Estimation and correction of ionospheric induced phase errors in SAR images using Coherent Scatterers

Coherent Scatterers (CSs) are usually detected in SAR data using spectral correlation techniques, by evaluating multilook images in the range direction. The first part of the paper demonstrates an alternative way to detect CSs by exploiting their inherent strong phase stability along frequency. The main advantage of the technique is the absence of a spatial average (necessary in the original procedure), which avoids loss of resolution. The second part of this work illustrates the use of CSs for the estimation and correction of phase errors along the synthetic aperture. Such source of errors may be originated by different effects as platform motion and atmospheric or ionospheric disturbances. For the correction of one and two-dimensional phase errors addressed here, a CSs based autofocus procedure was implemented and applied to simulated and real data.