To comparative evaluation of efficiency of the satellite communications systems using various orbits

This paper considers the limit relationship between the capacities of a separate transponder (beam) satellite, a multibeam transponder satellite and a multisatellite PCS, depending on their orbit altitudes for a number of significant cases. These cases include identical output in the beam or in the entire transponder satellite when the altitudes are different, and the apertures of the onboard multibeam antennas are identical or when the beam partial areas on the surface of the Earth are identical. The parameters mentioned, in their turn, determine the relationship of the power-mass characteristics, and, accordingly, costs of creating the orbital groupings. By comparing the latter with the capacities, it becomes possible to comparatively evaluate the specific costs for the transmission of an information unit, depending on the orbital altitude, number of satellites in the system, and the beams of the transponder-satellites