Terminal intercept guidance and autopilot for aircraft defense against an attacking missile via 3D sliding mode approach

This study focuses on an integrated guidance and autopilot (IGA) scheme for a defense missile trying to protect a cooperative aircraft from guided munitions which have the same capabilities as that of the defense missile. A higher-order sliding mode (HOSM) approach is used in the development of the IGA. A three-dimensional (3D) sliding surface vector is introduced to handle the roll-yaw/-pitch coupled motions for the IGA system design. Intermediate control variables for the IGA system are carefully selected and approximated time derivatives of a sliding surface are used such that the sliding surface structure is simple and sufficient to propagate the actuator input to the sliding surface. Potential of the IGA is demonstrated and analyzed with simulation results and performance comparison with a conventional guidance law is also presented.