inally, there is Radar Tools (RAT). Originally developed at TU Berlin the program is largely supported by Andreas Reigber at the German Aerospace Agency, DLR. How he manages to find the time to support RAT whilst running one of the World leading SAR technology development teams is beyond me, but he does (actually I think DLR have managed to warp space-time to add a few more hours to the day). RAT offers a wide range of SAR image processing tools, many of which do not appear in any other package (commercial or free). RAT offers routines for SAR image processing and analysis and polarimetric, interferometric, and PolInSAR processing. As such it goes beyond almost any other package (and certainly any freeware) in the range of processing available.