SubscribeA multi-partner, multi-national Automatic Collision Avoidance System (ACAS) development effort was initiated in 2000 by the U.S. Air Force.
The goal of this program was to develop and flight demonstrate the capability to automatically execute last-minute escape maneuvers to avoid impending collisions between aircraft for both manned as well as unmanned configurations.
Major participants in this effort include the USAF, FMV (Sweden), Boeing Company, Lockheed Martin, and Saab Aerospace.The effort involved initial algorithm assessment and feasibility evaluation by the three prime contractors followed by a common ACAS algorithm development. With the successful simulation demonstration of the ACAS logic in 2002, the program is currently proceeding to flight demonstration.
Due to the complex nature of the ACAS logic, coupled with the need to evaluate a wide range of potential collision scenarios, computer-based simulation was to be an integral tool in the algorithm development process.
While each organization possesses internal and/or proprietary simulation capabilities, there was no common simulation environment to allow convenient exchange of ACAS algorithm code between the partners. The inability to support this critical requirement threatened the success of the program.
In order to resolve this need, Bihrle Applied Research’s D-Six COTS simulation environment was employed by each partner to provide the common platform on which the ACAS algorithm was developed, tested, and evaluated. Following a successful demonstration of Boeing’s initial ACAS algorithm hosted in D-Six, all three major contractors along with the USAF adopted D-Six as the native algorithm development platform. The full-scale algorithm development is currently underway with all the partners concurrently and actively designing, evaluating, modifying and testing the ACAS logic. Because D-Six systems reside at each facility, algorithm design issues and logic flaws can be easily explored and identified.
As a result, solutions can be formulated, and code changes are easily shared between the engineers to be evaluated, discussed and finalized. Any changes can be uploaded to the team website for rapid dissemination and evaluation between the team members. This collaborative development process has been the key to the rapid development and system test capability that has allowed a complex, multi-national program such as this to progress from concept to flight in less than two years.
The desktop accessibility of D-Six allows engineers to easily perform collision avoidance simulation runs using pre-programmed control inputs or in manually piloted mode. The results can be replayed, plotted and analyzed between the program participants for a coordinated development effort from different sites and continents. Additionally, D-Six’s network capability provides the essential multi-vehicle simulation capability needed to design, evaluate and demonstrate the coordinated escape maneuvers between the colliding aircraft.
