Practical Horizon Plane for Low Earth Orbiting (LEO) Satellite Ground Stations

Communication via satellite begins when the satellite is positioned in the desired orbital position. Ground stations can communicate with LEO (Low Earth Orbiting) satellites only when the satellite is in their visibility region. The duration of the visibility and so the communication duration varies for each satellite pass at the ground station, specifically for LEO satellites which do move too fast over the Earth [1]. For low cost LEO satellite ground stations in urban environment it will be a big challenge to ensure communication down to the horizon. The communication at low elevation angles can be hindered through natural barriers. Thus, motion (appearance) detection of the satellite above natural barriers enables the practical horizon to be determined. Practical horizon differs from the ideal horizon. This paper discusses the satellites motion detection and the difference in between ideal and practical horizon. For this paper, data recorded at the Vienna satellite ground station within the Canadian space observation project “MOST” (Micro variability and Oscillations of Stars) are applied. 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 RadioFrequency Engineering of the University of Technology. Key-Words: LEO, satellite, horizon, elevation