Evaluation of Neural Network Verification Methods for Air-to-Air Collision Avoidance
Abstract
Neural network approximations have become attractive to compress data for automation and autonomy algorithms for use on storage-limited and processing-limited aerospace hardware. However, unless these neural network approximations can be exhaustively verified to be safe, they cannot be certified for use on aircraft. An example of such systems is the unmanned Airborne Collision Avoidance System (ACAS) Xu, which is a very popular benchmark for open-loop neural network control system verification tools. This paper proposes a new closed-loop extension of this benchmark, which consists of a set of 10 closed-loop properties selected to evaluate the safety of an ownship aircraft in the presence of a co-altitude intruder aircraft. These closed-loop safety properties are used to evaluate five of the 45 neural networks that comprise the ACAS Xu benchmark (corresponding to co-altitude cases) as well as the switching logic between the five neural networks. The combination of nonlinear dynamics and switching between five neural networks is a challenging verification task accomplished with star-set reachability methods in two verification tools. The safety of the ownship aircraft under initial position uncertainty is guaranteed in every scenario proposed.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 01, 2023
- Source ID
- 10.2514/1.d0255
Entities
People
- Diego Manzanas Lopez
- Hoang-Dung Tran
- Kerianne L. Hobbs
- Stanley Bak
- Taylor T. Johnson
Organizations
- Air Force Office of Scientific Research
- Air Force Research Laboratory
- Defense Advanced Research Projects Agency
- Division of Computing and Communication Foundations
- Office of Naval Research
- Stony Brook University
- University of Nebraska–Lincoln
- Vanderbilt University