Synthetic aperture radar echo signal processing method and device

Abstract

The invention provides a synthetic aperture radar echo signal processing method and device. The method comprises the following steps: extracting initial parameters based on satellite orbit and attitude information data; pre-correcting an original echo signal according to the initial parameter to obtain a pre-corrected echo signal; performing range gain compensation and azimuth directional diagram compensation based on the pre-corrected echo signal to obtain a compensated echo signal; and performing imaging gain correction on the compensated echo signal to obtain a corrected echo signal. Influences of transmitting power, receiver gain, ADC gain and system noise can be compensated at the same time, and radiation consistency correction is realized in combination with distance direction and azimuth direction antenna directional diagrams.

Description

Technical Field

[0001] This invention relates to the field of radar signal processing, and in particular to a method and apparatus for processing synthetic aperture radar echo signals. Background Technology

[0002] Synthetic Aperture Radar (SAR), as an active imaging radar system, has the capability to acquire surface information in all weather and at all times, and is widely used in fields such as Earth observation, environmental monitoring, disaster early warning, and national defense. The radiometric consistency of SAR imaging results is highly dependent on the accuracy of system calibration and correction, with radiometric calibration being a crucial step in ensuring data reliability and comparability. The purpose of radiometric calibration is to eliminate uncertainties caused by changes in system characteristics and external environmental factors, thereby stably converting the echo signal into the target's backscattering coefficient and ensuring that calibration parameters remain constant.

[0003] However, existing SAR systems still face several challenges in radiometric calibration. First, the instability of system calibration parameters is a significant issue. For example, transmitter power fluctuates with time and temperature, receiver and analog-to-digital converter gains may drift, and differences in system noise power under different operating conditions further affect radiometric consistency. These instabilities directly lead to uneven brightness in SAR images, severely reducing radiometric consistency. Second, the radiation patterns of SAR antennas in the range and azimuth directions are not ideally flat. Variations in range gain due to differences in incident angles and the weighting effect of the azimuth pattern on the Doppler spectrum manifest as radiation fluctuations or even striping effects in the imaging results. These problems are particularly pronounced in wide-swath imaging modes (such as ScanSAR and TOPS), and without effective compensation, they will severely impact image quality and subsequent quantitative analysis.

[0004] Some existing methods address these issues by performing equalization or radiometric correction in the image domain. However, these methods tend to amplify noise and struggle to fully compensate for errors caused by system gain variations and antenna patterns, especially in imaging modes with significant sub-aperture differences. Furthermore, existing technologies lack a unified processing framework. This fragmented approach not only increases implementation complexity but also makes it difficult to ensure consistency and stability across different processing stages.

[0005] Therefore, there is an urgent need for a synthetic aperture radar echo signal processing method and apparatus to improve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a synthetic aperture radar echo signal processing method and apparatus that can perform radiometric calibration in the echo domain before imaging, and can simultaneously compensate for transmit power, receiver gain, ADC gain and system noise, and complete radiometric consistency correction in conjunction with antenna pattern.

[0007] In a first aspect, the present invention provides a synthetic aperture radar echo signal processing method, comprising the steps of: extracting initial parameters based on satellite orbit and attitude information data; pre-correcting the original echo signal according to the initial parameters to obtain a pre-corrected echo signal; performing range gain compensation and azimuth pattern compensation based on the pre-corrected echo signal to obtain a compensated echo signal; and performing imaging gain correction on the compensated echo signal to obtain a corrected echo signal.

[0008] Optionally, it also includes: performing absolute radiometric calibration on the corrected echo signal to obtain calibration constants.

[0009] Optionally, the initial parameters extracted based on satellite orbit and attitude information data include: obtaining the satellite's three-dimensional position, velocity, and attitude information by reading the satellite orbit and attitude information data file; calculating the elevation and azimuth angles of each pulse based on the satellite orbit; and extracting the transmit power, receiver gain, ADC gain, range antenna pattern, and azimuth antenna pattern from the radar system's auxiliary calibration file.

[0010] Optionally, the original echo signal is pre-corrected according to the initial parameters: the amplitude and phase errors of the original echo signal are estimated using a calibration signal to correct the original echo signal, and the received signal is gain-corrected according to the receiver gain and temperature correction factor.

[0011] Optionally, performing range gain compensation and azimuth pattern compensation based on the pre-corrected echo signal to obtain the compensated echo signal includes: performing range compression on the pre-corrected echo signal using a matched filter and compensating using a range gain compensation operator to obtain the compensated signal; performing a fast Fourier transform on the compensated signal to obtain the azimuth spectrum; and performing compensation based on the azimuth spectrum and the azimuth gain compensation factor to obtain the compensated echo signal.

[0012] Optionally, performing imaging gain correction on the compensated echo signal to obtain the corrected echo signal includes: converting the compensated signal to the frequency domain using a fast Fourier transform, calculating the gain factor of the matched filter and the white noise gain factor; adjusting the signal amplitude according to the gain factor and the white noise gain factor, and restoring the frequency domain signal to the time domain to obtain the corrected echo signal.

[0013] Secondly, the present invention provides an apparatus comprising modules / units for performing any of the possible designs described in the first aspect. These modules / units can be implemented in hardware or by hardware executing corresponding software.

[0014] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a program executable on the processor, and when the program is executed by the processor, the electronic device implements a method for performing any of the possible designs described above.

[0015] Fourthly, the present invention provides a readable storage medium storing a program, which, when executed, implements a method of any possible design of any of the above aspects.

[0016] Fifthly, the present invention provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0017] The beneficial effects of the method of this invention are as follows: initial parameters are extracted based on satellite orbit and attitude information data; the original echo signal is pre-corrected according to the initial parameters to obtain a pre-corrected echo signal; range gain compensation and azimuth pattern compensation are performed based on the pre-corrected echo signal to obtain a compensated echo signal; imaging gain correction is performed on the compensated echo signal to obtain a corrected echo signal. This method can simultaneously compensate for the effects of transmit power, receiver gain, ADC gain, and system noise, and achieve radiation consistency correction by combining range and azimuth antenna patterns. Attached Figure Description

[0018] Figure 1 A flowchart illustrating a method provided in an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the structure of a device provided in an embodiment of the present invention;

[0020] Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention;

[0021] Figure 4 This is a comparison chart of SAR radiometric calibration results provided in an embodiment of the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art. The terms "comprising" and similar expressions used herein mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, but do not exclude other elements or objects.

[0023] The technical solutions of the embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the embodiments of the present invention, the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to limit the present invention. The singular expressions “a,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise. It should also be understood that in the following embodiments of the present invention, “at least one” and “one or more” refer to one or more (including two). The term “and / or” is used to describe the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character “ / ” generally indicates that the preceding and following related objects are in an “or” relationship.

[0024] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of the invention. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," and "in still other embodiments" appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including, but not limited to," unless otherwise specifically emphasized. The term "connection" includes both direct and indirect connections, unless otherwise stated. "First" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0025] In embodiments of the present invention, "exemplarily" or "for example" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design described as "exemplarily" or "for example" in embodiments of the present invention should not be construed as being more preferred or advantageous than other embodiments or design solutions. Rather, the use of "exemplarily" or "for example" is intended to present the relevant concepts in a specific manner.

[0026] like Figure 1 As shown, the present invention provides a synthetic aperture radar echo signal processing method, including the following steps:

[0027] S101, initial parameters are extracted based on satellite orbit and attitude information data.

[0028] In some embodiments, the initial parameters are extracted based on satellite orbit and attitude information data, including: obtaining the three-dimensional position, velocity and attitude information of the satellite by reading the satellite orbit and attitude information data file; calculating the elevation angle and azimuth angle of each pulse according to the satellite orbit; and extracting the transmit power, receiver gain, ADC gain, range antenna pattern and azimuth antenna pattern from the radar system's auxiliary calibration file.

[0029] S102, the original echo signal is pre-corrected according to the initial parameters to obtain the pre-corrected echo signal.

[0030] In some embodiments, since gain mismatch or phase error may occur between I / Q channels during SAR reception, in order to ensure signal consistency and accuracy, the original echo signal is pre-corrected according to the initial parameters: the amplitude and phase error are estimated using a calibration signal to correct the original echo signal, and the received signal is gain corrected according to the receiver gain and temperature correction factor.

[0031] S103, perform range gain compensation and azimuth pattern compensation based on the pre-corrected echo signal to obtain the compensated echo signal.

[0032] In some embodiments, range gain compensation and azimuth pattern compensation are performed based on the pre-corrected echo signal to obtain the compensated echo signal. This includes: using a matched filter to compress the range direction of the pre-corrected echo signal to improve range resolution, and then using a range gain compensation operator to obtain the compensated signal, thereby eliminating the influence caused by antenna gain changes; performing a Fast Fourier Transform (FFT) on the compensated signal to obtain the azimuth spectrum; performing compensation based on the azimuth spectrum and the azimuth gain compensation factor to adjust the azimuth gain, and then recovering the time-domain signal through an inverse Fourier transform (IFFT) to obtain the compensated echo signal.

[0033] S104, perform imaging gain correction on the compensated echo signal to obtain the corrected echo signal.

[0034] In some embodiments, performing imaging gain correction on the compensated echo signal to obtain the corrected echo signal includes: converting the compensated signal to the frequency domain using a fast Fourier transform, calculating the gain factor of the matched filter and the white noise gain factor; adjusting the signal amplitude according to the gain factor and the white noise gain factor, and restoring the frequency domain signal to the time domain to obtain the corrected echo signal.

[0035] In some embodiments, the method further includes: performing absolute radiometric calibration on the corrected echo signal to obtain calibration constants, such as calculating the energy of a standard point target by means of an integral method or a peak method to obtain the total energy of the point target, and using the known scattering cross-section of the point target to calculate the calibration constants, thereby achieving radiometric calibration.

[0036] The advantages of the embodiments of the present invention are as follows:

[0037] (1) Comprehensive gain and pattern correction: Existing image domain methods can only perform local radiometric correction on the image after imaging, which is difficult to fully compensate for errors caused by changes in system gain and antenna pattern. In contrast, this invention comprehensively considers the changes in system gain, noise power and antenna gain through echo domain correction, especially for the difference in gain in range and azimuth, which greatly improves imaging quality and radiometric consistency.

[0038] (2) Reducing radiation fluctuations and striping effects: Traditional methods often exhibit radiation fluctuations and striping effects in wide-swath imaging modes, and these are difficult to compensate for effectively. Through unified compensation in the echo domain, this invention significantly reduces the occurrence of these effects, especially in wide-swath imaging modes, and can maintain high image quality and consistency.

[0039] (3) Enhanced data reliability and comparability: Since the present invention can perform comprehensive gain correction and radiometric calibration in the echo domain, it eliminates the uncertainty caused by changes in the external environment and system characteristics, and ensures that the echo signal is stably converted into the backscattering coefficient of the target, which greatly enhances the reliability and comparability of the data and meets the needs of high-precision data analysis.

[0040] To facilitate understanding, this embodiment further elaborates on the specific implementation process of the above method in conjunction with a specific application scenario, which includes the following steps:

[0041] Step 1: Input and Parameter Acquisition

[0042] Input satellite orbit and attitude data: First, obtain the satellite's three-dimensional position, velocity, and attitude information by reading the satellite orbit and attitude information data file.

[0043] Based on the satellite orbit information, the elevation and azimuth angles corresponding to each pulse are calculated. The azimuth angle calculation method is described in detail below:

[0044]

[0045] in, It is an oblique perspective. The instantaneous oblique angle is calculated using the following formula:

[0046]

[0047] in For radar wave wavelength, For Doppler frequency, For radar platform speed.

[0048] Pitch angle The calculation method is described in detail below:

[0049]

[0050] in, For flight altitude, From the beam center perspective, The nearest slope distance to the target point.

[0051] Obtain the auxiliary calibration file of the radar system and extract the transmit power. Receiver gain ADC gain and range-to-antenna radiation pattern and azimuth antenna pattern These calibration parameters are used for signal gain compensation, noise correction, and pattern correction to ensure the radiation consistency of the echo signal.

[0052] Step 2: Perform pre-correction on the raw echo data

[0053] During SAR reception, gain mismatch (amplitude error) or phase asymmetry (phase error) may exist between the I / Q channels, leading to signal distortion. To correct this imbalance, IQ imbalance correction (i.e., pre-correction) is required on the original echo signal. In a SAR system, to eliminate amplitude and phase errors in the I / Q channels, estimation is needed using a known calibration signal. Let the ideal amplitude of the calibration signal be... The received signal amplitude is Then the amplitude error It can be calculated using the following formula:

[0054]

[0055] Similarly, let the ideal phase of the calibration signal be... The received signal phase is Phase error It can be calculated using the following formula:

[0056]

[0057] Original received signal It can be represented as:

[0058]

[0059] in, and This is the original I / Q signal;

[0060] The corrected echo signal is:

[0061]

[0062] According to the ADC gain in the calibration file Correct the received signal:

[0063]

[0064] in, The image signal for temperature correction of receiver gain.

[0065] Let the temperature correction factor for the receiver gain be... Gain correction is performed based on changes in ambient temperature.

[0066]

[0067] in, The image signal with temperature correction for receiver gain (i.e., the pre-corrected echo signal).

[0068] Step 3: Range-direction gain compensation

[0069] First, range compression is performed on the pre-corrected echo signal to improve range resolution by compressing the received wide pulse signal into a narrow pulse, thus achieving high-resolution imaging. Matched filtering is used for pulse compression. Then, an FFT transform is performed on the echo signal.

[0070]

[0071] in, Represents FFT transformation, This is the range-frequency domain signal. Multiply the range-frequency domain signal by the frequency-domain matched filter of the transmitted signal.

[0072]

[0073] in, The frequency domain expression for the matched filter is as follows:

[0074]

[0075] in, This is the conjugate time reversal of the transmitted signal.

[0076] Then, an inverse FFT is performed to obtain the distance-compressed signal:

[0077]

[0078] Range-directed gain compensation operator As shown below:

[0079]

[0080] in: It is the antenna gain when the elevation angle is zero; It is the antenna's elevation angle at the target. Gain at that point.

[0081] Image signal compensation is performed using a range gain compensation operator:

[0082]

[0083] in, The image signal after range gain compensation (i.e., the compensated signal).

[0084] Step 4: Azimuth and Direction Map Compensation

[0085] For echo signal Perform a Fast Fourier Transform (FFT) to obtain the azimuth spectrum. .

[0086] Azimuth gain compensation factor The gain of the antenna in the azimuth direction is calculated using the following formula:

[0087]

[0088] in: It is the antenna in azimuth angle Gain at time; It is the antenna's elevation angle at the target. Gain at the location; It is the antenna in azimuth angle Gain at the location. Based on the azimuth gain compensation factor, azimuth pattern correction is performed on the Doppler image data to obtain the compensated image:

[0089]

[0090] Performing an IFFT on the azimuth spectrum to recover the time-domain signal yields the compensated echo signal. This ensures that the gain compensation in the azimuth direction is effective.

[0091] Step 5: Imaging Gain Correction

[0092] The compensated signal from step 4 is transformed to the frequency domain using FFT to obtain the signal. :

[0093]

[0094] For the power spectrum is The steady-state process of the system, the matched filter gain factor yes:

[0095]

[0096] The white noise gain factor is:

[0097]

[0098] The gain factor is used to adjust the signal amplitude, compensating for gain variations caused by the matched filter and white noise.

[0099]

[0100] in, This is the frequency domain signal after compensating for gain changes caused by the matched filter and white noise. Finally, the signal is restored to the time domain to obtain the corrected echo signal:

[0101]

[0102] Step 6: Absolute Radiation Calibration

[0103] The standard point target energy can be obtained using the integral method or the peak method.

[0104] The integration method primarily obtains the energy of a point target by integrating the impulse response over a specific region. Let the point target be an N x N region centered at the peak point. Let the number of pixels in the integration region be... The number of pixels in the background area is The pixel intervals in the azimuth and range directions are respectively Calculate the total energy of the point target within the integration region:

[0105]

[0106] in, This represents the intensity value of the i-th pixel.

[0107] The calibration constant is calculated based on the energy of the standard point target and its known scattering cross-section. The calculation method is as follows:

[0108]

[0109] in, The backscattering coefficients at a known point are... The angle of incidence is denoted as .

[0110] The calibration constants before and after compensation using this method were calculated using spaceborne SAR data, and the results are as follows: Figure 4 As shown, the stability of the SAR radiometric calibration constant is significantly improved by applying the method of this invention. Before compensation, the standard deviation of the calibration constant was 0.82 dB, with a fluctuation range of -22.16 dB to -18.65 dB. After compensation, the standard deviation of the calibration constant was reduced to approximately 0.20 dB, and the fluctuation range was reduced to -22.44 dB to -21.56 dB. The change in standard deviation indicates that the accuracy of the calibration constant is increased after compensation, demonstrating that the compensation method effectively reduces the instability caused by differences in system gain, noise, and antenna pattern, thereby achieving reliability and consistency in radiometric calibration.

[0111] like Figure 2As shown, based on the above method, the present invention provides a synthetic aperture radar echo signal processing device, comprising: an extraction unit 201, used to extract initial parameters based on satellite orbit and attitude information data; a pre-correction unit 202, used to pre-correct the original echo signal according to the initial parameters to obtain a pre-corrected echo signal; a compensation unit 203, used to perform range gain compensation and azimuth pattern compensation based on the pre-corrected echo signal to obtain a compensated echo signal; and a correction unit 204, used to perform imaging gain correction on the compensated echo signal to obtain a corrected echo signal.

[0112] It should be understood that all relevant content of each step involved in the above method embodiments can be referenced to the functional description of the corresponding functional module, and will not be repeated here. Furthermore, the use of suffixes such as "module," "component," or "unit" to represent elements is merely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "component," or "unit" can be used interchangeably. Terminals can be implemented in various forms. For example, the terminals described in this invention may include mobile terminals such as mobile phones, tablets, laptops, handheld computers, personal digital assistants (PDAs), portable media players (PMPs), navigation devices, wearable devices, smart bracelets, pedometers, etc., as well as fixed terminals such as digital TVs and desktop computers. The following description will use mobile terminals as examples; those skilled in the art will understand that, in addition to elements specifically designed for mobile purposes, the construction according to embodiments of the present invention can also be applied to fixed-type terminals.

[0113] In other embodiments of the present invention, an electronic device 300 is disclosed, such as... Figure 3 As shown, the device may include: one or more processors 301; memory 302; display 303; one or more application programs (not shown); and one or more computer programs 304. These devices can be connected via one or more communication buses 305. The one or more computer programs 304 are stored in the memory 302 and configured to be executed by the one or more processors 301. The one or more computer programs 304 include instructions that can be used to perform actions such as... Figure 1 Each step in the corresponding embodiment.

[0114] Processor 301 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0115] The memory 302 can be an internal storage unit of the electronic device 300, such as a hard disk or RAM of the electronic device 300. The memory 302 can also be an external storage device of the electronic device 300, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, or FlashCard equipped on the electronic device 300. Furthermore, the memory 302 can include both internal and external storage units of the electronic device 300. The memory 302 is used to store computer programs and other programs and data required by the electronic device. The memory 302 can also be used to temporarily store data that has been output or will be output.

[0116] The computer program 304 can be divided into one or more modules / units. The one or more modules / units can be a series of computer program instruction segments that can perform a specific function. The instruction segments are used to describe the execution process of the computer program 304 in the electronic device 300.

[0117] In addition to the above-described structure, those skilled in the art will understand that Figure 3 This is merely an example of electronic device 300 and does not constitute a limitation on electronic device 300. Electronic device 300 may include more or fewer components than shown, or combine certain components, or different components. For example, electronic device may also include input / output devices, network access devices, buses, etc.

[0118] Those skilled in the art will understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the functions described above can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this invention. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0119] Based on the above embodiments, the present invention also discloses a computer-readable storage medium having at least one computer program stored thereon, wherein the computer program, when executed by a processor, implements the methods described in the foregoing embodiments.

[0120] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing a processor. The program can be stored in a computer-readable storage medium, which is a non-transitory medium, such as random access memory, read-only memory, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disk, and any combination thereof. The storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. This available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., digital video disc (DVD)), or a semiconductor medium (e.g., solid-state drive (SSD)).

[0121] The descriptions of the processes or structures corresponding to the above figures each have their own emphasis. For parts of a process or structure that are not described in detail, please refer to the relevant descriptions of other processes or structures.

[0122] Although the embodiments of the present invention have been described in detail above, it will be apparent to those skilled in the art that various modifications and variations can be made to these embodiments. The above descriptions are merely embodiments of the present invention and do not limit the patent scope of the present invention. However, it should be understood that such modifications and variations fall within the scope and spirit of the present invention. Moreover, the present invention described herein may have other embodiments and can be implemented or realized in various ways. All equivalent transformations made based on the description and drawings of the present invention, or direct or indirect applications in related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for processing synthetic aperture radar echo signals, characterized in that, Including the following steps: Initial parameters are extracted based on satellite orbit and attitude information data; The original echo signal is pre-corrected according to the initial parameters to obtain the pre-corrected echo signal. Based on the pre-corrected echo signal, range gain compensation and azimuth pattern compensation are performed to obtain the compensated echo signal. The compensated echo signal is subjected to imaging gain correction to obtain the corrected echo signal.

2. The method according to claim 1, characterized in that, Also includes: The corrected echo signal is subjected to absolute radiometric calibration to obtain calibration constants.

3. The method according to claim 1 or 2, characterized in that, The initial parameters extracted from satellite orbit and attitude information data include: By reading the satellite orbit and attitude information data file, the satellite's three-dimensional position, velocity, and attitude information can be obtained; The elevation and azimuth angles of each pulse are calculated based on the satellite orbit, and the transmit power, receiver gain, ADC gain, range antenna pattern, and azimuth antenna pattern are extracted from the radar system's auxiliary calibration file.

4. The method according to claim 1, characterized in that, The original echo signal is pre-corrected based on the initial parameters: The original echo signal is corrected by estimating amplitude and phase errors using a calibration signal, while the received signal is gain-corrected based on receiver gain and temperature correction factors.

5. The method according to claim 1, characterized in that, Based on the pre-corrected echo signal, range gain compensation and azimuth pattern compensation are performed to obtain the compensated echo signal, which includes: The pre-corrected echo signal is compressed in the range direction using a matched filter and compensated using a range gain compensation operator to obtain the compensated signal. Perform a Fast Fourier Transform on the compensated signal to obtain the azimuth spectrum; The compensated echo signal is obtained by performing compensation based on the azimuth spectrum and azimuth gain compensation factor.

6. The method according to claim 5, characterized in that, The compensated echo signal is subjected to imaging gain correction to obtain the corrected echo signal, which includes: The compensated signal is converted to the frequency domain using a fast Fourier transform, and the gain factor of the matched filter and the white noise gain factor are calculated. The signal amplitude is adjusted according to the gain factor and white noise gain factor, and the frequency domain signal is restored to the time domain to obtain the corrected echo signal.

7. A synthetic aperture radar echo signal processing apparatus, used in the method according to any one of claims 1-6, characterized in that, include: The extraction unit is used to extract initial parameters based on satellite orbit and attitude information data; The pre-correction unit is used to pre-correct the original echo signal according to the initial parameters to obtain the pre-corrected echo signal. The compensation unit is used to perform range gain compensation and azimuth pattern compensation based on the pre-corrected echo signal to obtain the compensated echo signal. The correction unit is used to perform imaging gain correction on the compensated echo signal to obtain the corrected echo signal.

8. An electronic device, characterized in that, The device includes a memory and a processor, wherein the memory stores a program that can run on the processor, and when the program is executed by the processor, causes the electronic device to perform the method of any one of claims 1-6.

9. A readable storage medium storing a program, characterized in that, When the program is executed, it implements the method of any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the method of any one of claims 1-6.

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