slide 48

In geodesy, the focus is on surface displacements rather than the topographic face. To extract the face of surface displacements from the topographic face, a technique called differential in SAR, de-in-SAR, is used. By obtaining the episodic height edge of SAR pixels and using the known formula for the topographic face, the topographic face can be reconstructed. The episodic height can be obtained from the DEM, allowing for the removal of the topographic face from the in-SAR measurement. Removing other effects allows for the determination of the face of surface displacements between two SAR acquisition times. In geodesy, surface displacements are focused more than the topographic face. But how to extract the face of surface displacements from the topographic face? The technique to remove the topographic face is called differential in SAR, de-in-SAR. We know the formula for the topographic face. So if we can obtain the episodic height edge of SAR pixels, the topographic face can be reconstructed. The episodic height can be obtained from the DEM, and we then can remove the topographic face from the in-SAR measurement. If we remove other effects, we can obtain the face of surface displacements between two SAR acquisition time.