High precision compensation method for airborne SAR orientation space-variant motion error

Abstract

The invention belongs to the radar technology field, discloses a high precision compensation method for an airborne SAR orientation space-variant motion error and aims to precisely compensate the higher-order orientation space-variant motion error. The method comprises steps that an echo signal is received by an airborne SAR radar device, and two-step compensation for the echo signal is carried out; distance partitioning of the echo signal after two-step compensation is carried out; orientation partitioning of the echo signal after distance partitioning is carried out; an orientation space-variant motion error of a center point of an ith sub block of the echo signal after orientation partitioning is calculated, and a polynomial of a stationary phase point of the sub block is further solved; the center point of the ith sub block is taken as reference, the stationary phase point of the sub block is solved, a compensation function is constructed, the sub block is compensated by employing the compensation function, reverse FFT is carried out, and an image of the sub block after compensation is acquired; images of all sub blocks after compensation are acquired, and an airborne SAR image after compensation is acquired.

Description

technical field [0001] The invention relates to the field of radar technology, in particular to a high-precision compensation method for an airborne SAR azimuth space-varying motion error, which can be used for error compensation of the airborne SAR azimuth space-varying motion. 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 var...

AI Technical Summary

Problems solved by technology

SATA is the most 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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