SAR (synthetic aperture radar) geometric correction method for modifying error equivalent RD (range-Doppler) model

Abstract

The invention provides an SAR (synthetic aperture radar) geometric correction method for modifying an error equivalent RD (range-Doppler) model. The SAR geometric correction method includes firstly, creating range-Doppler equations on the basis of modifying for the error equivalent RD model; secondly, performing primary Tailor series expansion for the equations obtained in the first step to obtain an error equation; thirdly, solving the error equation obtained in the second step by a least square process; and fourthly, geometrically positioning each pixel by the modified range-Doppler equations after the error equation is solved so as to geometrically correct SAR. The SAR geometric correction method has the advantages that required control points are few, the requirement on the uniform distribution character of the control points is low, and an excellent result can be obtained by a conventional numerical solution process without iteration.

Description

technical field [0001] The invention relates to a SAR geometric correction method based on error equivalent RD model correction, relates to the field of synthetic aperture radar (SAR) signal processing, and specifically relates to the field of synthetic aperture radar image geometric correction processing. Background technique [0002] Image geometric correction is an important part of spaceborne SAR data processing. Only through geometric correction, each pixel of the SAR image is endowed with geographical location information, can the SAR image truly become the carrier of geospatial information and support subsequent applications. The accuracy of geometric correction of SAR images has a crucial influence on the application benefits of SAR images. SAR geometric correction can generally be divided into two types: uncontrolled correction (also known as system-level geometric correction) and controlled correction. The system-level geometric correction refers to the geometric ...

AI Technical Summary

Problems solved by technology

[0012] 2) The efficiency of solving ill-conditioned equations is low, and there may be cases where iterations do not converge

However, on the one hand, iteration will lead to a decrease in the efficiency of the solution; on the other hand, even with better solution methods such as spectral correction, iterative non-convergence may still occur

[0013] In short, the robustness and robustness of the existing technical solutions need to be improved, and the dependence on the number of control points and uniform distribution needs to be further reduced

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