Orbit error estimation and update imaging method based on high orbit sar image self-focusing

Abstract

The application discloses a kind of orbit error estimation and updating imaging method based on high orbit SAR image self-focusing, comprising: full-aperture SAR echo data is divided into sub-aperture echo data, according to each sub-aperture echo data to each sub-scene is imaged to determine the full-aperture phase error of each sub-scene, according to full-aperture phase error inversion three-dimensional error of orbit, according to three-dimensional error of orbit updating orbit data and to the observed imaging scene is imaged.According to the method provided in the application, the error of the orbit is directly calculated by the SAR echo data, rather than by the GPS data, which can avoid the position error caused by the GPS monitoring satellite data;Direct imaging of the scene by sub-aperture echo data, rather than modeling and then simulating imaging, can avoid the precision loss in the simulation process;So as to improve the orbit accuracy and imaging accuracy.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar signal processing, and particularly relates to a kind of orbit error estimation and update imaging based on high orbit SAR image self focusing. BACKGROUND

[0002] The high-orbit synthetic aperture radar (SAR) system is an active radar located in the geosynchronous orbit, has an ultra-long synthetic aperture time, is not affected by geographical conditions and weather conditions, and can realize long-time reconnaissance of a specific area. Therefore, the high-orbit synthetic aperture radar (SAR) system plays an important role in target imaging and observation. With the development of high-resolution space-borne SAR, orbit error has become a decisive factor restricting the improvement of the resolution of space-borne SAR. As an important error source, the orbit error can affect the imaging results of the SAR and is one of the main limiting factors affecting the image quality. In order to eliminate the orbit error, a plurality of methods have been developed.

[0003] The main way to eliminate the orbit error at present is the precise orbit determination technology. The precise orbit determination technology establishes a precise orbit determination error model based on the satellite body structure, and is usually used when the satellite orbit data recorded by the GPS system is obtained for compensation. However, because the high-orbit SAR satellite is located outside the GPS positioning system, the use of satellite data of the positioning system will cause a large position error; because the precise orbit determination technology is to simulate the scene by using the data obtained by the GPS positioning system and then perform imaging, some errors will also be caused in the process of simulation modeling. This results in that the imaging quality precision of the precise orbit determination technology is not high and cannot meet the imaging requirements. SUMMARY

[0004] The embodiment of the application provides a kind of orbit error estimation and update imaging method based on high orbit SAR image self focusing, can solve the problem that the imaging quality precision of precise orbit determination technology is not high and cannot meet the imaging requirements.

[0005] In the first aspect, the embodiment of the application provides a kind of orbit error estimation and update imaging method based on high orbit SAR image self focusing, and the method comprises the following steps:

[0006] The synthetic aperture radar (SAR) echo data is divided into a plurality of sub-aperture echo data according to the sub-aperture division;

[0007] Each distance sub-scene is imaged according to the sub-aperture echo data, and the full-aperture phase error of each distance sub-scene is determined according to the distance sub-scene image, wherein all the distance sub-scenes constitute an imaging scene to be observed;

[0008] The three-dimensional error of the orbit is inversed according to the full-aperture phase error;

[0009] The updated orbit data is obtained according to the three-dimensional error updating the orbit data, and the detection image is obtained according to the updated orbit data.

[0010] In a possible implementation manner of the first aspect, the SAR echo data can be pulse compressed to obtain pulse-compressed SAR echo data; and the pulse-compressed SAR echo data can be divided into sub-aperture SAR echo data according to sub-aperture division; and the sub-aperture SAR echo data can be point multiplied with a window function to obtain sub-aperture echo data.

[0011] In a possible implementation manner of the first aspect, the maximum contrast phase error of each sub-aperture in a distance sub-scene can be calculated by using a maximum contrast autofocusing method according to the sub-scene image; the maximum contrast phase errors of all sub-apertures in the same distance sub-scene can be spliced, and the gradient of each maximum contrast phase error can be calculated; the linear component of the gradient of the maximum contrast phase error can be determined according to the gradient of the maximum contrast phase error of the overlapping pulses of two adjacent sub-apertures in the same distance sub-scene; and the full-aperture phase error of the distance sub-scene can be obtained by coherently combining the maximum contrast phase error according to the linear component.

[0012] In a possible implementation manner of the first aspect, the three-dimensional error of the orbit can be inversed by using a least square method according to the full-aperture phase error of each distance sub-scene.

[0013] In a possible implementation manner of the first aspect, the three-dimensional error of the orbit can satisfy the following formula:

[0014]

[0015] wherein, t a is an azimuth time, E() is the three-dimensional error of the orbit, p() is an instantaneous unit vector from the phase center of the antenna to the center of all distance sub-scenes at each azimuth time, λ is a wavelength, ψ e () is a full-aperture phase error matrix, and the kth column vector of the full-aperture phase error matrix is the full-aperture phase error of the kth distance sub-scene.

[0016] In a possible implementation manner of the first aspect, the three-dimensional error compensation can be subtracted from the orbit data to obtain updated orbit data.

[0017] In a possible implementation manner of the first aspect, the distance sub-scene can be obtained by uniformly and equidistantly dividing an imaging scene to be observed.

[0018] In the second aspect, an orbit error estimation and updating imaging device based on high-orbit SAR image autofocusing is provided, and the device comprises:

[0019] An echo data processing module is configured to divide SAR echo data according to a sub-aperture to obtain a plurality of sub-aperture echo data.

[0020] A full-aperture phase error estimation module is configured to image each distance sub-scene according to the sub-aperture echo data, and determine a full-aperture phase error of each distance sub-scene according to a distance sub-scene image, wherein all the distance sub-scenes constitute an imaging scene to be observed.

[0021] An orbit three-dimensional error inversion module is configured to invert a three-dimensional error of an orbit according to the full-aperture phase error.

[0022] An orbit updating module is configured to compensate and update orbit data according to the three-dimensional error to obtain updated orbit data.

[0023] A detection imaging module is configured to image according to the updated orbit data to obtain a detection image.

[0024] In a third aspect, an electronic device is provided, including a processor and a memory, wherein the memory is configured to store a computer program; the processor is configured to execute the computer program (instructions) stored in the memory to implement the method of the first aspect.

[0025] In a fourth aspect, a computer readable storage medium is provided, and the computer readable storage medium stores a computer program, when the computer program is executed, the method of the first aspect can be implemented.

[0026] Compared with the prior art, the method provided by the present application has the beneficial effects that: the method directly calculates the error of the orbit according to the SAR echo data, rather than calculating the error of the orbit according to the GPS data, so that the position error caused by the GPS monitoring satellite data can be avoided; the scene is directly imaged according to the sub-aperture echo data, rather than modeling and then simulating the imaging, so that the precision loss in the simulation process can be avoided; and thus the orbit precision and the imaging precision are improved. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 A flowchart of an orbit error estimation and updating imaging method based on high-orbit SAR image self-focusing is provided for the embodiments of the present application.

[0028] Figure 2 A flowchart of a method for determining a full-aperture phase error is provided for the embodiments of the present application.

[0029] Figure 3A schematic diagram of the structure of an orbital error estimation and update imaging device based on autofocusing of high-orbit SAR images provided in an embodiment of the present invention;

[0030] Figure 4 A trajectory deviation diagram provided for an embodiment of the present invention;

[0031] Figure 5 This is a schematic diagram illustrating the comparison of imaging effects provided in an embodiment of the present invention;

[0032] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0034] The orbital error estimation and updated imaging based on autofocus of high-orbit SAR images provided in this embodiment of the invention can be applied to electronic devices such as mobile terminals, personal laptops, and supercomputers. This embodiment of the invention does not impose any restrictions on the specific type of electronic device.

[0035] Figure 1 The diagram shown illustrates a method for orbit error estimation and image update based on autofocusing of high-orbit SAR images, provided by an embodiment of the present invention. As an example and not a limitation, method 100 can be applied to the aforementioned electronic device. Method 100 may include steps S101-S106, which are described below.

[0036] S101, the synthetic aperture radar SAR echo data is divided according to sub-aperture to obtain multiple sub-aperture echo data.

[0037] In one possible implementation, the SAR echo data can first be pulse-compressed to obtain pulse-compressed SAR echo data. Then, the pulse-compressed SAR echo data can be divided according to sub-apertures to obtain pulse-compressed sub-aperture SAR echo data. Finally, the sub-aperture echo data can be obtained by dot product of the pulse-compressed sub-aperture SAR echo data and a window function.

[0038] In one example, range pulse compression can be used to pulse compress SAR echo data.

[0039] Specifically, the pulse-compressed SAR echo data containing L pulses of the full aperture can be divided into N sub-apertures to obtain the pulse-compressed sub-aperture SAR echo data ss(t). r This reduces coherent processing time. Then it is combined with the window function rect. n (l) Dot product yields sub-aperture echo data ss n (tr l).

[0040] For example, when n·l0≤l≤n·l0+L a -1, the window function rect n (l) takes value 1, and 0 in other ranges. Wherein, l0 represents the sub-aperture spacing, L a represents the length of the sub-aperture, and l represents the L i (i=1,2,…,L)th pulse.

[0041] S102, image each range sub-scene according to the sub-aperture echo data to obtain a range sub-scene image.

[0042] In an example, the whole imaging scene to be observed can be divided into K i (i=1,2,…,K) range sub-scenes, and then each range sub-scene is imaged according to all the sub-aperture echo data in the range sub-scene to obtain a range sub-scene image.

[0043] For example, the imaging scene to be observed can be evenly divided into range sub-scenes.

[0044] S103, determine the full-aperture phase error of each range sub-scene according to the range sub-scene image.

[0045] In a possible implementation, the maximum contrast phase error of the n th sub-aperture in the k th range sub-scene can be calculated using the maximum contrast autofocusing method according to the range sub-scene image. All the maximum contrast phase errors of the k th range sub-scene are spliced, and the gradient of each maximum contrast phase error is calculated according to the spliced maximum contrast phase error. The linear component is calculated according to the error gradient of the pulses overlapping between adjacent two sub-apertures. Finally, the full-aperture phase error of the k th range sub-scene can be obtained by coherently combining the maximum contrast phase errors according to the linear component.

[0046] For example, the number of pulses overlapping between adjacent two sub-apertures is L a -l0.

[0047] For example, the full-aperture phase error of each range sub-scene can be represented by a full-aperture phase error matrix. The k th column vector in the full-aperture phase error matrix can be the full-aperture phase error of the k th range sub-scene.

[0048] That is: ψ e (t a )=[Ψ1(t a ,T1),Ψ2(t a ,T2),…,Ψ K (t aT K )];

[0049] wherein T k is the scene center point coordinate of the kth range sub-scene, t a is the azimuth time, ψ e (t a ) is the full-aperture phase error matrix, Ψ k (t a , T k ) is the full-aperture phase error of the kth range sub-scene.

[0050] Specifically, referring to Figure 2 , the maximum contrast phase error matrix at each sub-aperture time of each sub-scene can be determined by starting from the first range sub-scene and the first sub-aperture data, and then traversing the sub-aperture echo data of the same range sub-scene first, and then traversing the next range sub-scene.

[0051] Exemplarily, the nth column vector of the maximum contrast phase difference matrix of the kth range sub-scene is the maximum contrast phase error of the nth sub-aperture of the kth range sub-scene.

[0052] That is:

[0053] wherein ψ k (n) is the maximum contrast phase difference matrix of the kth range sub-scene, is the maximum contrast phase error of the nth sub-aperture of the kth range sub-scene.

[0054] In one example, the maximum contrast phase error can satisfy the following formula:

[0055]

[0056] wherein ψ is the maximum contrast phase error, I max is the brightness value of the brightest pixel in the range sub-scene image, and I min is the brightness value of the darkest pixel in the range sub-scene image.

[0057] Optionally, the full-aperture phase errors of multiple range sub-scenes can be calculated in parallel to reduce processing time and improve efficiency.

[0058] S104, according to the full-aperture phase error, the three-dimensional error of the orbit is inversed.

[0059] In one example, the three-dimensional error of the orbit can be calculated by using the least square method.

[0060] Exemplarily, the three-dimensional error of the orbit can satisfy the following formula:

[0061]

[0062] wherein t a is the azimuth time, E() is the three-dimensional error of the orbit, p() is the instantaneous unit vector from the antenna phase center to the center of all the range sub-scene at each azimuth time, and λ is the wavelength.

[0063] For example, p(t a ) is composed of p(t a , T k ), and p(t a , T k ) represents the instantaneous unit vector from the antenna phase center to the center of the kth range sub-scene.

[0064] S105, updating the orbit data according to the three-dimensional error to obtain updated orbit data.

[0065] In one example, the updated orbit data can be obtained by subtracting the three-dimensional error of the orbit from the current orbit data.

[0066] For example, the updated orbit data can satisfy the following formula:

[0067] S(t a ) = s(t a ) - E(t a )

[0068] wherein S(t a ) is the updated orbit data, and s(t a ) is the current orbit data.

[0069] S106, imaging according to the updated orbit data to obtain a detection image.

[0070] For example, imaging according to the updated orbit data can obtain a detection image of the imaging scene to be observed.

[0071] According to the method provided by the application, the error of the orbit is directly calculated from the SAR echo data, instead of from the GPS data, so that the position error caused by the GPS monitoring satellite data can be avoided; the scene is directly imaged from the sub-aperture echo data, instead of modeling and then simulating the imaging, so that the precision loss in the simulation process can be avoided; and thus the orbit precision and the imaging precision are improved.

[0072] Figure 3 Fig. 1 shows a structure schematic diagram of an orbit error estimation and update imaging device based on high-orbit SAR image self-focusing provided by an embodiment of the application, which is an example but not limitation, and the device 300 can include:

[0073] The echo data processing module 310 is configured to divide SAR echo data according to a sub-aperture to obtain a plurality of sub-aperture echo data.

[0074] The full-aperture phase error estimation module 320 is configured to image each distance sub-scene according to the sub-aperture echo data, and determine a full-aperture phase error of each distance sub-scene according to a distance sub-scene image, wherein all the distance sub-scenes constitute an imaging scene to be observed.

[0075] The orbit three-dimensional error inversion module 330 is configured to invert a three-dimensional error of an orbit according to the full-aperture phase error.

[0076] The orbit updating module 340 is configured to compensate and update orbit data according to the three-dimensional error to obtain updated orbit data.

[0077] The detection imaging module 350 is configured to image according to the updated orbit data to obtain a detection image.

[0078] In a possible implementation, the echo data processing module 310 can be specifically configured to perform pulse compression processing on the SAR echo data to obtain pulse-compressed SAR echo data, divide the pulse-compressed SAR echo data according to a sub-aperture to obtain pulse-compressed sub-aperture SAR echo data, and perform point multiplication on the pulse-compressed sub-aperture SAR echo data and a window function to obtain the sub-aperture echo data.

[0079] In a possible implementation, the full-aperture phase error estimation module 320 can be specifically configured to calculate a maximum contrast phase error of an nth sub-aperture in a kth distance sub-scene by using a maximum contrast autofocusing method according to a sub-scene image, splice N maximum contrast phase errors of the kth distance sub-scene, and calculate a gradient of each maximum contrast phase error, wherein N is a total number of sub-apertures, and determine a linear component according to a gradient of a maximum contrast phase error of an overlapping pulse of adjacent two sub-apertures, and perform coherent combination on the maximum contrast phase error according to the linear component to obtain a full-aperture phase error of the kth distance sub-scene.

[0080] In a possible implementation, the orbit three-dimensional error inversion module 330 can be specifically configured to invert a three-dimensional error of an orbit by using a least square method according to the full-aperture phase error of each distance sub-scene.

[0081] In a possible implementation, the three-dimensional error of the orbit can satisfy the following formula:

[0082]

[0083] wherein t a is the azimuth time, E() is the three-dimensional error of the orbit, p() is the instantaneous unit vector from the antenna phase center to the center of all range sub-scenarios at each azimuth time, λ is the wavelength, and ψ e () is the full-aperture phase error matrix, and the kth column vector of the full-aperture phase error matrix is the full-aperture phase error of the kth range sub-scenario.

[0084] In a possible implementation, the orbit updating module 340 can be specifically configured to subtract the three-dimensional error compensation from the orbit data to obtain updated orbit data.

[0085] In a possible implementation, the range sub-scenarios can be obtained by uniformly and equidistantly dividing the imaging scene to be observed.

[0086] According to the method provided in the application, the error of the orbit is directly calculated from the SAR echo data instead of the GPS data, so that the position error caused by the GPS monitoring satellite data can be avoided; the scene is directly imaged from the sub-aperture echo data instead of modeling and then simulating the imaging, so that the precision loss in the simulation process can be avoided; and thus the orbit precision and the imaging precision can be improved.

[0087] In order to better illustrate the beneficial effects of the method provided in the application, the following simulation experiments are performed:

[0088] Specifically, referring to Table 1 below, the simulation experiments can be performed by the parameter settings in Table 1.

[0089] Table 1 Simulation parameter table

[0090]

[0091]

[0092] Figure 4 A track deviation map provided by an embodiment of the application is shown.

[0093] Exemplarily, the simulation experiments are performed by the method provided in the application under the parameter settings provided in Table 1 above, and the orbit data of the satellite is obtained.

[0094] Referring to Figure 4 , Figure 4Figures (a), (b), and (c) show a comparison of orbital data in the x, y, and z directions, respectively. The blue lines represent ideal orbital data, while the red dashed lines represent orbital data estimated using the method provided by this invention. It can be seen that the orbital data obtained by this invention has a small deviation from the ideal orbital data, almost completely eliminating error interference, and closely matches the actual orbital data. The method provided by this invention can estimate relatively accurate satellite orbital data.

[0095] Figure 5 The diagram shown is a comparison of imaging effects provided by an embodiment of the present invention.

[0096] Figure 5 Image (a) in the image is generated using precise orbit determination technology. Figure 5 (b) in the figure is a detection image generated by the method provided by the present invention. See also Figure 5 As can be seen, the detection images generated by the method provided by this invention have higher accuracy.

[0097] Therefore, according to the method provided by the present invention, the orbital error is calculated directly from SAR echo data instead of from GPS data, which avoids the positional error caused by GPS monitoring satellite data; the scene is directly imaged from sub-aperture echo data instead of modeling first and then simulating imaging, which avoids the loss of accuracy in the simulation process; thereby improving orbital accuracy and imaging accuracy.

[0098] Figure 6 The diagram shown is a structural schematic of an electronic device provided in an embodiment of the present invention. Figure 6 The illustrated electronic device 600 may include: at least one processor 610 ( Figure 6 The diagram shows only one processor, a memory 620, and a computer program 630 stored in the memory 620 and executable on the at least one processor 610, which, when executing the computer program 630, implements the steps in any of the above method embodiments.

[0099] The electronic device 600 may be a robot or other processing device capable of implementing the above methods. This embodiment of the invention does not impose any restrictions on the specific type of electronic device.

[0100] Those skilled in the art will understand that Figure 6 This is merely an example of electronic device 600 and does not constitute a limitation on the electronic device. It may include more or fewer components than shown, or combine certain components, or use different components. For example, electronic device 600 may also include input / output interfaces.

[0101] The processor 610 can be a central processing unit (CPU), and can also be other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0102] The memory 620 can be an internal storage unit, such as a hard disk or a memory, in some embodiments. The memory 620 can also be an external storage device, such as a plug-in hard disk, a smart memory card (SMC), a secure digital (SD) card, a flash card, etc., in other embodiments. Further, the memory 620 can include both an internal storage unit and an external storage device. The memory 620 is used to store an operating system, application programs, a boot loader, data, and other programs, such as program codes of the computer program, etc. The memory 620 can also be used to temporarily store data that has been output or is to be output.

[0103] It should be understood that the size of the serial number of each step in the above embodiments does not mean the order of execution, and the execution order of each process should be determined according to its function and inherent logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0104] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the above-mentioned division of each functional unit and module is exemplified, and in actual application, the above-mentioned functions can be completed by different functional units and modules according to needs, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. Each functional unit and module in the embodiment can be integrated in one processing unit, or each unit can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or software functional unit. In addition, the specific names of each functional unit and module are only for easy distinction, and do not limit the protection scope of the present application. The specific working process of the unit and module in the above system can refer to the corresponding process in the foregoing method embodiment, which will not be described here.

[0105] The embodiment of the present application also provides a computer readable storage medium, the computer readable storage medium stores a computer program, and the computer program is executed by a processor to realize the steps in each method embodiment.

[0106] The embodiment of the present application provides a computer program product, when the computer program product runs on an electronic device, so that the electronic device executes to realize the steps in each method embodiment.

[0107] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer readable storage medium. Based on such understanding, the present application realizes all or part of the processes in the above-mentioned embodiment methods, which can be completed by a computer program instructing related hardware, and the computer program can be stored in a computer readable storage medium. The computer program can realize the steps in each method embodiment when executed by a processor. The computer program includes computer program code, which can be in the form of source code, object code, executable file or some intermediate form. The computer readable medium at least includes any entity or device capable of carrying the computer program code to the photographing device / terminal equipment, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium. For example, U disk, mobile hard disk, magnetic disk or optical disk, etc. In some jurisdictions, according to legislation and patent practice, the computer readable medium cannot be an electrical carrier signal and a telecommunication signal.

[0108] In the above embodiments, the description of each embodiment has its own focus, and the parts not described or recorded in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0109] Those skilled in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.

Claims

1. A method for orbit error estimation and update imaging based on high orbit SAR image self-focusing, characterized in that, The method comprises the following steps: synthetic aperture radar (SAR) echo data is divided into multiple sub-aperture echo data according to sub-aperture division; each distance sub-scene is imaged according to the sub-aperture echo data, and full-aperture phase error of each distance sub-scene is determined according to a distance sub-scene image, wherein all the distance sub-scenes constitute an imaging scene to be observed; three-dimensional error of an orbit is inversed according to the full-aperture phase error; updated orbit data is obtained by updating the orbit data according to the three-dimensional error, and a detection image is obtained by imaging according to the updated orbit data; wherein the determination of the full-aperture phase error of each distance sub-scene according to the distance sub-scene image comprises: the maximum contrast phase error of each sub-aperture in the distance sub-scene is calculated by using a maximum contrast autofocusing method according to the sub-scene image; the maximum contrast phase errors of all the sub-apertures in the same distance sub-scene are spliced, and the gradient of each maximum contrast phase error is calculated according to the spliced maximum contrast phase error; the linear component of the gradient of the maximum contrast phase error is determined according to the gradient of the maximum contrast phase error of the overlapping pulses of two adjacent sub-apertures in the same distance sub-scene; the full-aperture phase error of the distance sub-scene is obtained by coherently combining the maximum contrast phase error according to the linear component; wherein the inversion of the three-dimensional error of the orbit according to the full-aperture phase error comprises: the three-dimensional error of the orbit is inversed by using a least square method according to the full-aperture phase error of each distance sub-scene; the three-dimensional error of the orbit satisfies the following formula: wherein, is an azimuthal time instant, is a three-dimensional error of the orbit, is an instantaneous unit vector from the antenna phase center to the center of all the range sub-scenarios at each azimuthal time instant, is a wavelength, is a full-aperture phase error matrix, a kth column vector of the full-aperture phase error matrix being a full-aperture phase error of the kth range sub-scenario.

2. The method of claim 1, wherein, the division of the SAR echo data according to sub-aperture to obtain multiple sub-aperture echo data comprises: pulse compression processing is performed on the SAR echo data to obtain pulse-compressed SAR echo data; the pulse-compressed SAR echo data is divided into sub-aperture SAR echo data according to sub-aperture division; point multiplication is performed on the pulse-compressed sub-aperture SAR echo data and a window function to obtain the sub-aperture echo data.

3. The method of claim 1, wherein, the updating of the orbit data according to the three-dimensional error to obtain updated orbit data comprises: the three-dimensional error compensation is subtracted from the orbit data to obtain the updated orbit data.

4. The method according to any one of claims 1 to 3, characterized in that, The distance sub-scene is obtained by uniformly and equidistantly dividing the imaging scene to be observed.

5. An orbit error estimation and update imaging device based on high orbit SAR image self-focusing, characterized in that, The method comprises the following steps: an echo data processing module is configured to divide SAR echo data into multiple sub-aperture echo data according to sub-aperture division; a full-aperture phase error estimation module is configured to image each distance sub-scene according to the sub-aperture echo data, and determine full-aperture phase error of each distance sub-scene according to a distance sub-scene image, wherein all the distance sub-scenes constitute an imaging scene to be observed; an orbit three-dimensional error inversion module is configured to inverse three-dimensional error of an orbit according to the full-aperture phase error; an orbit updating module, configured to update orbit data according to the three-dimensional error compensation to obtain updated orbit data; a detection imaging module, configured to perform imaging according to the updated orbit data to obtain a detection image; wherein the full-aperture phase error estimation module is specifically configured to: calculate a maximum contrast phase error of each sub-aperture in a distance sub-scene according to the sub-scene image by using a maximum contrast autofocusing method; splice maximum contrast phase errors of all sub-apertures in the same distance sub-scene, and calculate a gradient of each maximum contrast phase error according to the spliced maximum contrast phase errors; determine a linear component of the gradient of the maximum contrast phase error according to the gradient of the maximum contrast phase error of the overlapping pulse of the adjacent two sub-apertures in the same distance sub-scene; coherently combine the maximum contrast phase error according to the linear component to obtain a full-aperture phase error of the distance sub-scene; wherein the orbit three-dimensional error inversion module is specifically configured to: invert the three-dimensional error of the orbit by using a least square method according to the full-aperture phase error of each distance sub-scene; the three-dimensional error of the orbit satisfies the following formula: wherein, is an azimuthal time instant, is a three-dimensional error of the orbit, is an instantaneous unit vector from the antenna phase center to the center of all the range sub-scenarios at each azimuthal time instant, is a wavelength, is a full-aperture phase error matrix, a kth column vector of the full-aperture phase error matrix being a full-aperture phase error of the kth range sub-scenario.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory, characterized in that the processor executes the computer program to implement the method of any one of claims 1-4.

7. A computer-readable storage medium storing a computer program, wherein the computer program comprises the following steps of: receiving a request for a resource from a client; determining whether the client is authorized to access the resource; and if the client is authorized to access the resource, providing the resource to the client. the computer program is executed by the electronic device to implement the method of any one of claims 1-4.

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