Optimal guidance-to-collision for an accelerating exo-atmospheric interceptor missile

A guidance-to-collision law that enables imposing a required heading angle is presented. This guidance law is derived by using the optimal control methodology, and is dependent on a unique zero-effort heading angle error and also on a variable denoted as zero-effort angle of attack. It is shown that this guidance law enables an accelerating interceptor to fly towards the target along a straight line, after the initial heading error is nulled. The trajectory imposed by this guidance law enables estimating the target's acceleration by using bearing only measurements. This is possible due to the imposed line-of-sight rotation, making the range between the two vehicles observable. Using a nonlinear two-dimensional simulation the performance of the guidance law is analyzed and compared to that of the classical proportional navigation, showing superior performance.