SAR Elevation Control Point Extraction Combining Multistrategy ATLAS Data Preference and Image Matching

To refine the geometric parameters of satellite-based SAR images and improve the stereo positioning accuracy, a method of SAR elevation control point extraction combining multistrategy ATLAS data preference and image matching has been developed. This method is based on the concept of optical remote sensing image elevation control point extraction from satellite-based laser altimetry data. The method employs various strategies, such as non-night observation photon filtering, high confidence photon selection, SRTM DEM-assisted coarse difference rejection, and large eccentricity elliptical filtering kernel flat area photon screening. To extract laser elevation points with high quality and flat area from ATLAS data for ATL03 level products. Then the geocoding of the slant range SAR images is performed using the SRTM DEM. The local Google Earth images are selected as the footprint images according to the plane coordinates of the laser elevation points. The rank self-similarity descriptor is used to match the footprint images with the SAR geocoded images. The coordinates of the SAR images corresponding to the laser elevation points are obtained. Thus, SAR elevation control points are extracted. The extraction of GF-3 SAR elevation control points was performed using ATLAS data from two regions: Dengfeng, China, and Yokosuka, Japan. The geometric parameter refinement of SAR images using extracted elevation control points significantly improved the accuracy of stereo positioning and verified that the method for extracting elevation control points described in this paper is feasible and effective.