CN118209984A - Space-based pair of air maneuvering target ISAR imaging method and device for jointly detecting priori information - Google Patents
Space-based pair of air maneuvering target ISAR imaging method and device for jointly detecting priori information Download PDFInfo
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Abstract
The invention discloses a space-based pair of air maneuvering target ISAR imaging method and equipment for jointly detecting priori information, and belongs to the technical field of radar imaging. Searching an air area containing a target by utilizing a narrow-band detection radar to obtain narrow-band detection point track information and target motion parameters; the radar is converted into a broadband imaging mode, and the radar is guided to keep the admission of the broadband imaging echo data of the target in the imaging period based on the target motion parameters; selecting a target stationary flight imaging echo data segment based on the narrow-band detection point track information; performing preliminary compensation on the target movement in the imaging period based on the target position and the Doppler speed; and performing target preliminary SAR imaging, and transforming the imaged data to a distance-pulse domain to perform envelope alignment and phase correction to obtain a target accurate ISAR imaging result. The invention can improve the signal-to-noise ratio, improve the envelope alignment and phase correction precision and improve the ISAR imaging quality of the space-based air maneuvering target.
Description
Technical Field
The invention belongs to the technical field of radar imaging, and particularly relates to a space-based pair of maneuvering target ISAR imaging method and equipment for jointly detecting priori information.
Background
The space-based radar is not limited by the sky and the sea, and is an effective means for realizing all-weather detection of high-value air targets outside the country. However, in order to achieve accurate hit of high-value targets in the air, accurate recognition of the targets in the air is required, and obtaining a two-dimensional image of the targets is one of important means for target recognition. Inverse Synthetic Aperture Radar (ISAR) can use the relative motion between radar and target to resolve two-dimensional imaging of non-cooperative targets, which is helpful for situation fine perception and accurate target identification, and therefore is widely appreciated in the military and civil fields. When the space-based radar images an air target, the ground background clutter is too strong, the backscattering coefficient of the air target radar is weak, so that the echo signal-to-noise ratio is low, in addition, the maneuverability of the air target is strong, and the maneuvering target ISAR imaging under the low signal-to-noise ratio is very challenging.
The traditional ISAR imaging algorithm is difficult to realize high-quality imaging under the conditions of low signal-to-noise ratio and target maneuvering, and a space-based effective ISAR imaging method for an air maneuvering target under a strong clutter background is needed to be provided.
Disclosure of Invention
The invention aims to provide a space-based pair of maneuvering target ISAR imaging method and equipment for jointly detecting priori information, which can improve signal-to-noise ratio, further improve envelope alignment and phase correction precision and improve space-based pair of maneuvering target ISAR imaging quality.
Specifically, in one aspect, the invention provides a space-based air maneuvering target ISAR imaging method for jointly detecting priori information, which comprises the following steps:
Acquisition of detection priori information: searching an air area containing a target by utilizing a narrow-band detection radar, after the target is detected, stably tracking the target for a set tracking time length, obtaining narrow-band detection point track information, and obtaining target motion parameters, wherein the target motion parameters comprise, but are not limited to, a target position, a Doppler speed, a navigational speed and a navigational direction;
Broadband imaging echo data acquisition: the narrow-band detection radar is converted into a broadband imaging mode, and the radar in the broadband imaging mode is guided to keep recording target broadband imaging echo data in an imaging period based on the target motion parameters in the detection priori information acquisition step;
smooth flight imaging echo data segment selection: selecting a target stationary flight imaging echo data segment from the recorded target broadband imaging echo data based on the narrow-band detection point track information;
And (3) performing primary compensation on target motion: based on the target position and Doppler speed acquired in the detection priori information acquisition step, performing preliminary compensation on target motion of the radar in a broadband imaging mode in an imaging period;
target broadband echo extraction: performing target preliminary SAR imaging based on the broadband echo data after the target motion preliminary compensation, and extracting data after the target preliminary SAR imaging;
target fine imaging: and transforming the data after the target primary SAR imaging to a distance-pulse domain, and carrying out envelope alignment and phase correction on the data to obtain a target accurate ISAR imaging result.
Further, the broadband imaging echo data acquisition specifically includes:
2-1) converting the narrow-band detection radar into a broadband imaging mode, and determining the initial pointing direction of a broadband beam based on the target position in the detection priori information acquisition step;
2-2) predicting the motion track of the target in the imaging period according to the target navigational speed and heading in the detection priori information acquisition step, and guiding the broadband wave beam to adjust the pointing direction according to the predicted target motion track, so that the target is kept in the wave beam coverage range in the imaging period, and broadband imaging echo data is acquired.
Further, based on the target position and the doppler velocity acquired in the detection prior information acquisition step, performing preliminary compensation on the target motion of the radar in the broadband imaging mode in the imaging period specifically includes:
4-1) obtaining a two-dimensional time domain echo signal after distance pulse compression through a distance matched filter:
4-2) transforming the two-dimensional time domain echo signals after the distance direction pulse compression to a distance frequency domain-azimuth pulse domain;
4-3) obtaining a target radial velocity V r, a target tangential velocity V c of a distance frequency domain-azimuth pulse domain and preliminarily compensating first-order and second-order migration momentum based on the target position, doppler radial velocity, navigational speed and heading acquired in the detection priori information acquisition step;
4-4) completing azimuth pulse compression through an azimuth matched filter, and realizing the primary SAR imaging of the moving target.
Further, the obtaining the two-dimensional time domain echo signal after the distance pulse compression through the distance matched filter includes:
Let the radar transmit signal be:
(1)
Wherein f c is radar carrier frequency, K r is distance frequency modulation, K r=Br/Tp,Br is radar bandwidth, T p is signal pulse width, Is a distance-wise fast time;
the distance-oriented matched filter is shown in the formula (2):
(2)
Wherein t m is azimuth slow time, ω ()' is azimuth envelope, (x 0,y0) is azimuth zero time moving target position, V s is satellite platform motion speed, V c is target tangential speed, R (t m) is the distance between the radar and the moving target in the azimuth slow time t m, c is the speed of light, and f c is the radar carrier frequency.
Further, after the distance pulse compressed two-dimensional time domain echo signal is transformed to a distance frequency domain-azimuth pulse domain, the phase calculation formula of the two-dimensional echo signal is as follows:
(5)
Phase of Comprising constant terms relating to the skew R c of the object at the initial moment of imagingPhase containing first order migration momentumAnd a phase containing second order migration momentum。
Further, the azimuth matched filter is shown as follows:
(6)
wherein f c is radar carrier frequency, c is light speed, R c is slant distance of an imaging initial moment target, V s is movement speed of a satellite platform, and t m is azimuth slow time.
Further, the target fine imaging specifically includes:
6-1) transforming the data after the extracted target preliminary SAR imaging to a distance-pulse domain through reverse direction compression operation;
6-2) performing envelope alignment on the distance-pulse domain echo of the target by adopting an envelope alignment method, wherein the envelope alignment method comprises, but is not limited to, a global method or a correlation method, and compensating for the deviation of the echo envelope in azimuth slow time caused by the translation of the target;
6-3) carrying out phase correction on the echo with the envelope aligned by adopting a phase correction method to compensate echo phase errors caused by target translation, wherein the phase correction method comprises a minimum entropy method or a phase gradient self-focusing method;
6-4) adopting an azimuth imaging algorithm to obtain a final ISAR image of the aerial target.
On the other hand, the invention also provides an space-based air maneuvering target ISAR imaging device for jointly detecting priori information, which comprises a memory and a processor; the memory stores a computer program that is executed by the processor to implement the steps of the method described above.
In yet another aspect, the present invention also provides a computer readable storage medium having stored thereon a computer program which when executed by a processor performs the steps of the above method.
The space-based pair of air maneuvering target ISAR imaging method and equipment for jointly detecting prior information have the following beneficial effects:
The space-based air maneuvering target ISAR imaging method and equipment for combining detection priori information creatively combines target position, doppler speed, navigational speed and heading priori information acquired by a space-based radar narrowband detection radar to perform ISAR imaging on an air maneuvering target; the method comprises the steps that aerial target detection and stable tracking are carried out on an aerial target through a narrow-band radar, information such as target position, doppler speed, navigational speed, course and the like is obtained, and the stable obtaining of target broadband echo data during imaging can be guided to the broadband radar; the target point track information obtained through narrow-band detection selects an imaging echo data segment of the stable flight of the target, so that motion compensation and imaging quality degradation caused by target maneuver can be avoided; the target broadband echo is subjected to preliminary compensation and imaging by utilizing narrow-band detection priori information, target broadband echo data are extracted in an SAR image domain, and as clutter cannot be accumulated in a coherent manner after motion compensation, a target can obtain a coherent accumulation benefit, so that the target broadband echo submerged by clutter can be extracted based on signal-to-noise ratio; based on the extracted target broadband echo data, envelope alignment and phase correction are further carried out, and finally, a target accurate ISAR image is obtained and used for subsequent aerial target recognition.
Drawings
FIG. 1 is a schematic illustration of a simulated aircraft model geometry according to an embodiment of the invention.
Fig. 2 is a schematic diagram of simulation test scene geometry according to an embodiment of the present invention.
Fig. 3 is a flow chart of a method of an embodiment of the present invention.
Fig. 4 is a schematic diagram of wideband distance pulse pressure data according to an embodiment of the present invention.
Fig. 5 is a schematic diagram of preliminary imaging aircraft target extraction results according to an embodiment of the invention.
Fig. 6 is a schematic diagram of aircraft target distance-pulse domain data according to an embodiment of the invention.
Fig. 7 is a schematic diagram of envelope alignment and phase correction results according to an embodiment of the present invention.
FIG. 8 is a schematic diagram of ISAR fine imaging results according to an embodiment of the present invention.
Detailed Description
The invention is described in further detail below with reference to the examples and with reference to the accompanying drawings.
One embodiment of the invention provides an ISAR imaging method for a space-based air maneuvering target by jointly detecting priori information. The satellite orbit is arranged at the orbit height of 450km and the orbit inclination angle of 30 degrees, the speed of a simulated airplane is 200m/s, the included angle between the flight direction and the azimuth direction is 70 degrees, the flight height is 15km, the simulated airplane geometric model is shown in fig. 1, the simulated scene is shown in fig. 2, the radar carrier frequency is 10GHz, the narrow-band detection bandwidth is 5MHz, and the broadband imaging bandwidth is 500MHz for example, so that the feasibility and the practicability of the invention are illustrated.
As shown in fig. 3, the space-based pair of air maneuvering target ISAR imaging method for jointly detecting prior information of the invention specifically comprises the following steps:
1. Acquisition of detection priori information: searching an air area containing a target (airplane) by utilizing a narrow-band detection radar, after the target is detected, stably tracking the target for a set tracking time length, obtaining narrow-band detection point track information, and obtaining target motion parameters, wherein the target motion parameters comprise, but are not limited to, target position, doppler speed, navigational speed and navigational course.
For the air target, the tracking duration may be set to 1-2 minutes.
2. Broadband imaging echo data acquisition: the narrow-band detection radar is converted into a broadband imaging mode, and the radar in the broadband imaging mode is guided to keep recording the broadband imaging echo data of the target in the imaging period based on the target motion parameters in the detection priori information acquisition step. The method specifically comprises the following steps:
2-1) converting the narrow-band detection radar into a broadband imaging mode, and determining the initial pointing direction of a broadband beam based on the target position in the detection priori information acquisition step;
2-2) predicting the motion track of the target in the imaging period according to the target navigational speed and heading in the detection priori information acquisition step, and guiding the broadband wave beam to adjust the pointing direction according to the predicted target motion track, so that the target is kept in the wave beam coverage range in the imaging period, and broadband imaging echo data is acquired.
3. Smooth flight imaging echo data segment selection: and selecting a target stable flight imaging echo data segment from the recorded target broadband imaging echo data based on the narrow-band detection point track information, so as to avoid motion compensation and imaging quality degradation caused by target maneuver.
And according to the target speed and heading information obtained by the narrow-band detection point track information, the data segment with stable target speed and heading can be regarded as a stable flight data segment. And selecting a data segment with stable target navigational speed and heading from the target broadband imaging echo data as a target stationary flight imaging echo data segment.
4. And (3) performing primary compensation on target motion: and performing preliminary compensation on the target motion of the radar in the broadband imaging mode in the imaging period based on the target position and the Doppler speed acquired in the detection priori information acquisition step.
4-1) Obtaining the two-dimensional time domain echo signal after distance pulse compression through a distance matched filter.
Parameterized modeling is performed on target motion during imaging, and radar emission signals are assumed to be:
(1)
Wherein f c is radar carrier frequency, K r is distance frequency modulation, K r=Br/Tp,Br is radar bandwidth, T p is signal pulse width, Is a distance-wise fast time.
The distance-oriented matched filter is shown in the formula (2):
(2)
Wherein t m is azimuth slow time, ω ()' is azimuth envelope, (x 0,y0) is azimuth zero time moving target position, V s is satellite platform motion speed, V c is target tangential speed, R (t m) is the distance between the radar and the moving target in the azimuth slow time t m, c is the speed of light, and f c is the radar carrier frequency. Fig. 4 shows a two-dimensional time domain echo signal after range-wise pulse compression, with a visible target broadband echo submerged in clutter and noise.
4-2) Transforming the distance pulse compressed two-dimensional time domain echo signal to a distance frequency domain-azimuth pulse domain.
The distance pulse compressed two-dimensional time domain echo signal is transformed into a distance frequency domain-azimuth pulse domain (i.e. f r~tm domain). After the frequency spectrum of the chirp model is approximately represented by a gate function, the two-dimensional echo signal in the f r~tm domain is represented as follows:
(3)
Wherein f r is distance frequency, rect (), is represented as a gate function, K r is distance frequency modulation, K r=Br/Tp,Br is radar bandwidth, T p is signal pulse width, T m is azimuth slow time, L s is azimuth synthetic aperture length, V s is motion speed of a satellite platform, V c is target tangential speed, f c is radar carrier frequency, c is light speed, and R (T m) is distance between an azimuth slow time T m radar and a moving target.
For a uniform linear motion target, the distance R (t m) between the radar and the moving target, the azimuth slow time t m and the slant distance R c of the target at the imaging initial moment approximately meet the following relation
(4)
Wherein R c is the slant distance of the target at the initial imaging time, V r is the radial speed of the target, and V s is the moving speed of the satellite platform.
By taking the equation (4) into the equation (3), the phase calculation equation of the two-dimensional echo signal from the frequency domain to the azimuth pulse domain can be obtained as follows:
(5)
Phase of Comprising constant terms relating to the skew R c of the object at the initial moment of imagingPhase containing first order migration momentumAnd a phase containing second order migration momentum. The phase containing the first order migration momentum is proportional to the target radial velocity v r, while the phase containing the second order migration momentum is mainly related to the target tangential velocity v c.
4-3) Obtaining the target radial velocity v r, the target tangential velocity v c of the distance frequency domain-azimuth pulse domain and the primary compensation of the first-order and second-order migration momentum based on the target position, the Doppler radial velocity, the navigational speed and the navigational direction obtained in the detection priori information obtaining step.
4-4) Completing azimuth pulse compression through an azimuth matched filter, and realizing the preliminary SAR imaging of the moving target.
The azimuth matched filter is shown as follows:
(6)
wherein f c is radar carrier frequency, c is light speed, R c is slant distance of an imaging initial moment target, V s is movement speed of a satellite platform, and t m is azimuth slow time.
5. Target broadband echo extraction: and (3) performing target preliminary SAR imaging based on the broadband echo data after the target motion preliminary compensation obtained in the step four, and extracting data after the target preliminary SAR imaging.
Because the target is subjected to preliminary compensation, the coherent processing benefits can be obtained, and the clutter power cannot be accumulated in a coherent manner, so that the signal-to-noise ratio of the target on the SAR image is improved, and the data of the target after preliminary SAR imaging can be extracted. The result of target extraction after preliminary imaging of the target is shown in fig. 5.
6. Target fine imaging: and D, converting the data extracted in the step five after the target primary SAR imaging into a distance-pulse domain, and carrying out envelope alignment and phase correction on the data to obtain a target accurate ISAR imaging result.
6-1) Transforming the extracted data of the preliminary SAR image of the target to the range-pulse domain through an inverse direction compression operation, as shown in FIG. 6.
6-2) Envelope alignment of the range-pulse domain echoes of the object using envelope alignment methods, including but not limited to global or correlation methods, to compensate for the slow time-shifted azimuth of the echo envelope due to the translation of the object.
6-3) Carrying out phase correction on the echo after envelope alignment by adopting a phase correction method, compensating echo phase errors caused by target translation, and the result after translation compensation is shown in fig. 7. The phase correction method includes, but is not limited to, a minimum entropy method or a phase gradient self-focusing method.
6-4) Adopting an azimuth imaging algorithm to obtain a final ISAR image of the aerial target, as shown in fig. 8, for subsequent target recognition.
According to the space-based air maneuvering target ISAR imaging method and the space-based air maneuvering target ISAR imaging device based on the combined detection prior information, the prior information such as the target position, the speed, the course and the like obtained by narrow-band detection is comprehensively utilized, a target stable imaging data segment is selected according to a target track, the signal-to-noise ratio is improved through preliminary imaging and target data extraction, the envelope alignment and phase correction precision are further improved, the space-based air maneuvering target ISAR imaging quality is improved, and specifically:
The space-based air maneuvering target ISAR imaging method and equipment for combining detection priori information creatively combines target position, doppler speed, navigational speed and heading priori information acquired by a space-based radar narrowband detection radar to perform ISAR imaging on an air maneuvering target; the method comprises the steps that aerial target detection and stable tracking are carried out on an aerial target through a narrow-band radar, information such as target position, doppler speed, navigational speed, course and the like is obtained, and the stable obtaining of target broadband echo data during imaging can be guided to the broadband radar; the target point track information obtained through narrow-band detection selects an imaging echo data segment of the stable flight of the target, so that motion compensation and imaging quality degradation caused by target maneuver can be avoided; the target broadband echo is subjected to preliminary compensation and imaging by utilizing narrow-band priori information, target broadband echo data are extracted in an SAR image domain, and as clutter cannot be accumulated in a coherent manner after motion compensation, a target can obtain a coherent accumulation benefit, so that the target broadband echo submerged by the clutter can be extracted based on signal-to-noise ratio; based on the extracted target broadband echo data, envelope alignment and phase correction are further carried out, and finally, a target accurate ISAR image is obtained and used for subsequent aerial target recognition.
In some embodiments, certain aspects of the techniques described above may be implemented by one or more processors of a processing system executing software. The software includes one or more sets of executable instructions stored or otherwise tangibly embodied on a non-transitory computer-readable storage medium. The software may include instructions and certain data that, when executed by one or more processors, operate the one or more processors to perform one or more aspects of the techniques described above. The non-transitory computer readable storage medium may include, for example, a magnetic or optical disk storage device, a solid state storage device such as flash memory, cache, random Access Memory (RAM), or other non-volatile memory device. Executable instructions stored on a non-transitory computer-readable storage medium may be in source code, assembly language code, object code, or other instruction format that is interpreted or otherwise executed by one or more processors.
A computer-readable storage medium may include any storage medium or combination of storage media that can be accessed by a computer system during use to provide instructions and/or data to the computer system. Such storage media may include, but is not limited to, optical media (e.g., compact Disc (CD), digital Versatile Disc (DVD), blu-ray disc), magnetic media (e.g., floppy disk, magnetic tape, or magnetic hard drive), volatile memory (e.g., random Access Memory (RAM) or cache), non-volatile memory (e.g., read Only Memory (ROM) or flash memory), or microelectromechanical system (MEMS) based storage media. The computer-readable storage medium may be embedded in a computing system (e.g., system RAM or ROM), fixedly attached to the computing system (e.g., a magnetic hard drive), removably attached to the computing system (e.g., an optical disk or Universal Serial Bus (USB) based flash memory), or coupled to the computer system via a wired or wireless network (e.g., network-accessible storage (NAS)).
While the application has been disclosed in terms of preferred embodiments, the embodiments are not intended to limit the application. Any equivalent changes or modifications can be made without departing from the spirit and scope of the present application, and are intended to be within the scope of the present application. The scope of the application should therefore be determined by the following claims.
Claims (9)
1. A space-based air maneuvering target ISAR imaging method for jointly detecting priori information, comprising the steps of:
Acquisition of detection priori information: searching an air area containing a target by utilizing a narrow-band detection radar, after the target is detected, stably tracking the target for a set tracking time length, obtaining narrow-band detection point track information, and obtaining target motion parameters, wherein the target motion parameters comprise, but are not limited to, a target position, a Doppler speed, a navigational speed and a navigational direction;
Broadband imaging echo data acquisition: the narrow-band detection radar is converted into a broadband imaging mode, and the radar in the broadband imaging mode is guided to keep recording target broadband imaging echo data in an imaging period based on the target motion parameters in the detection priori information acquisition step;
smooth flight imaging echo data segment selection: selecting a target stationary flight imaging echo data segment from the recorded target broadband imaging echo data based on the narrow-band detection point track information;
And (3) performing primary compensation on target motion: based on the target position and Doppler speed acquired in the detection priori information acquisition step, performing preliminary compensation on target motion of the radar in a broadband imaging mode in an imaging period;
target broadband echo extraction: performing target preliminary SAR imaging based on the broadband echo data after the target motion preliminary compensation, and extracting data after the target preliminary SAR imaging;
target fine imaging: and transforming the data after the target primary SAR imaging to a distance-pulse domain, and carrying out envelope alignment and phase correction on the data to obtain a target accurate ISAR imaging result.
2. The method for space-based on-air maneuvering target ISAR imaging by combining detection priori information according to claim 1, wherein the acquiring of the broadband imaging echo data specifically comprises:
2-1) converting the narrow-band detection radar into a broadband imaging mode, and determining the initial pointing direction of a broadband beam based on the target position in the detection priori information acquisition step;
2-2) predicting the motion track of the target in the imaging period according to the target navigational speed and heading in the detection priori information acquisition step, and guiding the broadband wave beam to adjust the pointing direction according to the predicted target motion track, so that the target is kept in the wave beam coverage range in the imaging period, and broadband imaging echo data is acquired.
3. The method for near-sky-based on-air maneuvering target ISAR imaging based on the space of the present invention according to claim 1, wherein the preliminary compensation for the target motion of the radar in the broadband imaging mode during the imaging period based on the target position and the doppler velocity acquired in the step of acquiring the detection prior information specifically comprises:
4-1) obtaining a two-dimensional time domain echo signal after distance pulse compression through a distance matched filter:
4-2) transforming the two-dimensional time domain echo signals after the distance direction pulse compression to a distance frequency domain-azimuth pulse domain;
4-3) obtaining a target radial velocity V r, a target tangential velocity V c of a distance frequency domain-azimuth pulse domain and preliminarily compensating first-order and second-order migration momentum based on the target position, doppler radial velocity, navigational speed and heading acquired in the detection priori information acquisition step;
4-4) completing azimuth pulse compression through an azimuth matched filter, and realizing the primary SAR imaging of the moving target.
4. The method for space-based on-air maneuvering target ISAR imaging by jointly detecting priori information according to claim 3, wherein the obtaining the two-dimensional time domain echo signal after the distance pulse compression by the distance matched filter comprises:
Let the radar transmit signal be:
(1)
Wherein f c is radar carrier frequency, K r is distance frequency modulation, K r=Br/Tp,Br is radar bandwidth, T p is signal pulse width, Is a distance-wise fast time;
the distance-oriented matched filter is shown in the formula (2):
(2)
Wherein t m is azimuth slow time, ω ()' is azimuth envelope, (x 0,y0) is azimuth zero time moving target position, V s is satellite platform motion speed, V c is target tangential speed, R (t m) is the distance between the radar and the moving target in the azimuth slow time t m, c is the speed of light, and f c is the radar carrier frequency.
5. The method for space-based on-air maneuvering target ISAR imaging by combining detection priori information according to claim 3, wherein after the two-dimensional time domain echo signals after distance pulse compression are transformed to a distance frequency domain-azimuth pulse domain, the phase calculation formula of the two-dimensional echo signals is as follows:
(5)
Phase of Comprising a constant term/>, related to the skew R c of the imaging initiation time targetPhase/>, comprising first order migration momentumAnd phase/>, which contains second order migration momentum。
6. A space-based air moving object ISAR imaging method in combination with detection of a priori information according to claim 3, wherein the matched filter of the azimuth direction is represented by the following formula:
(6)
wherein f c is radar carrier frequency, c is light speed, R c is slant distance of an imaging initial moment target, V s is movement speed of a satellite platform, and t m is azimuth slow time.
7. The method for space-based aerial maneuvering target ISAR imaging in combination with detection of a priori information according to claim 1, wherein the target fine imaging specifically comprises:
6-1) transforming the data after the extracted target preliminary SAR imaging to a distance-pulse domain through reverse direction compression operation;
6-2) performing envelope alignment on the distance-pulse domain echo of the target by adopting an envelope alignment method, wherein the envelope alignment method comprises, but is not limited to, a global method or a correlation method, and compensating for the deviation of the echo envelope in azimuth slow time caused by the translation of the target;
6-3) carrying out phase correction on the echo with the envelope aligned by adopting a phase correction method to compensate echo phase errors caused by target translation, wherein the phase correction method comprises a minimum entropy method or a phase gradient self-focusing method;
6-4) adopting an azimuth imaging algorithm to obtain a final ISAR image of the aerial target.
8. An space-based air maneuvering target ISAR imaging device for jointly detecting a priori information, the device comprising a memory and a processor; the memory stores a computer program, which is executed by the processor to implement the steps of the method according to any of claims 1-7.
9. A computer readable storage medium, on which a computer program is stored, characterized in that the computer program, when being executed by a processor, implements the steps of the method according to any of claims 1-7.
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