DEM Extraction over Mountainous Area and Its Accuracy Analysis with Phase Compensation Based Differential Interferometry

After analyzing the existing D-InSAR-based DEM construction algorithms,we propose a new DEM extraction algorithm based on phase compensatio.Firstly the simulated topographic phase is remored from the flattened interferogram to reduce its fringe rates.Then,the residual unwrapping phase is compensated with the simulated topographic phase to get the unwrapped interferogram,and refine the baseline estimation and extract height information.Experimental results show that the method can acquire a more accurate DEM over mountainous area.Compared with the conventional interferometric algorithm,the proposed methd can not only improve the accuracy of unwrapped phase,but also obtain a more accurate and significantly improved coherence map to reduce the masked area due to coherence threshold in phase unwrapping.While compared with the height compensation algorithm,the new algorithm can more effectively reduce the height errors due to residual systematic phase errors and stochastic errors caused by residual unwrapping phase and external DEM.