Safety-Critical Input-Constrained Nonlinear Intercept Guidance in Multiple Engagement Zones

2025-09-29

AI Summary

In multi-defender scenarios targeting stationary threats, interceptors face safety risks from unavoidable engagement zones (EZs) where guaranteed interception occurs. Method: This paper proposes an input-constrained nonlinear guidance law that replaces conventional defender modeling with a geometric EZ representation. It employs the log-sum-exp function to smoothly aggregate threat potentials from multiple EZs and explicitly incorporates actuator saturation constraints to ensure control feasibility and closed-loop stability. The design is grounded in nonholonomic kinematic modeling, enabling safe transit outside EZs and adaptive switching between evasion and pursuit as required. Contribution/Results: Simulation results demonstrate that the proposed law guarantees complete EZ avoidance throughout the entire flight trajectory under diverse initial conditions, while achieving high-precision, robust, and safe interception. The approach unifies threat-aware navigation and input-limited control within a rigorous geometric framework, enhancing operational safety in contested environments.

Technology Category

• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Natural Language Processing: Safety and Robustness
• Planning, Routing, and Scheduling: Model-Based Reasoning

Application Category

• Security and Privacy: Large-scale security measurements
• User Modeling, Personalization and Recommendation: Attacks and countermeasures in recommendation systems
• Semantics and Knowledge: Methods to enhance, augment, integrate or synergize semantic models such as knowledge graphs and LLMs

Abstract

This paper presents an input-constrained nonlinear guidance law to address the problem of intercepting a stationary target in contested environments with multiple defending agents. Contrary to prior approaches that rely on explicit knowledge of defender strategies or utilize conservative safety conditions based on a defender's range, our work characterizes defender threats geometrically through engagement zones that delineate inevitable interception regions. Outside these engagement zones, the interceptor remains invulnerable. The proposed guidance law switches between a repulsive safety maneuver near these zones and a pursuit maneuver outside their influence. To deal with multiple engagement zones, we employ a smooth minimum function (log-sum-exponent approximation) that aggregates threats from all the zones while prioritizing the most critical threats. Input saturation is modeled and embedded in the non-holonomic vehicle dynamics so the controller respects actuator limits while maintaining stability. Numerical simulations with several defenders demonstrate the proposed method's ability to avoid engagement zones and achieve interception across diverse initial conditions.

Problem

• Intercepting stationary targets under multiple defender threats
• Geometrically characterizing engagement zones for safety-critical guidance
• Handling input constraints while maintaining stability during interception

Innovation

• Geometric engagement zones define inevitable interception regions
• Smooth minimum function aggregates and prioritizes multiple threats
• Input saturation embedded in dynamics ensures actuator limits