Persistent Scatterer Analysis Using Dual-Polarization Sentinel-1 Data: Contribution From VH Channel

Abstract

The regular acquisition and relatively short revisit time of Sentinel-1 satellite improve the capability of a persistent scatterer interferometric synthetic aperture radar (PS-InSAR) as a suitable geodetic method of choice for measuring ground surface deformation in space and time. The SAR instrument aboard the Sentinel-1 satellite supports operation in dual polarization (HH–HV, VV–VH), which can be used to increase the spatial density of measurement points through the polarimetric optimization method. This study evaluates the improvement in displacement mapping by incorporating the information obtained from the VH channel of Sentinel-1 data into the PS-InSAR analysis. The method that has shown great success with different polarimetric data performs a search over the available polarimetric space in order to find a linear combination of polarization states, which yields the optimum PS selection criterion using the amplitude dispersion index (ADI) criterion. We applied the method to a dataset of 50 dual-polarized (VV–VH) Sentinel-1 images over Trondheim city in Norway. The results show overall increase of about 186% and 78% in the number of PS points with respect to the conventional channels of VH and VV, respectively. The study concludes that, using the ADI optimization, we can incorporate information from the VH channel into the PS-InSAR analysis, which otherwise is lost due to its low amplitude.