Method and device for suppressing target electric field detection noise based on marine environmental power

Abstract

A method and apparatus for suppressing noise in underwater target electric field detection based on marine environmental dynamic simulation is disclosed. The apparatus includes a marine buoy, an ADCP ocean current monitoring system, an Ag / AgCl electric field acquisition system, a data storage system, and an underwater target electric field detection noise suppression system. The system primarily monitors ocean currents and target signals, ensuring the watertightness of the equipment for normal operation. Using data from the ADCP ocean current monitoring system, a marine environmental hydrodynamic model is established based on FVCOM, and a marine environmental induced electric field model is constructed. Next, the electric field noise threshold is determined based on the marine environmental induced electric field model. Finally, considering multi-resolution analysis, the induced electric field threshold is calculated using data from each monitoring point in the marine monitoring array. A dynamic wavelet threshold denoising method is implemented, improving the accuracy of noise suppression in the target signal and obtaining an effective, realistic signal.

Description

Technical Field

[0001] This invention is mainly applied in the field of underwater detection, specifically involving a method and device, terminal and medium for suppressing target electric field detection noise based on marine environmental dynamics. Background Technology

[0002] Currently, with the need for deep-sea exploration, low-frequency electromagnetic signal detection technology in my country, as an emerging field, is rapidly developing in underwater electromagnetic detection. Low-frequency electromagnetic detection will have very broad application prospects in deep-sea exploration and development. However, marine environmental electric field noise, as one of the marine environmental fields, is always present and interferes with the detection of signals from targets at sea and underwater. The essence of the generation of the marine environmental electric field lies mainly in the fact that ocean currents can be regarded as the directional drift of charged particles, and the movement of seawater in the geomagnetic field cuts magnetic field lines, thereby generating induced electromotive force and induced current. This electric field is a major source of noise in target signals, affecting the data processing and identification accuracy of target signals. Therefore, in order to reduce the impact of marine environmental electromagnetic fields on target signals and improve the accuracy and efficiency of target detection, research on marine environmental electromagnetic field noise suppression is particularly important. Summary of the Invention

[0003] In view of the above problems, this invention provides a method and device for suppressing noise in underwater target electric field detection based on marine environmental dynamic simulation, solving the problem of background noise affecting target signals. According to the marine environment, a marine float array monitoring device is designed, including a marine float, an ADCP underwater current velocity acquisition instrument, Ag / AgCl electrodes, and an electric field acquisition device. To ensure its watertightness, the marine float mainly houses the acquisition and monitoring equipment, enabling the electronic detection equipment to operate normally in the ocean. The ADCP underwater current velocity acquisition instrument and Ag / AgCl electrodes are installed on the outside of the marine float, and a monitoring array is deployed in the ocean to detect ocean current movement and target signals in real time. While ensuring that the Ag / AgCl electrodes and circuit acquisition board acquire the actual signal, the environmental noise generated by seawater flow is calculated based on the ADCP underwater current velocity acquisition instrument and the FVCOM marine numerical model. Finally, based on the Mallat algorithm and wavelet multi-scale decomposition, a dynamic threshold denoising method is used to effectively separate the real target signal, improving the accuracy and efficiency of target detection.

[0004] S100. To achieve the above objective, according to one aspect of the present invention, a method for establishing a marine hydrodynamic model considering seawater momentum in a marine environment is proposed, comprising:

[0005] The ADCP device was used to monitor ocean current velocity. The collected ocean current data was then used to establish a refined hydrodynamic model of the marine research area by taking into account seawater momentum factors using the FVCOM ocean numerical model.

[0006] S200. Specifically, the marine background noise is determined by establishing a spatial rectangular coordinate system with the sea level as the coordinate system; analyzing the seawater movement and geomagnetic field components at different levels, constructing a marine environmental electric field model, and determining the marine environmental noise, including:

[0007] Based on the Max Planck theorem, the relationship between the induced electric field and the Earth's magnetic field can be constructed:

[0008]

[0009] In the formula, For conduction current density, The magnetic flux density is denoted by μ, where μ is the magnetic permeability. This refers to the electric field generated inside seawater, which acts as a conductor and cuts magnetic field lines during its movement. Seawater can be considered a giant conductor, and ocean currents can be seen as the directional drift of charged particles, with their velocity representing the current's speed. When seawater moves within the Earth's magnetic field, it cuts magnetic field lines, generating induced electromotive force and induced current, i.e.:

[0010]

[0011] S300. Considering the overall seawater flow, establish a rectangular coordinate system on the surface of the seawater flow, analyze the characteristics of seawater flow within the sea area, and calculate the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field, including:

[0012] Establish a rectangular coordinate system on the surface of the flowing seawater, with the origin at the sea surface, the x-axis pointing in the direction of the current, the y-axis at the sea surface, and the z-axis pointing towards the seabed. The x, y, and z axes follow a right-hand screw. The ideal ocean current velocity distribution is as follows:

[0013]

[0014] In the formula, V0 is the ocean current velocity at sea level, z1 represents the sea level, and z2 represents the ocean depth along the z-axis.

[0015] Based on the above analysis of ocean current velocity, the geomagnetic field component F is calculated. y The induced electric field is caused by the fact that seawater does not form a closed loop along the z-axis. The Lorentz force causes charged negative ions to accumulate on the sea surface, creating an upward-facing reverse electric field that exerts a force in the opposite direction on the positive ions, opposing the Lorentz force on the positive ions and reaching equilibrium. The current density along the z-axis is zero, i.e., J. Z =0, the magnitude of the electric field strength is:

[0016] E Z =-V x F y

[0017] From the geomagnetic field component F z The induced electric field and the Lorentz force on the positive ions in the seawater are along the negative y-axis, with a magnitude of f. y =-qV x F z The magnitude of the electric field strength is:

[0018]

[0019] S400 The specific target signal is collected by the Ag / AgCl electrode on the outside of the float. The target signal is stored in real time using the data storage system, which facilitates the subsequent dynamic threshold denoising of the target signal.

[0020] S500, the dynamic threshold denoising method utilizes real-time monitoring data from a monitoring array deployed in the ocean. Based on the ocean environmental electric field model generated by ocean currents described in S200, it calculates the ocean environmental electric field noise and target signal at each monitoring point. Then, based on the distribution of the ocean environmental electric field data, it determines the optimal threshold for signal noise and uses wavelet threshold denoising to remove noise to the greatest extent possible while preserving the effective signal. The dynamic threshold denoising method includes the following steps:

[0021] Step 1: Specifically, the target signal actually measured by the Ag / AgCl electrode and the electric field acquisition device is X(t). The actual signal includes the true target signal S(t) and the ocean electric field noise N(t), that is:

[0022] X(t) = S(t) + N(t)

[0023] Step 2: The acquired electric field signal X(t) is processed using discrete wavelet transform according to wavelet denoising methods, i.e.:

[0024]

[0025] Where X(t) is the actual measured target signal, the wavelet transform is to apply a basic wavelet function to the actual measured signal to shift the signal by τ, and then dot product it with the actual measured signal X(t) at different scales, where a > 0 is the scale factor, Ψ * Let Ψ be the wavelet basis function, τ be the signal shift, and the scaling factor a be the effect of the scaling factor a on the wavelet basis function Ψ. * In the scaling operation, R represents the real number field, and t represents the timing of the one-dimensional signal.

[0026] Step 3: Based on the Mallat algorithm and the wavelet multi-scale decomposition approach, determine the number of decomposition levels for the actual measured signal and determine the wavelet coefficients W in the wavelet transform. i .

[0027] Step 4: After obtaining the water flow velocity in each buoy of the marine environmental monitoring array, calculate the induced electric field noise according to the marine environmental electric field model generated by the ocean current movement described in S200, and use the probability distribution of the noise to determine the noise signal threshold T, thereby removing the background noise in the target signal more accurately.

[0028] Step 5: Based on the data collected by the device in each float in the monitoring array, repeat steps 1 to 4 to update the noise signal of each monitoring point in real time and obtain the threshold of each point, thus realizing the wavelet dynamic threshold denoising method.

[0029] According to a second aspect of the present invention, an underwater target electric field detection noise suppression device based on marine environmental dynamic simulation is provided, characterized in that it comprises:

[0030] The system comprises a marine buoy, an ADCP ocean current monitoring system, an Ag / AgCl electric field acquisition system, a data storage system, and an underwater target electric field detection noise suppression system. The ADCP ocean current monitoring system and the Ag / AgCl electric field acquisition system are installed externally on the marine buoy and primarily monitor ocean currents and acquire target signals. The data storage system is integrated inside the marine buoy to ensure the equipment's watertightness and normal operation.

[0031] The underwater target electric field detection noise suppression system further includes the following modules:

[0032] Marine environmental hydrodynamic module: The ADCP ocean current monitoring system is used to monitor ocean current velocity. Based on the FVCOM ocean numerical model and the collected ocean current data, a detailed marine environmental hydrodynamic model of the research area is established by comprehensively considering seawater momentum factors.

[0033] Marine environmental noise module: Using the sea level as the coordinate system, a spatial rectangular coordinate system is established to analyze the seawater movement and geomagnetic field components at different levels, construct a marine environmental electric field model, and determine marine environmental noise;

[0034] Electric field strength calculation module: Taking into account the seawater flow, a rectangular coordinate system is established on the surface of the seawater flow to analyze the characteristics of seawater flow in the sea area and calculate the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field.

[0035] Acquisition and Real-time Storage Module: Acquires and stores the target signal in real time, facilitating subsequent dynamic threshold denoising of the target signal;

[0036] Noise reduction module: Utilizing real-time monitoring data from a monitoring array deployed in the ocean, and based on the ocean environmental electric field model generated by ocean currents, the module calculates the ocean environmental electric field noise and target signal at each monitoring point; and determines the optimal threshold for signal noise based on the distribution of ocean environmental electric field data, using wavelet thresholding to remove noise to the greatest extent while protecting the effective signal.

[0037] According to a third aspect of the present invention, a terminal device is provided, comprising: a processor; and a memory connected to the processor, wherein the memory stores a computer program executable on the processor, the computer program, when executed by the processor, implementing the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation described above.

[0038] According to a fourth aspect of the present invention, a computer-readable storage medium is provided, the computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation as described above.

[0039] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0040] Compared with existing technologies, this invention is based on a wavelet dynamic denoising method, which leverages the advantages of multi-resolution analysis and localization to address background noise caused by ocean currents, processing non-stationary signals such as electromagnetic noise induced by seawater motion. It analyzes the induced electromagnetic field generated by ocean currents to address the uncertainty of ocean current motion. Specifically, based on the electromagnetic field generated by ocean current motion and its probability distribution density characteristics, an accurate wavelet threshold is determined, thereby determining the wavelet coefficients. This further improves the accuracy of noise suppression in the target signal, obtaining an effective and realistic signal.

[0041] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0042] Figure 1 This is a diagram of the real-time monitoring device for marine buoys in this invention;

[0043] Figure 2 This invention relates to the installation method of the water flow sensor and the electric field sensor.

[0044] Figure 3 This is the specific implementation process for suppressing electromagnetic field noise in the marine environment in this invention;

[0045] Figure 4 This is a schematic diagram illustrating the induced electromagnetic field generated by ocean currents cutting magnetic field lines in this invention. Detailed Implementation

[0046] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings. In one embodiment, a method for suppressing underwater target electric field detection noise based on marine environmental dynamic simulation includes the following specific steps:

[0047] S100. Considering the unique characteristics of real-time marine environmental monitoring, this invention uses a buoy as the carrier of the monitoring device, and designs the ADCP ocean current monitoring device on the outside of the buoy to monitor ocean current conditions in real time. A marine environmental hydrodynamic model is established using the data collected by the ADCP ocean current monitoring device.

[0048] Specifically, the ADCP device monitors ocean current velocities and uses the collected ocean current data to establish a refined hydrodynamic model of the marine research area by comprehensively considering tides, runoff, and wind fields using the FVCOM ocean numerical model.

[0049] Based on the original ocean control equations of the FVCOM model:

[0050]

[0051] In this system, using a Cartesian coordinate system as the standard, the x-axis points east, the y-axis points north, and the z-axis is perpendicular to the plane formed by the x and y axes. In the formula, u, v, and w represent the velocity components in the east, north, and vertical directions, respectively. F u F v These represent the momentum along the horizontal x-axis and y-axis, respectively. Where F... u F v The velocity components representing different directions of sea level are all horizontal momentum, only in different directions.

[0052] S200, taking into account the overall seawater flow, establishes a spatial rectangular coordinate system with the sea level, analyzes the seawater movement under different components and the magnitude of the geomagnetic field, and constructs an electromagnetic field model of the marine environment based on this.

[0053] Specifically, seawater is conductive, and ocean currents can be viewed as the directional drift of charged particles, with the drift velocity equal to the current velocity. When seawater moves within the Earth's magnetic field, it cuts magnetic field lines, generating an induced electromotive force (EMF) and an induced current. The EMF is generated by the Hall effect, caused by the Lorentz force acting on the charged particles in the Earth's magnetic field. According to the Hall effect, an electric potential difference is created by the accumulation of charges on both sides of the current. The current then acts as a power source. Using Maxwell's equations, the relationship between the induced electric and magnetic fields can be constructed:

[0054]

[0055] In the formula, For conduction current density, The magnetic flux density is denoted by μ, where μ is the magnetic permeability. The electric field generated inside the conductor by seawater cutting magnetic field lines due to its motion is specifically as follows:

[0056]

[0057] According to the speed of seawater movement The expression for the electric field vector induced in the Earth's magnetic field by ocean current motion in different components, with varying directions and magnitudes, can be expanded as follows:

[0058]

[0059] in, It is a unit vector in the x, y, and z directions of the coordinate system, ν x ,ν y ,ν z F represents the three velocity components of the coordinate axes respectively. x F y F z It is the geomagnetic field vector. The three magnetic field components on the coordinate axes.

[0060] Based on the above electric field vector expression, the three components of the electric field intensity can be calculated, and then the horizontal electric field intensity E can be calculated. h The total electric field strength E is given by the following formula:

[0061]

[0062] For the geomagnetic field, a right-handed rectangular coordinate system is established based on the direction of the geomagnetic field at the research point. The positive x-direction is magnetic north, the positive y-direction is magnetic east, and the positive z-direction is downward. The origin of the coordinate system is taken at sea level. Assume I is the magnetic inclination, θ is the angle between the projection of the total geomagnetic field intensity onto the horizontal plane and the geomagnetic north pole, and F is the magnitude of the geomagnetic field (related to Earth's longitude and latitude). Then the vector... Its components in the coordinate system are:

[0063]

[0064] The magnitude of the magnetic field in the horizontal direction is F. h The formula is as follows:

[0065]

[0066] Within a certain region, the magnitude and direction of the geomagnetic field can be considered constant. Therefore, given the magnitude and direction of the geomagnetic field (as well as magnetic inclination and magnetic declination), the various components of the geomagnetic field at the location can be calculated.

[0067] S300. Considering the overall seawater flow, establish a rectangular coordinate system on the surface of the seawater flow, analyze the characteristics of seawater flow in the sea area, and calculate the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field.

[0068] Specifically, due to temporal and geographical differences in sea surface heating, cooling, evaporation, and precipitation, as well as the redistribution of seawater density caused by wind, uneven seawater density distribution occurs, resulting in gradient currents. When wind action on the sea surface has ceased and temperature and precipitation evaporation remain relatively constant over extended periods, the motion of large-scale gradient currents moving across the vast ocean is almost unchanging with time and space; we can assume that such seawater gradient currents are constant.

[0069] Analyzing ocean current motion, assuming seawater is an incompressible irrotational fluid, ocean currents can be simplified into uniform ocean currents with constant velocity in the direction of flow, and the velocity field is distributed only in the plane perpendicular to the direction of ocean current flow.

[0070] Depend on Figure 4 As shown, a rectangular coordinate system is established on the surface of the flowing seawater. The origin is located at the sea surface, the x-axis points in the direction of the current, the y-axis is at the sea surface, and the z-axis points to the seabed. The x, y, and z axes follow a right-hand screw. The idealized current velocity distribution is as follows:

[0071]

[0072] In the formula, V0 is the ocean current velocity at sea level, z1 represents the sea surface, and z2 represents the ocean depth along the z-axis.

[0073] Based on the above analysis of ocean current velocity, the geomagnetic field component F is calculated. y The induced electric field. Positive ions in seawater moving in the Earth's magnetic field will experience the Lorentz force. Where q represents the charge of the charged ion. The velocity of ions This represents the magnitude of the Earth's magnetic field. Therefore, it is determined by the Earth's magnetic field component F. y The resulting Lorentz force points towards the seabed along the z-axis, and its magnitude is f. Z =qV x F y Since seawater does not form a closed loop along the z-axis, the Lorentz force causes charged negative ions to accumulate on the sea surface, creating an upward-facing reverse electric field. This field exerts a force in the opposite direction on the positive ions, opposite to the Lorentz force on the positive ions, and they reach equilibrium. Therefore, the current density along the z-axis is zero, i.e., J. Z =0, the magnitude of the electric field strength is:

[0074] E Z =-V x Fy

[0075] Taking sea level as the reference point, along the negative z-axis, the potential difference (i.e., the induced electromotive force) between the seawater and the sea surface is:

[0076]

[0077] The potential distribution can be calculated based on the ocean current velocity distribution:

[0078]

[0079] Similarly, the calculation of the geomagnetic field component F z The induced electric field and the Lorentz force on the positive ions in the seawater are along the negative y-axis, with a magnitude of f. y =-qV x F z The magnitude of the electric field strength is:

[0080]

[0081] S400. The target signal acquisition mainly relies on the Ag / AgCl electrode on the outside of the marine buoy, whose main function is to receive the electric field signal of the marine target. Secondly, in order to make the electric field acquisition device waterproof, an electric field signal storage device is integrated inside the marine buoy, and watertight measures are taken on the outside of the marine buoy; its main purpose is to collect and store the electric field signal of the marine target in real time for subsequent determination of the marine environmental electric field noise threshold.

[0082] S500, the dynamic threshold denoising method described above utilizes real-time monitoring data from a monitoring array deployed in the ocean. Based on the ocean environmental electric field model generated by ocean currents as described in S200, it calculates the ocean environmental electric field noise at each monitoring point, determines the optimal signal noise threshold based on the distribution of the ocean environmental electric field data, and uses wavelet threshold denoising to remove noise to the greatest extent while protecting the effective signal. The dynamic threshold denoising method includes the following steps:

[0083] Step 1: Specifically, the Ag / AgCl electrode and electric field acquisition device collect the target signal. Generally, the measured target signal mainly includes the target's true signal and marine electromagnetic noise. Assuming the actual measured target signal is X(t), then the actual signal mainly contains the target's true signal S(t) and marine electromagnetic noise N(t), that is:

[0084] X(t) = S(t) + N(t)

[0085] Where X(t) is the actual measured target signal, and the ocean induced electric field noise N(t) mainly comes from the induced electric field generated by seawater cutting through the geomagnetic field.

[0086] Step 2: The acquired electric field signal X(t) is processed using discrete wavelet transform according to wavelet denoising methods, i.e.:

[0087]

[0088] Where X(t) is the actual measured target signal, i is the number of layers, and wavelet transform is the signal shift τ of the actual measured signal using a function of the basic wavelet, followed by the inner product of the wavelet with the actual measured signal X(t) at different scales, where a > 0 is the scale factor, and Ψ * Let Ψ be the wavelet basis function, τ be the signal shift, and the scaling factor a be the effect of the scaling factor a on the wavelet basis function Ψ. * In the scaling operation, R represents the real number field, and t represents the timing of the one-dimensional signal.

[0089] Step 3: After determining the wavelet basis functions, determine the magnitude of the layered wavelet coefficients and the signal segment f. i Amplitude A in the frequency domain i Positively correlated W i ∝A i That is, frequency domain amplitude A i The larger the value, the greater the corresponding wavelet coefficient W. i The larger the value, the more complex the signal becomes. At this point, based on the Mallat algorithm and wavelet multi-scale decomposition, the actual measured signal X(t) is divided into multiple coefficient layers. Where i represents different layer numbers, W i Let represent the wavelet decomposition coefficients of the i-th level. The relationship between the decomposition level and the frequency is as follows:

[0090]

[0091] In the formula, fs is the sampling frequency, Range(i) is the frequency range corresponding to the wavelet coefficients of the i-th layer, and the number of decomposition layers can be determined by the frequency range of the target signal;

[0092] Step four, in the wavelet decomposition, specifically regarding the dynamic threshold values ​​for the wavelet coefficients, involves calculating the induced electric field noise signals of different components based on the real-time ocean current velocity data collected by the ADCP device and the ocean environmental electric field model theory described in S200. This yields the noise signal set N(t). Assuming that in a certain sea area, after acquiring the water flow velocity data of each buoy in the ocean environmental monitoring array, the induced electric field noise is calculated using the electric field calculation model generated by ocean current motion described in S003, resulting in the induced electric fields at M different times. If the sample is a random vector for taking a threshold value, then the random vector... set in At this time, the random vector For the ocean induced electric field noise N(t)

[0093] The threshold is determined based on the density distribution of the induced electric field sample:

[0094]

[0095] Where, p i =P(T=t) i ) represents the probability of the sample occurring randomly, δ(tt) i The value of the random variable is given; this allows us to determine the actual distribution of the ocean induced electric field noise. The actual measured signal X(t) is then decomposed into wavelet coefficients. The threshold T is determined using the actual distribution of the ocean induced electric field noise. The threshold is used to define the effective signal and the noise signal. The specific operation is as follows:

[0096] According to hard thresholding denoising, the threshold function is:

[0097]

[0098] In the formula W i These are the wavelet coefficients after wavelet transform, and T is the threshold. When the absolute value of the wavelet coefficient is less than the threshold, it is set to zero; when it is greater than the threshold, it is left unchanged.

[0099] The threshold quantization of wavelet coefficients is as follows:

[0100] W T =sing(W i )·F T (W i )

[0101] In the formula, W T These are wavelet coefficients after threshold quantization, W i These are the wavelet decomposition coefficients of the i-th decomposition layer, sing is the sign function, and F... T (W i ) is the threshold function; T is the threshold;

[0102] Step 5: Using the data from each monitoring point in the marine monitoring array, repeat steps 1 to 4 to update the noise signal of each monitoring point in real time and obtain the threshold of each point. This realizes the dynamic wavelet threshold denoising method, which effectively removes the background noise of the ocean current induced electric field from the target signal and obtains the accurate target real signal.

[0103] In one embodiment, it further includes an underwater target electric field detection noise suppression device based on marine environmental dynamics simulation, characterized in that it comprises:

[0104] Sea floats (such as) Figure 1As shown), the system includes an ADCP ocean current monitoring system, an Ag / AgCl electric field acquisition system, a data storage system, and an underwater target electric field detection noise suppression system; among them, the ADCP ocean current monitoring system and the Ag / AgCl electric field acquisition system are installed on the exterior of a marine buoy (e.g., Figure 2 As shown in the image, it mainly monitors ocean currents and collects target signals; the data storage system is integrated inside the buoy at sea to ensure the watertightness of the equipment and its normal operation.

[0105] The underwater target electric field detection noise suppression system further includes the following modules:

[0106] Marine environmental hydrodynamic module: The ADCP ocean current monitoring system is used to monitor ocean current velocity. Based on the FVCOM ocean numerical model and the collected ocean current data, a detailed marine environmental hydrodynamic model of the research area is established by comprehensively considering seawater momentum factors.

[0107] Marine environmental noise module: Using the sea level as the coordinate system, a spatial rectangular coordinate system is established to analyze the seawater movement and geomagnetic field components at different levels, construct a marine environmental electric field model, and determine marine environmental noise;

[0108] Electric field strength calculation module: Taking into account the seawater flow, a rectangular coordinate system is established on the surface of the seawater flow to analyze the characteristics of seawater flow in the sea area and calculate the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field.

[0109] Acquisition and Real-time Storage Module: Acquires and stores the target signal in real time, facilitating subsequent dynamic threshold denoising of the target signal;

[0110] Denoising module: Utilizing real-time monitoring data from a monitoring array deployed in the ocean, and based on the ocean environmental electric field model generated by ocean current movement in step S200, calculates the ocean environmental electric field noise and target signal at each monitoring point; and determines the optimal threshold for signal noise based on the distribution of ocean environmental electric field data, using wavelet thresholding to remove noise to the greatest extent while protecting the effective signal.

[0111] The implementation process of the marine environment hydrodynamic module is as follows: The marine environment hydrodynamic model is implemented using FVCOM, and the governing equations in the Cartesian coordinate system are:

[0112]

[0113] In this system, using the Cartesian coordinate system as the standard, the x-axis points east, the y-axis points north, and the z-axis is perpendicular to the plane formed by the x and y axes; where u, v, and w represent the velocity components in the east, north, and vertical directions, respectively; F u F v These represent the horizontal momentum along the x-axis and y-axis, respectively. Specifically, Fu F v The velocity components representing different directions of sea level are all horizontal momentum, only in different directions.

[0114] The implementation process of the marine environmental noise module is as follows:

[0115] Seawater is conductive, and ocean currents can be viewed as the directional drift of charged particles, with the drift velocity being the ocean current velocity. When seawater moves in the Earth's magnetic field, it cuts magnetic field lines, generating induced electromotive force (EMF) and induced current. The EMF is generated by the Hall effect, caused by the Lorentz force acting on the charged particles in the Earth's magnetic field. According to the Hall effect, charge accumulates on both sides of the ocean current, forming a potential difference. At this point, the ocean current acts as a power source. Using Maxwell's equations, the relationship between the induced electric field and the induced magnetic field can be constructed:

[0116]

[0117] In the formula, For conduction current density, Let μ be the magnetic flux density generated by the seawater flow, μ be the permeability, and ε be the permittivity. The electric field strength generated inside the conductor by seawater cutting magnetic field lines due to its motion is specifically as follows:

[0118]

[0119] According to the speed of seawater movement The electric field vector expression induced by ocean current motion in the Earth's magnetic field for different components of direction and magnitude is expanded as follows:

[0120]

[0121] in, It is a unit vector in the x, y, and z directions of the coordinate system, ν x ,ν y ,ν z F represents the three velocity components of the coordinate axes respectively. x F y F z It is the geomagnetic field vector. The three magnetic field components on the coordinate axes;

[0122] Based on the above electric field vector expression, the three components of the electric field intensity can be calculated, and then the horizontal electric field intensity E can be calculated. h The total electric field strength E is given by the following formula:

[0123]

[0124] For the geomagnetic field, a right-handed rectangular coordinate system is established based on the direction of the geomagnetic field at the research point; the positive x-direction is magnetic north, the positive y-direction is magnetic east, and the positive z-direction is downward, with the origin at sea level; let I be the magnetic inclination, θ be the angle between the projection of the total geomagnetic field intensity onto the horizontal plane and the geomagnetic north pole, and F be the magnitude of the geomagnetic field, which is related to the Earth's longitude and latitude; then the geomagnetic field vector... Its components in the rectangular coordinate system are:

[0125]

[0126] The magnitude of the magnetic field in the horizontal direction is F. h The formula is as follows:

[0127]

[0128] The specific contents of the electric field strength calculation module are as follows:

[0129] Establish a rectangular coordinate system on the surface of the flowing seawater, with the origin at the sea surface, the x-axis pointing in the direction of the current, the y-axis at the sea surface, and the z-axis pointing to the seabed. The x, y, and z axes follow a right-hand screw. The idealized current velocity distribution is as follows:

[0130]

[0131] In the formula, V0 is the ocean current velocity at sea level, z1 represents the sea level, and z2 represents the ocean depth along the z-axis;

[0132] Based on the ocean current velocity, the calculation of the geomagnetic field component F y The induced electric field; positive ions in seawater moving in the Earth's magnetic field will be subject to the Lorentz force. The role of , where q represents the charge of the charged ion, Indicates the velocity of ions. This represents the magnitude of the Earth's magnetic field; therefore, it is determined by the Earth's magnetic field component F. y The resulting Lorentz force points towards the seabed along the z-axis, and its magnitude is f. Z =qV x F y Since seawater does not form a closed loop along the z-axis, the Lorentz force causes charged negative ions to accumulate on the sea surface, creating an upward-facing reverse electric field. This field exerts a force in the opposite direction on the positive ions, opposite to the Lorentz force on the positive ions, and they reach equilibrium. Therefore, the current density along the z-axis is zero, i.e., J Z =0, the magnitude of the electric field strength is:

[0133] E Z =-V x F y

[0134] With sea level as the reference point, along the negative z-axis, the potential difference between the seawater and the sea level, i.e., the induced electromotive force, is:

[0135]

[0136] The potential distribution can be calculated based on the ocean current velocity distribution:

[0137]

[0138] Similarly, the calculation of the geomagnetic field component F z The induced electric field and the Lorentz force on the positive ions in the seawater are along the negative y-axis, with a magnitude of f. y =-qV x F z The magnitude of the electric field strength is:

[0139]

[0140] In the acquisition and real-time storage module, the target signal is acquired by the Ag / AgCl electric field acquisition system outside the ocean buoy, and the target signal is stored in real time using the data storage system.

[0141] The specific contents of the noise reduction module are as follows:

[0142] Specifically, the target signal actually measured by the Ag / AgCl electrode and the electric field acquisition device is X(t). The actual signal includes the true target signal S(t) and the ocean electric field noise N(t), that is:

[0143] X(t) = S(t) + N(t)

[0144] The acquired target signal X(t) is denoised using a discrete wavelet transform according to the wavelet thresholding method, i.e.:

[0145]

[0146] Where X(t) is the actual measured target signal, the wavelet transform is to apply a basic wavelet function to the actual measured signal to shift the signal by τ, and then dot product it with the actual measured target signal X(t) at different scales, where a > 0 is the scale factor, Ψ * Let Ψ be the wavelet basis function, τ be the signal shift, and the scaling factor a be the effect of the scaling factor a on the wavelet basis function Ψ. * In scaling, R represents the real number field, and t represents the time sequence of the one-dimensional signal;

[0147] Based on the Mallat algorithm and the wavelet multi-scale decomposition approach, the number of decomposition levels of the actual measured signal is determined, and then the wavelet coefficients W in the wavelet transform are determined. i ;

[0148] After obtaining the water flow velocity in each buoy of the marine environmental monitoring array, the induced electric field noise is calculated based on the marine environmental electric field model generated by the ocean current movement in step S200. The noise signal threshold T is determined by the probability distribution of the noise, thereby removing the background noise in the target signal more accurately.

[0149] Based on the data collected by the device in each float in the monitoring array, steps one to four are repeated to update the noise signal of each monitoring point in real time and obtain the threshold of each point, thus realizing the wavelet dynamic threshold denoising method.

[0150] This application embodiment also provides a terminal device, which includes: a processor; and a memory connected to the processor, wherein the memory stores a computer program that can run on the processor, and the computer program, when executed by the processor, implements the specific process of the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation described above.

[0151] This application provides a computer-readable storage medium storing a computer program, characterized in that, when executed by a processor, the computer program implements the specific process of the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation as described above.

[0152] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0153] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0154] The scope of protection of this invention is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its scope and spirit. If these modifications and variations fall within the scope of the claims of this invention and their equivalents, then the intent of this invention also includes these modifications and variations.

Claims

1. A method for suppressing noise in underwater target electric field detection based on marine environmental dynamics simulation, characterized in that, Includes the following steps: Step S100: Monitor ocean current velocity using the ADCP ocean current monitoring system. Based on the FVCOM ocean numerical model and the collected ocean current data, establish a detailed marine environmental hydrodynamic model for the research area, taking into account seawater momentum factors. Step S200: Using the sea level as the coordinate system, establish a spatial rectangular coordinate system, analyze the seawater movement and geomagnetic field components at different levels, construct a marine environmental electric field model, and determine marine environmental noise. Step S300: Considering the overall seawater flow, establish a rectangular coordinate system on the surface of the seawater flow, analyze the characteristics of seawater flow in the sea area, and calculate the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field. The specific implementation process is as follows: Establish a rectangular coordinate system on the surface of the flowing seawater, with the origin located at the sea surface. The axis is oriented in the direction of ocean current flow. The axis is located at the sea surface. The axis points to the seabed. , , Following a right-handed spiral, the idealized ocean current velocity distribution is: In the formula, The ocean current velocity at sea level. Represents sea level. Representative along The ocean depth of the axis; Calculate the geomagnetic field component based on the ocean current velocity. The induced electric field; positive ions in seawater moving in the Earth's magnetic field will be subject to the Lorentz force. The role of, among which, It represents the amount of charge of a charged ion. Indicates the velocity of ions. This represents the magnetic field strength generated by the flow of seawater; therefore, it is determined by the geomagnetic field component. The resulting Lorentz force along The axis points towards the seabed, and its size is... Because seawater is No closed loop is formed along the axial direction. The Lorentz force causes charged negative ions to accumulate on the sea surface, creating an upward, reverse electric field that exerts a force in the opposite direction on the positive ions, opposite to the Lorentz force on the positive ions, thus achieving equilibrium. Therefore, along the... The current density in the axial direction is zero, that is... The magnitude of the electric field strength is: With sea level as the reference point, along the negative z-axis, the potential difference between the seawater and the sea level, i.e., the induced electromotive force, is: The potential distribution can be calculated based on the ocean current velocity distribution: Similarly, the calculation of the geomagnetic field components The induced electric field, the Lorentz force on positive ions in seawater along... In the negative direction of the axis, its magnitude is The magnitude of the electric field strength is: ； Step S400: Acquire and store the target signal in real time to facilitate subsequent dynamic threshold denoising of the target signal; Step S500: Using real-time monitoring data from a monitoring array deployed in the ocean, and based on the ocean environmental electric field model generated by ocean current movement in step S200, calculate the ocean environmental electric field noise and target signal at each monitoring point; and determine the optimal threshold for signal noise based on the distribution of ocean environmental electric field data, and use wavelet thresholding to remove noise to the greatest extent possible while protecting the effective signal.

2. The method according to claim 1, characterized in that: In step S100, the marine environmental hydrodynamic model is implemented using FVCOM, and the governing equations in the Cartesian coordinate system are: Among them, the Cartesian coordinate system is used as the standard. The axis points east. The axis points north. The axis is perpendicular to , The plane formed; where , , These represent the velocity components in the east, north, and vertical directions, respectively. , They represent the level Axial momentum and Axial momentum, specifically, , The velocity components representing different directions of sea level are all horizontal momentum, only in different directions.

3. The method according to claim 2, characterized in that: The specific implementation process of step S200 is as follows: Seawater is conductive, and ocean currents can be viewed as the directional drift of charged particles, with the drift velocity being the ocean current velocity. When seawater moves in the Earth's magnetic field, it cuts magnetic field lines, generating induced electromotive force (EMF) and induced current. The EMF is generated by the Hall effect, caused by the Lorentz force acting on the charged particles in the Earth's magnetic field. According to the Hall effect, charge accumulates on both sides of the ocean current, forming a potential difference. At this point, the ocean current acts as a power source. Using Maxwell's equations, the relationship between the induced electric field and the induced magnetic field can be constructed: In the formula, For conduction current density, The magnetic flux density generated by the flow of seawater. Permeability, Where is the dielectric constant. The electric field strength generated inside the conductor by seawater cutting magnetic field lines due to its motion is specifically as follows: According to the speed of seawater movement The electric field vector expression induced by ocean current motion in the Earth's magnetic field for different components of direction and magnitude is expanded as follows: in, , , It is a unit vector in the x, y, and z directions of the coordinate system. , , These represent the three velocity components of the coordinate axes, , , It is the geomagnetic field vector. The three magnetic field components on the coordinate axes; Based on the above electric field vector expression, the three components of the electric field intensity can be calculated, and then the electric field intensity in the horizontal direction can be calculated. and total electric field strength The formula is as follows: For the geomagnetic field, a right-handed rectangular coordinate system is established based on the direction of the geomagnetic field at the research point; The positive direction is magnetic north. The positive direction is magnetic east. Positive direction downwards, with the origin of the coordinate system at sea level; let... It is the magnetic tilt angle. The angle between the projection of the total geomagnetic field intensity onto the horizontal plane and the geomagnetic north pole is given. The magnitude of the Earth's magnetic field is related to the Earth's longitude and latitude; therefore, the Earth's magnetic field vector... Its components in the rectangular coordinate system are: The magnitude of the magnetic field in the horizontal direction is The formula is as follows: 。 4. The method according to claim 3, characterized in that: In step S400, the target signal is collected by the Ag / AgCl electric field acquisition system outside the ocean buoy, and the target signal is stored in real time using the data storage system.

5. The method according to claim 1, characterized in that: The specific implementation process of step S500 is as follows: Step 1: Specifically, the target signal actually measured by the Ag / AgCl electrode and the electric field acquisition device is... Therefore, the actual signal contains the true signal of the target. and ocean electric field noise ,Right now: Step 2: Acquire the target signal Based on the wavelet thresholding denoising method, discrete wavelet transform is used, namely: in, For the actual measured target signal, wavelet transform is used to shift the actual measured signal using a function of a basic wavelet. Then, at different scales, the target signal was compared with the actual measured signal. Inner product, where As a scale factor, For wavelet basis functions, For signal displacement, scale factor Its function is to adjust the wavelet basis functions. In scaling, R represents the real number field, and t represents the time sequence of the one-dimensional signal; Step 3: Based on the Mallat algorithm and the wavelet multi-scale decomposition approach, determine the number of decomposition levels for the actual measured signal, and then determine the wavelet coefficients in the wavelet transform. ; Step 4: After obtaining the water flow velocity in each buoy of the marine environmental monitoring array, calculate the induced electric field noise based on the marine environmental electric field model generated by the ocean current movement in step S200, and determine the noise signal threshold at this location using the noise probability distribution. This allows for more precise removal of background noise from the target signal; Step 5: Based on the data collected by the device in each float in the monitoring array, repeat steps 1 to 4 to update the noise signal of each monitoring point in real time and obtain the threshold of each point, thus realizing the wavelet dynamic threshold denoising method.

6. A noise suppression device for underwater target electric field detection based on marine environmental dynamic simulation, characterized in that, include: The system comprises a marine buoy, an ADCP ocean current monitoring system, an Ag / AgCl electric field acquisition system, a data storage system, and an underwater target electric field detection noise suppression system. The ADCP ocean current monitoring system and the Ag / AgCl electric field acquisition system are installed externally on the marine buoy to monitor ocean currents and acquire target signals. The data storage system is integrated inside the marine buoy to ensure the equipment's watertightness and normal operation. The underwater target electric field detection noise suppression system further includes the following modules: Marine environmental hydrodynamic module: The ADCP ocean current monitoring system is used to monitor ocean current velocity. Based on the FVCOM ocean numerical model and the collected ocean current data, a detailed marine environmental hydrodynamic model of the research area is established by comprehensively considering seawater momentum factors. Marine environmental noise module: Using the sea level as the coordinate system, a spatial rectangular coordinate system is established to analyze the seawater movement and geomagnetic field components at different levels, construct a marine environmental electric field model, and determine marine environmental noise; Electric field strength calculation module: Taking into account the seawater flow, a rectangular coordinate system is established on the surface of the flowing seawater. The characteristics of seawater flow within the sea area are analyzed, and the electric field strength of the induced electric field generated by the seawater flow due to its movement in the geomagnetic field is calculated. The specific implementation process is as follows: Establish a rectangular coordinate system on the surface of the flowing seawater, with the origin located at the sea surface. The axis is oriented in the direction of ocean current flow. The axis is located at the sea surface. The axis points to the seabed. , , Following a right-handed spiral, the idealized ocean current velocity distribution is: In the formula, The ocean current velocity at sea level. Represents sea level. Representative along The ocean depth of the axis; Calculate the geomagnetic field component based on the ocean current velocity. The induced electric field; positive ions in seawater moving in the Earth's magnetic field will be subject to the Lorentz force. The role of, among which, It represents the amount of charge of a charged ion. Indicates the velocity of ions. This represents the magnetic field strength generated by the flow of seawater; therefore, it is determined by the geomagnetic field component. The resulting Lorentz force along The axis points towards the seabed, and its size is... Because seawater is No closed loop is formed along the axial direction. The Lorentz force causes charged negative ions to accumulate on the sea surface, creating an upward, reverse electric field that exerts a force in the opposite direction on the positive ions, opposite to the Lorentz force on the positive ions, thus achieving equilibrium. Therefore, along the... The current density in the axial direction is zero, that is... The magnitude of the electric field strength is: With sea level as the reference point, along the negative z-axis, the potential difference between the seawater and the sea level, i.e., the induced electromotive force, is: The potential distribution can be calculated based on the ocean current velocity distribution: Similarly, the calculation of the geomagnetic field components The induced electric field, the Lorentz force on positive ions in seawater along... In the negative direction of the axis, its magnitude is The magnitude of the electric field strength is: ； Acquisition and Real-time Storage Module: Acquires and stores the target signal in real time, facilitating subsequent dynamic threshold denoising of the target signal; Noise reduction module: Utilizing real-time monitoring data from a monitoring array deployed in the ocean, and based on the ocean environmental electric field model generated by ocean currents, the module calculates the ocean environmental electric field noise and target signal at each monitoring point; and determines the optimal threshold for signal noise based on the distribution of ocean environmental electric field data, using wavelet thresholding to remove noise to the greatest extent while protecting the effective signal.

7. A terminal device comprising: processor; The processor includes a memory connected to the processor, which stores a computer program that can run on the processor, the computer program being executed by the processor to implement the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation as described in any one of claims 1-5.

8. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the underwater target electric field detection noise suppression method based on marine environmental dynamic simulation as described in any one of claims 1-5.

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