A condition to select one from two SAR autofocus algorithms based on signal-to-clutter ratio

摘要

Autofocus algorithm is often used to compensate the phase error in received signal of synthetic aperture radar. Mapdrift and PCA(Phase Gradient Autofocus) are two of the most popular autofocus algorithms. Because Mapdrift estimates phase errors using two images that are reconstructed by divided spectra of the observed image, its accuracy of phase estimation is constant and low. PGA estimates phase errors using the phase of isolated point targets, therefore its accuracy of phase estimation depends on Signal-to-Clutter ratio of the point targets.