Development of a 6- DOF Trajectory Simulation Model for Asymmetric Projectiles

Abstract

Precision is important to modern artillery where long range cannons can fire unguided and guided projectiles for many kilometres. Precision projectiles are in demand, because it is both cost effective (increasing the chance to hit the target with the first shot) and reduce collateral damage (minimises the risk of hitting friendly forces). This requires accurate prediction of the flight path using trajectory simulation models. The so-called 6-DOF projectile exterior ballistic model is the most complex simulation model and allows for the modelling of all the projectile motions. The aim of this study was to develop and verify the correctness of a 6 Degrees-of-Freedom trajectory simulation model known as 6-DOF, by conducting case studies to gain insight in the flight behaviour of mortar bombs. This literature study provided valuable insight on the various trajectory simulation models. The information from this literature was used to define models to be incorporated in a 6-DOF trajectory simulation that can be used to analyse both symmetric and asymmetric projectiles. Based on the case studies selected in the verification part used for this study, the input data requirements for each case study selected for modelling purposes, were entered into the 6-DOF model and output results were generated. The 6-DOF output results were compared to results from other simulation programs, as well as the results that predicted by analytical solutions. The 6-DOF model produced similar outputs, within a difference of +0.36% to +0.49% in range and - 0.31% to -2.70% in drift, to that of the PRODAS V3 program. The differences between the results from the two programs are relatively small, except for drift. In addition, the results illustrated that the 6-DOF model and WinFast program produce comparable results when starting with the same initial parameters. Lastly, the 6-DOF model program was conducted case studies to find possible causes for the flight behaviour of real test results captured during the dynamic firing of mortar bombs. The results of the cases study indicated good agreement with experimental results. The 6-DOF results matches the radar data captured during dynamic testing.