Abstract
The precise knowledge of the ephemerides of the geostationary satellites is a key point in mission control for the satellite control agencies both for planning manoeuvres and for checking their results. The major goal of the PASAGE project (Astrometric Positioning of Geostationary Satellites) is to use earth-based astrometric observations for obtaining precise ephemerides and the subsequent orbit determination. In order to carry out this special ground-based astrometric application, we have developed special algorithms and techniques that make it possible for us to achieve accuracies of a few tenths of an arc second in the geostationary satellite apparent topocentric positions, even from places with high light pollution.
