INSAR Flat-earth Phase Removal Approach Based on DEM to Settlement Area

The difficulties of phase unwrapping was increased with the existence of flat-earth phase removal, at the same time,it covered up the real topographical conditions.In order to solve this problem,the paper presented a method of re-flattening. based on DEM to eliminate flat-earth phase, with the interferogram, and then chose some special control points to construct polynomial fitting, removed residual phase and noise. By analyzing the ALOS/PALSAR at the mine subsidence area, the contrast experiment was carried out. The results showed that the method can clearly reflect the earth's surface changes, reduce the surface deformation error, get a more accurate interferogram phase and improve the precision of the INSAR interferometry.