Comparison of Observation Performance of Urban Displacement Using ALOS-1 L-band PALSAR and COSMO-SkyMed X-band SAR Time Series Images

We applied PSInSAR to two SAR satellite (ALOS-1 and COSMO-SkyMed) images and analyzed the difference in displacement observation performance according to sensor characteristics. The building layer was extracted from the digital topographic map, and the PS extracted from the SAR image was classified into two groups (building structure and ground surface) for density analysis. The density of PS extracted from the research area was 0.023 point/m(2) for ALOS-1 PALSAR and 0.1 point/m(2) for COSMO-SkyMed, more than 4 times PS was extracted compared to ALOS-1. In addition, not only the PS density in the building, but also the density in the ground were greatly increased. The average displacement velocity of ALOS-1 PALSAR is within +/- 1 cm/yr, while for COSMO-SkyMed it is within +/- 0.3 cm/yr. Although it is difficult to make quantitative comparisons because it does not use the data for the same period, it can be said that the accuracy of X-band SAR system is very high compared to the L-band. In consideration of PS observation density and observation accuracy of displacement, X-band SAR data is very effective in research where it is important to acquire useful signals from the ground surface, such as ground subsidence and sinkhole.