CSL (Centre Spatial de Liege) developed a complete InSAR processor as part of the Belgian National Remote Sensing Program. This processor makes use of a new 2D complex interpolator used in coregistration of SAR images, an adapted filter and a phase unwrapping method based on residue connection guided by coherency measurements. We sketch the methods and present the results we obtained on a reference interferometric pair made available by the ESA FRINGE working group.
"Development of an interferometric SAR processor", Proc. SPIE 2584, Synthetic Aperture Radar and Passive Microwave Sensing, (21 November 1995); doi: 10.1117/12.227148; https://doi.org/10.1117/12.227148