A time advantage function-based solution to two-player circular target defense games

Abstract

This paper investigates a two-player circular target defense game where a defender, constrained to the target boundary, protects the target region from an intruder. The study incorporates limited observation capabilities for both agents, deriving conditions under which the defender can intercept the intruder or the intruder can breach the target. This work formulates the problem as a Game of Kind, introducing a time advantage function that quantifies the game outcome: when the function is non-negative, the intruder dominates the game, selecting an invasion point on the target boundary that maximizes the time advantage (maximizing terminal separation from the defender) to ensure successful penetration; when the function is negative, the defender strategically deviates from the target boundary and utilizes the boundary of dominance region (defined by intersections of the agent isochrones) to derive optimal interception trajectories. Numerical simulations validate the proposed method, demonstrating how the time advantage function enables clear winner determination and strategy derivation, bridging theoretical game theory with practical sensing constraints.