多基线差分雷达干涉测量的大型人工线状地物形变监测

Preliminary Research on Large-scale Man-made Linear Features Deformation Monitoring Using Multi-baseline Differential SAR Interferometry

大型人工线状地物是人类改造自然的产物,同人类生活息息相关。本文从大型人工线状地物定义出发,阐述了其形变现象、成因及衍生灾害;并利用多基线差分雷达干涉测量技术(Differential Synthetic Aperture Radar Interferometry,DInSAR)实施大型人工线状地物形变监测。通过多数据源实验(ENVISAT ASAR,广州;PALSAR,香港大屿山;TerraSAR-X,深圳),分析了当前高级DInSAR方法,包括永久散射体和相干目标法在监测大型人工线状地物形变上的能力。实验结果表明,采用了不同的影像干涉对组合策略,永久散射体法适合大数据量SAR影像处理,而相干目标法适合小数据量SAR影像分析。微波穿透性和垂直临界基线随波长增加而增加。因此,在波段选择上,低相干区宜选用长波SAR数据(比如ALOS PALSAR)以获取稳健反演结果;而高相干区宜选用短波TerraSAR-X或者ENVISATASAR数据,以获取高精度地表形变场。结合线状地物几何和物理特性,分别从先验基础GIS/GPS数据、SAR数据源选择、PS点提取和模型改进四方面进行分析和探讨,认为面向线状地物形变监测多基线DInSAR模型的研发是亟待解决的问题。

Large-scale Man-made Linear Features（LMLFs）,resulting from nature remarking,have played an essential role in physical distribution and energy transportation.Though with a wide extension,those linear features primarily concentrate upon infrastructure field,including dams,bridges,highways,railways,metro-lines and pipes.As the development of spaceborne SAR technology,multi-baseline Differential SAR Interferometry（DInSAR） overcomes the spatial/temporal decorrelation and mitigates atmospheric effects in DInSAR procedures,revealing competent for large-area deformation measurement with millimetric-centimetric accuracy.This technology is capable of achieving temporal evolutions,which is significant for the stability management of observed features.In this paper,the LMLF＇s deformation phenomena,causes and derivative hazards are firstly described.After that,the multi-baseline DInSAR methods are applied for their ground deformation monitoring.Multi-source SAR data,including ENVISAT ASAR（Guangzhou）,PALSAR（Lantau Island,Hong Kong）,TerraSAR-X（Shenzhen）,are used for experiments,the capabilities of the Permanent Scatterers（PS） method and Coherent Targets（CT） method are analyzed.The results demonstrate that,with different interferometric image pair combinations,the PS method is more suitable for the large number of SAR images because of the applied single reference image strategy,and vice versa.Generally,the wave penetrability and critical normal baseline increase with the wavelength.Therefore,when low coherent regions are encountered,the longer wavelength SAR data,such as L-band ALOS PALSAR,are preferred to generate high quality inteferograms,bringing about robust ground deformation results;in contrast,the short wavelength data are selected for high coherent areas,such as TerraSAR-X and ENVISAT-ASAR,to retrieve deformations with high accuracy.Taking the geometric and scattering characteristics of LMLFs into consideration,four viewpoints including thematic layers and GPS observation data,SAR images selection,PS candidates extraction and model improvement are discussed for deformation monitoring using multi-baseline DInSAR methods.Finally,from the experiments and analysis,one can conclude future works should be carried out especially in LMLF-oriented DInSAR model development.