This step is of influence for the coregistration using a DEM ( DEMASSIST step). For this coregistration the master and slave images should be aligned as good as possible with the DEM. The master is aligned with respect to the DEM using a simulated amplitude image (M_TIMING step). This could also have been done for the slave image, however, we have chosen to use the master-slave fine coregistration because this is probably more precise for the relative timing. Therefore, an error in the master timing will propagate to the slave timing, however, the relative DEM position is consistent.