Add to ORKGThis paper presents the first step towards the realization of a solid state high power amplifier (SSPA) for Galileo, the European Global Navigation Satellite System. The idea is to have a reliable and performing power amplifier capable to replace the current solution based on the adoption of a Travelling Wave Tube Amplifier (TWTA) at a lower mass, weight and higher efficiency. Preliminary prototypes have been designed, realized and tested, using the GH50-10 GaN technology, provided by United Monolithic Semiconductor foundry. Experimental results (in continuous wave operating mode) have shown efficiency and output power levels higher than 60% and 80W respectively, at 1575.42MHz (Galileo E1 band)