Factorized Geometrical Autofocus for Synthetic Aperture Radar Processing

A fast autofocus algorithm for synthetic aperture radar processing

Synthetic Aperture Radar ( S A R ) has become a valuable instrument with applications in reconnaissance and remote sensing. High resolution SAR imaging requires the motion of the radar platform to be known very accurately. Otherwise phase errors are induced in the processing of the raw S A R data, and bad focusing results. In particular, a constant error in the measured along track velocity or ...

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...

Synthetic-Aperture Radar Processing Using Fast Factorized Back-Projection

Synthetic aperture radar (SAR) is a general method for generating high-resolution radar maps from low-resolution aperture data which is based on using the relative motion between the radar antenna and the imaged scene. Originally conceived in the early 1950s [1], it is extensively used to image objects on the surface of the Earth and the planets [2]. A synthetic aperture is formed using electro...

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....

Autofocus for inverse synthetic aperture radar (ISAR) imaging