• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.6
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• pp.728-735
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• 2015

A gas gun system to replicate the flight motions of large caliber spin-stabilized ammunition has been investigated experimentally and numerically. The system is specially designed to study aerodynamic characteristics and dynamics of a flight body ejected from a cargo shell or a subsonic projectile itself at up to 2,000 rpm and 100 m/s. Raynolds-averaged Navier-Stokes equations with a overset mesh technique and 6-DOF dynamics were solved to decide the chamber pressure according to the muzzle velocity input by users. The predicted velocity values show less than 6 % of discrepancies compared to experimental data. The system has successfully been tested for the simulation of deployment of a parafoil for a 155 mm gun-launched projectile.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.376-383
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• 2017

This paper describes the gyroscopic stability and the drag characteristics of the smart munition with a course correction fuze(CCF). A ballistic analysis was conducted to figure out the effect of the canards on the gyroscopic stability of the projectile. The analysis used the commercial ammunition performance evaluation software: Projectile Design and Analysis System(PRODAS). In particular, we compared the PRODAS analysis results to real field test results to investigate the influence of the CCF mounted projectile. In addition, some ballistic simulations were carried out to provide the conditions suitable for wind tunnel tests. Experimental results show that the added drag force by the canards is almost uniform regardless of the Mach number when the projectile is at the normal position where the angle of rotation and the angle of attack are both 0 degrees. However, as the angle of attack of the projectile increases, the additional drag force depends on the deflection of the canards.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.5
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• pp.405-412
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• 2015

This paper represents a filter design to estimate the airspeed of a spin-stabilized, trajectory-correctible artillery ammunition. Due to the limited power and space in operational point of view, the airspeed sensor is not installed, and thus the airspeed need to be estimated using limited sensor measurements. The only IMU measurements(three-axis specific forces and angular rates) are used in this application. The extended Kalman filter algorithm is applied since a linear filter can not cover the its wide operational range in airspeed and altitude. In the implementation of the EKF, the state and measurement equations are transformed into the no-roll frame for simple form of Jacobian matrix. The simulation study is conducted to evaluate the performance of the filter under various environment conditions of sensor noise and wind turbulence. In addition, the effect of the choice in filter design parameters, i.e. process error covariance matrices is analyzed on the performance of the estimation of airspeed and angular rates.