Effect of dynamics on operational characteristics of on-board deployable space antenna

Abstract

Space radio communication is widely used in different communication systems all over the world. Antenna is one of the central units of space radio communications. Lately, there is a tendency to apply large deployable antennas in orbit. A great number of narrow beams with high gain factor, global and control beams with a possibility of changing the covered area after Earth commands can be formed using such kind of antenna. It provides a high level of flexibility when using satellite communication systems.

A number of the complicated engineering problems should be solved when developing antenna of such a class. In particular, these are the problems of antenna deploying, keeping its shape, the effect of antenna on the dynamics of a carrying space vehicle, as well as studying the parameters of reception areas with accounting for the spacecraft dynamics. In satellite communication systems the spacecraft’s position towards a ground-based station changes in time due to orbital movement of space vehicles and different disturbing factors, which define both orbital movement changes and vehicle orientation. It is known that due to power losses a deviation of the beam from the «ground station - space-craft» direction should not exceed a hundredths fraction of a degree.

The paper presents an analysis of the effects of dynamic processes, spacecraft orientation, on characteristics of the large on-board space antenna. The real pattern of the signal reflection accounting for the spacecraft dynamics is compared with the directive pattern of antenna. Procedure is given for the constructing of cover areas, which ensure carrying out a safe radio communication with taking into account dynamic process of spacecraft’s orientation. The problems are considered of bringing the antenna into operational condition when the spacecraft has been injected into orbit.