Italian unmanned space vehicle mission: Flight results of the Virtual Air Data algorithm

During the first Dropped Transonic Flight Test mission, carried out by the Italian Aerospace Research Center, although most of the mission objectives were achieved, several failures and operative limitations of the onboard hardware instrumentations were experienced. In order to solve such problems in the successive flight tests and thus to improve the vehicle survival to failures, more robust navigation algorithms were designed. In particular, a novel air data estimation algorithm named Virtual Air Data was designed, providing virtual air data quantities, obtained from a combination of inertial measurements with weather forecast data coming from a meteorological model, representing the onboard virtual sensor. This algorithm was successfully tested during the second mission, and the flight results presented in this article show the effectiveness of the proposed approach. This algorithm may work as a backup solution for conventional air data systems when an Air Data System failure occurs. In addition, the Virtual Air Data architecture appears to be a viable solution to overcome the common limitations of the conventional Air Data Systems. Finally, similarities between the performed second mission and a typical Terminal Area Energy Management flight phase of a re-entry winged vehicle also demonstrate applicability of such technologies to re-entry missions.