Calculation of Accurate Antenna Pointing for Terminals Working with Geosynchronous Communications Satellites.

摘要

Terminals working with communications satellites must have the capability to produce accurate antenna pointing from information provided by the operations center. Usually it takes the form of an (mean) element set for the satellite orbit, which must be propagated by the terminals and from which pointing must be calculated. This report addresses the problem for geosynchronous communications satellites, most non-Soviet communications satellites being in such orbits. First the nature of geosynchronous orbit propagation is summarized, with principal perturbations highlighted, and then the problem of element set transfer is discussed from a practical point of view. Since most operations centers do not maintain element sets for their satellites (but rather receive ephemeris information from another source), this discussion is designed to maximize the accuracy and lifetime of a transferred element set. An example is provided to demonstrate the need for compatible element sets and software, and to show a solution to a timely problem involving element set transfer. This report was presented at the Sixteenth Meeting of The Technical Cooperation Program (TTCP) Subgroup S (Communication Technology and Information Systems) Technical Panel STP-6 (Space Communications), which was held at the Royal Signals and Radar Establishment (RSRE), Malvern, United KIngdom, 4-8 December 1989. (rh)