DEM Generation of a Volcano Using Airborne InSAR

摘要

Nowadays, we are able to obtain DEM (Digital Elevation Model) using airborne interferometric SAR (InSAR). However, radar shadowing and layover interfere with generation of the DEM in mountainous areas with steep terrain. To generate the complete DEM in the area, it is necessary to observe with different incident angles and directions, and to compound the DEMs obtained from difference locations. In addition, if we use a small airplane, which tends to be affected by turbulence, the generated DEM contains some errors caused by intense fuselage sway. Therefore, in case of map projection, location errors are caused, and it is very difficult to compound the DEM with accuracy. The volcanic eruption of Miyake Island in Japan, which occurred in July 2000, caused a large-scale cave-in. We observed the crater by an airborne InSAR with two different incident angles from four directions in order to generate the DEM of the inside of the caved crater. After acquisition of the data, we tried to improve the accuracy of the DEM. The method is to repeat the following process, namely motion compensation in consideration of the rough target height in the azimuth compression in time domain and the InSAR data processing. As a result, we were able to obtain comparatively accurate DEM covering the whole of Miyake Island with the inside height information of the crater.