Engagement-Zone-Aware Input-Constrained Guidance for Safe Target Interception

This paper addresses target interception in contested, GPS-denied environments with multiple finite-range, moving defenders. Conventional methods impose conservative stand-off constraints based on maximum engagement distance and neglect actuator limitations, while safety-critical designs typically rely on online optimization. Instead, we formulate safety constraints using defender-induced engagement zones (regions of the attacker’s state space from which capture becomes inevitable under the defenders’ current capability). To account for actuator limits, the nonholonomic vehicle model is augmented with input saturation dynamics, and a time-varying safe-set tightening parameter is proposed to handle transient constraint violations by adaptively contracting the admissible safe region. To ensure scalable safety enforcement, a log-sum-exp operator combines individual defender threat measures. The proposed safety framework yields an explicit feedback guidance law that coordinates interception and safety objectives without online optimization. Additionally, the guidance law relies only on relative information and supports distributed implementation without knowledge of the defender’s control inputs. Lyapunov-based analysis provides sufficient conditions guaranteeing target interception, practical safety across all defender engagement zones, and satisfaction of actuator bounds. An input-constrained guidance law based on conservative maximum engagement range is also developed. Simulation studies demonstrate reduced interception time and shorter trajectories compared to conventional methods while maintaining safety.