Nowadays, several free or commercial tools for INSAR, DINSAR and even PS INSAR exist. A brief inventory of
current suites is drawn and shows their main capabilities. The objective of this work is the handling and the validation of
our use of DORIS, a free processing suite. For this purpose, the organization of the processing is studied and compared
to another one (SARSCAPE, a commercial software). It appears that both chains contain identical or similar steps but,
some stages are missing or are replaced by a different one. Experiments are then held with DORIS and SARSCAPE
using the same data set: two ASAR images covering the 2003 Bam (Iran) earthquake and a SRTM3 DEM. Using DORIS
and SARSCAPE, it leads to comparable results, which allows validating our use of DORIS (and also SARSCAPE).
However, linear and non linear residual differences occur. In the same way, dissimilarities are observed with other
published results. These dispecrancies are interpreted as resulting from residual geometric inaccuracies. One solution to
reduce these artefacts is a simple surface compensation but the orbital parameters are then not corrected. Finally, this
work may give some help for a better understanding of any DINSAR processing chain.