Synthetic aperture radar integrated imaging method and device

Abstract

The present invention provides a synthetic aperture radar integrated imaging method and device, and relates to the field of synthetic aperture radar imaging. The synthetic aperture radar integrated imaging method comprises: receiving echo data of a synthetic aperture radar, wherein the echo data comprises scanning mode echo data and progressive scanning mode echo data; performing azimuth preprocessing on the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics; performing range processing on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics; performing azimuth pulse pressure processing on the scanning mode echo data and the progressive scanning mode echo data after range processing, so as to obtain an integrated imaging image of the synthetic aperture radar.

Description

Technical Field

[0001] The present invention relates to the field of synthetic aperture radar (SAR) imaging, and in particular to a SAR integrated imaging method and a device thereof. Background Art

[0002] Synthetic aperture radar has the ability to work all day and all weather, and is an important microwave remote sensing method. According to different imaging modes, it can be divided into scanning mode synthetic aperture radar (Scanning Synthetic Aperture Radar, Scan SAR), progressive scanning mode synthetic aperture radar (Terrain Observation by Progressive ScanSAR, TOPS SAR), etc. Figure 1 As shown in the figure, Scan SAR obtains a wide range width by periodically switching the beam in the range direction, and still uses the strip mode in the azimuth direction. Because Scan SAR uses a discontinuous Burst working mode, the antenna azimuth gain obtained by the target is inconsistent, resulting in a scallop effect in the azimuth direction of the SAR image. Figure 2 As shown in the figure, TOPSSAR controls the main lobe of the beam to point to a fixed rotation center based on Scan SAR. This mode also works in Burst mode, but during its operation, the antenna beam not only swings and irradiates alternately along the range direction, but also scans from back to front along the azimuth direction at the same time, so that all targets can obtain the same antenna gain, thus eliminating the scallop effect.

[0003] Scan SAR works in Burst mode. Although this mode expands the range mapping bandwidth, it has the problem of azimuth echo output time aliasing. The center frequencies of targets in different azimuth positions in Scan SAR echoes are different, so theoretically each target requires a different azimuth matched filter. If this is done, the imaging efficiency will be extremely low. TOPSSAR also works in Burst mode and also has the problem of echo azimuth output time aliasing. In addition, due to the change of Doppler center caused by active scanning of azimuth beam, its Doppler spectrum will be tilted compared to Scan SAR, resulting in the Doppler bandwidth being much larger than the pulse sampling frequency, which in turn causes aliasing of the azimuth spectrum. Therefore, the echo data of TOPS SAR and Scan SAR have different spectral characteristics, and the echoes of the two modes require two specific algorithms to achieve high-efficiency and unambiguous imaging.

[0004] Existing Scan SAR generally uses spectral analysis algorithm (SPECAN) or extended chirp scaling (ECS) algorithm for imaging, while TOPS SAR generally needs to be processed by Deramp and then use the improved CS algorithm to achieve imaging. Therefore, different imaging programs need to be switched when imaging SAR of different modes, that is, the imaging programs of Scan SAR and TOPS SAR are not compatible. Summary of the invention

[0005] In view of this, the embodiment of the present invention provides a synthetic aperture radar integrated imaging method and device, which can realize integrated imaging processing of TOPS SAR and Scan SAR modes to solve the problem that the imaging programs of Scan SAR and TOPS SAR are not compatible. At the same time, the existing TOPS imaging algorithm is simplified, the algorithm compatibility and processing efficiency are improved, the development cost is reduced, and the real-time imaging requirements of synthetic aperture radar can be met.

[0006] According to one aspect of the present invention, a synthetic aperture radar integrated imaging method is provided, comprising: receiving echo data of a synthetic aperture radar, wherein the echo data comprises scanning mode echo data and progressive scanning mode echo data; performing azimuth preprocessing on the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics; performing range processing on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics; performing azimuth pulse pressure processing on the scanning mode echo data and the progressive scanning mode echo data after the range processing, so as to obtain an integrated imaging image of the synthetic aperture radar.

[0007] In some embodiments, the range processing of the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics comprises: synchronously performing range processing on the scanning mode echo data and the progressive scanning mode echo data in a unified processing manner; the azimuth pulse pressure processing of the scanning mode echo data and the progressive scanning mode echo data after the range processing comprises: synchronously performing azimuth pulse pressure processing on the scanning mode echo data and the progressive scanning mode echo data after the range processing in a unified processing manner.

[0008] In some embodiments, the azimuth preprocessing of the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics includes: compressing the spectrum of the progressive scanning mode echo data in a specific area; performing azimuth fast Fourier transform on the compressed progressive scanning mode echo data; and performing azimuth time axis and frequency axis transformation on the progressive scanning mode echo data after the azimuth fast Fourier transform.

[0009] In some embodiments, compressing the spectrum of the progressive scanning mode echo data in a specific area includes: compressing the spectrum of the progressive scanning mode echo data in a specific area by multiplying the progressive scanning mode echo data with a reference signal.

[0010] In some embodiments, before performing azimuth fast Fourier transform on the compressed progressive scanning mode echo data, the method further includes: padding a portion of azimuth point numbers of the progressive scanning mode echo data with zeros.

[0011] In some embodiments, the range processing of the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectral characteristics includes: performing azimuth fast Fourier transform on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectral characteristics, and then multiplying the data by a linear frequency modulation scaling function to obtain scanning mode echo data and progressive scanning mode echo data with linear frequency modulation scaling; performing range fast Fourier transform on the scanning mode echo data and the progressive scanning mode echo data with linear frequency modulation scaling, and then multiplying the data by a range compression function to obtain scanning mode echo data and progressive scanning mode echo data with range compression; performing range inverse Fourier transform on the scanning mode echo data and the progressive scanning mode echo data with range compression, and then multiplying the data by a phase compensation function to obtain scanning mode echo data and progressive scanning mode echo data with phase compensation.

[0012] In some embodiments, the performing azimuth pulse pressure processing on the scanning mode echo data and the progressive scanning mode echo data after range processing to obtain the integrated imaging image of the synthetic aperture radar comprises: performing azimuth inverse Fourier transform on the scanning mode echo data and the progressive scanning mode echo data after range processing, and then multiplying the transformed data by a de-skew function to obtain de-skewed scanning mode echo data and progressive scanning mode echo data; performing azimuth Fourier transform on the de-skewed scanning mode echo data and the progressive scanning mode echo data to obtain the integrated imaging image of the synthetic aperture radar.

[0013] According to another aspect of the present invention, a synthetic aperture radar integrated imaging device is provided, comprising: a data receiving module, configured to receive echo data of a synthetic aperture radar, wherein the echo data comprises scanning mode echo data and progressive scanning mode echo data; an azimuth preprocessing module, connected to the data receiving module, the azimuth preprocessing module being configured to perform azimuth preprocessing on the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics; a range processing module, connected to the azimuth preprocessing module, the range processing module being configured to perform range processing on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics; an azimuth pulse compression module, connected to the range processing module, the azimuth pulse compression module being configured to perform azimuth pulse compression processing on the scanning mode echo data and the progressive scanning mode echo data after range processing to obtain an integrated imaging image of the synthetic aperture radar.

[0014] In some embodiments, the data receiving module is connected to the azimuth preprocessing module and the range processing module at the same time, and the data receiving module is also configured to transmit the scanning mode echo data to the range processing module for processing, and transmit the progressive scanning mode echo data to the azimuth preprocessing module for processing.

[0015] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of synthetic aperture radar imaging using Scan mode in the prior art.

[0017] Figure 2 It is a schematic diagram of synthetic aperture radar imaging using TOPS mode in the prior art.

[0018] Figure 3 The flowchart of the synthetic aperture radar integrated imaging method according to an embodiment of the present invention is schematically shown.

[0019] Figure 4 The structural block diagram of a synthetic aperture radar integrated imaging device according to an embodiment of the present invention is schematically shown.

[0020] Figure 5 The following schematically shows a flow chart of a synthetic aperture radar integrated imaging method according to yet another embodiment of the present invention.

[0021] Figure 6The plane geometry diagram of the synthetic aperture radar using the TOPS mode imaging according to an embodiment of the present invention is schematically shown.

[0022] Figure 7 Schematically shows Figure 6 The azimuth spectrum diagram of the echo data of TOPS mode imaging before azimuth preprocessing is shown.

[0023] Figure 8 Schematically shows Figure 6 The azimuth spectrum diagram of the echo data of TOPS mode imaging after azimuth preprocessing is shown.

[0024] Fig. 9 The azimuth frequency spectrum diagram of echo data imaged by a synthetic aperture radar in Scan mode according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0025] In order to more clearly explain the purpose, technical solutions and advantages of the present invention, the embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings. It should be understood that the following description of the embodiments is intended to explain and illustrate the overall concept of the present invention, and should not be understood as limiting the present invention. In the specification and the drawings, the same or similar reference numerals refer to the same or similar parts or components. For the sake of clarity, the drawings are not necessarily drawn to scale, and some well-known parts and structures may be omitted in the drawings.

[0026] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. The wording "one" or "an" does not exclude multiple. "Including" or "comprising" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top" or "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0027] Figure 3 The flowchart of the synthetic aperture radar integrated imaging method according to an embodiment of the present invention is schematically shown.

[0028] like Figure 3 As shown, in this embodiment, a synthetic aperture radar integrated imaging method may include steps S10 to S40:

[0029] In step S10 , the echo data of the synthetic aperture radar is received, wherein the echo data includes scanning mode echo data and progressive scanning mode echo data.

[0030] In this article, the scanning mode echo data refers to the echo data received in the Scan SAR mode, and the progressive scanning mode echo data refers to the echo data received in the TOPS SAR mode.

[0031] In step S20, azimuth preprocessing is performed on the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics.

[0032] In step S30, range processing is performed on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics.

[0033] In step S40, pulse compression processing is performed in azimuth direction on the scanning mode echo data and the progressive scanning mode echo data after range processing to obtain an integrated imaging image of the synthetic aperture radar.

[0034] Through the embodiments of the present invention, integrated imaging processing of TOPS SAR and Scan SAR can be realized to solve the problem that the imaging programs of Scan SAR and TOPS SAR are not compatible. At the same time, the existing TOPS imaging algorithm is simplified, the algorithm compatibility and processing efficiency are improved, the development cost is reduced, and the real-time imaging requirements of synthetic aperture radar can be met.

[0035] Figure 4 The structure block diagram of the synthetic aperture radar integrated imaging device according to an embodiment of the present invention is schematically shown. Figure 4 As shown, the synthetic aperture radar integrated imaging device 100 may include a data receiving module 10, an azimuth preprocessing module 20, a range processing module 30, and an azimuth pulse compression module 40. The data receiving module 10 may be used to perform the above step S10, the azimuth preprocessing module 20 may be used to perform the above step S20, the range processing module 30 may be used to perform the above step S30, and the azimuth pulse compression module 40 may be used to perform the above step S40. The synthetic aperture radar integrated imaging device 100 has the same technical features and beneficial effects as the synthetic aperture radar integrated imaging method, so it will not be repeated.

[0036] Figure 5 The following schematically shows a flow chart of a synthetic aperture radar integrated imaging method according to yet another embodiment of the present invention. Figure 6 The plane geometry diagram of the synthetic aperture radar using the TOPS mode imaging according to an embodiment of the present invention is schematically shown. Figure 7Schematically shows Figure 6 The azimuth spectrum diagram of the echo data of TOPS mode imaging before azimuth preprocessing is shown. Figure 8 Schematically shows Figure 6 The azimuth spectrum diagram of the echo data of TOPS mode imaging after azimuth preprocessing is shown. Fig. 9 The azimuth frequency spectrum diagram of echo data imaged by a synthetic aperture radar in Scan mode according to an embodiment of the present invention is schematically shown.

[0037] like Figure 5 As shown, the data receiving module 10 is configured to receive the echo data of the synthetic aperture radar SAR, wherein the echo data includes the scanning mode echo data and the progressive scanning mode echo data. The scanning mode echo data is the echo data received in the ScanSAR mode, and the progressive scanning mode echo data is the echo data received in the TOPS SAR mode. The beam scanning modes of ScanSAR and TOPS SAR are different, and the SAR echo data received in the two modes have different Doppler spectrum characteristics, such as Figure 7 and Fig. 9 As shown in the figure, the azimuth spectra of TOPS mode echo data and Scan mode echo data are respectively plotted. It can be seen that the TOPS mode echo data has the problems of azimuth output time aliasing of Scan mode echo data and Doppler spectrum aliasing of beamforming mode echo data. Judging and distinguishing echo data according to imaging mode can solve the azimuth spectrum aliasing problem of TOPS mode echo data before unifying the TOPS mode echo data and Scan mode echo data.

[0038] In some embodiments, the SAR echo data received by the data receiving module 10 may include an imaging mode description of the echo data, and the SAR echo data may be transmitted to different processing modules according to the imaging mode description. In other words, the data receiving module 10 may also have the function of judging the echo data mode.

[0039] As an example, some of the received SAR echo data are acquired through Scan SAR, and some of the echo data are acquired through TOPS SAR. The imaging mode descriptions are recorded in the auxiliary files of these echo data. The data receiving module 10 can quickly identify these imaging mode descriptions and transmit the SAR echo data of different imaging modes to the corresponding modules through different interfaces or paths for processing, thereby improving the efficiency of echo data recognition and processing.

[0040] like Figure 5As shown, the azimuth preprocessing module 20 can be connected to the data receiving module 10, and the azimuth preprocessing module 20 is configured to perform azimuth preprocessing on the TOPS mode echo data so that the TOPS mode echo data and the Scan mode echo data have the same azimuth spectrum characteristics for subsequent unified processing. In some embodiments, the azimuth preprocessing on the TOPS mode echo data may include: first compressing the spectrum of the TOPS mode echo data in a specific area, then performing azimuth fast Fourier transform on the compressed TOPS mode echo data, and then performing azimuth time axis and frequency axis transformation on the TOPS mode echo data after the azimuth fast Fourier transform. By simplifying the preprocessing steps of the TOPS mode echo data, the tediousness of azimuth back-processing is avoided, and the problem of azimuth spectrum aliasing of the TOPS mode echo data can be eliminated, so that the subsequent algorithm for processing the TOPS mode echo data and the algorithm for processing the Scan mode echo data can be combined.

[0041] In some embodiments, before performing azimuth fast Fourier transform on the compressed TOPS mode echo data, some azimuth point numbers of the TOPS mode echo data may be padded with zeros to comply with the Nyquist theorem, i.e., to restore the original signal from the sampled signal without distortion, the sampling frequency should be greater than 2 times the highest signal frequency.

[0042] Combine the following Figure 5 , Figure 6 , Figure 7 , Figure 8 , Fig. 9 To further illustrate the process of orientation preprocessing.

[0043] like Figure 6 As shown in the plane geometry diagram of synthetic aperture radar SAR imaging using TOPS mode, R rot =V s / ω r Indicates the shortest distance from the virtual rotation center to the ground, V s represents the azimuth flight speed of the synthetic aperture radar SAR platform, ω r represents the beam rotation angular velocity, R s It represents the shortest slant distance from the synthetic aperture radar SAR platform to the target. Figure 7 As shown in the azimuth spectrum diagram of TOPS mode echo data, represents the azimuth time, f η It indicates the azimuth Doppler frequency. It can be seen that the Doppler center of the TOPS mode echo data changes with the azimuth time, and the Doppler center change frequency can be expressed as: .

[0044] like Figure 5As shown, in this embodiment, a reference signal Sref ( ), the reference signal Sref( ) is multiplied with the TOPS mode echo data, thereby compressing the spectrum of the TOPS mode echo data into a specific area, which is usually a smaller area.

[0045] As an example, the reference signal Sref( ) can be obtained according to the following formula:

[0046]

[0047] Wherein, λ represents the wavelength of the echo data.

[0048] Next, the number of partial azimuth points of the TOPS mode echo data compressed in a smaller area may be appropriately filled with zeros.

[0049] As an example, the zero padding can be calculated using the following formula:

[0050]

[0051] Among them, N a Indicates the number of azimuth points of TOPS mode echo data, △N a represents the number of zero padding, PRF represents the sampling frequency, B d =2V s / D a , D a is the antenna aperture in azimuth. Indicates rounding up.

[0052] Then, the zero-filled TOPS mode echo data is subjected to azimuth fast Fourier transform (FFT). Transformed to '.

[0053] To this end, a new azimuth frequency variable f is introduced η ', with 'Corresponding. The new azimuth sampling interval △ ' can be expressed as:

[0054]

[0055] After the transformation, the new sampling frequency PRF' can be expressed as:

[0056]

[0057] According to the Nyquist theorem, the new sampling frequency PRF' should be no less than B d .

[0058] In this way, the azimuth spectrum processing of TOPS mode echo data can be realized, and the azimuth spectrum diagram of the processed TOPS mode echo data can be shown as follows: Figure 8 It can be seen that the signal processed by the azimuth preprocessing module 20 is not aliased in the new frequency axis.

[0059] The azimuth spectrum of the Scan mode echo data can be shown as Fig. 9 As shown in the figure, the echo data in Scan mode does not need azimuth preprocessing and is the received original echo data. Figure 8 and Fig. 9 It can be seen that the TOPS mode echo data after azimuth preprocessing and the original Scan mode echo data have the same azimuth spectrum characteristics, so they can be processed uniformly in the subsequent imaging processing flow.

[0060] Please continue reading Figure 5 , the range processing module 30 can be connected to the azimuth preprocessing module 20, and the range processing module 30 is configured to perform range processing on the Scan mode echo data and the TOPS mode echo data having the same azimuth spectrum characteristics. In this embodiment, the data receiving module 10 can also be directly connected to the range processing module 30, so that the data receiving module 10 directly transmits the Scan mode echo data to the range processing module 30 for processing. In some embodiments, the Scan mode echo data and the TOPS mode echo data can be synchronously processed in the range in a unified processing manner. Through the unified processing method, the processing flow of the TOPS mode echo data and the Scan mode echo data can be integrated, and only one set of programs can be used to process the echo data of the two modes at the same time, thereby reducing the development cost and improving the imaging efficiency.

[0061] like Figure 5 As shown, the range processing module 30 can perform range processing on the Scan mode echo data and the TOPS mode echo data having the same azimuth spectrum characteristics based on the CS algorithm. Specifically, the process may include the following:

[0062] First, after performing azimuth FFT on the Scan mode echo data and TOPS mode echo data with the same azimuth spectrum characteristics, they can be multiplied by the chirp scaling function H1 to obtain the chirp-scaling Scan mode echo data and TOPS mode echo data. In this way, the range migration trajectories of all targets can be made consistent.

[0063] As an example, the linear frequency modulation scaling function H1 can be obtained according to the following formula:

[0064]

[0065] Where H1 represents the linear frequency modulation scaling function, f η represents the azimuth Doppler frequency, a scl (f η ) represents the scaling factor, a scl (f η )=1 / β(f η )-1,β(f η ) represents the migration parameter, , c represents the speed of light, R ref represents the reference slant range, R0 represents the shortest slant range from a point target to the synthetic aperture radar platform, and the more accurate hyperbolic equation in the Doppler domain R(f η ;R0)=R0 / β(f η ), the original range modulation frequency k r The distance-azimuth coupling of the received signal will also change with distance: .

[0066] Next, the linear frequency modulated Scan mode echo data and TOPS mode echo data are subjected to range FFT and multiplied by the range compression function H2 to obtain range compressed Scan mode echo data and TOPS mode echo data. In this way, range compression, secondary range compression and consistent range migration correction can be achieved.

[0067] As an example, the range compression function is given by the following formula:

[0068]

[0069] Among them, H2 represents the distance compression function, f r Indicates the distance frequency.

[0070] Then, the range-compressed Scan mode echo data and TOPS mode echo data are inversely transformed in the range direction and multiplied by the phase compensation function H3 to obtain the phase-compensated Scan mode echo data and TOPS mode echo data. In this way, the additional phase introduced by the variable scaling can be offset.

[0071] As an example, the phase compensation function is given by the following formula:

[0072]

[0073] Where H3 represents the phase compensation function, The additional phase introduced by the variable scale can be expressed as: .

[0074] Thus, the range processing of the Scan mode echo data and the TOPS mode echo data is completed. After the range processing, the signal has been focused in the range direction, and the azimuth pulse pressure can be performed next.

[0075] Please continue reading Figure 5 The azimuth pulse compression module 40 is connected to the range processing module 30. The azimuth pulse compression module 40 is configured to perform azimuth pulse compression processing on the Scan mode echo data and the TOPS mode echo data after the range processing to obtain an integrated imaging image of the synthetic aperture radar. In some embodiments, the azimuth pulse compression processing can be performed synchronously on the Scan mode echo data and the TOPS mode echo data after the range processing in a unified processing manner. The advantages of using a unified processing method have been described in the previous text, so they will not be repeated here.

[0076] like Figure 5 As shown, the azimuth pulse compression module 40 can perform azimuth pulse compression processing on the Scan mode echo data and the TOPS mode echo data after range processing based on the spectrum analysis (SPECAN) algorithm to obtain an integrated imaging image of the synthetic aperture radar. Specifically, it may include the following process:

[0077] First, the Scan mode echo data and TOPS mode echo data processed in the range direction can be subjected to IFFT in the azimuth direction and multiplied by the de-skewing function H4 to obtain de-skewing Scan mode echo data and TOPS mode echo data. In this way, the azimuth signal can be converted into a single-frequency sinusoidal signal, and targets at different azimuth positions correspond to different frequencies.

[0078] As an example, the de-skewing function H4 may be derived according to the following formula:

[0079]

[0080] Then, the de-skewing Scan mode echo data and TOPS mode echo data are subjected to azimuth FFT. After de-skewing, the azimuth FFT is performed and the target is compressed to the frequency k. a η c In the corresponding frequency unit, k a represents the azimuth linear modulation rate, η c Indicates the zero Doppler moment of the target.

[0081] Through the above embodiment, the SPECAN method is used to perform directional pulse compression, and the azimuth is finally focused in the frequency domain, avoiding the aliasing problem of time domain output.

[0082] At this point, the technical solution of the present invention has been described, and the integrated imaging image of the synthetic aperture radar can be finally obtained, that is, the integrated imaging processing of Scan SAR and TOPS SAR is completed. Through the data receiving, azimuth preprocessing, range processing and azimuth pulse compression process of the above embodiment, the present invention improves the original TOPS SAR azimuth variable calibration imaging algorithm, omits the "spectrum recovery" step in the preprocessing stage, avoids time aliasing, and thus can avoid the original post-processing step, making the azimuth pulse compression simple and compatible with the imaging algorithm of Scan SAR. The imaging processing of the two modes can be completed with a set of programs, reducing the development cost and achieving a good focusing effect.

[0083] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0084] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A synthetic aperture radar integrated imaging method, characterized in that: include: Receiving echo data of a synthetic aperture radar, wherein the echo data includes scanning mode echo data and progressive scanning mode echo data; The progressive scanning mode echo data is subjected to azimuth preprocessing so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics; the progressive scanning mode echo data is subjected to azimuth preprocessing so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics, comprising: compressing the spectrum of the progressive scanning mode echo data in a specific area; performing azimuth fast Fourier transform on the compressed progressive scanning mode echo data; performing azimuth time axis and frequency axis transformation on the progressive scanning mode echo data after azimuth fast Fourier transform; Performing range processing on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics; The scanning mode echo data and the progressive scanning mode echo data processed in the range direction are subjected to pulse compression processing in the azimuth direction to obtain an integrated imaging image of the synthetic aperture radar.

2. The integrated imaging method according to claim 1, characterized in that: The range-direction processing of the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics comprises: synchronously performing range processing on the scanning mode echo data and the progressive scanning mode echo data in a unified processing manner; The step of performing azimuth pulse pressure processing on the scanning mode echo data and the progressive scanning mode echo data after range processing includes: The azimuth pulse pressure processing is synchronously performed on the scanning mode echo data and the progressive scanning mode echo data after the range processing in a unified manner.

3. The integrated imaging method according to claim 1, characterized in that: The compressing the spectrum of the progressive scanning mode echo data in a specific area includes: By multiplying the progressive scanning mode echo data with a reference signal, the frequency spectrum of the progressive scanning mode echo data is compressed in a specific area.

4. The integrated imaging method according to claim 1 or 2, characterized in that: Before performing azimuth fast Fourier transform on the compressed progressive scanning mode echo data, the method further includes: Zero padding is performed on some azimuth point numbers of the progressive scanning mode echo data.

5. The integrated imaging method according to claim 1, characterized in that: The range-direction processing of the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics comprises: After performing azimuth fast Fourier transform on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics, multiplying them by a linear frequency modulation scaling function to obtain linear frequency modulation scaled scanning mode echo data and progressive scanning mode echo data; After performing range-direction fast Fourier transform on the linear frequency modulation-scaled scanning mode echo data and the progressive scanning mode echo data, the data are multiplied by a range-direction compression function to obtain range-direction compressed scanning mode echo data and the progressive scanning mode echo data; After performing inverse Fourier transform in the range direction on the range-compressed scanning mode echo data and the progressive scanning mode echo data, the data are multiplied by a phase compensation function to obtain phase-compensated scanning mode echo data and progressive scanning mode echo data.

6. The integrated imaging method according to claim 1, characterized in that: The step of performing azimuth pulse compression processing on the scanning mode echo data and the progressive scanning mode echo data after range processing to obtain an integrated imaging image of the synthetic aperture radar includes: After performing inverse Fourier transform in azimuth on the range-processed scanning mode echo data and the progressive scanning mode echo data, multiplying the data by a de-skewing function to obtain de-skewed scanning mode echo data and progressive scanning mode echo data; The de-slanted scanning mode echo data and the progressive scanning mode echo data are subjected to azimuth Fourier transform to obtain an integrated imaging image of the synthetic aperture radar.

7. A synthetic aperture radar integrated imaging device, characterized in that: include: A data receiving module is configured to receive echo data of a synthetic aperture radar, wherein the echo data includes scanning mode echo data and progressive scanning mode echo data; The azimuth preprocessing module is configured to perform azimuth preprocessing on the progressive scanning mode echo data so that the progressive scanning mode echo data and the scanning mode echo data have the same azimuth spectrum characteristics; the azimuth preprocessing module is further configured to compress the spectrum of the progressive scanning mode echo data in a specific area; perform azimuth fast Fourier transform on the compressed progressive scanning mode echo data; perform azimuth time axis and frequency axis transformation on the progressive scanning mode echo data after azimuth fast Fourier transform; A range processing module, configured to perform range processing on the scanning mode echo data and the progressive scanning mode echo data having the same azimuth spectrum characteristics; The azimuth pulse compression module is configured to perform azimuth pulse compression processing on the scanning mode echo data and the progressive scanning mode echo data after range processing to obtain an integrated imaging image of the synthetic aperture radar.

8. The integrated imaging device according to claim 7, characterized in that: The data receiving module is connected to the azimuth preprocessing module and the range processing module at the same time, and is also configured to transmit the scanning mode echo data to the range processing module for processing, and transmit the progressive scanning mode echo data to the azimuth preprocessing module for processing.

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