1. Department of Information Engineering, Polo Universitario “Città di Prato”, 59100 Prato, Italy
2. Telespazio (Leonardo & Thales Company), 00156 Rome, Italy
3. Department of Movement, Human and Health Sciences, University of Rome “Foro Italico”, 00135 Rome, Italy
4. Department of Information Engineering, University of Florence, 50139 Florence, Italy