| 时间序列InSAR技术中的形变模型研究 |
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| 引用本文： | 张永红,吴宏安,孙广通.时间序列InSAR技术中的形变模型研究[J].测绘学报,2012,41(6):864-869. |
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| 作者姓名： | 张永红 吴宏安 孙广通 |
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| 作者单位： | 1. 中国测绘科学研究院;
2. 防灾科技学院 |
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| 基金项目： | 国家863计划，对地观测技术国家测绘地理信息局重点实验室项目 |
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| 摘 要： | 时间序列InSAR技术,包括PS-InSAR技术和小基线集InSAR技术, 能有效克服传统D-InSAR的失相干限制, 逐步成为形变测量中的实用化技术。但是, 现有时间序列InSAR技术主要采用线性函数对真实形变进行模拟, 在真实形变呈现强烈的非线性时, 这种处理将不能得到正确的形变结果。本文就时间序列InSAR的形变模型问题展开研究, 首先从干涉相位模型解算的方法入手, 深入分析了线性形变模型的不足, 当干涉点目标的密度不够并且真实形变的非线性较强时, 干涉相位方程的解将会发散。根据魏尔斯特拉斯逼近定理, 提出以高阶多项式取代线性形变模型, 并给出了基于多项式形变模型的干涉相位方程解算方法。 利用太原市2003-2009年的23景ENVISAT ASAR影像, 分别采用线性形变模型和三次多项式形变模型, 利用小基线集技术进行了形变反演。将这两种方法得到的结果分别与水准测量结果进行了比较。结果表明, 采用多项式形变模型不仅能取得更高的形变测量精度，而且能提高点目标的密度。由于高阶多项式总能比低阶多项式更准确地拟合连续函数, 因此本文提出的多项式形变模型在时间序列InSAR形变监测中具有广泛的应用价值。
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| 关 键 词： | 合成孔径雷达干涉测量 形变监测 时间序列InSAR 多项式模型 |
| 收稿时间： | 2011-10-12 |
| 修稿时间： | 2012-06-13 |
Deformation Model of Time Series Interferometric SAR Techniques |
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| ZHANG Yonghong,WU Hongan,SUN Guangtong.Deformation Model of Time Series Interferometric SAR Techniques[J].Acta Geodaetica et Cartographica Sinica,2012,41(6):864-869. |
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| Authors: | ZHANG Yonghong WU Hongan SUN Guangtong |
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| Institution: | 1.Chinese Academy of Surveying and Mapping,Beijing 100830,China;2.Department of Disaster Prevention Engineering,Institute of Disaster Prevention,Sanhe 065201,China |
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| Abstract: | Abstract: Time series Interferometric SAR (InSAR) techniques represented by permanent scatterers InSAR and small baseline subset approaches overcome the decorrelation limitations associated with traditional repeat-path differential SAR interferometry, thus have been gradually put into operational uses for ground deformation mapping. It is usually assumed that the deformation process can be modeled as a dominant linear component plus a nonlinear residual component when time series InSAR techniques are used. Whereas, if the real deformation scenario presents strong nonlinearity, this kind of deformation model may bring out erroneous results. This paper focuses on the deformation model of time series InSAR analysis. At first, the process of solving the interferometric phase equations and estimating the linear deformation rate is analyzed for a typical time series InSAR analysis. When the reality of deformation is deviated significantly from a linear model, and at the same time the density of extracted point targets is not good enough, the linear deformation rate can not be estimated accurately. Then, on the basis of the famous Weierstrass approximation theorem, we propose a polynomial deformation model, that is, the whole deformation will be represented by a polynomial plus the residual rather than a straight line plus a nonlinear component. Also the method to solve the interferometric phase equations under the polynomial deformation model is given. The proposed method is tested to map the ground subsidence of Taiyuan, Shanxi province of China. Totally 23 ALOS PALSAR images acquired between 2003 and 2009 are processed with the small baseline approach. In comparison, the small baseline approach with both the linear deformation model and a three-order polynomial deformation model are conducted. Both results of subsidence retrieval are compared with the leveling observation. It is demonstrated that the small baseline approach with the 3-order polynomial model can not only achieve more accurate deformation estimate, but also generate denser point targets. Since a continuous process can always be better approximated by a higher-order polynomial than a lower-order one, the proposed polynomial deformation model has the potential of replacing the wide-used linear deformation model for time series InSAR analysis. |
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| Keywords: | SAR interferometry deformation mapping time series InSAR polynomial deformation model |
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