ACES, the Airspace Concept Evaluation System. Visualizing the Future of Civil Aviation.

Flying today can be frustrating. More air traffic means airport congestion, lost revenues, longer delays for passengers, and shorter decision times for air traffic controllers. And the number of flights each day is projected to keep increasing. Researchers and planners are working on solutions to the nation's airspace capacity problems. The Airspace Concept Evaluation System, or ACES, provides them with a way to assess the system-wide impacts of new aviation concepts and technologies.

ACES is able to simulate the complex interplay of the air traffic system using a software architecture based on agents. These are individual assemblies of mathematical models designed to emulate the functions of a particular airspace entity. As ACES runs, these agents generate streams of data that emulate the interactions between real-life air traffic control and aircraft, making decisions and explicitly communicating just as their real-world counterparts would do. ACES collects this data into a chronological sequence that can be closely analyzed later. The result is detailed information about the dynamic evolution of traffic and delays in the system. ACES creates agents for each airport, flight, and airline in the NAS; each TRACON and ARTCC; as well as the System Command Center. The simulation captures the dynamics of the system as reflected in the tens of thousands of individual data streams that are collected by ACES and compiled in a standardized database format for analysis. Using this data, researchers can evaluate how the NAS will handle future flight demand and how the system will respond to disruptions, such as bad weather. ACES' extraordinary modeling flexibility lets researchers study the system-wide benefits and impacts of new ideas.

ACES provides researchers with many benefits. ACES is scalable. Scenarios can be tailored to reflect different levels of complexity from a single center to the entire National Airspace System. For large scenarios, multiple computers provide faster processing. ACES is realistic. The results of ACES simulations reflect high fidelity modeling with communications, delays, and ripple effects shown as they would occur in real life. This allows analysts to determine cause and effect in the system. ACES is configurable. ACES is written in Java and runs under Windows and Linux. The system can be run in configurations ranging from a single laptop to a cluster of high-end workstations. ACES' customizable data collection tools store all data from the simulation for further evaluation. ACES is open. Users can easily modify ACES to reflect changing systems; and even revolutionary paradigm shifts in aviation and air traffic control, such as micro-jets, unmanned air vehicles, and de-hubbing. This flexibility results from ACES open source code, as well as, the use of the Department of Defense's High Level Architecture, or HLA, and the Cybele agent framework.

A number of groups are already using ACES. One, is NASA's Advanced Airspace Concept, or AAC. AAC is a novel approach for increasing airspace capacity. It includes significant changes in pilots' and controllers' activities, and introduces sophisticated automated tools for assurance of separation between aircraft. ACES open architecture allowed engineers to insert models to analyze AAC's improvements in transition and en route airspace capacity. Even more significantly, researchers were able to incorporate actual AAC algorithms into ACES agents. This is allowing them to test and improve the logic of the AAC strategic resolution algorithms, resolving problems well in advance of expensive field tests.

Other users are applying ACES to make policy decisions. For example, ACES runs are being used in conjunction with environmental models to understand the noise and emissions impacts of transformational strategies for the next generation NAS.

Air travel plays a vital role in our nation's economic health, mobility, and security. ACES is the flexible, configurable, high-fidelity solution for visualizing the future of civil aviation.