Flight mechanics of a novel guided spin-stabilized projectile concept

Abstract

Precision-guided munitions are of interest to the Army as a means of both reducing collateral damage and increasing the chance of desired effect with the first round fired. Many technical barriers must be overcome to effectively guide a gun-launched projectile. Gun tubes are rifled to impart the appropriate spin to gyroscopically stabilize a statically unstable projectile. Extremely high spin rates complicate the guidance problem for precision-guided munitions. Manoeuvres achieved through some control mechanism must be actuated at the projectile spin rate. Few control mechanisms have been developed for spin-stabilized projectiles. A novel manoeuvre concept is introduced in this effort. The effectiveness of this concept was investigated through a fundamental derivation of flight mechanics and aerodynamic modelling. This derivation and simulation implementation was verified with existing six degree-of-freedom methods. The manoeuvrability of the airframe and power requirements was assessed by the development of a flight control law. Results suggest sufficient manoeuvrability since the control authority is larger than the ballistic dispersion. The guided airframe exhibited no dynamic flight instabilities. Estimates of the power requirements were within current battery technology and size constraints.