Merging and Spacing (M&S) in ACES is a software product written in the Java programming language that adds scheduling and management of flights into and out of an airport for the Airspace Concepts Evaluation System (ACES) simulation. ACES is a systems-level simulation that portrays NAS-wide flight. The ACES simulation, prior to the delivery of the M&S product in 2010, was limited to a node/queuing model for the terminal airspace, which means that it modeled the time an aircraft would generally take from its metering fix to/from a runway, but it did not provide a model for its physical location during that flight phase. The M&S software uses the IAI Kinematic Trajectory-Generator to model actual physical trajectories through the terminal airspace, and uses a scheduling algorithm along with various managers for waypoints (specific locations along the route) to direct each arriving and departing aircraft to a trajectory and schedule that not only behaves according to the performance characteristics of the specific aircraft, but also maintains the FAA’s requirements for wake vortex spacing during flight. This allows Langley research using ACES for the physical behaviors in the complex terminal airspace for the first time.

NASA’s Systems Analysis, Integration, and Evaluation (SAIE) Program uses system-level simulations to assess feasibility, costs, and benefits of NextGen technologies. Modeling and study of the interaction of the en-route phase of flight with the arrival and departure phases is one critical area of study, and requires four-dimensional modeling of flights for arrival and departure routing to be able to integrate other tools such as Traffic Flow Management, Conflict Detection, and Dynamic Airspace Configuration.

This software is unique because it adds a previously unavailable capability for arrival and departure flight scheduling in the terminal airspace to a systems-level NASA simulation tool (ACES). This also allows ACES to be one of the first system-level simulation tools to have this ability. The software is also unique (compared to other NASA efforts in progress) because it implements spacing based on NASA Langley’s AMSTAR algorithms, which are airborne spacing algorithms. With a relatively small effort, an interface could be written to allow this software to interface to any NAS-wide simulation that was capable of modeling 4D aircraft trajectories all the way to the ground.

This work was done by Patricia C. Glaab and Jeremy C. Smith of Langley Research Center; and Jensan Chen, Yunshen Tang, Yun Teng, Yinchuan Zhang, Nikhil Nigam, and Arthur Feinberg of Intelligent Automation, Inc. LAR-18042-1

NASA Tech Briefs Magazine

This article first appeared in the September, 2015 issue of NASA Tech Briefs Magazine.

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