The invention relates to a data server (40) used in a system (10) for supplying complementary data, so-called augmentation data, for satellite navigation signals. The inventive server (40) is especially adapted to be used with elements that are compatible with those used in EGNOS technology (European Geostationary Navigation Overlay Service). Said system (10) for supplying augmentation data for the satellite navigation signals comprises at least one calculator (20) for the determination of said augmentation data, said augmentation data being determined from data transmitted by at least one receiving station (S01. . . SON) receiving navigation information sent by means of at least one satellite. Said server (40) comprises a first inlet (401) for receiving the augmentation data transmitted by the calculator (20), a first outlet (402) for transmitting the augmentation data towards at least one user (U01. . . UOK), and a second outlet (403) for re-emitting the augmentation data towards the calculator (20) with a delay that is pre-determined in relation to the reception at the first inlet (401).