短基线INSAR相干点探测及应用

短基线INSAR相干点探测及应用 Stable pointwise target detection method and small baseline subset INSAR used in beijing subsidence monitoring 刘利敏 LIU Limin 1 first-author 宫辉力 GONG Huili 2 3 余洁 YU Jie 1 2 3 李小娟 LI Xiaojuan 2 3 柯樱海 KE Yinghai 2 3 武汉大学遥感信息工程学院 武汉大学遥感信息工程学院 School of Remote Sensing and Information Engineering, Wuhan University School of Remote Sensing and Information Engineering, Wuhan University 首都师范大学资源环境与旅游学院 首都师范大学资源环境与旅游学院 College of Resources Environment and Tourism, Capital Normal University College of Resources Environment and Tourism, Capital Normal University 首都师范大学资源环境与地理信息系统北京市重点实验室 首都师范大学资源环境与地理信息系统北京市重点实验室 Beijing Key Laboratory of Resource Environment and Geographic Information System, Capital Normal University Beijing Key Laboratory of Resource Environment and Geographic Information System, Capital Normal University 提出一种结合子孔径相关测度的时序高相干点探测方法,首先对时序SAR影像进行谱分解获得子孔径视图,通过时序子孔径相关测度进行强散射点筛选,然后分别根据振幅离差和干涉相位空间相关性,对目标点进行相位稳定性分析,探测出既满足强散射且在时间序列上散射稳定的高相干点。利用改进的点探测方法和短基线INSAR技术,对北京2003—2009年间40景ASAR影像进行相位建模,获取地面沉降时空分布特征,分析典型地物时序沉降过程,研究北京地面沉降与地下水开采关系。结果表明:相比已有方法,本文结合子孔径相关测度的高相干点探测结果更准确可靠;利用本文点探测方法反演的历史累积沉降信息,与水准结果一致,平均速率之差在3.69 mm/a以内,中误差为1.36 mm/a;研究区地面沉降最大速率达92.25 mm/a,空间不均匀分布明显,地面沉降量与地下水开采量呈分段的非线性相关。 Identification of stable pointwise target is an important procedure in multi temporal multi-temporal INSAR analysis and application in monitoring regional surface deformation. The accurate identification result helps to improve the land subsidence inversion precision.Various methods for pointwise target detection have been proposed during the past two decades from different respective. The methods can be divided into some main categories according to the criteria for coherence point selection, such as amplitude dispersion index DA, signalto-Clutter ratio and phase stability. The DA method performs a time series analysis on amplitude instead of phase, and reflects the stability of series amplitude. The advantage of coherence point selection by phase stability can identify some special objects with a stable phase, which further increases the density of the stable pointwise target points, but ignores the highly scattering reflection characteristics of the coherent point. The existing methods take insufficient account of the overall features of stable pointwise targets. For ensuring stable scattering mechanism and temporal stability of pointwise target, an improved method with subaperture correlation was proposed in this paper. First, the subaperture correlation properties IHP of SAR images were obtained by spectral decomposition. Then the stability of targets is evaluated based on series two-aperture spectral coherence, by which the coherence points with high scattering could be identified and detect as PSC1.The DA threshold is utilized as the second criterion, which means any pixel in PSC1 with amplitude dispersion less than 0.4 can be determined as PSC2 Then phase stability analysis was carried out to screen out the true stable points from PSC2 with the Characteristics of high scattering mechanism and temporal stability. The experiments of stable pointwise target detection were performed using 33 high resolution SAR images collected by the Terra SAR X-band radar sensor covering Beijing. The detection results demonstrated that the improved method can detect more accurate and reliable pointwise targets than those identified by traditional methods To further confirm the effectiveness of the proposed method, the small subset INSAR technique based on the proposed coherence point detection method was adopted to retrieve the ground deformation by 40 scenes dataset acquired from 2003 to 2009 in Beijing. The vertical surface displacement rates during this period was validated by the leveling observations, with RMSE =1.36 mm/a, indicating two types of subsidence matched very well. The maximum subsidence rate of Beijing in investigated area has reached –92.25 mm/a, with an obvious uneven spatial distribution. Subaperture correlation is sensitivity to the high scattering body and can ensure stable scattering mechanism and temporal stability of pointwise target. Both coherence point detection results and the primary surface deformation proved the effectiveness of the proposed method. The deformation result during 2003–2009 has undergone severe land subsidence with high spatial aggregation characteristic, and the regional subsidence and the groundwater exploitation reveal good corresponding relationship, the more exploitation, the higher deformation rate. 子孔径分解 高相干点探测 短基线INSAR 时空分布 地下水 Subaperture decompositions high coherence point detection small subset INSAR Temporal-spatial distribution ground water TN957.52 国家自然科学基金（编号:41130744,41171335,41401493）;国家重点基础研究发展计划（973计划）前期研究专项课题（编号:2012CB723403）~~ 2021-06-09 4 20