CN114002666A - Method and equipment for extracting satellite-borne ATI-SAR ocean current flow velocity under any antenna configuration - Google Patents
Method and equipment for extracting satellite-borne ATI-SAR ocean current flow velocity under any antenna configuration Download PDFInfo
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Abstract
The invention discloses a method and a device for extracting the flow velocity of satellite-borne ATI-SAR ocean current under any antenna configuration, wherein the method comprises the following steps: calculating the amplitude phase error between the channels according to the echo signals of the channel A and the channel B in the reference region, compensating the target region to be processed, and realizing channel correction; obtaining a distance course under any antenna configuration through analysis of a space-borne ATI-SAR space geometric relationship, and obtaining imaging results of two channels by adopting a BP imaging algorithm on echo signals of a channel A and a channel B which are corrected through the channels; conjugate multiplication is carried out on the imaging results of the channel A and the channel B to obtain an interference phase of the scene echo; obtaining an equivalent model calculation method under any antenna configuration through space-borne ATI-SAR space geometric relation analysis, and obtaining ocean current mixing speed according to the equivalent model; and extracting the radial velocity of the ocean current according to the ocean current mixing velocity. The invention can realize the ocean current velocity inversion of the satellite-borne ATI-SAR echo under any antenna configuration without registering among channels, thereby improving the processing efficiency.
Description
Technical Field
The invention relates to a synthetic aperture radar to sea remote sensing, in particular to a method and equipment for extracting the flow velocity of an ATI-SAR ocean current on a satellite under any antenna configuration.
Background
The ocean flow field is one of the most important parameters of the ocean power environment, and the ocean flow field which has high resolution, large mapping area, high observation frequency and high measurement precision and is obtained by using the Synthetic Aperture Radar (SAR) has huge potential and advantages. The interference phase diagram can be used for directly calculating and obtaining the linear velocity component of the radar vision and then separating the flow field velocity by various methods, so that the acquisition of the interference phase under various complex configurations is also an essential part.
Meanwhile, for strabismus echoes of two channels, when a conventional imaging algorithm (such as wk algorithm and RD algorithm) is adopted, a target is imaged at an azimuth zero-frequency position, so that the azimuth direction and the distance direction of the two channels have deviation, and registration (frequency phase compensation) between the channels is required before an interference phase is extracted.
Disclosure of Invention
The purpose of the invention is as follows: in order to solve the technical problems mentioned in the background art, the invention provides a method and a device for extracting the ocean current flow rate of an ATI (satellite-borne-orbit interference-SAR) under any antenna configuration, which can realize the inversion of the ocean current flow rate of an ATI-SAR echo under any antenna configuration without the need of inter-channel registration and improve the processing efficiency.
The technical scheme is as follows: a method for extracting the flow velocity of satellite-borne ATI-SAR ocean currents under any antenna configuration comprises the following steps:
calculating the amplitude phase error between the channels according to the echo signals of the channel A and the channel B in the reference region, and compensating the target region to be processed by using the amplitude phase error between the channels to realize channel correction;
obtaining a distance history under any antenna configuration through analysis of a space-borne ATI-SAR space geometric relationship, and obtaining imaging results of two channels by adopting a BP imaging algorithm on echo signals of a channel A and a channel B which are corrected through the channels based on the distance history;
conjugate multiplication is carried out on the imaging results of the channel A and the channel B to obtain an interference phase of the scene echo;
obtaining an equivalent model calculation method under any antenna configuration through space-borne ATI-SAR space geometric relation analysis, and obtaining ocean current mixing speed according to the equivalent model;
and removing the Bragg phase velocity in the ocean current mixing velocity and the large-scale wave orbital velocity to obtain the radial velocity of the ocean current.
Further, calculating the inter-channel amplitude phase error according to the echo signals of the reference region channel a and the reference region channel B includes: and performing two-dimensional frequency domain self-adaptive correction processing on the echo signals of the channel A and the channel B in the reference area to obtain the inter-channel amplitude-phase error of the channel A and the channel B.
Further, the two-dimensional frequency domain adaptive correction process includes: firstly, carrying out azimuth iterative processing, then carrying out distance iterative processing, and solving the optimal solution of the following objective function:
Z1(f,Ω)、Z2(f, omega) respectively represent echo data of the channel A and the channel B in a two-dimensional frequency domain, f represents an azimuth frequency domain, omega represents a distance frequency domain, h represents a distance frequency domain1,2(omega) represents a compensation function for the distance frequency domain, D1,2(f) A compensation function representing the azimuth frequency domain.
Further, the method for calculating the equivalent model under any antenna configuration through analysis of space-borne ATI-SAR space geometric relationship comprises the following steps:
novel antenna structure is constructed based on space inclined plane geometric relation of antennaThe figure, wherein the geometrical relationship of the space inclined plane is as follows: the satellite moves along the direction of a y axis at a speed V, the two antennas are distributed in point symmetry along the origin of a coordinate plane at a distance of 2d, an included angle between a connecting line between the two antennas and the x axis is theta, the initial distance between the moving target and the coordinate center at the moment when t is 0 is R, the included angle between the connecting line between the moving target and the origin of the moving target and the x axis is gamma, and the speed of the moving target along the line of sight of the radar is Vr(ii) a The constructed novel antenna configuration diagram is as follows: the new x-axis direction is the slant distance direction between the target and the origin of the symmetrical distribution of the two antennas, and the new y-axis direction is the direction perpendicular to the new x-axis on the imaging plane;
the equivalent model is represented as: the equivalent base length is 2d · sin (theta-gamma), the equivalent satellite velocity is v · cos (gamma), and the equivalent target radial velocity is
The time delay based on this equivalent model is expressed as:
the corresponding interference phases are:
according to the interference phase, obtaining the ocean current mixing speed:
λ is the radar wavelength.
Further, the approximate calculation formula of the Bragg phase velocity is:
cprepresenting Bragg wave phase velocity, and g is gravity acceleration; g (theta)ω) A spread function, theta, representing the wind directionωIs the included angle between the radar sight line direction and the wind direction, and l is an expansion factor.
The present invention also provides a computer apparatus comprising:
one or more processors;
a memory; and
one or more programs stored in the memory and configured to be executed by the one or more processors, which when executed by the processors, implement the ATI-SAR ocean current velocity extraction method on-board a satellite in any antenna configuration of the present invention.
Has the advantages that: the method can realize the inversion of the ocean current velocity of the satellite-borne ATI-SAR echo under any antenna configuration, and simultaneously provides a solution and a path for analyzing the speed measurement performance of the satellite-borne ATI-SAR ocean current under the complex baseline condition (the condition that the antenna squints and the mixed baseline exist). Meanwhile, for the strabismus echoes of the two channels, different imaging algorithms are adopted, and the final imaging positions of the same target are different. When the wk algorithm is adopted, the target is imaged at an azimuth zero-frequency position, so that the azimuth direction and the distance direction of the two channels are deviated, and the registration (frequency phase compensation) between the channels is required before the interference phase is extracted. When the BP algorithm is adopted, if the ground grid is selected as a reference point, the azimuth position and the distance position of the same target after imaging in the two channels are completely consistent under any channel included angle and radar oblique angle, registration is not needed, and the experimental efficiency is greatly improved.
Drawings
FIG. 1 is a general flow chart of a method for extracting the flow velocity of an ATI-SAR ocean current on a satellite with any antenna configuration according to an embodiment of the invention;
FIG. 2 is a geometric diagram of any antenna configuration of an embodiment of the present invention;
FIG. 3 is an equivalent geometry diagram for any antenna configuration of an embodiment of the present invention;
FIG. 4 is an echo of channel A after range pulse pressure in accordance with an embodiment of the present invention;
FIG. 5 is an echo of channel B after range pulse pressure in accordance with an embodiment of the present invention;
FIG. 6 is a BP imaging result of channel A of an embodiment of the present invention;
FIG. 7 is the BP imaging result of channel B of an embodiment of the present invention.
Detailed Description
The technical scheme of the invention is further explained by combining the attached drawings.
The invention provides a method for extracting the ocean current velocity of an ATI-SAR on a satellite under any antenna configuration. A CPU (central processing unit) of a computer used for a simulation experiment is i7-9700@3.00GHz eight cores, and a memory is 16 GB. Specific SAR system simulation parameters are shown in table 1.
TABLE 1
Referring to fig. 1, the method for extracting the flow velocity of the satellite-borne ATI-SAR ocean current under any antenna configuration comprises the following steps:
step 1, channel correction: and obtaining the amplitude-phase error between the channels by using the echo signals of the two channels in the reference region, and compensating the target region.
First, a sea island is selected as a reference area, and since the altitude of the area is approximately 0 and there is no radial velocity, there is no mixed interference phase introduced along the flight path and the vertical flight path. And then, performing two-dimensional frequency domain self-adaptive correction processing on the echo signals of the channel A and the channel B to obtain the inter-channel amplitude-phase error of the channel A and the channel B. And finally, compensating the estimated channel amplitude phase error to a target area to be processed to realize channel correction. Channels a, B are sometimes also referred to as channel one, channel two or first channel, second channel.
Specifically, step 1 can be implemented by:
suppose Zi(f, Ω) (i ═ 1,2) represents echo data of two channels in two-dimensional frequency domain, where f represents azimuth frequency domain, Ω represents distance frequency domain, and Z representsi(f, Ω) (i ═ 1,2) can be expressed as:
wherein a (f) represents the common amplitude and phase portion between the two channels, h1(omega) and h2(omega) represents the transfer function of the two channels, respectively, D1(f) And D2(f) Showing the two-way antenna pattern between the two channels, f · Δ T shows the phase difference in the azimuth frequency domain due to the channel separation, Δ T shows the time delay between the channels.
The radar echo data is transformed to the range-doppler domain, when the system azimuth phase error mainly comprises two parts, the first part is a linear phase part caused by the interval between channels, and the second part is a non-linear phase part caused by the difference of the receiving antenna pattern between different channels and the transfer function of the channel at the back end of the antenna. The first part can be theoretically represented as:
wherein f ismIndicating the corresponding Doppler of the mth Doppler cellLe frequency, d represents the separation between the two channels, and V represents the speed of motion of the radar platform.
From equation (3), Δ T can be expressed as:
two-dimensional frequency domain self-adaptive correction processing is carried out on echo signals of the channel A and the channel B, and the two-dimensional frequency domain self-adaptive correction algorithm is essentially to solve the following optimal solution of an objective function:
the objective function can be understood as: by finding the compensation function h of the distance frequency domain1,2Compensation function D of (omega) and azimuth frequency domain1,2(f) The difference between the two channels is minimized. Meanwhile, the two-dimensional self-adaptive correction algorithm considers that the channel errors are mutually independent in an azimuth frequency domain and a distance frequency domain. For details on two-dimensional adaptive correction algorithms see the reference "Gierull, C.H. digital Channel Balancing of Along-Track Interferometric SAR data.2003, 42.".
The solution to the objective function can be expressed as:
where the superscript symbol denotes a conjugate operation, the solution may be further expressed as an iterative structure:
wherein the content of the first and second substances,
data representing the second channel after n iterations.
As can be seen from equations (8) and (9), the two-dimensional adaptive correction algorithm first performs azimuth-direction iterative processing on the two-channel data of the reference region, and then performs distance-direction iterative processing, and so on. Convergence is generally achieved after 3-4 iterations. The essence of the channel correction is that the data of the channel two is corrected to be identical to the data of the channel one by taking the channel one as a reference and carrying out iterative processing, namely, the compensation quantity is
And then multiplying the compensation quantity by the two-dimensional frequency domain two-channel data point of the target area to realize channel correction.
Step 2, introducing a BP imaging algorithm into satellite-borne ATI-SAR signal processing:
and obtaining a distance history under any antenna configuration through analysis of a space-borne ATI-SAR space geometric relationship, and obtaining imaging results of the two channels by adopting a BP imaging algorithm on echo signals of the channel A and the channel B which are corrected through the channels based on the distance history.
In this embodiment, step 2 is implemented by the following preferred scheme:
(2-1) distance direction compression: the radar echo pulse signals are subjected to pulse pressure processing through a matched filter;
(2-2) distance direction interpolation: calculating the slant distance between each pixel point of the imaging area and the radar antenna at each pulse moment, and usually performing distance interpolation calculation by using a method of performing inverse Fourier transform after zero padding in a frequency domain;
(2-3) meshing: dividing an imaging area into grids, obtaining all grid point targets, and enabling each pixel in a finally formed SAR image to represent one grid;
(2-4) backprojection: the distance R of the radar from each grid point at each azimuth time (time of transmitting pulse) is calculateduvAnd calculating the two-way time delay
And the delay time Δ t of all grid points with respect to the nearest distance reference point. RuvU and v in (1) are respectively expressed as corresponding points of the imaging area in the distance direction and the azimuth direction, and c is expressed as the speed of light.
(2-5) coherent superposition: utilizing the delay time Deltat of each grid point, calculating the corresponding echo value by interpolation, and carrying out phase compensation and superposition on the echo value of the grid point in the previous direction by the compensation amount
λ is denoted as the radar wavelength.
The BP algorithm refers to the idea of 'time delay-superposition', in radar application, distance direction matching is carried out on echo signals received by a radar receiving antenna, phase amplitude information contained in echo data is obtained, inverse Fourier transform is carried out through IFFT, time delay of a receiving and transmitting antenna combination is obtained, and finally signals are accumulated to be subjected to coherent addition to obtain a target function. See the reference, "research on BP-based InSAR imaging algorithm and multi-baseline phase unwrapping algorithm [ D ]. university of electronic technology, 2014.
Step 3, extracting interference phases: conjugate multiplication is carried out on the imaging results of the channel A and the channel B to obtain an interference phase of the scene echo;
step 4, extracting the ocean current mixing speed under any antenna configuration: an equivalent model calculation method under any antenna configuration is obtained through space-borne ATI-SAR space geometric relation analysis, and ocean current mixing speed is obtained according to the equivalent model.
In this embodiment, step 4 is implemented by the following method:
and (3) considering the general spatial inclined plane geometrical relationship according to the project situation, and obtaining a novel antenna configuration diagram. FIG. 2 is a geometric diagram of an arbitrary antenna configuration, considering an inclined plane geometryIn this relationship, the satellite moves in the y-axis direction at a velocity v. The two antennas are distributed in point symmetry along the original point in the figure, the distance is 2d, and the included angle between the connecting line between the two antennas and the x axis is theta. The starting distance between the moving target and the coordinate center is R (t is 0 moment), and the included angle between the connecting line of the moving target and the origin and the x axis is gamma. The speed of the moving object along the line of sight of the radar is Vr。
Due to the squint processing, the equivalent plane of the novel antenna can be constructed. Fig. 3 is an equivalent geometry diagram for any antenna configuration. The new X-axis direction is the slant distance direction between the target and the origin of the two antenna symmetric distributions, and the new y-axis direction is the direction perpendicular to the new X-axis on the imaging plane (i.e. X in fig. 3)cAnd YcA shaft). The equivalent base length is 2d · sin (theta-gamma), the equivalent satellite velocity is v · cos (gamma), and the equivalent target radial velocity is
Under the above equivalent model, the time delay can be expressed as:
the corresponding interference phases are:
in the above formula, VrIs the target speed of the line of sight of the radar,
the velocity projected to the sea surface by the radar line of sight contains the doppler velocity of the wave motion and the like.
From step 3 and equation (11), the extracted ocean current mixing velocity is:
step 5, separating ocean current radial velocity under any antenna configuration: and removing the Bragg wave phase velocity and the large-scale wave orbital velocity in the ocean current mixing velocity to obtain the radial velocity of the ocean current.
The ocean current mixing velocity can be expressed as:
Vr＝Vc+Vwind+Vo+Vb (13)
in the above formula, VcThe velocity, V, of the sea surface flow field itselfwindIs the flow velocity, V, caused by the wind field on the sea surfaceoIs the large scale wave orbital velocity, VbIs the Bragg phase velocity. Wherein the sum of the surface velocity induced by the sea surface wind field and the velocity of the sea surface flow field itself is considered to be the required sea surface velocity, i.e. Vs＝Vc+Vwind。
In order to obtain sea surface flow field information, the large-scale wave orbital velocity and Bragg phase velocity must be removed. The large-scale wave orbital velocity is a fast variation process and has periodicity, and the average value of the large-scale wave orbital velocity is 0, so that the large-scale wave orbital velocity can be removed by spatial averaging, but the ocean current and Bragg phase velocities are slow variation processes and are in the same order of magnitude and are not easy to remove.
The Bragg wave phase velocity comprises two Bragg waves with opposite directions, wherein one Bragg wave is a Bragg wave which propagates close to the radar direction, and the other Bragg wave is a Bragg wave which propagates far away from the radar direction. The phase velocity of the Bragg wave contained in the doppler velocity obtained from the phase diagram of the forward-track interference is essentially the weighted vector sum of the phase velocities of the Bragg waves propagating in the two different directions. The calculation formula of the Bragg wave phase velocity is as follows:
wherein g is the acceleration of gravity, λ is the radar wavelength, θ is the incident angle, i.e. the angle between the x axis and the line between the two antennas in the above-mentioned geometric relationship of inclined planes. The proportion of the Bragg waves propagating in two different directions can be expressed by an expansion function of the wind direction as follows:
wherein, thetaωThe angle between the line of sight and the wind direction of the radar is defined by a spreading factor, which is related to the radar frequency and is usually 2-5. Thus, the Bragg phase velocity in doppler velocity can be expressed as:
as shown in fig. 4, the echo of the channel a after pulse pressure based on the BP algorithm, fig. 5 the echo of the channel B after pulse pressure based on the BP algorithm, fig. 6 the BP imaging result of the channel a, and fig. 7 the BP imaging result of the channel B, so that the interference phase difference value at the position of the dual-channel target is-0.0736 radian. The theoretical interference phase difference obtained by an equivalent model calculation method based on any antenna configuration is 0 radian. By echo simulation under five complex configurations of table 2, the effectiveness of the equivalent model calculation method under any antenna configuration can be verified by comparing theoretical values with actual values.
TABLE 2
According to another embodiment of the present invention, there is provided a computer apparatus including:
one or more processors;
a memory; and
one or more programs stored in the memory and configured for execution by the one or more processors, which when executed by the processors, implement a method for extracting a velocity of ATI-SAR ocean current on-board any antenna configuration as described in method embodiments.
As will be appreciated by one skilled in the art, embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the scope of protection thereof, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: after reading this disclosure, those skilled in the art will be able to make various changes, modifications and equivalents to the embodiments of the invention, which fall within the scope of the appended claims.
Claims (10)
1. A method for extracting the flow velocity of satellite-borne ATI-SAR ocean currents under any antenna configuration is characterized by comprising the following steps:
calculating the amplitude phase error between the channels according to the echo signals of the channel A and the channel B in the reference region, and compensating the target region to be processed by using the amplitude phase error between the channels to realize channel correction;
obtaining a distance history under any antenna configuration through analysis of a space-borne ATI-SAR space geometric relationship, and obtaining imaging results of two channels by adopting a BP imaging algorithm on echo signals of a channel A and a channel B which are corrected through the channels based on the distance history;
conjugate multiplication is carried out on the imaging results of the channel A and the channel B to obtain an interference phase of the scene echo;
obtaining an equivalent model calculation method under any antenna configuration through space-borne ATI-SAR space geometric relation analysis, and obtaining ocean current mixing speed according to the equivalent model;
and removing the Bragg phase velocity in the ocean current mixing velocity and the large-scale wave orbital velocity to obtain the radial velocity of the ocean current.
2. The method for extracting the ATI-SAR ocean current velocity under any antenna configuration according to claim 1, wherein the step of calculating the amplitude phase error between the channels according to the echo signals of the channel A and the channel B in the reference area comprises the following steps: and performing two-dimensional frequency domain self-adaptive correction processing on the echo signals of the channel A and the channel B in the reference area to obtain the inter-channel amplitude-phase error of the channel A and the channel B.
3. The extraction method of the ATI-SAR ocean current velocity under any antenna configuration as claimed in claim 2, wherein the two-dimensional frequency domain adaptive correction processing comprises: firstly, carrying out azimuth iterative processing, then carrying out distance iterative processing, and solving the optimal solution of the following objective function:
Z1(f,Ω)、Z2(f, omega) respectively represent echo data of the channel A and the channel B in a two-dimensional frequency domain, f represents an azimuth frequency domain, omega represents a distance frequency domain, h represents a distance frequency domain1,2(omega) represents a compensation function for the distance frequency domain, D1,2(f) A compensation function representing the azimuth frequency domain.
4. The ATI-SAR ocean current velocity extraction method under any antenna configuration as claimed in claim 3, wherein the iterative form of the solution of the objective function is represented as:
the superscript symbol indicates a conjugate operation,
data representing channel B after n iterations.
5. The ATI-SAR ocean current velocity extraction method under any antenna configuration as claimed in claim 1, wherein the reference area is an ocean area with altitude of approximately 0 and no radial velocity.
6. The method for extracting the ATI-SAR ocean current velocity under any antenna configuration according to claim 1, wherein the step of obtaining the distance history under any antenna configuration through analysis of the ATI-SAR spatial geometrical relationship comprises the following steps:
the radar echo pulse signals are subjected to pulse pressure processing through a matched filter;
calculating the slant distance between each pixel point of the imaging area and the radar antenna at each pulse moment;
dividing an imaging area into grids, obtaining all grid point targets, and enabling each pixel in a finally formed SAR image to represent one grid;
calculating the distance R of the radar to each grid point at each azimuth momentuvAnd calculating the two-way time delay tuvAnd the delay time Δ t of all grid points relative to the nearest distance reference point;
and calculating the corresponding echo value by interpolation by using the delay time deltat of each grid point, and performing phase compensation and superposition on the echo value of the grid point in the previous direction.
7. The method for extracting the ATI-SAR ocean current flow velocity under any antenna configuration according to claim 1, wherein an equivalent model calculation method under any antenna configuration is obtained through analysis of the ATI-SAR space geometric relationship, and obtaining the ocean current mixing velocity according to the equivalent model comprises the following steps:
constructing a novel antenna configuration diagram based on the spatial inclined plane geometric relationship of the antenna, wherein the spatial inclined plane geometric relationship is as follows: the satellite moves along the direction of a y axis at a speed V, the two antennas are distributed in point symmetry along the origin of a coordinate plane at a distance of 2d, an included angle between a connecting line between the two antennas and the x axis is theta, the initial distance between the moving target and the coordinate center at the moment when t is 0 is R, the included angle between the connecting line between the moving target and the origin of the moving target and the x axis is gamma, and the speed of the moving target along the line of sight of the radar is Vr(ii) a The constructed novel antenna configuration diagram is as follows: the new x-axis direction is the slant distance direction between the target and the origin of the symmetrical distribution of the two antennas, and the new y-axis direction is the direction perpendicular to the new x-axis on the imaging plane;
the equivalent model is represented as: the equivalent base length is 2d · sin (theta-gamma), the equivalent satellite velocity is v · cos (gamma), and the equivalent target radial velocity is
The time delay based on this equivalent model is expressed as:
the corresponding interference phases are:
according to the interference phase, obtaining the ocean current mixing speed:
λ is the radar wavelength.
8. The extraction method of the ATI-SAR ocean current velocity under any antenna configuration is characterized in that the large-scale wave orbit velocity is removed through space averaging.
9. The method for extracting the ATI-SAR ocean current velocity under any antenna configuration according to claim 7, wherein the approximate calculation formula of the Bragg phase velocity is as follows:
cprepresenting Bragg wave phase velocity, and g is gravity acceleration; g (theta)ω) A spread function, theta, representing the wind directionωIs the included angle between the radar sight line direction and the wind direction, and l is an expansion factor.
10. A computer device, comprising:
one or more processors;
a memory; and
one or more programs, wherein the one or more programs are stored in the memory and configured for execution by the one or more processors, which when executed by the processors implement the ATI-SAR ocean current velocity extraction method on-board any antenna configuration as recited in any of claims 1-9.
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