Inverse Estimation of the Flight Dynamics of a Hypersonic Aircraft Prototype via Shock Wave Measurements

This study investigates the inverse estimation of the trajectory, position, velocity, and roll angle of objects moving at supersonic speeds based on the emitted shock waves, recorded by a sensor array. The inverse problem is solved in the context of supersonic free-flight tests. Space-time pressure signatures for the forward solution of the free-flight shock emission are calcu lated by solving the Euler equations using the advection upstream splitting method for the body in supersonic flight. Subsequently the computed bound ary conditions on the H/L=5 cylinder surrounding the trajectory are used for the inverse estimation of the roll angle given a set of shock wave field measurements. The pressure field is modelled using a hybrid aeroacoustic computational fluid dynamics model paired with an equivalent multipole ap proach where equivalent sources align with the shock wave detachment points on the trajectory for the respective sensors. The proposed methods are val idated using experimental shock wave recordings where scaled-down proto types of a hypersonic aircraft were launched from a cannon with a velocity of Mach 4.72. Electromagnetic radio direction and ranging measurements, high-speed camera recordings and cardboard penetration measurements sup port the findings.