Autofocus for inverse synthetic aperture radar (ISAR) imaging

Autofocus for inverse synthetic aperture radar (ISAR) imaging

Backprojection Autofocus for Synthetic Aperture Radar

In synthetic aperture radar (SAR), many adverse conditions may cause errors in the raw phase-history data. Autofocus methods are commonly used in SAR to mitigate the effects of these problems. Over the years, many types of autofocus have algorithms have been created, however, each has implicit assumptions restricting their use. The backprojection image formation algorithm places few restriction...

Adaptive CLEAN Algorithm for High Resolution Inverse synthetic aperture radar (ISAR) Imaging For Vehicular Application

High resolution RADAR images of contiguous targets like vehicles on road often suffer from side lobe enhancement. This leads to false alarm in target detection and degradation in image quality. In this paper, adaptive CLEAN algorithms are introduced to eliminate side lobe enhancement and significantly improve the target detection with better image quality. The effectiveness of the CLEAN algorit...

Synthetic Aperture Radar Imaging with Motion Estimation and Autofocus

We introduce from first principles a synthetic aperture radar (SAR) imaging and target motion estimation method that is combined with compensation for radar platform trajectory perturbations. The main steps of the method are (a) segmentation of the data into properly calibrated small apertures, (b) preliminary motion estimation from the data using the Wigner transform and the ambiguity function...

Synthetic-aperture radar autofocus by maximizing sharpness.

To focus a synthetic-aperture radar image that is suffering from phase errors, a phase-error estimate is found that, when it is applied, maximizes the sharpness of the image. Closed-form expressions are derived for the gradients of a sharpness metric with respect to phase-error parameters, including both a point-by-point (nonparametric) phase function and coefficients of a polynomial expansion....