相位补偿SAR差分干涉提取山区DEM算法及精度分析

首先,将去平干涉相位和外部DEM模拟的地形相位作差分,以降低干涉图的条纹率。然后,采用模拟的地形相位对差分干涉图的解缠相位进行补偿得到去平干涉图的解缠相位,并用此相位进行基线精化和高程提取。实验结果表明,该算法可得到高程精度更高的山区DEM。与常规干涉算法相比,它不仅可改善解缠精度,还可得到更加真实且相干性明显改善的相干图,减少因相干性低于解缠时设定的相干性阈值而产生的高程空洞区。相比于＂高程补偿＂算法,其可更有效地削弱残余系统相位以及解缠和外部DEM引入的随机相位误差的影响。

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.