Moving-target instantaneous distance Doppler imaging method based on detuning and keystone processing

Abstract

The invention discloses a moving-target instantaneous distance Doppler imaging method based on detuning and keystone processing; and problems that larger range migration exists in the traditional moving-target moving technology under a circumstance that moving-target motion parameters are unknown and complete azimuth spectra are not included in a baseband are mainly solved. The realizing process comprises the following steps of: (1) receiving an original synthetic aperture radar echo signal and carrying out Fourier transform on the echo signal at range; (2) constructing an azimuth detuning function so as to detune the echo signal; (3) removing linear walking momentum of the echo signal by using Keystone transform; (4) estimating an azimuth fuzzy number of the echo signal after the linear walking momentum is removed and filtering the echo signal at azimuth; and (5) carrying out inverse Fourier transform and Fourier transform on the echo signal, which is filtered at azimuth, at both the azimuth and the range, so as to obtain an imaging result of the echo signal; and according to the invention, an imaging effect of a moving target can be effectively improved; and the moving-target instantaneous distance Doppler imaging method based on detuning and keystone processing, disclosed by the invention, can be used for the field of moving target detection, identification and imaging.

Description

technical field [0001] The invention belongs to the field of radar signal processing, in particular to an instantaneous range Doppler imaging method of a moving target. It can be used for SAR imaging processing on airborne and spaceborne platforms. Background technique [0002] Synthetic Aperture Radar (SAR) imaging has been widely used in civil and military fields including moving target detection and imaging. Since the moving target moves in the SAR image and cannot correctly reflect its true position, it is hoped to detect the moving target. repositioning, and even imaging. [0003] In the SAR system, for the moving target, the long synthetic aperture time makes the echo signal of the moving target have a larger azimuth bandwidth, which not only improves the signal-to-noise ratio, but also effectively improves the resolution. However, the large azimuth bandwidth will also cause the baseband not to contain the complete azimuth spectrum, which may lead to artifacts in the...

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Problems solved by technology

[0007] The purpose of the present invention is to address the deficiencies of the above-mentioned prior art, and to provide an instantaneous range Doppler imaging method for a moving target based on deflection and keystone processing when the motion parameters of the moving target are unknown, so as to solve the problem of large distance migration. The problem of dynamic correction and large azimuth bandwidth does not contain the complete azimuth spectrum in the baseband

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