汪友军, 胡俊, 刘计洪, 孙倩. 融合InSAR和GNSS的三维形变监测:利用方差分量估计的改进SISTEM方法[J]. 武汉大学学报 ( 信息科学版), 2021, 46(10): 1598-1608. DOI: 10.13203/j.whugis20210113
引用本文: 汪友军, 胡俊, 刘计洪, 孙倩. 融合InSAR和GNSS的三维形变监测:利用方差分量估计的改进SISTEM方法[J]. 武汉大学学报 ( 信息科学版), 2021, 46(10): 1598-1608. DOI: 10.13203/j.whugis20210113

融合InSAR和GNSS的三维形变监测:利用方差分量估计的改进SISTEM方法

  • 摘要: 利用干涉合成孔径雷达(interferometric synthetic aperture radar, InSAR)技术可以获取空间连续的地表形变监测结果,但仅能得到真实三维形变在雷达视线方向上的一维投影,降低了地表形变解译的可靠性。全球导航卫星系统(global navigation satellite system, GNSS)可提供高精度的三维形变结果,但其空间分辨率较低。因此可通过融合InSAR和GNSS来实现高精度高空间分辨率的三维地表形变监测。提出利用方差分量估计(variance component estimation, VCE)方法对经典的联合大地和卫星同步形变测量值的应变张量估计(simultaneous and integrated strain tensor estimation from geodetic and satellite deformation measurements, SISTEM)方法进行改进,发挥SISTEM方法可以考虑相邻点地表形变的空间相关性的优势,优化了函数模型中InSAR和GNSS观测的构成比例,引入VCE方法精确估计了各类观测值的后验方差,进而实现了高精度的三维地表形变测量。首先通过设计模拟实验对所提方法进行了验证,然后将该方法应用于2007年夏威夷基拉韦厄火山喷发案例中。相较于SISTEM方法,该方法在东西、南北、垂直向解算的形变精度均有大幅提升。

     

    Abstract:
      Objectives  Simultaneous and integrated strain tensor estimation from geodetic and satellite deformation measurements(SISTEM) is a popular method in this field due to its advantage of no-need for the interpolation of global navigation satellite system(GNSS) observations. However, the performance of the SISTEM method is greatly limited due to theinaccurate determination of the prior variance.
      Methods  Va-riance component estimation(VCE) algorithm is introduced to improve the SISTEM method.The strain model (SM) is used to establish the linear relationship between three-dimensional surface deformation of the target point and those of the neighborhood point.Different from the SISTEM method that only employs the InSAR observations of the target point when constructing the function model, the proposed method not only employs the InSAR observations of the target point, but also exploits an amount of nearest InSAR observations around it.This can improve the reliability of the SISTEM method in the region of lacking GNSS observations. In order to meet the requirement of VCE that the number of all types of observations are roughly equal, the number of both types of InSAR observations (i.e., ascending and descending) are approximately 3 times as that of GNSS observations.
      Results  Compared with those of the SISTEM method, the root mean square error(RMSE)from the proposed method achieve an improvement of 56.3%, 41.9% and 41.8% in east west(EW), south north(NS), up down(UD) components, respectively.In addition, the average weights of the interferometric synthetic aperture radar(InSAR) and GNSS observations derived from the proposed method is closer to the theoretical value than those from the SISTEM method. The real data experiments were then carried out by using the data acquired from the area near Kilauea Volcano on the island of Hawaii, US, including 29 GNSS observations and two pairs of ALOS PALSAR images in 2007. As expected, the accuracies of the proposed method are also improved by 31.4%, 18.6% and 22.8% in EW, NS, UD components, respectively, compared with those of the SISTEM method.
      Conclusions  It is found that the proposed method has better resistance to spatial decorrelation in the regions without sufficient GNSS data since more InSAR observations were used to form the observation equation.In addition, the results from the proposed method are less affected by local abrupt deformation.

     

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