Advanced Receiver Autonomous Integrity Monitoring extends RAIM to multiple constellations and dual frequency, with the goal of providing worldwide coverage of vertical guidance for aircraft. Availability simulations have shown that ARAIM based on GPS L1-L5 and Galileo E1-E1a could provide global coverage of vertical guidance. However these simulations rely on a set of assumptions on the measurements. In this paper we analyze a set GPS and Galileo measurements collected in flight. We characterize the multipath of different signal combinations and compare them to the models assumed in the ARAIM simulations. Using these models we apply the ARAIM airborne algorithm for set of constellation – signal configurations.