A full-aperture processing method for spotlight SAR based on time domain de-aliasing

A processing method and full-aperture technology, applied in the direction of radio wave reflection/re-radiation, instruments, measurement devices, etc., can solve the problems of aliasing, self-focusing processing that cannot be merged, and limit applications, etc., to achieve compensation error phase and efficient execution , the effect of improving image quality

Active Publication Date: 2022-03-08
AEROSPACE INFORMATION RES INST CAS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the azimuth and time domain of the spotlight SAR data processed by this method are aliased, which makes the autofocus processing unable to integrate with this method, which limits the application of this method to spotlight SAR data with long synthetic aperture time

Method used

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  • A full-aperture processing method for spotlight SAR based on time domain de-aliasing
  • A full-aperture processing method for spotlight SAR based on time domain de-aliasing
  • A full-aperture processing method for spotlight SAR based on time domain de-aliasing

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Embodiment 1

[0084] The present invention uses the airborne spotlight SAR system and scene parameters shown in Table 1 to perform simulation to verify the effectiveness of the technical solution of the present invention.

[0085] Table 1 Simulation airborne spotlight SAR system parameters and scene parameters

[0086]

[0087] figure 2 is the distribution of point targets in the scene, the point targets are separated by 1.1Km in the distance direction and 0.4Km in the azimuth direction.

[0088] image 3 is the amplitude image after RCMC of target echo data at the center point of the scene (processed in step 102): (a) RD domain amplitude image, (b): two-dimensional time domain amplitude image, (c): image 3 (a) The frequency-time diagram of the Short Time Inverse Fourier Transform (STIFT) along the azimuth frequency in the range unit where the target is located. image 3 In (a), the distance unit where the point target is located is smooth and stable along the azimuth frequency ampl...

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Abstract

The invention discloses a full-aperture processing method of spotlight SAR based on time-domain de-aliasing, comprising: step 1, removing the aliasing of spotlight SAR data in the azimuth frequency domain after preprocessing; step 2, using a frequency-domain imaging algorithm , perform range migration correction RCMC on the spotlight SAR data after dealiasing in the azimuth frequency domain; Step 3, remove the aliasing of the spotlight SAR data in the azimuth time domain after range migration correction RCMC; Step 4, use the phase gradient to automatically The focusing algorithm PGA performs error phase estimation and compensation on the spotlight SAR data after time domain dealiasing; step 5, removes the aliasing of the spotlight SAR data in the azimuth frequency domain after the phase error compensation, and then uses the azimuth matched filter to complete the focusing Focusing of beam SAR data. Through the invention, the full-aperture focusing processing of spotlight SAR data under long synthetic aperture time can be realized simply, efficiently and accurately.

Description

technical field [0001] The invention relates to a full-aperture processing method of a beamforming synthetic aperture radar (Synthetic Aperture Radar, SAR). Background technique [0002] Spatial geometric resolution is the core performance index of synthetic aperture radar. This active microwave remote sensing device obtains high resolution in the range direction of the target scene by transmitting large-bandwidth frequency modulation signals, and obtains high resolution in azimuth direction through azimuth synthetic aperture technology. . Spotlight SAR is the imaging mode with the highest azimuth resolution among all SAR imaging modes. By controlling the pointing of the radar antenna beam, the target in the scene is always irradiated during the whole data acquisition process, which greatly increases the image quality of the scene. The azimuth synthetic aperture angle of the medium target improves the azimuth resolution of the target and breaks the limitation of the azimuth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01S13/90
CPCG01S13/9011G01S13/9052
Inventor 邓云凯任明山张衡禹卫东陈圳
Owner AEROSPACE INFORMATION RES INST CAS
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