto the horizontal plane has a certain relationship with the wave direction, as shown in the following formula.

[0049]

[0050] Where ψ is the heading angle, which can be directly given by the magnetic sensor; θ is the pitch angle; γ is the roll angle; α is the angle between the longitudinal axis of the floating carrier in the horizontal plane and the heading.

[0051] At this time, the wave direction is:

[0052] ξ=360°-α (11)

[0053] Where ξ is the direction of wave movement, that is, the wave direction; α is the angle between the longitudinal axis of the floating carrier in the horizontal plane and the heading.

[0054] Beneficial technical effects of the present invention:

[0055] The present invention proposes a wave characteristic value measurement device and method based on a motion reference unit, which can significantly improve the accuracy and efficiency of wave characteristic value measurement. By integrating advanced motion reference unit sensors and data processing algorithms, more accurate wave height, period and wave direction information is provided. This improvement not only helps the design and safety assessment of marine engineering, but also provides reliable data support for meteorological forecasting and marine environmental monitoring. In addition, the method is easy to deploy and maintain and is suitable for a variety of marine application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 It is a schematic diagram of a wave characteristic value measuring device based on a motion reference unit according to a preferred embodiment of the present invention;

[0057] Figure 2 is an overall flow chart of a preferred embodiment of the present invention;

[0058] Figure 3 A schematic diagram of a wave vertical displacement curve of a preferred embodiment of the present invention;

[0059] Figure 4 A schematic diagram of the upper zero crossing point of the dynamic baseline of a preferred embodiment of the present invention;

[0060] Figure 5 This is a diagram showing the movement of a floating carrier along with waves according to a preferred embodiment of the present invention;

[0061] Figure 6 The rose diagram of wave direction calculation of the corresponding wave in the preferred embodiment of the present invention;

[0062] Figure 7 Schematic diagram of main wave direction statistical calculation according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0064] The features of various aspects of the embodiments of the present invention will be described in detail below. In the detailed description below, many specific details are proposed to fully understand the present invention. However, it is obvious to those skilled in the art that the present invention can also be implemented without these specific details. The following description of the embodiments is only for a better understanding of the present invention by illustrating examples of the present invention. The present invention is not limited to any specific settings and methods provided below, but covers all product structures, any improvements, replacements, etc. of the methods covered without departing from the spirit of the present invention. In the various drawings and the following description, known structures and technologies are not shown to avoid unnecessary ambiguity of the present invention.

[0065] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other, and the embodiments can refer to and quote each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0066] Example 1

[0067] like Figure 1 As shown, a wave characteristic value measuring device based on a motion reference unit includes a floating carrier, a magnetic sensor arranged in the floating carrier, a motion reference unit, a collection unit, and a data processing unit; the collection unit is connected in communication with the motion reference unit and the magnetic sensor, and is used to collect vertical acceleration information and attitude information output by the motion reference unit, and the heading angle information of the floating carrier output by the magnetic sensor in real time; the data processing unit is connected in communication with the collection unit, and is used to obtain vertical acceleration information, attitude information, and heading angle information, and use the vertical acceleration information to obtain the vertical displacement information of the carrier moving with the wave, and the vertical displacement information is used to identify the time information and relative height of each wave crest and trough of the sea wave through the wave dynamic baseline algorithm crossing the zero point, and then the wave height and wave period of the sea wave are obtained through a statistical method; and the direction of the wave is calculated using the attitude angle information and heading angle information. The floating carrier selects a spherical buoy.

[0068] Example 2

[0069] like Figure 2 As shown, a wave characteristic value measurement method based on a motion reference unit, using a wave characteristic value measurement device based on a motion reference unit described in Example 1, comprises the following steps:

[0070] Step 1: Start the MRU built into the floating carrier and perform initialization work such as alignment. After the initialization is completed, start collecting the vertical acceleration information and attitude information of the floating carrier;

[0071] Step 2: In order to obtain accurate vertical displacement information, the vertical motion of the floating carrier under wave excitation is first regarded as the superposition of several cosine waves with different amplitudes and periods, and expressed as a function of time t:

[0072]

[0073] In the formula, A j ,ω j as well as Represent the amplitude, characteristic frequency and initial phase of the jth cosine wave component. m Represents the number of cosine wave components in the vertical motion fitting process. The relationship between the position and acceleration of each cosine wave component is shown in the following formula:

[0074]

[0075] From Formula 5, it can be seen that the cosine wave components that make up the vertical motion of the floating carrier all satisfy the following expression:

[0076]

[0077] here They represent the jth cosine wave component (j=1,...,N m ) displacement, velocity and acceleration. The state quantity of each cosine wave component is established:

[0078]

[0079] At the same time, the acceleration output of each cosine wave component is measured as:

[0080]

[0081] This gives the state space model of the system:

[0082]

[0083] The output of the system is z That is, the actual accelerometer output result is theoretically the superposition of the acceleration outputs of each cosine wave component. However, the actual measurement result contains several error terms that need to be compensated:

[0084]

[0085] Where g is the gravitational acceleration constant; θ and γ represent the pitch angle and roll angle respectively; b z and z represents the accelerometer zero bias and some noise interference terms.

[0086] Vertical motion state equation:

[0087]

[0088] w k is the system noise, v k It is known from the above that the vertical motion of the floating carrier is composed of the cosine wave components x j Jointly inspire:

[0089]

[0090] State transition matrix:

[0091]

[0092] In the formula

[0093]

[0094] Δt is the sampling period; measurement matrix:

[0095]

[0096] The vertical displacement and velocity of the floating carrier are taken as the state variables of the system, and the accelerometer output projected by the geographic coordinate system is taken as the quantity measurement; at the same time, the power spectrum analysis of the accelerometer output is performed, and its frequency identification result ω j Input as initial parameters of the system model.

[0097] Select the SRUKF algorithm process covariance matrix Q k , measurement noise matrix R k And the initial error matrix P 0 And set the rest of the initial model parameters. According to the initial error matrix initial value P 0 The sigma point used to capture the mean and covariance of the state distribution is selected based on the information, and the sigma point is transferred nonlinearly; the time update and measurement update steps are completed according to the sampling points obtained after the transformation; the state one-step prediction, measurement prediction, error covariance matrix and other related parameters obtained after the above two steps are filtered and updated, and the displacement z of multiple cosine wave components is calculated through continuous iterative calculation. j and speed The estimated results are output and the results will be stored in X k The displacement of the ship's heave motion is given by X k The corresponding displacement component estimation results are vector-superimposed to obtain the actual velocity of the heave motion; similarly, the actual velocity of the heave motion is obtained by superimposing the estimation results of each velocity component.

[0098] The traditional method of judging wave height and wave period uses the zero-crossing method based on the constant baseline. When the waves change drastically, this method may cause the baseline to fail to pass through most of the waves, resulting in zero point loss, which ultimately increases the error. Therefore, it is of great significance to use a suitable dynamic baseline to assist in judging wave height and wave period by changing the definition of the baseline. The schematic diagram of wave characteristic value and the zero-crossing diagram of the dynamic baseline are shown in the figure below. Figure 3 , Figure 4 As shown. Figure 3 It can be seen that when the waves change drastically, the baseline may not pass through all the waves in the sampling period. Figure 4 The dynamic baseline used can pass through most of the waves within the sampling period.

[0099] In step 3, at the beginning and the end of the entire sampling period, when the position of the sampling point number is less than the specified window point number, the average of all sampling points before / after the sampling point is used as the value of the sampling point.

[0100] The method for determining whether the current sampling point is an upper zero point in step 4 is:

[0101] s(n) 0 (n), s(n+1)≥s 0 (n+1) (16)

[0102] Where s(n) is the nth sampling point of the wave curve, s 0 (n) is the nth point of the baseline.

[0103] Figure 5 The following are four diagrams of floating carriers moving with waves. The direction of the waves shown in the figure is from left to right. Figure 5 When the carrier is at position a, the tilt angle of the carrier is the largest and it is easier to measure. At this time, the carrier is at the upper zero point. As shown in the figure, the direction of the longitudinal axis of the carrier is the direction of the wave transmission at this time. Therefore, the state of the carrier at the upper zero point is counted, and the projection direction of the longitudinal axis of the carrier coordinate system on the horizontal plane under the navigation system is taken as the wave direction.

[0104] Figure 6 It is a schematic diagram of the rotation of the carrier coordinate system relative to the navigation coordinate system in step 5. It can be seen from the figure that the angle a between the projection of the positive longitudinal axis of the carrier in the horizontal plane of the navigation coordinate system and the north direction in the navigation coordinate system is the wave direction.

[0105] Figure 7 is a rose diagram of the probability of wave direction at different times of a simulated data. During the sampling period, the wave direction of each wave cycle is recorded. After obtaining the wave direction of all wave cycles in the sampling period, the following is drawn: Figure 7 ​A wave direction rose diagram is created, and the wave direction with the highest probability of occurrence is taken as the main wave direction in the sampling period.

Claims

1. A wave characteristic value measurement device based on a motion reference unit, characterized in that: The invention comprises a floating carrier, a magnetic sensor arranged in the floating carrier, a motion reference unit, a collection unit and a data processing unit; the collection unit is connected in communication with the motion reference unit and the magnetic sensor, and is used for real-time collection of vertical acceleration information and attitude information output by the motion reference unit, and heading angle information of the floating carrier output by the magnetic sensor; the data processing unit is connected in communication with the collection unit, and is used for obtaining vertical acceleration information, attitude information and heading angle information, and using the vertical acceleration information to obtain vertical displacement information of the carrier moving with the waves, and using the wave dynamic baseline algorithm crossing the zero point to identify the time information and relative height of each crest and trough of the waves for the vertical displacement information, and then using the statistical method to obtain the wave height and wave period of the waves; and using the attitude angle information and heading angle information to calculate the direction of the waves.

2. A wave characteristic value measuring device based on a motion reference unit according to claim 1, characterized in that: The floating carrier is a spherical buoy.

3. A wave characteristic value measurement method based on a motion reference unit, using a wave characteristic value measurement device based on a motion reference unit according to any one of claims 1 to 2, characterized in that: The steps include: Step 1: Start the built-in motion reference unit in the floating carrier. After initialization, start collecting the vertical acceleration information and attitude information of the floating carrier; Step 2: Select the wave spectrum frequency band of 0.05-0.2 Hz, perform spectrum analysis on the vertical acceleration information, and identify the cosine wave components that constitute the vertical motion of the floating carrier under the multi-frequency state; Step 3: According to the vertical motion expression of the carrier based on the random wave model, the displacement and velocity of each cosine wave component of the vertical motion are selected as the state quantity, and the output of the motion reference unit is used as the quantity measurement to establish a state space model; the displacement and velocity information of each cosine wave component is obtained by square root unscented Kalman filtering, and the vertical displacement information h of the floating carrier in the motion time period t is obtained after vector superposition. z , and the vertical displacement information h of the floating carrier movement z As the vertical information h of the wave heaving motion, the vertical displacement curve of the wave in the time period t is plotted; Step 4: Determine the average length of the sliding window according to the sampling frequency and the total number of sampling points in the time period t, and take the mean of all sampling points in the sliding window as the value of the middle sampling point of the sliding window, which is recorded as the calculation sampling point; Slide the window in the direction of increasing time until the window slides through the entire time period t to obtain all calculation sampling points; All calculated sampling points are smoothly connected to obtain the wave dynamic baseline within time period t; Step 5: Define the upper zero point as the intersection point where the wave vertical displacement curve crosses the wave dynamic baseline upward, take the vertical distance between the maximum wave crest sampling value and the maximum wave trough sampling value between two adjacent upper zero points as the wave height of the corresponding wave, and take the time difference between the two adjacent upper zero points as the wave period of the corresponding wave; Step 6: Calculate the wave direction of the corresponding wave according to the attitude angle output by the motion reference unit at the upper zero point.

4. A wave characteristic value measurement method based on a motion reference unit according to claim 3, characterized in that: In step 3, each frequency component identified in step 2 is expressed as a function of time t: In the formula, A j ,ω j as well as Respectively represent the amplitude, characteristic frequency and initial phase of the jth cosine wave component; N m Represents the number of cosine wave components in the vertical motion fitting process; the relationship between the position and acceleration of each cosine wave component is shown in the following formula: From formula (5), it can be seen that the cosine wave components that make up the vertical motion of the floating carrier all satisfy the following formula (6): z j (t), They represent the displacement, velocity and acceleration of the jth cosine wave component constituting the motion of the floating carrier at time t respectively; The state quantity of each cosine wave component is established: Here x k,j Represents the state quantity x j The kth state component of k=1,2,3;ω j represents the characteristic frequency of the jth cosine wave component; z j , They represent the displacement and velocity of the jth cosine wave component constituting the motion of the floating carrier respectively; At the same time, the acceleration output of each cosine wave component is measured as: This gives the state space model of the system:

5. A wave characteristic value measurement method based on a motion reference unit according to claim 3, characterized in that: In step 5, the zero crossing point is recorded as s0(n), and the maximum peak h between (s0(n+1)-s0(n)) is nm With the maximum trough h nl The vertical distance between nm -h nl ) as the wave height h of the corresponding wave n ,but as the wave period of the corresponding wave; Where n is the number of sampling point sequence points; s0(n) is the nth zero crossing point; h nm and h nl h are the absolute heights of the maximum peak and maximum trough of the wave curve from time n to (n+1) relative to the baseline; n That is, the wave height from n to (n+1); is the time when the nth zero crossing occurs; Δt n It is the difference between the time when the (n+1)th zero crossing occurs and the time when the nth zero crossing occurs.

6. A wave characteristic value measurement method based on a motion reference unit according to claim 3, characterized in that: In step 6, the specific process of calculating the zero-crossing wave direction according to the attitude angle includes: selecting the navigation coordinate system as the north-east-earth coordinate system, taking the carrier coordinate system vertically downward as the positive longitudinal axis; projecting the longitudinal axis of the floating carrier into the horizontal plane, and calculating the angle α between the longitudinal axis of the floating carrier and the heading in the horizontal plane according to the following formula: Where, ψ is the heading angle, which can be directly given by the magnetic sensor; θ is the pitch angle; γ is the roll angle; The wave direction is calculated according to the following formula: ξ=360°-α (11) Where ξ is the direction of wave motion, that is, the wave direction.

7. A wave characteristic value measurement method based on a motion reference unit according to claim 3, characterized in that: The method further includes step 7, wherein the horizontal azimuth in the navigation coordinate system is evenly divided into a plurality of azimuth intervals, and the probability of occurrence of the wave direction in each azimuth interval in the time period t is statistically calculated according to the following formula (12), and the azimuth interval with the highest occurrence probability is selected as the main wave direction in the time period t; Where: R i is the frequency of the wave direction in the i-th direction interval; n i is the number of times the wave direction appears in the i-th direction interval; N is the number of wave periods in the ocean data.

8. An electronic device, characterized in that: include: a memory and a processor, the memory and the processor being coupled; The memory stores program instructions, and when the program instructions are executed by the processor, the electronic device executes a wave characteristic value measurement method based on a motion reference unit as described in any one of claims 3 to 7.

9. A computer-readable storage medium, characterized in that: It includes a computer program, which, when running on an electronic device, enables the electronic device to execute a wave characteristic value measurement method based on a motion reference unit as described in any one of claims 3 to 7.

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