Andrew Crowell

Analysis of the Aircraft to Aircraft Conflict Properties in the National Airspace System

*† ‡ The primary function of administering the United States’ National Airspace System (NAS) is the air traffic controller task of actively monitoring assigned aircraft and resolving the conflicts (i.e. losses of minimum separations between aircraft) anticipated some time in the future. To mitigate the safety risks of increased traffic growth and effectively designing automation to aid in the separation management task, knowledge of the characteristics or properties of the conflicts is required. This paper reports on a comprehensive study that has examined these properties by collecting traffic data from all 20 NAS en route centers, developing software models to determine these events, implementing experimental design techniques to calibrate them, validating the models by comparing to advanced operational systems, and presenting detailed graphical and statistical analysis of the results. I. Introduction In the United States, the overall system of managing and controlling air traffic is known as the National Airspace System (NAS), which is administered by the Federal Aviation Administration (FAA). Detailed procedures involving restrictions on routing, speeds, and altitudes are an integral part of the NAS. These restrictions severely reduce the amount of aircraft traffic that NAS can accommodate, yet are needed to ensure the high level of safety required. At the heart of these operations is the human air traffic controller who must synthesize many pieces of timely information including radar surveillance information and flight data. Their fundamental responsibility is to ensure the safety of the aircraft flying within their regions of airspace in the most efficient means possible. To accomplish this, air traffic controllers actively monitor their aircraft and then resolve any conflicts (i.e., loss of minimum separation between aircraft or restricted airspace) predicted some time into the future. Furthermore, these resolutions are administered by air traffic controller voice instructions via radio transmissions to the aircraft. In the current system, there are automation systems that aid the air traffic controller mainly in the monitoring part of the task such as the ground based tactical and strategic conflict probes. In the en route centers, typically managing the aircraft above 18,000 feet, the Host Computer System’s (HCS) Conflict Alert function provides tactical alerts. The upgrade to the HCS, still under development, called the En Route Automation Modernization (ERAM), replaces Conflict Alert with several categories of alerts with the basic function requiring a minimum of 75 seconds warning. The User Request Evaluation Tool (URET), developed by MITRE Corporation’s Center for Advanced Aviation System Development, is an example of a strategic conflict probe in operation in the en route centers. It predicts conflicts up to 20 minutes in the future with typically a minimum warning of five minutes. Even with the aid of ground-based conflict probes, the task of separating aircraft will become increasingly difficult, since most air traffic service providers in the United States and Europe anticipate significant growth in air traffic. The growth is expected to out pace the capacity limits of the aviation systems, resulting in greater congestion and inefficiency. The interagency Joint Development Planning Office (JPDO) in the United States foresees a traffic demand increase by 2025 up to three times the number of flights of today’s traffic. 1 Given the need for enhanced safety and efficiency, broad categories of advances in ground and airborne automation are required. The JDPO, as established in their charter under the “Vision-100” legislation (Public Law 108-176) signed by President G. W. Bush in December 2003, has mandated a next generation operational concept of the NAS for 2025. 1 This next generation

An interactive 4D visualization system for air traffic concept analysis

The Federal Aviation Administration (FAA) and supporting organizations are developing new concepts to improve efficiency and safety of the National Airspace System (NAS). Some of these concepts change current restrictions, introduce new maneuvers, or provide better decision support to air traffic controllers. Each of these concepts requires extensive research and validation before it can be integrated into the NAS. Many different analysis tools are used to determine benefits, limitations, and requirements of these concepts. Some of these tools provide statistical metrics of the concepts, while others show the concepts visually. However, many of these are specialized tools built specifically for analyzing one concept or a small subset of concepts in a specific region of the NAS. When a new concept is introduced, it is often difficult to find a tool that can easily be adapted to help analyze it. The Concept Analysis Branch at the FAA is tasked with analyzing many of these concepts for feasibility and benefits determination before requirements development occurs. In order to assist in this task, the Concept Analysis Branch has developed a flexible, extensible, interactive 4D visualization tool for analysis of virtually any aviation concept. Flexible Flight Traffic Exploration Visualization 4D (FliteViz4D) was created as a unique development platform specifically directed at visualizing air traffic concepts in three-dimensional space, with two additional temporal dimensions for current time and future time. It allows concepts such as 4D Trajectory Based Operations, National Convective Weather Forecast, and 3D Path Arrival Management to be visualized in all their dimensions. This was accomplished by using object-oriented design concepts in the development of FliteViz4D to provide unparalleled flexibility and extensibility. New concepts can be added into the visualization using plugins with no changes to the existing platform. The user can decide which plugins to use, determining exactly how Flite-Viz4D runs and what is visualized. The result is a powerful visualization and analysis system, scalable from a single airport to the entire world, which can be used to analyze any concept that could possibly be visualized abstractly or physically. This paper will provide an overview of the system, providing several examples of how it has been used in recent studies, how it will be used in future studies, and how it can be utilized by other organizations in the aviation industry.

An Algorithmic Method for Regression Analysis of Conflict Probe Accuracy

A conflict probe is one of the most important elements in a safe and efficient air traffic control system. It supports the human air traffic controllers by alerting to potential situations where aircraft may violate separation standards sometime in the future. As the conflict probe is upgraded, whether in the development stage or after deployment, the developers must be sure that its performance does not degrade. In order to test this, a conflict probe is analyzed by comparing it either to another conflict probe or to a previous version of itself. This paper presents a software program developed by FAA analysts for algorithmically comparing two conflict probes, using many of the methods an analyst would use in a manual comparison. The algorithm is presented and verified mathematically. Finally, a comprehensive example is presented that illustrates how the software program can be utilized in the development and maintenance of a conflict probe.

A Visualization Tool for Analysis of Air Traffic Management Scenarios and Automation

*† ‡ § ** Scenario Graphical User Interface (ScenarioGUI) is a new information visualization tool that allows analysts to graphically display large areas of air traffic data in order to view patterns of air traffic management flows, aircraft-to-aircraft conflicts and conflict predictions. An aircraft-to-aircraft conflict occurs when there is a loss of the minimum separation standard between two aircraft. Conflict predictions are alerts generated by a Decision Support Tool (DST) called a Conflict Probe that attempts to predict potential future conflicts. The ScenarioGUI application was developed by the Software Engineering, Graphics and Visualization group at Rowan University in conjunction with the Simulation and Analysis Team at the Federal Aviation Administration (FAA). ScenarioGUI is an application developed in Java that enables the FAA to both analyze the results of non-realtime air traffic simulations and the performance of conflict alerts produced by DSTs. This paper explores the development, implementation, and use of ScenarioGUI.

Enhanced Star Glyphs for Multiple-Source Data Analysis

The analysis of large sums of data can be extremely difficult to perform if the data is not presented graphically. As a result, many graphing techniques have been developed, such as scatter plots, histograms. Generally, the main purpose of graphically displaying data is to do one of two things: First, to find the general average of where most of the data lies. Second, to find the outliers, the data points that are most distant from the others. Our visualization will attempt to find both by using a multitude of common graphing techniques to expand upon the traditional star glyph and create a new way of graphing data. These techniques include clustering, using color as identifiers, and 3D graphing capabilities to present more data that would not be possible of being shown in a two dimensional environment. We apply our techniques to compare several air traffic trajectory predictors currently being analyzed by the U.S. Federal Aviation Administration.

PieVis: Interactive Graph Visualization Using a Rings-Based Tree Drawing Algorithm for Children and Crust Display for Parents

The quality of a graph drawing algorithm is often measured by its edge crossings, angular resolution, aspect ratio, and node labeling. Algorithms for drawing trees in general are segregated from algorithms for drawing graphs. In this paper we present a graph visualization system that uses a novel interconnection between a tree drawing algorithm and graph drawing techniques. First, the graph is transformed into a tree and nodes that have multiple parent connections within the graph are duplicated within the tree. While some of the connection information is lost during this transformation, the multiple connections can be regained by interactively displaying the details based on the degree of interest. We use an edgeless rings-based visualization which allows edge crossings and angular resolution issues to be eliminated and has a desirable aspect ratio of 1. Finally, a circular labeling method is used that provides user-friendly labels that do not overlap and clearly show node affiliation.

Accuracy Comparison of an Operational and Experimental Strategic Conflict Probe

The primary function of administering the United States’ National Airspace System (NAS) is the air traffic controller task of actively monitoring assigned aircraft and resolving the conflicts (i.e. losses of minimum separations between aircraft) anticipated some time in the future. The transformation of the current NAS is a planned evolution and will rely on communication digitally between air and ground and between aircraft with the use of enhanced trajectory-based operations and automation tools. To mitigate the safety risks of increased traffic growth and effectively designing automation to aid in the separation management task, research and development is required to improve the accuracy and usability of decision support tools. The paper presents the performance of an experimental strategic conflict probe model used in the development and validation of enhanced separation management concepts. Furthermore, this papers reports on a comprehensive design of experiment optimizing its performance and a comparison of its capability to an advanced operational system.