A new practical guidance law for a guided projectile

This paper addresses a new guidance law and its implementation for a guided projectile of a modern artillery. The well known PNG (Proportional Navigation Guidance) is not adequate for this purpose because it produces unwished guidance command for the entile flight so that severe range loss of the artillery or huge guidance error can be caused. Under the premise that the current projectile's trajectory must be slightly disturbed from the desired ballistic trajectory, how to correct the ballistic trajectory is the point of interest. In this paper, we proposed a new guidance law to correct the trajectory in some flight region and after the termination of the guidance the projectile follows a ballistic trajectory onto the target. The proposed guidance law is quite similar to PNG in its form except the correction rate of flight path angle is newly included instead of the line-of-sight rate of PNG. To calculate the correction rate of the flight path angle, we need to predict the free-fall impact point of the projectile. We also suggest a precision impact point prediction method based on a neural network nonlinear function approximator. The proposed guidance method can be easily implemented on a low grade on-board computer and works in real-time manner.