1. Department of Telecommunications and Systems Engineering, IEEC-CERES, Universitat Autònoma de Barcelona (UAB), Barcelona, Spain
2. Institute of Space Technology and Space Applications (ISTA), Universität der Bundeswehr München, Neubiberg, Germany
3. Aeronautics Institute of Technology (ITA), São José dos Campos, Brazil
4. European Commission, Joint Research Centre (JRC), Ispra, Italy