1. Joint Research Centre (JRC), European Commission, 21027 Ispra, VA, Italy
2. School of Civil and Construction Engineering, Oregon State University, Corvallis, OR 97331, USA
3. Faculty of Geodesy and Cartography, Department of Geodesy and Geodetic Astronomy, Warsaw University of Technology, 00-661 Warsaw, Poland
4. Directorate General for Defence Industry and Space (DG DEFIS), European Commission, 1049 Brussel, Belgium