Accurate trajectory prediction for typical artillery projectile

Abstract

A full six degree-of-freedom nonlinear model is proposed for the accurate prediction at short and long range trajectories of high and low spin stabilized projectiles via atmospheric flight. The model includes Earth's rotation and ellipsoidal shape, Magnus effect and the atmospheric wind. Furthermore, a modified standard atmospheric model to simulate air density and the speed of sound is used. The computation is performed in time marching scheme. The fourth-order Runge Kutta method is employed for integration. Aerodynamic forces and moments are calculated using aerodynamic coefficients of the projectile that predicted using PRODAS program. The computational flight analysis takes into consideration all the aerodynamics variations by means of the variable aerodynamic coefficients. The computational results of the proposed synthesized analysis give satisfactory agreement. The Static stability, also called gyroscopic stability, for the developed projectile model, is examined to ensure the projectile would remain gyroscopically stable in flight. In addition, the correction capability of range using a drag ring brake module is presented. The simulation results show that the impact accuracy of a conventional projectile using this drag brake module can be improved. The drag ring brake is found to be highly capable for range correction. The deploying of drag brake in early stage of trajectory results in large range correction. The correction occasion time can be predefined depending on required correction of range.