Applicazione e valutazione di accuratezza di un modello radargrammetrico per stereo coppie COSMO-SkyMed acquisite in modalità Spotlight

Digital elevation models have large relevance in some territorial applications, such as topographic mapping, spatial and temporal change detection, feature extraction and data visualization. Two different methods to extract absolute or relative elevation from SAR data are interferometry and radargrammetry, both using a couple of images of the same area acquired from two different points of view. At present, the importance of the radargrammetric approach is rapidly growing due to the new high resolution imagery (up to 1 m GSD) which can be acquired by COSMO-SkyMed, TerraSAR-X and RADARSAT-2 sensors in Spotlight mode. It is well known that the two main steps for DSMs generation from SAR imagery according to the radargrammetric approach are the stereo pair orientation and the image matching for the detection of homologous points. In this paper the topics related to image orientation of SAR stereo pairs through an orientation model based on geometric reconstruction are investigated. The new model, implemented in the scientific software SISAR (Software per Immagini Satellitari ad Alta Risoluzione ) has been tested on two SAR stereo pair acquired in Spotlight mode on the test site of Mausanne (Southern France) and on Merano (Northern Italy). The same data set has been tested in the commercial software PCI Geomatica v. 10.3, in order to evaluate the accuracy of the orientation performed with Toutin rigorous orientation model.