On-board high resolution SAR imaging method based on azimuth spatial variation error compensation

Abstract

The invention belongs to a radar technology field, and discloses an on-board high resolution SAR imaging method based on azimuth spatial variation error compensation. The on-board high resolution SAR imaging method comprises steps that an on-board SAR radar is used to receive an echo signal, and is used for the range pulse pressure, the range migration correction, and the azimuth Fourier transform of the echo signal sequentially to acquire an azimuth wave number field signal; the azimuth partitioning of the azimuth wave number field signal is carried out in various range gates to acquire various azimuth sub-block signals after the azimuth partitioning; corresponding azimuth matched filtering functions in the various azimuth sub-blocks are calculated in a point-to-point manner, and coarse resolution imaging is carried out; coarse resolution images are calculated, and then the azimuth Fourier transform is carried out, and integration of azimuth number spectrum is realized by wave cyclic shift and splicing, and then the complete wave number spectrum of the corresponding range gate is acquired, and then azimuth inverse Fourier transform is carried out; the azimuth partitioning and the spectrum integration of the various range gates are carried out sequentially in a repeated manner until processing results corresponding to all of the range gates are acquired, and therefore a full resolution imaging result is acquired.

Description

technical field [0001] The invention belongs to the technical field of radar, and in particular relates to an airborne high-resolution SAR imaging method based on azimuth space-variation error compensation, which can be used for airborne high-resolution SAR imaging. Background technique [0002] Motion compensation is an important signal processing link in airborne Synthetic Aperture Radar (SAR) imaging. Under the condition of long synthetic aperture and high-resolution imaging, the accuracy of motion compensation is crucial to the imaging results of low-altitude small UAV-borne SAR, and its influence will be manifested as spatial variability in the range and azimuth directions. The compensation of airborne SAR range space-variant motion error mainly adopts "two-step compensation method". However, this method has limitations. When the movement of the aircraft fluctuates greatly or the radar works in the high-band, the influence of the residual azimuth space variation error ...

AI Technical Summary

Problems solved by technology

SATA is efficient but affects its accuracy due to the assumption that the sub-aperture motion error is constant

PTA can more accurately compensate for azimuth space-varying errors, but the azimuth wavenumber spectrum process does not take into account the influence of residual phase, so its accuracy is still limited

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