Galileo System Navigation Antenna for Global Positioning

Within the frame of Galileo project, EADS CASA ESPACIO has been developing the navigation antenna for the space segment of the future European Global Positioning System. The main antenna requirements are the isoflux corrected pattern in the earth coverage (12.67deg semi-cone angle), circular polarisation, (around 1 dB axial ratio in the coverage), two independent self-diplexed L band (1.15-1.6 GHz) transmit bands operation (two channels E5 and E6 in Low Band 2 x 50 W and one channel LI in High Band 75W) and high parameters stability (including phase centre location and group delay). The selected design is a 1.4 m diameter flat array of 45 stacked patches with hexagonal lattice and less than 14 kg weight, manufactured in suspended substrate multi-layer printed technology developed by EADS CASA ESPACIO in previous projects. The design includes array design, beam forming networks, structural design and thermal control. One electrical model has been manufactured and qualified along with the two flight models of the demonstrator GSTB-V2 (Galileo System Test Bed-Version 2) [1], one of them to be launched at the end of 2007, on-board GIOVE-B satellite (see figure 1). The design description and test results are presented.