Robust estimating three-dimensional ground motions from fusion of InSAR and GPS measurements

InSAR can monitor surface defomation with high spatial resolution and high precision, but only in the line-of-sight (LOS) direction. In other side, GPS can monitor completely three-dimensional surface displacements, but only at sparse sites. A robust method based on the Gibbs energy function and BFGS method is used to derive three-dimensional ground motions from the fusion of InSAR and GPS measurement. Comparing to the previous approaches in the literatures, the robust method has the immunity to the numerical instability of the energy function, and therefore always produce stable and high precision solutions. The new method is then applied to area of Southern California. It is demonstrate that the robust method can estimate rigorous and reliable three-dimensional displacements even in the case of small number or unevenly distribution of GPS sites.