The approximation capability of artificial neural networks has been applied
to the midcourse guidance problem to overcome the difficulty of deriving a
n on-board guidance algorithm based on optimal control theory. This approac
h is to train a neural network to approximate the optimal guidance law in f
eedback form using the optimal trajectories computed in advance, Then the t
rained network is suitable for real-Lime implementation as well as generati
ng suboptimal commands. In this paper, the advancement of the neural-networ
k approach to the current level from the design procedure to the three-dime
nsional flight is described. (C) 2001 Published by Elsevier Science Ltd.