Flush Air-Data Sensing System for a Hypersonic Flight Experimental Vehicle

This paper presents the design progress on a flush air-data sensing (FADS) system for a hypersonic winged vehicle with an ogive-shaped nose. Target conditions for the FADS system are Mach 3.0–7.0 with angles of attack up to [Formula: see text] and sideslip up to [Formula: see text]. A surface pressure database was generated through a viscous numerical simulation for the vehicle nose. The FADS system was designed to estimate air data in real-time at hypersonic speeds by using some unique combinations of differential pressures obtained at the nose surface, which are correlated with air-data states. The surface pressure database and designed estimation algorithms were validated by comparing with wind tunnel experimental results. Results indicated that the designed FADS system can estimate air data within the uncertainty of 5.2% for the freestream Mach number, 7.0% for the dynamic pressure, [Formula: see text] for the angle of attack, and [Formula: see text] for the angle of sideslip in the range of Mach 4.0–7.0. Other air data, such as static pressure and altitude, were also successfully estimated along with the assumed flight trajectory. The proposed FADS algorithm can estimate air data with an acceptable level of uncertainty while retaining robustness against sensor failures at a low computational cost.