Iterative Atmospheric Phase Screen Compensation for Near-Real-Time Ground-Based InSAR Measurements Over a Mountainous Slope

Abstract

In this paper, an atmospheric phase screen (APS) compensation algorithm for a near real-time Ground-Based InSAR (GB-InSAR) over a mountainous area is investigated. A novel APS compensation scheme is proposed to compensate the fluctuated APS caused by a spatial 3D inhomogeneous refractivity index distribution without any a priori knowledge of moving location. The proposed method simultaneously addresses to identify moving pixels by a criterion of absolute velocity estimated by the Coherent Pixels Technique (CPT). The proposed method consists mainly of three steps; (1) the stratified APS compensation, (2) identification of moving pixel candidate, and (3) the residual APS (remained APS after (1)) compensation by Kriging interpolation. The steps mentioned above are iteratively applied in order to increase the accuracy of the whole process. In this framework, we develop the 2D quadratic polynomial model of the refractivity index with respect to slant range and topographic height for modeling the stratified APS. Furthermore, a prediction of the residual APS is achieved by applying the IRF-k Kriging interpolation, taking into account the non-stationarity of the residual APS. We evaluate the proposed method using zerobaseline GB-DInSAR data over a mountainous area located in Minami-Aso, Kumamoto, Japan through the near real-time postlandslide measurement campaign.

A Novel Near-Real-Time GB-InSAR Slope Deformation Monitoring Method

“…In recent years, a large number of GB-InSAR atmospheric correction methods have been proposed, such as ground control points [23], meteorological data [24], modeling corrections [25], etc. In [26], an atmospheric phase correction method that could be used for near-real-time monitoring was further proposed. However, these methods are all based on phase unwrapping, which inevitably reduces the efficiency and accuracy of data processing.…”