A DEM fusion method for ascending and descending orbit StereoSAR DEMs in complicated mountain areas considering SAR echo intensity

Abstract

To extract the high-quality DEM in complicated mountain areas, a DEM fusion method for ascending and descending orbit StereoSAR DEMs considering Synthetic Aperture Radar (SAR) echo intensity is proposed. After the analysis for the influence of terrain features and SAR side-looking imaging characteristics on radar echo intensity and DEM accuracy, four TerrasAR-X images with the stripmap mode and the 3 m spatial resolution covering a certain area of Maoxian County, Sichuan Province, China, was selected as the experimental area. StereoSAR technology was used to extract the ascending orbit StereoSAR DEM and the descending orbit StereoSAR DEM, respectively, and the corresponding radar echo intensity map was calculated. Then, while comparing the radar echo intensity corresponding to the same point position, DEM fusion was carried out, and the accuracy of DEM before and after the fusion was analyzed with the ground points measured by GNSS-RTK as reference data. Finally, a high-quality DEM with a 3 m spatial resolution in the experimental area was obtained. The DEM accuracy was improved on all slopes, and the mean absolute deviation (MAD) improved to 4.798 m, the standard deviation (SD) improved to 6.087 m and the LE90 improved to 40.48 m. The experimental results indicate that the fusion method of high-resolution ascending and descending orbit StereoSAR DEMs considering SAR echo intensity can effectively extract DEM with high accuracy and reliability, which can provide technical support for obtaining high-quality terrain information in similar areas.