The Influence of SAR Image Resolution, Wavelength and Land Cover Type on Characteristics of Persistent Scatterer

Abstract

Persistent Scatterers (PS) are points selected by Persistent Scatterer for Synthetic Aperture Radar Interferometry (PS-InSAR) technology. PS density and quality determine the accuracy of deformation monitoring results. A comprehension of PS and its influencing factors could provide suggestions for data selection and parameter setting in the time series of InSAR, and it can also provide the decision basis for radar satellite engineers to select imaging modes for different application requirements. PS characteristics are mainly affected by SAR image resolution, wavelength and land cover type, etc. However, these influencing factors are coupled together, so it is difficult to study the relationship between the single factor and PS characteristics. Therefore, this paper adopted the Split-Spectrum to TerraSAR datasets to construct a series of simulated SAR datasets with different resolutions while keeping the other imaging parameters the same. We found that the PS density presents a declining linear trend as the bandwidth (resolution) decreases, while the deformation patterns of PS obtained from different bandwidth datasets are consistent. In addition, we proposed a simplified model to estimate the PS density obtained from 1/k bandwidth datasets. Then, we compared the PS results obtained from X-band TerraSAR datasets and C-band Sentinel-1A datasets and analyzed the reason for the difference from the perspective of spatiotemporal decorrelation. Finally, combined with the land cover map and Bayesian estimation, we obtained the distribution probability of PS on land cover types.