1. Department of Electrical and Electronics Engineering, Lebanese International University, Mazraa, 146404 Beirut, Lebanon
2. LAPLACE, University of Toulouse, UPS, INPT 118 route de Narbonne, 31062 Toulouse Cedex 9, France
3. CNES, 18 avenue Edouard Belin, 31401 Toulouse Cedex 9, France