Analysis of spacecraft antenna systems: Implications for STEREO/WAVES

International audienceThe STEREO/WAVES experiment is considered to provide measurements of the non-thermal radio spectrum from a few kHz up to about 16 MHz, performed by three 6-m long orthogonal monopole antennas and a set of receivers (fixed-, high-, and low frequency receiver). This system performs real-time calculation of antenna voltage coherence products and, then, enables the determination of direction of arrival and polarization state of incident radio waves. Analysis of such kind of antenna system is necessary in order to define the reception properties which crucially depend on the overall spacecraft configuration. The concept of effective length vector ( heff) determination is applied to yield corresponding information on the deviation of heff from the physical rods, in dependence of frequency. Various methods are evaluated (rheometry for frequencies up to 1 MHz), wire-grid modelling and in-flight calibration, and their implication to the SWAVES experiment are discussed