Identification of aerodynamic coefficients of a kinetic energy projectile from flight data

A technique to identify the aerodynamic coefficients of a kinetic energy (KE) projectile using flight data is proposed. Generally speaking, the flight of a projectile is governed by a six-degree-of-freedom model in which eight aerodynamic coefficients also play a part. We will firstly show that only three of the aerodynamic coefficients have an influence on the measurable quantities (velocity, roll rate). We thus propose a reduced model to represent the projectile flight and then an identification technique based on the optimization of a functional that calls into play aerodynamic measurements and coefficients. The minimization of the functional leads to a non-linear system which, after its resolution, supplies the aerodynamic coefficients of the KE projectile and a recalculated flight that better corresponds to the measured flight data.