Formally Verified Next-Generation Airborne Collision Avoidance Games in ACAS X

by   Rachel Cleaveland, et al.

The design of aircraft collision avoidance algorithms is a subtle but important challenge that merits the need for provable safety guarantees. Obtaining such guarantees is nontrivial given the unpredictability of the interplay of the intruder aircraft decisions, the ownship pilot reactions, and the subtlety of the continuous motion dynamics of aircraft. Existing collision avoidance systems, such as TCAS and the Next-Generation Airborne Collision Avoidance System ACAS X, have been analyzed assuming severe restrictions on the intruder's flight maneuvers, limiting their safety guarantees in real-world scenarios where the intruder may also be changing its course. This work takes a conceptually significant and practically relevant departure from existing ACAS X models by generalizing them to hybrid games with first-class representations of the ownship and intruder decisions coming from two independent players. By proving the existence of winning strategies for the resulting Adversarial ACAS X in differential game logic, collision-freedom is established for the rich encounters of ownship and intruder aircraft with independent decisions along differential equations for flight paths with evolving vertical/horizontal velocities. We present three classes of models of increasing complexity: single-advisory infinite-time models, bounded time models, and infinite time, multi-advisory models. Within each class of models, we identify symbolic conditions and prove that there then always is a possible ownship maneuver that will prevent a collision between the two aircraft.


page 4

page 9

page 11


Collision Risk and Operational Impact of Speed Change Advisories as Aircraft Collision Avoidance Maneuvers

Aircraft collision avoidance systems have long been a key factor in keep...

Optimizing Collision Avoidance in Dense Airspace using Deep Reinforcement Learning

New methodologies will be needed to ensure the airspace remains safe and...

End to end collision avoidance based on optical flow and neural networks

Optical flow is believed to play an important role in the agile flight o...

Energy-Optimal Motion Planning for Agents: Barycentric Motion and Collision Avoidance Constraints

As robotic swarm systems emerge, it is increasingly important to provide...

Introducing MISS, a new tool for collision avoidance analysis and design

The core aspects and latest developments of Manoeuvre Intelligence for S...

Goal-Aware RSS for Complex Scenarios via Program Logic

We introduce a goal-aware extension of responsibility-sensitive safety (...

Envelopes and Waves: Safe Multivehicle Collision Avoidance for Horizontal Non-deterministic Turns

We present an approach to analyzing the safety of asynchronous, independ...

Please sign up or login with your details

Forgot password? Click here to reset