Aerodynamic parameter identification for symmetric projectiles: An improved gradient based method

In order to estimate the aerodynamic coefficients of a symmetric projectile from free flight range data, an algorithm using traditional linear theory with non-linear programming is investigated. The linear theory solution is reformulated resulting in matrix expressions of improved compactness and simplicity, which provide predictions of yaw, pitch, crossrange, and altitude as functions of downrange travel. The new solution is easily differentiated with respect to aerodynamic coefficients such that a gradient based output error estimation algorithm naturally follows. Numerical results are presented and compared to a previous method that required finite differencing for gradient estimates.