Time-To-Reach Separation and Safety Filtering for Safe, Fair, and Efficient Multi-Agent Coordination

TL;DR

This paper introduces a multi-agent coordination framework for urban aerial traffic management using minimum time-to-reach metrics to ensure safe, fair, and efficient merging of aerial vehicles in congested airspace.

Contribution

It proposes a novel safety filtering and priority assignment method based on Hamilton-Jacobi reachability and TTR metrics for urban air traffic coordination.

Findings

Improves safety, fairness, and efficiency in congested merging scenarios.

Uses TTR-based priority assignment for temporal and spatial separation.

Enhances collision avoidance with minimal guidance modifications.

Abstract

Advanced Air Mobility (AAM) operations are expected to significantly increase aerial traffic in urban airspace, requiring autonomous traffic management systems to ensure collision-free operations in highly congested environments. In this paper, we propose a multi-agent coordination framework that uses minimum time-to-reach (TTR) as a unifying metric for priority assignment, temporal separation, and safety filtering. We focus on the problem of coordinating multiple aerial vehicles merging into an air corridor while maintaining safe separation between vehicles. Vehicles are assigned arrival-consistent priority based on TTR, and target TTR values are used to enforce temporal spacing that induces spatial separation. A priority-consistent safety filtering layer based on Hamilton-Jacobi reachability value functions ensures collision avoidance while minimally modifying the reference guidance. Simulation results in a highly congested corridor merging scenario show that the proposed method improves safety, fairness, and efficiency compared to time-optimal guidance and priority-agnostic safety filtering.