The IXV guidance, navigation and control subsystem: Development, verification and performances

The Intermediate eXperimental Vehicle (IXV) [1] is an ESA re-entry lifting body demonstrator built to verify in-flight the performance of critical re-entry technologies. The IXV was launched on February the 11th, 2015, aboard Europe's Vega launcher.The IXV´s flight and successful recovery represents a major step forward with respect to previous European re-entry experience with the Atmospheric Re-entry Demonstrator (ARD) [2], flown in October 1998. The increased in-flight manoeuvrability achieved from the lifting body solution permitted the verification of technologies over a wider re-entry corridor. Among other objectives, which included the characterisation of the re-entry environment through a variety of sensors, special attention was paid to Guidance, Navigation and Control (GNC) aspects, including the guidance algorithms for the lifting body, the use of the inertial measurement unit measurements with GPS updates for navigation, and the flight control by means of aerodynamic flaps and reaction control thrusters.This paper presents the overall Design, Development and Verification logic that has been successfully followed by the GNC and Flight Management (FM) subsystem of the IXV. It also focuses on the interactions between the GNC and the System, Avionics and OBSW development lifecycles and how an integrated and incremental verification process has been implemented by ensuring the maximum representativeness and reuse through all stages.