In-Orbit Trend Analysis of Galileo Satellites for Power Sources Degradation Estimation Frederic Bard, Aurore Carré, Pablo Fernandez, Maria Nestoridi, Sergio Alia, Aakesh Datta and Olabisi Durodola E3S Web Conf., 16 (2017) 13005 Published online: 23 May 2017 DOI: 10.1051/e3sconf/20171613005