FindRepe finds (and optionally deletes) duplicated files by content, not name. It uses MD5 and SHA1 hashes to compare files. It can also compare just by file name.
The Next ESA SAR Toolbox (NEST) is used for reading, post-processing, analyzing, and visualizing the large archive of data from ESA SAR missions, including ERS-1 and 2 and ENVISAT, RADARSAT-2, TerraSAR-X, ALOS PALSAR, and Cosmo-Skymed.