1. Research Centre for Spatial Information and Telecommunications Department, University Politehnica of Bucharest (UPB), Bucharest, Romania
2. Laboratoire Grenoble Images Parole Signal Automatique, Université Grenoble Alpes, Saint-Martin-d'Hères, France
3. European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), AG Noordwijk, The Netherlands
4. Telecommunications Department, University Politehnica of Bucharest (UPB), Bucharest, Romania