Ebook: Analytical model development and impulse thrusters pairing guidelines for trajectory corrections of spin - stabilized projectiles

American institute of Aeronautics and Astronautics. – 17 p.A novel method for correcting the trajectory of artillery projectile using pairs of impulse thrusters is described in this paper. Standard thruster-guided spin-stabilized projectile usually incorporates squibs at the center-of-mass in order to avoid generating yaw and thus increasing the drag. However, by locating the impulse thrusters aft of the center-of-mass, it is possible to increase significantly the correction in drift. This is explained by the fact that in such case, the deflection results from the aerodynamic jump due to the projectile oscillation in addition to that of the impulses when the thruster is located aft of the projectile. In order to benefit from the added drift correction obtained by locating the thrusters, a way from the -center-of-mass and avoid the added drag generated by the induced pitching and yawing motion, an optima) combination of thruster can be achieved by considering pairs of impulses which have the double objective of maximizing the deflection and minimizing the drag due to the oscillations. In this paper, the linear theory of ballistic is used to develop an analytical model representing the motion of a projectile subjected to. impulse thrusters. Using the linearized equations of angular motion and considering ideal cases, the optimization scheme for using double impulses is defined by three rules. The latter are then assessed in the case of actual projectiles, using 6-DOF computations.