Performance analysis of 3-dimensional PPNG law against a high speed target

We use a Lyapunov-like approach along with the so-called `LOS plane´ vector analysis method to analyze the performance of the 3-dimensional PPNG law against a `high speed target´ which maneuvers with time-varying normal acceleration. Here, `high speed target´ designates a target whose present velocity is at least 1/√2 times as fast as that of a missile pursuing it. The analysis result is much far more general than those presented in the prior literature and can theoretically explain the high performance of the PPNG law. Our approach is also expected to be useful for the design and analysis of other PPNG-like missile guidance laws