A Study on the Improvement of Modified Proportional Navigation Guidance

It is well known that proportional navigation (PN) is used as a terminal guidance law when a missile intercepts its target. But PN does not always provide“optimal”guidance, especially during the boost phase of the missile guidance. Modified proportional navigation (MPN) was proposed for an accelerating missile. However, it assumes the axial acceleration of the missile as constant. On the other hand, in a practical scenario, the missile would be accelerated non-linearly and drastically by a solid rocket motor. In our study, the MPN law is revisited and evaluated with the aim of optimization. We propose a new method which improves the MPN. In our method, a missile and a target are considered as point masses. We assume the missile as a short-range air-to-air missile with a solid rocket motor, and its acceleration is a non-linear function of multiple variables. To maintain the missile speed at high levels as much as possible at the end of engagement (near collision), it is critical that kinetic energy be conserved. In order to achieve this objective, we tried to make the missile lift coefficient as small as possible. Under these conditions, we conducted numerical analyses, and successfully realized a more optimal trajectory than that of MPN. On the other hand, we also successfully reduced the area of the inner launch boundary of the missile.