Deformation Field Formation Algorithm Based on Modified Kriging Interpolator in GNSS-Based InBSAR

Global navigation satellite system-based bistatic synthetic aperture radar interferometry (GNSS-based InBSAR) is a radar remote sensing technique for measuring surface deformation with mm-level accuracy. However, it suffers from a low signal-to-noise ratio (SNR) and low image resolution, resulting in few persistent scatterers (PS) extracted. Thus, deformation measurements are more sparsely compared with other InSAR and an accurate interpolator is needed to obtain the deformation field. In this letter, a deformation field formation algorithm based on a modified Kriging interpolator is proposed to obtain the deformation field over the whole scene in GNSS-based InBSAR. First, the deformation measurements on the PS are divided into two sets by an adaptive threshold, and then the linear optimal matching model is constructed to overcome the invalidity of fitting parameters. Second, the spherical model re-fitting is used to obtain the final Kriging weights. The raw data of Beidou navigation satellites are used to validate the effectiveness of the proposed algorithm.