Development and evaluation of a six degrees of freedom model of a 155 mm artillery projectile

Sammanfattning: In this Master Thesis, the author has evaluated a six degrees of freedom model of a 155 mm artillery projectile commonly used in the Swedish Armed Forces and compared it to a modified point mass trajectory model of the same projectile. Uncertainties in the six degrees of freedom model were assumed to evaluate the precision of the model compared to the precision of the real fire data. The models were simulated using the software FLAMES, thatuses a spherical earth model, terrain data and measured atmospheric conditions. The real fire data comes from a number of fire series performed by the Swedish Armed Forces in 2001. The results showed that six degrees of freedom model was accurate in length but had an upwards 35 % error in drift when verified against a firetable. When the six degrees of freedom model was compared to a modified point mass model and real fire hits the mean distance to target was about 250 m. A plausible reason for this large mean distance is that the in data used in this thesis had to low order of accuracy. This thesis also showed a large difference in angle of attack between the models during high elevation simulations as well as when there was wind present. The results for the six degrees of freedom model with uncertainties showed that 90 % of all projectiles hit within a 50 m x 75 m ellipse, at a simulated fire distance of about 16 km.