Intermodulation by Uplink Signal at Low Earth Orbiting Satellite Ground Station

The project "MOST" (Microvariability and Oscillations of Stars) is a Canadian micro satellite space telescope mission. The micro satellite carries a Rumak-Maksutov telescope with an aperture of 15 cm. The size of the satellite is 65 cm times 65 cm times 30 cm and the mass is about 65 kg. The goals of the mission are to analyze the inner structure of stars, set a lower limit to the age of the universe and to search for Exoplanets. The project MOST consists of a low Earth orbiting (LEO) Satellite and three ground stations, one of them in Vienna (W. Weiss and W. Keim, 2003). The Vienna ground station system was set up at the Institute for Astronomy of the University of Vienna in cooperation with the Institute of Communications and Radio-Frequency Engineering of the Vienna University of Technology. The ground satellite station in Vienna is installed in urban area with high penetration of GSM 1800 mobile systems. This paper presents the investigations related to the possibility of disturbances by the intermodulation factors generated by uplink signal and GSM 1800 mobile signals