Motion Compensation for Squint Mode Spotlight SAR Imaging Using Efficient 2D Interpolation

Abstract

In the squint mode airborne spotlight synthetic aperture radar system using the range migration algorithm (RMA), autofocus (AF) technique yields poor results due to the squint spreading of the point spread function (PSF) of a scatterer. Thus, two-dimensional (2D) interpolation is required to direct PSF blurring in cross-range direction, to improve the cross-range resolution Delta(y) and to remove the spatially-varying sidelobe. Because conventional 2D interpolation requires huge computation time and yields large computation errors, we propose an efficient 2D interpolationt echnique for squint-mode RMA composed of two 1D interpolations.Simulation results using the measured turbulence data show Delta(y) was improved considerably and PSF was successfully focused by the proposed method with a reduced computation time.