Guidance problems with flight time constraints are considered in this article.A new virtual leader scheme is used for design of guidance laws with time constraints.The core idea of this scheme is to adopt a virtual leader for real missiles to convert a guidance problem with time constraints to a nonlinear tracking problem,thereby making it possible to settle the problem with a variety of control methods.A novel time-constrained guidance(TCG) law,which can control the flight time of missiles to a prescribed time,is designed by using the virtual leader scheme and stability method.The TCG law is a combination of the well-known proportional navigation guidance(PNG) law and the feedback of flight time error.What's more,this law is free of singularities and hence yields better performances in comparison with optimal guidance laws with time constraints.Nonlinear simulations demonstrate the effectiveness of the proposed law.
