Enhanced Precise Point Positioning for GNSS Users. - José Miguel Juan Zornoza; Manuel Hernández-Pajares; Jaume Sanz Subirana; Pere Ramos-Bosch; Angela Aragon-Angel; Raul Orus; Washington Ochieng; Shaojun Feng; Marti Jofre; Pedro Coutinho; Jaron Samson; Michel Tossaint (IEEE Trans. Geosci. Remote. Sens., 2012)