The scope of the present work is to analyze the effective coverage of TT&C subsystem of a LEO satellite at an altitude of 700 kilometres. The antenna assembly is made of two units, Main and Fill-In Antennas, accommodated on opposite sides of the spacecraft. Starting from the free-space radiation performance of each of the two antennas, the problem of predicting the global TT&C subsystem radiation pattern in the presence of the spacecraft is treated in order to identify potential blind areas or interferences caused by the neighboring structures. The prediction of electromagnetic fields scattered in complex environments is usually a hard task since the solution cannot generally be expressed in a simple and/or closed analytical form. Therefore a variety of numerical methods have been developed in literature. The effectiveness of a single method depends on the type of the electromagnetic environment and the working frequencies. The calculations of the global TT&C subsystem radiation pattern in presence of the main spacecraft structures are carried out by using full-wave electromagnetic software, CST MICROWAVE STUDIO® (CST MWS) Integral Solver. The Integral Solver is ideally suited for structures that are electrically large with respect to the wavelength, when dominated by electrical conductors. This solver uses a combination of an open boundary integral formulation and a Multilevel Fast Multi-Pole Method (MLFMM), exhibiting an optimal complexity in terms of memory and simulation time compared to the traditional Method of Moment (MoM).
Marcello Zolesi, Thales Alenia Space