This paper addresses a novel GPS antenna system for spin-stabilized sounding rockets and launch vehicles. It describes the concept as well as the first realization of the newly developed system. Furthermore it presents the results of on-ground tests conducted on a turn-table with
the system installed into a mock-up of a rocket section. The promising outcome of these tests justified the subsequent preparation of a flight experiment. In the second part of this paper, the results of the maiden flight of the IGAS system onboard a real sounding rocket, the Rexus-4 vehicle, are summarised and discussed. The qualification flight has demonstrated that the system, in general, performs well and even outperforms the traditionally used combination of tip and blade antennas. However, it has also been recognized, that further adaptations in the GPS receiver software
