Safety-Guaranteed Go-Around Decision Framework Based on Funnel for Automatic Carrier Landing Systems

Existing go-around decision methods for Automatic Carrier Landing Systems (ACLSs) are mainly based on altitude deviation. The safe region implied by these methods is therefore effectively single-dimensional, which can lead to overly conservative and incomplete go-around decisions because the remaining state deviations are not evaluated. This paper proposes a safety-guaranteed go-around decision framework based on a funnel that explicitly characterizes the time-varying safe region in the multi-dimensional state space throughout the landing process, thereby enabling safe and precise decisions. A six-dimensional funnel is then computed backward from the terminal set using sum-of-squares programming while accounting for nonlinear dynamics, actuator saturation constraints, and prescribed bounded uncertainties. The resulting funnel guarantees that all closed-loop trajectories initialized within it remain within the subsequent funnel and reach the terminal set at the final time. In the online stage, the online go-around decision module evaluates at each sampling instant whether the complete six-dimensional state deviation lies inside the corresponding precomputed funnel and outputs either the continue-landing decision or the go-around decision. Simulation results show that incorporating the range state reduces the mean, maximum, and standard deviation of the terminal altitude deviations by approximately 68%, 64%, and 66%, respectively, and the corresponding statistics of the terminal range deviations by approximately 99%. Under a representative deck-motion disturbance, the framework remains effective after the six-dimensional funnel is recomputed offline. The proposed method also avoids unnecessary go-around decisions when the altitude component exceeds the conventional threshold but the complete six-dimensional state deviation remains inside the funnel.