基于临时相干目标监测非城区地表形变

Monitoring ground deformation of non-urban areas based on temporarily coherent targets

永久散射体干涉测量技术(PSInSAR)地表形变监测能力受限于稳定散射体的空间分布密度,在PS点稀疏的非城区不再有效。本文基于临时相干目标(temporarily coherent targets,TCT)局部时序高相干性和在非城区广泛分布的特点,提出改进算法以解决该难题。该算法通过顾及季节性周期变化筛选干涉对以保留TCT信息,并利用双阈值联合筛选法提取TCT,采用多次差分挖掘、分离TCT相位,最后反演得到TCT形变速率和高程修正量。利用TCT算法,采用24景Sentinel-1A卫星影像提取了靖边县2014-10-23—2016-05-09期间地表形变信息。通过PSInSAR的对比验证,表明临时相干目标时序分析方法能显著提高非城区监测目标空间分布密度并能有效地监测非城区地表形变。

The ground deformation monitoring based on permanent scatterers interferometric synthetic aperture radar(PSInSAR)is limited by the spatial distribution density of the PS,especially in non-urban areas with sparse PS distribution.To address this,an improved algorithm is proposed based on temporarily coherent targets(TCT)which maintain high coherence of partial observation period and whose spatial distribution is rich in non-urban areas.After incorporating the seasonal characteristics of ground scatterers,the algorithm screens the interferometric pair to preserve the TCT which can be distinguished by dual-threshold method.After mining and separating the interferometric phase information by multi-differential process,the deformation velocity and elevation correction of TCT are inversed.Twenty-four Sentinel-1A SAR images,acquired between 2014-10-24 and 2016-05-09,are processed to extract the ground deformation of TCT in Jingbian County,Shaanxi Province.Compared with PSInSAR,the results provide evidence that multitemporal analysis method of temporarily coherent targets can significantly increase the spatial distribution density of monitoring targets,as well as effectively and reliably monitor the ground deformation in non-urban areas.