基于差分干涉SAR的煤田火区地表形变监测

Differential SAR Interferometry for the Monitoring of Underground Coal Spontaneous Combustion Zone Surface Deformation

煤田火区地表形态变化是煤火监测和分析的可用指标之一。由于矿区地表严重的去相干噪声,使得星载合成孔径雷达干涉测量技术应用于煤田火区地表形变检测比较困难。结合煤田火区地表形变特点,利用L波段的ALOS PALSAR数据进行差分干涉处理,利用干涉条纹频率精确估计基线,并用自适应滤波方法降低去相干噪声的影响。在去除平地相位和参考地形相位后,获取煤田火区的地表形变。研究表明:地表形变与煤火燃烧具有一定的相关关系,通过地表形变分析有助于对地下煤火燃烧情况的判断;利用差分干涉SAR技术检测煤田火区地表形变,进而对煤火进行监测和分析是可行的。

The surface deformation is one of the available indicators for monitoring and analysis of the coalfield fire area. However, it is difficult to extract surface deformation in the coalfield area if serious decorrelation noise exists. Based on analyzing the surface deformation characteristics of the coalfield fire area and comparing a variety of SAR datasets, the authors chose L band ALOS PALSAR dataset to conduct a differential synthetic aperture radar interferometry processing. Interferometric fringe was calculated for estimating the accurate baseline. The adaptive filter method was used to eliminate decorrelation noise after generating interferogram. Then surface deformation in the coal mine fire zone was extracted after two processes, i. e. , flattening and topography phase removal. It is found that surface deformation is correlated with the coal spontaneous combustion zone to some extent, as evidenced by past in situ investigation and data analysis. The surface deformation analysis is helpful to confirming the situation of the underground coal fire burning. The on - site verification proves that detecting surface deformation of the underground coal spontaneous combustion zone by D -InSAR is acceptable.