External ballistics is the part of the science of ballistics that deals with the behaviour of a non-powered projectile in flight. External ballistics is frequently associated with firearms, and deals with the behaviour of the bullet after it exits the barrel and before it hits the target, so it lies between transitional ballistics and terminal ballistics.
To satisfy the requirements of developing ground-to-air trajectory correction, based on external ballistics and the characteristic of impulse engines, found one corrected model .