Geometric approach to capture analysis of PN guidance law

A novel approach to capture analysis of the proportional navigation (PN) guidance law is presented in this paper. The capturabilities of the pure PN guidance law and the true PN guidance law are qualitatively studied using the differential geometric formulations. A unified post-launch capture condition for PN guidance law is developed and expressed in terms of geometric angle and relative motion parameters instead of the initial conditions. Simulation results indicate that the proposed capture condition is more crucial at the end of the engagement. Also, the acceleration/deceleration of the missile has a distinct influence on the interception performance of the PN guidance law, and a constant thrust works viable and effectively in improving the performance of the PN guidance law.