Accuracy Assessment of Digital Elevation Model Generated by SAR Stereoscopic Technique Using COSMO-Skymed Data
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RESEARCH ARTICLE
Accuracy Assessment of Digital Elevation Model Generated by SAR Stereoscopic Technique Using COSMO-Skymed Data Ritesh Agrawal1 • Anup Das1 • A. S. Rajawat1 Received: 6 October 2017 / Accepted: 8 August 2018 Indian Society of Remote Sensing 2018
Abstract Radargrammetry technique using the stereoscopic synthetic aperture radar (SAR) images is used for the generation of a digital elevation model (DEM) of a region requires only the amplitude images. SAR stereoscopic technique is analogous to the stereo-photogrammetric technique where the optical stereoscopic images are used for DEM generation. While the advantages of the SAR images are their indifference to atmospheric transparency and solar illumination conditions, the side-looking geometry of the SAR increases the complexity in the SAR stereo analysis. The availability of high spatial and temporal resolution SAR data in recent years has facilitated generation of high-resolution DEM with greater vertical accuracy using radargrammetric technique. In the present study, attempt has been made to generate the DEM of Dehra Dun region, India, from the COSMO-Skymed X-band SAR data-pair acquired at 8 days interval through the radargrammetry technique. Here, radargrammetric orientation approach has been adopted to generate the DEM and various issues and processing steps with the radargrammetry technique have been discussed. The DEM was validated with ground measured elevation values using a differential global positioning system and the root-mean-square error of the DEM was found as 7.3 m. The DEM was compared with the reference DEM of the study area generated from the Cartosat-1 stereo data with a model accuracy of 4 m. Keywords Digital elevation model (DEM) Stereoscopic SAR images Radargrammetry COSMO-Skymed Dehra Dun region
Introduction Spaceborne imaging synthetic aperture radar (SAR) data have shown tremendous potential in generation of digital elevation model (DEM) of land surfaces (Zebker and Goldstein 1986; Mercer 1995; Bamler 1999; Dongchen et al. 2004; Parihar et al. 2011; Das et al. 2014). SAR Electronic supplementary material The online version of this article (https://doi.org/10.1007/s12524-018-0835-6) contains supplementary material, which is available to authorized users. & Ritesh Agrawal [email protected] Anup Das [email protected] A. S. Rajawat [email protected] 1
Space Applications Centre, Jodhpur Tekra, Satellite Area, Ahmedabad, Gujarat 380015, India
image pairs acquired at two different incidence angles in the same node or at same incidence angles in opposite nodes with a short interval (few days–weeks) can be used for radargrammetry analysis. The SAR stereoscopic technique, also known as the radargrammetry is analogous to the stereo-photogrammetric technique where optical stereoscopic images are used for generation of a DEM. In analogy with the photogrammetry, the radargrammetry is based on a stereo model coming from two or more SAR images. Although the idea, the procedures and the resulting products
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