Evaluation and comparison of different radargrammetric approaches for Digital Surface Models generation from COSMO-SkyMed, TerraSAR-X, RADARSAT-2 imagery: Analysis of Beauport (Canada) test site P. Capaldo a,⇑ , A. Nascetti a , M. Porfiri a , F. Pieralice a , F. Fratarcangeli a , M. Crespi a , T. Toutin b a DICEA, Geodesy and Geomatics Division, University of Rome ‘‘La Sapienza’’, Italy b Natural Resources Canada, Canada Centre for Remote Sensing, Ottawa, Ontario, Canada article info Article history: Received 2 November 2013 Received in revised form 13 May 2014 Accepted 13 May 2014 Available online xxxx Keywords: High resolution SAR imagery Radargrammetry Orientation models Digital Surface Models abstract In this manuscript we analyze the potentialities of the radargrammetric DSMs generation using high res- olution SAR imagery acquired by three different platforms (COSMO-SkyMed, TerraSAR-X and RADARSAT- 2), with particular attention to geometric orientation models. Two orientation models are considered and compared: Toutin’s model (Canada Center for Remote Sensing), implemented in the commercial software package PCI-Geomatica and based on Ground Control Points (GCPs), and the radargrammetric model implemented in the scientific software SISAR (University of Rome La Sapienza), based on images metada- ta orbital information only. Moreover, a comparison between the DSMs following the image matching approaches implemented in PCI-Geomatica and SISAR has been performed. The analysis has been carried out over Beauport test site (Quebec, Canada), where three overlapping stereopairs, one for each of the mentioned platform, were acquired and a LiDAR ground truth and a dense set of GNSS Check points (CPs) are available. The presented results appear promising: DSMs accuracy are within 4 and 5 m for all sensors, independently from orientation model (with or without GCP) and image matching approach, provided good relative orientation is guaranteed, what mainly attains to the quality of metadata orbital information. Ó 2014 Published by Elsevier B.V. on behalf of International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). 1. Introduction The satellite remote sensing technology offers the opportunity to have continuous observation of Earth’s surface for application, with short acquisitions and revisit times, satisfying the demand for monitoring rapid changes in the ground and anthropic activi- ties. In particular, the SAR (Synthetic Aperture Radar) high resolu- tion satellite imagery could offer night-and-day and all-weather functionality (clouds, haze and rain penetration), that represents an important advantage for time-series analysis and for rapid mapping. Starting from SAR data, one of the most important derived prod- ucts are the Digital Surface Models (DSMs). These products allow to have a synoptic knowledge of the land morphology, with different level of accuracy and details, depending on the characteristics of the sensor. There are two main techniques to generate DSMs from SAR data: the well-known interferometric approach and the less used but promising radargrammetric one (Hanssen, 2001; Rossi et al., 2012). Radargrammetry was first used in the 1950s and it represents an alternative solution able to avoid the classical decorrelation problem affecting the interferometric technique especially over areas with vegetation/forest. Then, the radargrammetric approach was less and less used, due to the quite low resolution in amplitude of radar image, if com- pared to their high resolution in phase (Leberl, 1990). Presently, the interest for the radargrammetric approach to DSMs generation has been growing thanks to the availability of very high resolution imagery acquired by new SAR sensors, as COSMO-SkyMed (CSK), RADARSAT-2 (R2) and TerraSAR-X (TSX), which are able to supply imagery up to 1 m GSD (Ground Sample Distance) (Toutin and Gray, 2000; Capaldo et al., 2011; Perko et al., 2011; Balz et al., 2013; Gutjahr et al., 2013). In particular, the Italian CSK mission is a four-satellite constellation (the last was launched in 2010), http://dx.doi.org/10.1016/j.isprsjprs.2014.05.007 0924-2716/Ó 2014 Published by Elsevier B.V. on behalf of International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). ⇑ Corresponding author. Tel.: +39 0644585087. E-mail addresses: paola.capaldo@uniroma1.it (P. Capaldo), andrea.nascetti@ uniroma1.it (A. Nascetti), martina.porfiri@uniroma1.it (M. Porfiri), francesca.pieralice@ uniroma1.it (F. Pieralice), francesca.fratarcangeli@uniroma1.it (F. Fratarcangeli), mattia.crespi@uniroma1.it (M. Crespi), thierry.toutin@CCRS.Nrcan.gc.ca (T. Toutin). ISPRS Journal of Photogrammetry and Remote Sensing xxx (2014) xxx–xxx Contents lists available at ScienceDirect ISPRS Journal of Photogrammetry and Remote Sensing journal homepage: www.elsevier.com/locate/isprsjprs Please cite this article in press as: Capaldo, P., et al. Evaluation and comparison of different radargrammetric approaches for Digital Surface Models gen- eration from COSMO-SkyMed, TerraSAR-X, RADARSAT-2 imagery: Analysis of Beauport (Canada) test site. ISPRS J. Photogram. Remote Sensing (2014), http://dx.doi.org/10.1016/j.isprsjprs.2014.05.007