Optimal three-dimensional glide for maximum reachable domain

A problem of optimal three-dimensional glide for maximum reachable domain is solved by using both the second-order gradient method (GM) and the singular perturbation method (SPM). This problem is essentially an extension of the maximum-range glide problem, in which the flight is constrained in a vertical plane. A set of closed-loop guidance laws which are implementable on an on-board computer are derived by using the SPM. With a numerical example, the trajectory produced by the closed-loop guidance laws is shown to have the same characteristics with the one computed by using the GM. Also, the maximum reachable domain computed by using the SPM is shown to be smaller than the one computed by using the GM.