Airborne high resolution synthetic aperture radar accurate motion compensation method

Abstract

The invention belongs to the technical field of radar and discloses an airborne high resolution synthetic aperture radar accurate motion compensation method which comprises the following steps: an airborne SAR receives an echo signal and performs envelope coarse compensation and phase position coarse compensation operation on the echo signal, and a coarsely compensated echo signal is obtained; the coarsely compensated echo signal is orderly subjected to range direction partitioning operation and azimuth direction partitioning operation, and N sub-blocks are obtained; residual motion error of a central point of an ith sub-block is calculated, a residual motion error compensation function of the central point of the ith sub-block is determined, and an original azimuth matching filtering function and an accurate azimuth matching filtering function are obtained; a final compensation function of the central point of the ith sub-block is determined according to the original azimuth matching filtering function, the accurate azimuth matching filtering function and the residual motion error compensation function; the ith sub-block is subjected to accurate motion compensation operation according to the final compensation function, and a compensation image of the ith sub-block is obtained till a compensation image of an airborne synthetic aperture radar is obtained.

Description

technical field [0001] The invention relates to the technical field of radar, in particular to an accurate motion compensation method of an airborne high-resolution synthetic aperture radar, which can realize the motion error compensation of the synthetic aperture radar. Background technique [0002] Motion Compensation (MOCO) is a key issue in airborne Synthetic Aperture Radar (SAR) imaging. Especially for small UAV-borne platforms, accurate MOCO is a difficult task. [0003] The traditional "two-step" MOCO method combines the CSA (Chirp Scaling Algorithm, frequency modulation and scaling) algorithm to compensate for airborne motion errors. The method compensates the range non-spatial-variant and range-space-variant motion errors step by step, and has high efficiency. However, after the first step of MOCO, the residual range space-varying motion error phase will affect the accuracy of Range Cell Migration Correction (RCMC) in the two-dimensional wavenumber domain. precis...

AI Technical Summary

Problems solved by technology

However, after the first step of MOCO, the residual range space-varying motion error phase will affect the accuracy of Range Cell Migration Correction (RCMC) in the two-dimensional wavenumber domain. precision

For large swath imaging, although the distance block is usually used, and then the method of splicing the distance sub-blocks is used for processing, the impact of the distance spatial variability of the motion error in the range sub-blocks on RCMC cannot be ignored.

Distance partitioning requires block overlap, and dense distance partitioning consumes processing efficiency and storage capacity to a certain extent

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