An improved omega‑k imaging method for subaperture SAR with large squint

Abstract

The invention belongs to the technical field of SAR imaging, and particularly relates to an improved sub-aperture SAR chirp scaling Omega-K imaging method. The method includes the specific steps of firstly, conducting range-direction Fourier transform on original echo data; secondly, conducting azimuth-direction matched filtering on a signal, multiplying the signal by a rotation correction function, and achieving the forward lateral processing for a wave number spectrum supporting area; thirdly, conducting azimuth-direction Fourier transform on the signal, and conducting azimuth resampling interpolation a two-dimensional wave number field; fourthly, multiplying the signal by a unified phase compensation function, conducting expansion Stolt interpolation, and achieving the range-direction spatial position field focusing through the range inverse Fourier transform; fifthly, multiplying the signal by a deramp correction function, conducting azimuth inverse Fourier transform, multiplying the azimuth spatial position by an azimuth position correction function in the azimuth spatial position field, and finally achieving the azimuth-direction wave number field focusing through the azimuth Fourier transform. The method is wide in application range, capable of achieving the high-resolution imaging, and can be used for the fields of ground mapping, target recognition and the like.

Description

technical field [0001] The invention belongs to the technical field of SAR imaging, in particular to an improved Omega-K imaging method for sub-aperture SAR high squint, which can be used for SAR imaging processing of airborne and spaceborne platforms. Background technique [0002] As an active detection tool, SAR (Synthetic Aperture Radar) can perform high-resolution microwave imaging of observation scenes, and has been widely used in the field of remote sensing. It obtains high-resolution characteristics in the range dimension by transmitting broadband signals, while the azimuth dimension uses Doppler information generated by platform motion to achieve high resolution. [0003] In recent years, with the maturity and development of various imaging algorithms, while taking into account the imaging quality, real-time performance has become an essential requirement for many imaging systems. The concept of sub-aperture solves the contradiction between imaging quality and imagi...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to propose an improved Omega-K imaging method for sub-aperture SAR with large squint. Sampling solves the spatial variation of the azimuth modulation frequency, thereby improving the imaging quality in the case of high squint

At the same time, the invention can be applied to sub-aperture data imaging, solves the problem of azimuth aliasing due to the small support area of ​​sub-aperture azimuth position, and realizes unified windowing processing of azimuth

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