Differential evolution based 3-D guidance law for a realistic interceptor model

• This paper solves the real world problem of tactical missile guidance, in which optimality is sought to be achieved using the evolutionary computing method of differential evolution.
• A valid criticism against optimization by evolutionary computing methods is that they are computationally intensive, as compared to gradient based methods.
• By posing the problem as that of finding the coefficients of a third order polynomial, the dimensionality of the problem is so greatly reduced that online implementation in real time is shown to be possible.
• The results so obtained are compared against conventional methods in the guidance literature.

This paper presents a novel, soft computing based solution to a complex optimal control or dynamic optimization problem that requires the solution to be available in real-time. The complexities in this problem of optimal guidance of interceptors launched with high initial heading errors include the more involved physics of a three dimensional missile–target engagement, and those posed by the assumption of a realistic dynamic model such as time-varying missile speed, thrust, drag and mass, besides gravity, and upper bound on the lateral acceleration. The classic, pure proportional navigation law is augmented with a polynomial function of the heading error, and the values of the coefficients of the polynomial are determined using differential evolution (DE). The performance of the proposed DE enhanced guidance law is compared against the existing conventional laws in the literature, on the criteria of time and energy optimality, peak lateral acceleration demanded, terminal speed and robustness to unanticipated target maneuvers, to illustrate the superiority of the proposed law.