重复轨道InSAR处理中的频域滤波研究

在重复轨道InSAR(synthetic aperture radar interferom etry)处理干涉测量中,干涉图像对在方位向和距离向的频谱偏移是重要的去相干因素,严重影响干涉图的质量,必须对主辅图像对采取适当的频域滤波。本文提出了一种方位向频域滤波和距离向频域滤波的处理流程,即根据频域特征选择在精配准前后做频域滤波。它既能保证精配准的准确度,又能充分降低频谱偏移导致的去相干,从而保证干涉图的高质量。利用4组不同时间间隔和垂直基线距的ERS-1/2 SLC(single look comp lex)数据对进行实验验证,通过对频域滤波前后相干图和残差点的对比分析,验证了本处理流程的有效性。

Spectral Filtering for Repeat-pass SAR Interferometry

In repeat-pass synthetic aperture radar interferometry,the decorrelation caused by azimuth and range spectral shifts leads to a deterioration of the quality of SAR interferogram.There is a need to put proper spectral filters on the main and slave images.The paper discusses a new spectral filtering procedure that performs filtering before and after fine coregistration according to spectral characteristics.The procedure will reduce spectral misalignment,improve the accuracy of fine coregistration,and at last obtain high quality of interfeorgram.Four pairs of ERS-1/2 SLC data with different time interval and nominal baseline are used to analyze the validity of our method.Results show that the average values of coherence after spectral filtering flow are higher than that before spectral filtering flow,moreover the amount of residues is highly decreased.These give evidence to the goodness of the procedure.