Oceanic vortex sar imaging simulation method and related device thereof

Abstract

This application relates to a marine vortex SAR imaging simulation method, comprising: acquiring marine environmental data of a target marine vortex region; generating a first geostrophic velocity field based on the sea surface dynamic height data, and generating a second geostrophic velocity field based on the three-dimensional temperature data and three-dimensional salinity data; performing a weighted summation of the first and second geostrophic velocity fields according to their respective weight values ​​to generate a composite geostrophic field corresponding to the target marine vortex region; and performing SAR simulation imaging on the target marine vortex region based on the composite geostrophic field to obtain a simulated SAR image of the target marine vortex region. Based on the above method, the problem of unclear details due to resolution limitations in sea surface dynamic height data can be improved; and the characteristics of vortices can be more fully represented, increasing the imaging effect of SAR in marine vortex imaging simulation applications.

Description

Technical Field

[0001] This application relates to the field of marine vortex imaging simulation technology, and in particular to a marine vortex SAR imaging simulation method and related equipment. Background Technology

[0002] Ocean eddies are important mesoscale and sub-mesoscale phenomena in the ocean, significantly impacting global material and thermohaline transport, climate change, marine engineering, and military activities. Synthetic Aperture Radar (SAR) is widely used in the marine field, but its image interpretation and imaging mechanisms in ocean eddies require further investigation.

[0003] Extensive research has been achieved in ocean surface eddies based on satellite data such as sea surface height and temperature. However, sea surface dynamic height data only observes sea surface height information and cannot characterize underwater information, and its resolution is relatively low. Furthermore, reanalysis data depends on the numerical model type, and the resulting three-dimensional temperature and salinity data may differ from the actual ocean. Therefore, among related technologies, SAR performs poorly in ocean eddy imaging simulation applications. Summary of the Invention

[0004] The present invention provides a marine vortex SAR imaging simulation method and related equipment, which at least solves the problem of poor imaging effect of SAR in marine vortex imaging simulation application scenarios in related technologies.

[0005] In a first aspect, embodiments of the present invention provide a marine vortex SAR imaging simulation method, comprising:

[0006] Acquire marine environmental data of the target ocean eddy region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data;

[0007] A first geostrophic velocity field is generated based on the sea surface dynamic height data, and a second geostrophic velocity field is generated based on the three-dimensional temperature data and three-dimensional salinity data.

[0008] The composite geostrophic field corresponding to the target ocean vortex region is generated by weighted summation based on the weight values ​​corresponding to the first geostrophic velocity field and the second geostrophic velocity field.

[0009] Based on the composite geostrophic flow field, SAR simulation imaging is performed on the target ocean vortex region to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0010] According to an embodiment of the present invention, generating a first geostrophic velocity field based on the sea surface dynamic height data includes:

[0011] Based on the sea surface dynamic height data, determine the first zonal velocity component and the first meridional velocity component corresponding to the first geostrophic velocity field;

[0012] The first geostrophic velocity field is determined based on the first latitudinal velocity component and the first meridional velocity component.

[0013] According to an embodiment of the present invention, the first latitudinal velocity component can be calculated based on the following formula (1), and the first meridional velocity component can be calculated based on the following formula (2):

[0014]

[0015]

[0016] Where u1 is the first latitudinal velocity component, v1 is the first longitudinal velocity component, SLA is the sea surface height anomaly in the sea surface dynamic height data, is the gravitational acceleration, f is the Coriolis force frequency, x is the distance along the latitudinal direction, and y is the distance along the longitudinal direction.

[0017] The first geostrophic velocity field can be calculated based on the following formula (3):

[0018]

[0019] Wherein, U1 is the first geostrophic velocity field, u1 is the first latitudinal velocity component, and v1 is the first meridional velocity component.

[0020] According to an embodiment of the present invention, generating a second geostrophic velocity field based on the three-dimensional temperature data and three-dimensional salinity data includes:

[0021] Based on the three-dimensional temperature data and the three-dimensional salinity data, determine the second zonal velocity component and the second meridional velocity component corresponding to the second geostrophic velocity field;

[0022] The second geostrophic velocity field is determined based on the second latitudinal velocity component and the second meridional velocity component.

[0023] According to an embodiment of the present invention, the second latitudinal velocity component can be calculated based on the following formula (4), and the second meridional velocity component can be calculated based on the following formula (5):

[0024]

[0025]

[0026] Where u2 is the second latitudinal velocity component, v2 is the second meridional velocity component, g is the gravitational acceleration, f is the Coriolis force frequency, ρ is the seawater density, ρ0 is the average seawater density, x, y, z are the coordinate axes of the rectangular coordinate system, z0 is the reference layer depth, and z is the sea surface depth.

[0027] The density ρ of seawater can be calculated based on the following formula (6):

[0028]

[0029] Where S is the seawater salinity, T is the seawater temperature, p is the pressure, ρ(S,T,0) is the seawater density at 0 m, and K(S,T,p) is the bulk modulus.

[0030] The first geostrophic velocity field can be calculated based on the following formula (7):

[0031]

[0032] Wherein, U2 is the second geostrophic velocity field, u2 is the second latitudinal velocity component, and v2 is the second meridional velocity component.

[0033] According to an embodiment of the present invention, the composite geostrophic flow field can be calculated according to the following formula (8):

[0034] U = A × U1 + B × U2 (8)

[0035] Wherein, U is the composite geostrophic flow field, U1 is the first geostrophic flow velocity field, U2 is the second geostrophic flow velocity field, A is the weight value of the first geostrophic flow velocity field, and B is the weight value of the second geostrophic flow velocity field.

[0036] According to an embodiment of the present invention, the step of performing SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field to obtain a simulated SAR image corresponding to the target ocean vortex region includes:

[0037] The equilibrium equations of the action spectrum are calculated and solved based on the composite geostrophic flow field and the sea surface wind field.

[0038] The sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the action spectrum balance equation and the background sea surface normalized backscattering coefficient.

[0039] The modulated sea surface backscattering coefficient is calculated based on the normalized backscattering coefficient of the background sea surface. The modulation method includes tilt modulation, hydrodynamic modulation, and velocity beam modulation.

[0040] The overall backscattering coefficient of the target ocean vortex region is determined based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient. SAR simulation imaging is then performed based on the overall backscattering coefficient to obtain a simulated SAR image corresponding to the target ocean vortex region.

[0041] Secondly, embodiments of the present invention provide a marine vortex SAR imaging simulation device, comprising:

[0042] The acquisition module is used to acquire marine environmental data of the target ocean vortex region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data.

[0043] The generation module is used to generate a first geostrophic velocity field based on the sea surface dynamic height data, and to generate a second geostrophic velocity field based on the three-dimensional temperature data and the three-dimensional salinity data.

[0044] The generation module is further configured to perform a weighted summation based on the weight values ​​corresponding to the first geostrophic velocity field and the second geostrophic velocity field, respectively, to generate a composite geostrophic field corresponding to the target ocean vortex region;

[0045] The simulation module is used to perform SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field, so as to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0046] Thirdly, embodiments of the present invention provide an electronic device, including: a processor, and a memory storing a program, wherein the program includes instructions that, when executed by the processor, cause the processor to perform the method according to the first aspect.

[0047] Fourthly, embodiments of the present invention provide a non-transitory machine-readable medium storing computer instructions, wherein the computer instructions are used to cause the computer to perform the method according to the first aspect.

[0048] The beneficial effects of this invention's embodiments: The ocean vortex SAR imaging simulation method provided by this invention generates a first geostrophic velocity field using sea surface dynamic height data from ocean environmental data, and a second geostrophic velocity field using three-dimensional temperature data and three-dimensional salinity data from ocean environmental data. Subsequently, corresponding weight values ​​are assigned to the first and second geostrophic velocity fields, and a composite geostrophic field corresponding to the target ocean vortex region is obtained through weighted summation. Finally, SAR simulation imaging of the target ocean vortex region is performed based on the composite geostrophic velocity field to obtain a simulated SAR image of the target ocean vortex region. Based on the above method, combining sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data improves the problem of unclear details in sea surface dynamic height data due to resolution limitations. The comprehensive consideration of sea surface dynamic height and three-dimensional temperature and salinity information ensures the realism of ocean vortices and more fully represents their characteristics, further enhancing the imaging effect of SAR in ocean vortex imaging simulation applications.

[0049] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0051] Figure 1 A flowchart of a marine vortex SAR imaging simulation method provided as an exemplary embodiment of the present invention.

[0052] Figure 2a A velocity contour map of a first geostrophic flow velocity field is provided as an exemplary embodiment of the present invention.

[0053] Figure 2b A velocity vector distribution diagram of a first geostrophic flow velocity field is provided as an exemplary embodiment of the present invention.

[0054] Figure 3a A velocity contour map of a second geostrophic velocity field is provided as an exemplary embodiment of the present invention.

[0055] Figure 3b A velocity vector distribution diagram of a second geostrophic velocity field is provided as an exemplary embodiment of the present invention.

[0056] Figure 4aA velocity contour map of a composite geostrophic flow field is provided as an exemplary embodiment of the present invention.

[0057] Figure 4b A velocity vector distribution diagram of a composite geostrophic flow field is provided as an exemplary embodiment of the present invention.

[0058] Figure 5 This is a schematic diagram of the line-of-sight velocity gradient of a radar in a composite geostrophic flow field, provided as an exemplary embodiment of the present invention.

[0059] Figure 6 This is a schematic diagram of the backscattering coefficient distribution of an L-band HH polarization SAR ocean vortex based on a composite geostrophic flow field, provided as an exemplary embodiment of the present invention.

[0060] Figure 7 This is a schematic diagram of a marine vortex SAR imaging simulation device provided as an exemplary embodiment of the present invention.

[0061] Figure 8 This is a schematic diagram of an electronic device provided as an exemplary embodiment of the present invention. Detailed Implementation

[0062] Embodiments of this embodiment will now be described in more detail with reference to the accompanying drawings. While some embodiments of this embodiment are shown in the drawings, it should be understood that this embodiment can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this embodiment. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this embodiment.

[0063] Figure 1 A flowchart illustrating a marine vortex SAR imaging simulation method as provided in an exemplary embodiment of the present invention. See also... Figure 1 The method includes the following steps.

[0064] Step S101: Obtain marine environmental data of the target ocean eddy region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data.

[0065] Step S102: Generate a first geostrophic velocity field based on sea surface dynamic height data, and generate a second geostrophic velocity field based on three-dimensional temperature data and three-dimensional salinity data.

[0066] Step S103: The composite geostrophic field corresponding to the target ocean vortex region is generated by weighted summation based on the weight values ​​of the first geostrophic velocity field and the second geostrophic velocity field.

[0067] Step S104: Perform SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0068] First, marine environmental data of the target ocean eddy region is acquired. In this embodiment, the marine environmental data includes sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data.

[0069] In this embodiment, sea surface dynamic height data refers to the height change data of the sea surface caused by dynamic factors such as wind and waves. In oceanography, sea surface dynamic height is an approximate measurement of the high or low gravitational potential of the sea surface. It uses the anomaly in sea surface height caused by the unevenness of the water column to measure the gravitational potential of the sea surface. Three-dimensional temperature data refers to the seawater temperature data at different depths in three-dimensional space. Three-dimensional salinity data refers to the seawater salinity data at different depths in three-dimensional space.

[0070] In an optional embodiment, the aforementioned marine environmental data can be obtained based on the Copernicus Marine Environment Monitoring Service (CMEMS). Synthetic aperture radar can be installed on aircraft, satellites, spacecraft, and other flight platforms to conduct all-day, all-weather observations of the sea surface.

[0071] After acquiring sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data of the target ocean vortex region, a first geostrophic velocity field can be generated based on the sea surface dynamic height data, and a second geostrophic velocity field can be generated based on the three-dimensional temperature data and three-dimensional salinity data.

[0072] In this embodiment, geostrophic flow refers to the seawater flow when the horizontal pressure gradient force and the Coriolis force (GROUP force) caused by changes in sea surface height or seawater density are in equilibrium under ideal conditions without considering factors such as seawater turbulence and friction. It is also called gradient flow and is divided into density flow and inclined flow. The geostrophic flow velocity field refers to the distribution of seawater flow velocity in different positions and directions in the geostrophic flow. It is a spatial field that can reflect the flow characteristics and variation law of the geostrophic flow.

[0073] In this embodiment, when generating the first geostrophic velocity field based on sea surface dynamic height data, the first latitudinal velocity component and the first meridional velocity component corresponding to the first geostrophic velocity field can be determined based on the sea surface dynamic height data, and then the first geostrophic velocity field can be determined based on the first latitudinal velocity component and the first meridional velocity component.

[0074] Specifically, the first latitudinal velocity component can be calculated based on the following formula (1), and the first meridional velocity component can be calculated based on the following formula (2):

[0075]

[0076]

[0077] Where u1 is the first latitudinal velocity component, v1 is the first longitudinal velocity component, SLA is the sea surface height anomaly in the sea surface dynamic height data, g is the gravitational acceleration, f is the Coriolis force frequency, x is the distance along the latitudinal direction, and y is the distance along the longitudinal direction.

[0078] The first geostrophic velocity field can be calculated based on the following formula (3):

[0079]

[0080] Wherein, U1 is the first geostrophic velocity field, u1 is the first latitudinal velocity component, and v1 is the first meridional velocity component.

[0081] In this embodiment, when generating the second geospheric velocity field based on three-dimensional temperature data and three-dimensional salinity data, the second latitudinal velocity component and the second meridional velocity component corresponding to the second geospheric velocity field can be determined first based on the three-dimensional temperature data and three-dimensional salinity data, and then the second geospheric velocity field can be determined based on the second latitudinal velocity component and the second meridional velocity component.

[0082] Specifically, the second latitudinal velocity component can be calculated based on the following formula (4), and the second meridional velocity component can be calculated based on the following formula (5):

[0083]

[0084]

[0085] Where u2 is the second latitudinal velocity component, v2 is the second meridional velocity component, g is the gravitational acceleration, f is the Coriolis force frequency, ρ is the seawater density, ρ0 is the average seawater density, x, y, z are the coordinate axes of the rectangular coordinate system, z0 is the reference layer depth, and z is the sea surface depth.

[0086] The density ρ of seawater can be calculated based on the following formula (6):

[0087]

[0088] Where S is the seawater salinity, T is the seawater temperature, p is the pressure, ρ(S,T,0) is the seawater density at 0 m, and K(S,T,p) is the bulk modulus.

[0089] The velocity field of the first geostrophic flow can be calculated based on the following formula (7):

[0090]

[0091] Wherein, U2 is the second geostrophic velocity field, u2 is the second latitudinal velocity component, and v2 is the second meridional velocity component.

[0092] After generating the first geostrophic velocity field based on sea surface dynamic height data and the second geostrophic velocity field based on three-dimensional temperature and three-dimensional salinity data, the composite geostrophic velocity field corresponding to the target ocean vortex region can be generated by weighted summation based on the weight values ​​of the first and second geostrophic velocity fields.

[0093] In this embodiment, the composite geostrophic flow field can be calculated according to the following formula (8):

[0094] U = A × U1 + B × U2 (8)

[0095] Wherein, U is the composite geostrophic flow field, U1 is the first geostrophic flow velocity field, U2 is the second geostrophic flow velocity field, A is the weight value of the first geostrophic flow velocity field, and B is the weight value of the second geostrophic flow velocity field.

[0096] In an optional embodiment, the weight values ​​corresponding to the first and second geospatial velocity fields can be set according to specific implementation needs. In this embodiment, the weight values ​​corresponding to the first and second geospatial velocity fields are not specifically limited.

[0097] After obtaining the composite geostrophic current field, SAR simulation imaging of the target ocean vortex region can be performed based on the composite geostrophic current field to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0098] Specifically, the action spectrum equilibrium equation can be calculated and solved based on the composite geostrophic flow field and the sea surface wind field.

[0099] In this embodiment, the action spectrum equilibrium equation is first calculated and solved based on the composite geostrophic flow field and the sea surface wind field. The action spectrum equilibrium equation is shown in the following formula (9):

[0100]

[0101] Where N is the microscale wave action spectral density, x = (x, y) is the spatial position vector, and k = (k x ,k y ) is the wavenumber vector, U is the composite geostrophic flow field, and c g Let S(x,k,t) be the group velocity of the modulated wave, and let S(x,k,t) be the source function.

[0102] In this embodiment, the source function may include the sum of wind field input, nonlinear wave-wave interaction, and diffusion effects.

[0103] Then, the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the action spectrum equilibrium equation.

[0104] In this embodiment, the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the above-mentioned action spectrum balance equation and the normalized backscattering coefficient of the background sea surface. The relationship between the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the normalized backscattering coefficient of the background sea surface is shown in the following formula (10):

[0105]

[0106] Where δσ is the sea surface backscattering coefficient generated by the complex geostrophic flow field disturbance, σ0 is the normalized backscattering coefficient of the background sea surface, γ is the ratio of Bragg group velocity to phase velocity, and τ r Indicates the relaxation time. δE represents the line-of-sight velocity gradient between the composite geostrophic flow field and the radar, E0 represents the modulation of the wave energy spectrum density generated by the composite geostrophic flow field, and E0 represents the unmodulated wave energy spectrum density.

[0107] Then, the modulated sea surface backscattering coefficient is calculated based on the normalized backscattering coefficient of the background sea surface. In this embodiment, the modulation methods include tilt modulation, hydrodynamic modulation, and velocity beam modulation.

[0108] In this embodiment, the normalized backscattering coefficient (NRCS) of the background sea surface can first be obtained based on the wave parameters and radar parameters.

[0109] Specifically, the normalized backscattering coefficient of the background sea surface is calculated by combining sea surface wind field, wavelength, wave height, wave direction and other wave parameters, radar band, incident angle and resolution and other input radar parameters. The calculation formula is shown in the following formula (11):

[0110] σ0(θ) pp =4πk 4 cos 4 θ|g pp (θ)| 2 W(2k sinθ,0) (11)

[0111] Where W(·) is the two-dimensional wave power spectrum, g pp (θ) represents the Fresnel coefficient, PP represents the polarization mode, and k = (k x ,k y ) is the wavenumber vector, and θ is the radar incident angle.

[0112] Then, based on the normalized backscattering coefficient of the background sea surface mentioned above, the modulated sea surface backscattering coefficient is calculated.

[0113] The modulated sea-surface backscattering coefficient can be calculated based on the following formula (12):

[0114]

[0115] in, Here, σ is the modulation transfer function, σ is the modulated sea surface backscattering coefficient, σ0 is the normalized background sea surface backscattering coefficient, and FFT is the Fourier transform. For velocity-focused modulation function, The coefficients are related to the wave spectrum. In this embodiment, the effects of tilt, hydrodynamics, and velocity beam modulation can be combined to simulate ocean vortex SAR imaging.

[0116] Specifically, the sea surface is typically composed of long-wavelength swells and short-wavelength wind waves. Long waves exhibit linear tilt modulation and hydrodynamic modulation effects on short waves. Furthermore, SAR imaging requires consideration of velocity beam modulation. The modulated sea surface backscattering coefficient is obtained by comprehensively considering tilt modulation, hydrodynamic modulation, and velocity beam modulation.

[0117] In this embodiment, the modulation methods include tilt modulation, hydrodynamic modulation, and velocity beamforming modulation. The following provides a detailed description of tilt modulation, hydrodynamic modulation, and velocity beamforming modulation:

[0118] 1. Tilt modulation

[0119] Tilt modulation occurs because long waves cause short waves to tilt, resulting in incident electromagnetic waves illuminating different locations on the sea surface at varying local incident angles, thus altering the backscattering coefficient. Long waves can be imaged in SAR images using tilt modulation. The tilt modulation transfer functions for HH and VV polarizations differ, while the VV polarization tilt modulation transfer function... As shown in the following formula (13), the polarization tilt modulation transfer function of HH As shown in the following formula (14):

[0120]

[0121]

[0122] Where, k l Let θ' be the component of the wave vector in the radar line of sight, and θ′ be the local incident angle.

[0123] 2. Fluid dynamics modulation

[0124] Hydrodynamic modulation refers to the wave-current interaction between long waves or ocean currents and short waves, causing the short waves to converge and diverge. The hydrodynamic modulation transfer function T... h As shown in the following formula (15):

[0125]

[0126] Where μ is the relaxation factor, ω is the angular frequency, k is the wave number of the ocean wave spectrum, and Y r +iY i It is a complex vector representing the feedback.

[0127] 3. Velocity-focused modulation

[0128] Velocity beam modulation transfer function As shown in the following formula (16):

[0129]

[0130] Where R represents the distance between the target and the platform, V represents the platform speed, and λ is the radar incident angle.

[0131] Finally, the overall backscattering coefficient of the target ocean vortex region is determined based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient. SAR simulation imaging is then performed based on the overall backscattering coefficient to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0132] In this embodiment, the backscattering coefficient of the sea surface generated by the perturbation of the composite geostrophic flow field and the modulated backscattering coefficient of the sea surface are superimposed to obtain the overall backscattering coefficient of the target ocean vortex region. SAR simulation imaging is then performed to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0133] The overall backscattering coefficient can be calculated based on the following formula (17):

[0134] σ e =σ+δσ (17)

[0135] Where, σ e σ is the overall backscattering coefficient, σ is the modulated sea surface backscattering coefficient, and δσ is the sea surface backscattering coefficient generated by the disturbance of the composite geostrophic flow field.

[0136] The following describes a marine vortex SAR imaging simulation method provided by the present invention with reference to specific embodiments.

[0137] Taking ocean eddy region A as an example, the first step is to acquire ocean environmental data for ocean eddy region A. This data includes sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data. This ocean environmental data can be obtained based on the Copernicus Marine Environment Monitoring Service (CMEMS).

[0138] When generating the first geostrophic velocity field based on sea surface dynamic height data, the first zonal velocity component and the first meridional velocity component corresponding to the first geostrophic velocity field can be determined based on the sea surface dynamic height data. Then, the first geostrophic velocity field corresponding to ocean eddy region A can be determined based on the first zonal velocity component and the first meridional velocity component. The velocity contour map of the first geostrophic velocity field is shown below. Figure 2a As shown; the velocity vector distribution diagram of the first geospatial velocity field is as follows. Figure 2b As shown in the figure, the arrows point in the direction of velocity, and the length of the arrows represents the magnitude of the velocity.

[0139] When generating the second geospheric velocity field based on three-dimensional temperature and salinity data, the second zonal velocity component and the second meridional velocity component corresponding to the second geospheric velocity field can be determined first based on the three-dimensional temperature and salinity data. Then, the second geospheric velocity field corresponding to ocean eddy region A can be determined based on the second zonal velocity component and the second meridional velocity component. The velocity contour map of the second geospheric velocity field is shown below. Figure 3a As shown; the velocity vector distribution diagram of the second geodynamic velocity field is as follows. Figure 3b As shown in the figure, the arrows point in the direction of velocity, and the length of the arrows represents the magnitude of the velocity.

[0140] The first and second geostrophic velocity fields were then interpolated using the cubic method to a unified high resolution of 0.002°, and weighted by 0.3 and 0.7 respectively. The two fields were then superimposed with these weights to simulate the composite geostrophic field corresponding to the target ocean vortex region. The velocity contour map of the composite geostrophic field is shown below. Figure 4a As shown; the velocity vector distribution diagram of the composite geostrophic flow field is as follows. Figure 4b As shown in the figure, the arrows point in the direction of velocity, and the length of the arrows represents the magnitude of the velocity.

[0141] Subsequently, the action spectrum equilibrium equation is calculated and solved based on the composite geostrophic flow field and the sea surface wind field. Then, the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the action spectrum equilibrium equation and the background sea surface normalized backscattering coefficient. Finally, the modulated sea surface backscattering coefficient is calculated based on the background sea surface normalized backscattering coefficient, and the modulation method includes tilt modulation, hydrodynamic modulation, and velocity beam modulation.

[0142] In this embodiment, the normalized backscattering coefficient of the background sea surface can first be obtained based on the wave parameters and radar parameters.

[0143] Specifically, the normalized backscattering coefficient of the sea surface is calculated by combining sea surface wind field, wavelength, wave height, wave direction, and other wave parameters, as well as radar parameters such as radar band, incident angle, and resolution. In this embodiment, the sea surface wind field has a wind direction of 0°, a wind speed of 8 m / s, a wavelength of 300 m, a wave height of 0.5 m, a wave direction of 300°, a radar band of L-band, HH polarization, an incident angle of 45°, and a resolution of 0.002°.

[0144] The overall backscattering coefficient of the target ocean vortex region is determined based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient. SAR simulation imaging is then performed based on this overall backscattering coefficient to obtain a simulated SAR image of the target ocean vortex region. A schematic diagram of the radar's line-of-sight velocity gradient, which is needed to determine the sea surface backscattering coefficient of the ocean vortex, is shown below. Figure 5 As shown; a schematic diagram of the distribution of sea surface backscattering coefficients of L-band HH polarization SAR ocean vortex based on composite geostrophic current field is shown below. Figure 6 As shown.

[0145] Based on the above-described marine vortex SAR imaging simulation method provided in the embodiments of the present invention, the embodiments of the present invention also provide a marine vortex SAR imaging simulation device, such as... Figure 7 As shown, the ocean vortex SAR imaging simulation device includes: an acquisition module 701, a generation module 702, and a simulation module 703.

[0146] The acquisition module 701 is used to acquire marine environmental data of the target ocean vortex region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data.

[0147] The generation module 702 is used to generate a first geostrophic velocity field based on the sea surface dynamic height data, and to generate a second geostrophic velocity field based on the three-dimensional temperature data and the three-dimensional salinity data.

[0148] The generation module 702 is further configured to perform a weighted summation based on the weight values ​​corresponding to the first geostrophic velocity field and the second geostrophic velocity field, respectively, to generate a composite geostrophic field corresponding to the target ocean vortex region;

[0149] The simulation module 703 is used to perform SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field, so as to obtain the simulated SAR image corresponding to the target ocean vortex region.

[0150] Optionally, the generation module 702 is specifically used to determine the first latitudinal velocity component and the first meridional velocity component corresponding to the first geocurrent velocity field based on the sea surface dynamic height data; and to determine the first geocurrent velocity field based on the first latitudinal velocity component and the first meridional velocity component.

[0151] Optionally, the first latitudinal velocity component can be calculated based on the following formula (18), and the first meridional velocity component can be calculated based on the following formula (19):

[0152]

[0153]

[0154] Where u1 is the first latitudinal velocity component, v1 is the first longitudinal velocity component, SLA is the sea surface height anomaly in the sea surface dynamic height data, g is the gravitational acceleration, f is the Coriolis force frequency, x is the distance along the latitudinal direction, and y is the distance along the longitudinal direction.

[0155] The first geostrophic velocity field can be calculated based on the following formula (20):

[0156]

[0157] Wherein, U1 is the first geostrophic velocity field, u1 is the first latitudinal velocity component, and v1 is the first meridional velocity component.

[0158] Optionally, the generation module 702 is specifically used to determine the second latitudinal velocity component and the second meridional velocity component corresponding to the second geospheric velocity field based on the three-dimensional temperature data and the three-dimensional salinity data; and to determine the second geospheric velocity field based on the second latitudinal velocity component and the second meridional velocity component.

[0159] Optionally, the second latitudinal velocity component can be calculated based on the following formula (21), and the second meridional velocity component can be calculated based on the following formula (22):

[0160]

[0161]

[0162] Where u2 is the second latitudinal velocity component, v2 is the second meridional velocity component, g is the gravitational acceleration, f is the Coriolis force frequency, ρ is the seawater density, ρ0 is the average seawater density, x, y, z are the coordinate axes of the rectangular coordinate system, z0 is the reference layer depth, and z is the sea surface depth.

[0163] The density ρ of seawater can be calculated based on the following formula (23):

[0164]

[0165] Where S is the seawater salinity, T is the seawater temperature, p is the pressure, ρ(S,T,0) is the seawater density at 0 m, and K(S,T,p) is the bulk modulus.

[0166] The second geostrophic velocity field can be calculated based on the following formula (24):

[0167]

[0168] Wherein, U2 is the second geostrophic velocity field, u2 is the second latitudinal velocity component, and v2 is the second meridional velocity component.

[0169] Alternatively, the composite geostrophic flow field can be calculated according to the following formula (25):

[0170] U = A × U1 + B × U2 (25)

[0171] Wherein, U is the composite geostrophic flow field, U1 is the first geostrophic flow velocity field, U2 is the second geostrophic flow velocity field, A is the weight value of the first geostrophic flow velocity field, and B is the weight value of the second geostrophic flow velocity field.

[0172] Optionally, the simulation module 703 is specifically used to calculate and solve the action spectrum balance equation based on the composite geostrophic flow field and the sea surface wind field. Then, based on the action spectrum balance equation and the normalized backscattering coefficient of the background sea surface, it determines the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance; then, based on the normalized backscattering coefficient of the background sea surface, it calculates the modulated sea surface backscattering coefficient, where the modulation method includes tilt modulation, hydrodynamic modulation, and velocity beamforming modulation; based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient, it determines the overall backscattering coefficient of the target ocean vortex region, and performs SAR simulation imaging based on the overall backscattering coefficient to obtain a simulated SAR image corresponding to the target ocean vortex region.

[0173] This invention also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor. The memory stores a computer program executable by the at least one processor, which, when executed by the at least one processor, causes the electronic device to perform the method of this invention.

[0174] The present invention also provides a non-transitory machine-readable medium storing a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of the present invention.

[0175] This invention also provides a computer program product, including a computer program, wherein the computer program, when executed by a computer's processor, is used to cause the computer to perform the method of this invention.

[0176] refer to Figure 8 The present invention will now describe a structural block diagram of an electronic device that can serve as a server or client in embodiments of the present invention, which is an example of a hardware device that can be applied to various aspects of the present invention. The electronic device is intended to represent various forms of digital electronic computer devices, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0177] like Figure 8 As shown, the electronic device includes a computing unit 801, which can perform various appropriate actions and processes according to a computer program stored in a read-only memory (ROM) 802 or a computer program loaded from a storage unit 808 into a random access memory (RAM) 803. The RAM 803 may also store various programs and data required for the operation of the electronic device. The computing unit 801, ROM 802, and RAM 803 are interconnected via a bus 804. An input / output (I / O) interface 805 is also connected to the bus 804.

[0178] Multiple components in the electronic device are connected to I / O interface 805, including: input unit 806, output unit 807, storage unit 808, and communication unit 809. Input unit 806 can be any type of device capable of inputting information into the electronic device. Input unit 806 can receive input digital or character information and generate key signal inputs related to user settings and / or function control of the electronic device. Output unit 807 can be any type of device capable of presenting information and may include, but is not limited to, a display, speaker, video / audio output terminal, vibrator, and / or printer. Storage unit 808 may include, but is not limited to, disks and optical discs. Communication unit 809 allows the electronic device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks, and may include, but is not limited to, modems, network cards, infrared communication devices, wireless communication transceivers, and / or chipsets, such as Bluetooth devices, WiFi devices, WiMax devices, cellular communication devices, and / or the like.

[0179] The computing unit 801 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the computing unit 801 include, but are not limited to, CPUs, graphics processing units (GPUs), various special-purpose artificial intelligence (AI) computing chips, various computing units running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. The computing unit 801 performs the various methods and processes described above. For example, in some embodiments, the method embodiments of the present invention can be implemented as a computer program tangibly contained in a machine-readable medium, such as storage unit 808. In some embodiments, part or all of the computer program can be loaded and / or installed on an electronic device via ROM 802 and / or communication unit 809. In some embodiments, the computing unit 801 can be configured to perform the methods described above by any other suitable means (e.g., by means of firmware).

[0180] Computer programs for implementing the methods of embodiments of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor or controller of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus, such that when executed by the processor or controller, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0181] In the context of embodiments of the present invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. A machine-readable signal medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0182] It should be noted that the term "comprising" and its variations used in the embodiments of the present invention are open-ended, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". The modifications of "one" and "multiple" mentioned in the embodiments of the present invention are illustrative and not restrictive. Those skilled in the art should understand that, unless explicitly indicated otherwise in the context, they should be understood as "one or more".

[0183] The user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in the embodiments of the present invention are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with the relevant laws, regulations and standards of the relevant countries and regions, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0184] The steps described in the method embodiments provided by this invention can be performed in different orders and / or in parallel. Furthermore, the method embodiments may include additional steps and / or omit the steps shown. The scope of protection of this invention is not limited in this respect.

[0185] The term "embodiment" in this specification refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply independence or alternativeity from other embodiments. The various embodiments in this specification are described in a related manner, with reference to each other for similar or identical parts. In particular, for apparatus, device, and system embodiments, since they are substantially similar to method embodiments, the description is relatively simple, and relevant details are referred to in the description of the method embodiments.

[0186] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. A marine vortex SAR imaging simulation method, characterized in that, include: Acquire marine environmental data of the target ocean eddy region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data; A first geostrophic velocity field is generated based on the sea surface dynamic height data, and a second geostrophic velocity field is generated based on the three-dimensional temperature data and three-dimensional salinity data. The composite geostrophic field corresponding to the target ocean vortex region is generated by weighted summation based on the weight values ​​corresponding to the first geostrophic velocity field and the second geostrophic velocity field. Based on the composite geostrophic flow field, SAR simulation imaging is performed on the target ocean vortex region to obtain the simulated SAR image corresponding to the target ocean vortex region; The step of performing SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field to obtain a simulated SAR image corresponding to the target ocean vortex region includes: The equilibrium equations of the action spectrum are calculated and solved based on the composite geostrophic flow field and the sea surface wind field. The sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the action spectrum balance equation and the background sea surface normalized backscattering coefficient. The modulated sea surface backscattering coefficient is calculated based on the normalized backscattering coefficient of the background sea surface. The modulation methods include tilt modulation, hydrodynamic modulation and velocity beam modulation. The overall backscattering coefficient of the target ocean vortex region is determined based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient. SAR simulation imaging is then performed based on the overall backscattering coefficient to obtain a simulated SAR image corresponding to the target ocean vortex region.

2. The method according to claim 1, characterized in that, The step of generating the first geostrophic velocity field based on the sea surface dynamic height data includes: Based on the sea surface dynamic height data, determine the first zonal velocity component and the first meridional velocity component corresponding to the first geostrophic velocity field; The first geostrophic velocity field is determined based on the first latitudinal velocity component and the first meridional velocity component.

3. The method according to claim 2, characterized in that, The first latitudinal velocity component can be calculated based on the following formula (1), and the first meridional velocity component can be calculated based on the following formula (2): （1）； （2）； in, The first latitudinal velocity component, The first meridional velocity component, This is an anomaly in the sea surface height data. It is the acceleration due to gravity. For the Coriolis force frequency, This represents the distance along the latitude direction. This represents the distance along the meridian. The first geostrophic velocity field can be calculated based on the following formula (3): （3）； in, For the first geostationary velocity field, The first latitudinal velocity component, This represents the first meridional velocity component.

4. The method according to claim 1, characterized in that, A second geostrophic velocity field is generated based on the aforementioned three-dimensional temperature and three-dimensional salinity data, including: Based on the three-dimensional temperature data and the three-dimensional salinity data, determine the second zonal velocity component and the second meridional velocity component corresponding to the second geostrophic velocity field; The second geostrophic velocity field is determined based on the second latitudinal velocity component and the second meridional velocity component.

5. The method according to claim 4, characterized in that, The second latitudinal velocity component can be calculated based on the following formula (4), and the second meridional velocity component can be calculated based on the following formula (5): （4）； （5）； in, The second latitudinal velocity component, The second meridional velocity component, It is the acceleration due to gravity. For the Coriolis force frequency, The density of seawater, The average density of seawater, , , The directions of the coordinate axes in a rectangular coordinate system For reference layer depth, Sea surface depth; Seawater density It can be calculated based on the following formula (6): （6）； in, For seawater salinity, For seawater temperature, For pressure, The density of seawater is 0m. Bulk modulus; The first geostrophic velocity field can be calculated based on the following formula (7): （7）； in, For the second geostationary velocity field, The second latitudinal velocity component, This is the second meridional velocity component.

6. The method according to any one of claims 2 to 5, characterized in that, The composite geostrophic flow field can be calculated according to the following formula (8): （8）； in, It is a complex geostrophic flow field. For the first geostationary velocity field, For the second geostationary velocity field, The weight values ​​for the first geodynamic velocity field are: This represents the weight value of the second geostationary velocity field.

7. A marine vortex SAR imaging simulation device, characterized in that, include: The acquisition module is used to acquire marine environmental data of the target ocean vortex region, including sea surface dynamic height data, three-dimensional temperature data, and three-dimensional salinity data. The generation module is used to generate a first geostrophic velocity field based on the sea surface dynamic height data, and to generate a second geostrophic velocity field based on the three-dimensional temperature data and the three-dimensional salinity data. The generation module is further configured to perform a weighted summation based on the weight values ​​corresponding to the first geostrophic velocity field and the second geostrophic velocity field, respectively, to generate a composite geostrophic field corresponding to the target ocean vortex region; The simulation module is used to perform SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field, so as to obtain the simulated SAR image corresponding to the target ocean vortex region. The step of performing SAR simulation imaging on the target ocean vortex region based on the composite geostrophic flow field to obtain a simulated SAR image corresponding to the target ocean vortex region includes: The equilibrium equations of the action spectrum are calculated and solved based on the composite geostrophic flow field and the sea surface wind field. The sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance is determined based on the action spectrum balance equation and the background sea surface normalized backscattering coefficient. The modulated sea surface backscattering coefficient is calculated based on the normalized backscattering coefficient of the background sea surface. The modulation methods include tilt modulation, hydrodynamic modulation and velocity beam modulation. The overall backscattering coefficient of the target ocean vortex region is determined based on the sea surface backscattering coefficient generated by the composite geostrophic flow field disturbance and the modulated sea surface backscattering coefficient. SAR simulation imaging is then performed based on the overall backscattering coefficient to obtain a simulated SAR image corresponding to the target ocean vortex region.

8. An electronic device, comprising: A processor, and a memory storing a program, wherein the program includes instructions that, when executed by the processor, cause the processor to perform the method according to any one of claims 1 to 6.

9. A non-transitory machine-readable medium storing computer instructions, wherein, The computer instructions are used to cause the computer to perform the method according to any one of claims 1 to 6.

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