Design of an aerial combat guidance law using virtual pursuit point concept

Abstract

In this thesis, a virtual pursuit point (VPP) based combat guidance law for autonomous close air-to-air combat of a UCAV is proposed, and X-Plane based nonlinear six-degrees-of-freedom combat simulation results are presented. For realizing practical implementation and good real-time performance, the guidance law is designed using the VPP concept and a typical pure pursuit guidance law. For the guidance design phase, states that are observable and available from the radar for practical implementation are identified and determined. VPPs are introduced to perform tactical maneuvers, including lag and lead pursuit courses. The VPPs consist of virtual lag and lead points. These points are generated based on energy-maneuverability analysis for turn performance, weapon characteristics, and basic fighter maneuver principles of manned fighters. The tactical velocity command, which is essential for an engagement is designed based on the determined optimal flight region by the corner velocity and altitude and environmental parameters such as the opponent’s velocity, relative distance, deviation, and aspect angle. In addition, a normal load factor command is constrained for the management of excessive specific energy. Then, an algorithm for generating a single point using the VPPs and determining the type of maneuvers is introduced by the vehicle’s state-based probabilistic functions. This smoothing technique generates a single pursuit point with a constrained sequence that switches maneuvers between lead and lag. For performance validation, the X-Plane-based real-time combat simulator is employed for testing with a human pilot in a manner similar to that in heuristic approaches. The combat simulation results indicate that the VPP-based guidance law produces plausible maneuvers for one-on-one close air-to-air engagement. The proposed methodology has the advantage of not only allowing wide-ranging combat maneuvers from high-g agile to delicate gunshot maneuvers but also pe...