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MITRE's Center for Advanced Aviation System Development (CAASD): Wake Turbulence R&D - Past, Present, and Planned
April 3, 2007
Clark Lunsford
A Predictive Model of User Equipage Costs for Future Air Traffic Services and Capabilities: An ADS-B Example
May 15, 2006
Kent V. Hollinger, James D. Nickum, Doyle T. Peed, Todd M. Stock
View abstract [+]
Many new technological solutions are considered in efforts to imporve the efficience and capacity of the National Airspace System (NAS). Most of these technologies require the addition or modification of equipment not only on the ground, but also in the aircraft that operate in the NAS. Because it is increasingly difficult for the Federal Aviation Administration (FAA) to justify mandates for forced aircraft equipage, it is often necessary to depend upon the aircraft owner/operators to voluntarily equip their aircraft with the needed technology. If these aircraft equipage costs are too high, the owner/operators may not equip their aircraft and the overall program might not proceed as desired.
Presented is a methodology that can be used to estimate the user equipage costs for future air traffic services and capabilities. Included is a forecast of future United States (U.S.) aircraft broken down by model for Air Transport (AT) aircraft and by type for General Aviation (GA) aircraft. This forecast, when combined with model or type specific aircraft knowlege, provides an estimate of the future mix of aircraft capabilities, and can be utilized for any technology under study. The model considers aircraft classification and architecture to determine equipage states and identifies transition costs between each state. Also, methods for estimating owner/operator reactions and repsonses to the availability of the new technology, as well as the impact and cost of a possible equipage mandate, are presented.
An Example of usage of the the model is presented that analyzes Automatic Dependent Surveillance-Broadcast (ADS-B) equipage costs for the applications of broadcast surveillance and cockpit display of traffic information (CDTI) operational procedures. The presented methodology may also be used for other technological solutions, including navigation and communications.
AviationSimNetTM Specification
October 26, 2005
David J. Bodoh, Phillip L. Brown, Patricia A. Liguori, Matthew E. Pollack
View abstract [+]
This document is a specification for creating and executing distributed air traffic control (ATC) human-in-the-loop (HITL) simulations over a public, wide area network. Know as AviationSimNet, this specification was developed mostly by adopting existing industry standards for network communications, in both simulation and voice protocols. This specification builds upon other distributed simulation efforts, and will continue to evolve according to the needs of the aviation research community.
The scope of this specification includes definitions of the technologies required to support data and voice inter-communication in a controlled, simulated environment that models ATC Simulations. It also includes the required protocols for using those technologies in order to facilitate implementations of this specification over a common network. This document does not provide instruction on how to adapt any existing simulation capability to comply with the AviationSimNet specification. Rather, it provides the rules and limitations that can be used to achieve such goals. This document also does not address any activities associated with conducting analyses of a simulation execution. AviationSimNet requirements are highlighted throughout this document. Any application that satisfies these requirements is considered "AviationSimNet-compatible."
Section of this document provides and introduction to the domain and technologies covered by AviationSimNet, as well as Definitions that are relevant to AviationSimNet. Section 2 covers data communication protocols among simulation applications. Section 3 covers voice communication protocols among live participants of the simulation. Section 4 provides and overview of some security measures for using AviationSimNet over a public network. Section 5 addresses performance, throughput and latency. A complete list of all the AviationSimNet requirements is listed in the appendix.
AviationSimNetTM Demo (60MB)
October 26, 2005
David J. Bodoh, Phillip L. Brown, Patricia A. Liguori, Matthew E. Pollack
2004 Technical & Professional Activities
May 1, 2005
Technical and Professional Activities 2003 - Contributing to Aviation Every Day
November 5, 2004
Plan for Defining Flow Constrained Areas from Automatically-Generated Weather Products on the Traffic Situation Display
September 15, 2003
Celesta G. Ball, Kelly A. Connolly, Laurel S. Rhodes
View abstract [+]
The MITRE Corporations Center for Advanced Aviation System Development (CAASD) is exploring operational concepts related to Flow Constrained Areas (FCAs) used in conjunction with severe convective weather forecast information. Displays from several weather products have been implemented in the Enhanced Traffic Management System (ETMS) and are currently available to traffic managers. Utilizing information provided by these products and other weather data, it would be feasible for traffic managers to create FCAs that correspond to the forecast storm locations and parameters. Potentially, these FCAs could be an aid in traffic flow management (TFM) planning by:
Providing TFM planning capabilities with more precise and timely forecasted storm information and updates, and
Reducing the time and effort traffic managers expend in interpreting and mentally integrating the weather forecast information they receive with the TFM planning process.
This document describes additions and changes to the current Collaborative Decision Making (CDM) capabilities and processes needed to allow the implementation of weather products as Weather FCAs in the ETMS, specifically to the Traffic Situation Display (TSD) displays and interactions.
Spectrum Depletion Analysis
April 1, 2003
Melvin J. Zeltser; Frederick R. Morser; Philip Long; Frank Box
View abstract [+]
The Very High Frequency (VHF) spectrum for air/ground (A/G) communications has become very crowded. It is becoming difficult for the Federal Aviation Administration (FAA) to find frequency assignments to meet the demand for additional air traffic control (ATC) services. The unit of measure for A/G voice supply and demand is a circuit. In September 2001, the Next-Generation Air/Ground Radio Communications System (NEXCOM) Aviation Rulemaking Committee (NARC) recommended that the FAA extend the life of the existing 25-kilohertz (kHz) amplitude-modulation (25AM) system. Recommendation 1 in the NARC report stated the FAA should Continue to aggressively manage frequency assignments to prolong the useful life of the 25AM circuit allocation in support of Air Traffic Services. The need to aggressively manage the spectrum is more pertinent than ever because of the economic factors the aviation industry is facing since the events of September 11, 2001. The economic impact of transition to new avionics will be relatively great for an industry that is struggling to remain economically viable.
Strategic Air Traffic Control Planning and Spring 2000
July 15, 2002
Kenneth P. Lamon, Joshua W. Pepper, Matthew A. Yankey
View abstract [+]
This paper gives an overview of FAA and airspace user initiativesknown collectively as Spring 2000undertaken prior to the summer of 2000, the most congested summer ever for air traffic in the United States. It examines the performance of the national airsace system during that summer, focusing on the effects of weather and increased traffic volume on delays and cancellations. It also discusses the costs to airlines of delays and cancellations.
Fewer Air Traffic Delays in the Summer of 2001
June 15, 2002
Ken Lamon
View abstract [+]
The FAA worries a lot about summer. Not only is summer the time when many people want to travel, it is also the peak of the convective weather season-a time when thunderstorms can and do pop up unexpectedly in the middle of some of the nation's busiest airspace. During the summers of 1999 and 2000, these thunderstorms collided with a bumper crop of passengers from a booming economy, breaking all records for delays and cancellations.
The drop in air travel since September 11 should give passengers some relief from delays in 2002, but it's inevitable that traffic will return and eventually surpass previous levels. The FAA estimates that the current slump in air travel will last just a year or two. Over the long term, it expects airline passenger traffic to increase 30% over the next ten years. With this in mind, it is worthwhile for us to review the performance of the National Airspace System (NAS) during the most recent summer-the summer of 2001
Development and Assessment of Problem Resolution Capabilities for the En Route Sector Controller
October 15, 2001
Daniel B. Kirk, Karen C. Bowen, Winfield S. Heagy, Nicholas E. Rozen, Karen J. Vietz
View abstract [+]
This paper provides and overview of Problem Analysis, Resolution and Ranking (PARR) capabilities being developed to assist en route air traffic controllers. PARR is envisioned as an enhancement to the User Request Evaluation Tool (URET) capability of Free Flight Phase 1, and has been designated as priority research for the follow-on Free Flight Phase 2 effort. Also included is an overview of the initial PARR capabilities and summary of results from ongoing evaluations with active field controllers; and an overview of the techniques being developed for the PARR functional performance, benefits assessment and initial results. Finally, there are descriptions of concepts for the enhancement of URET and PARR to assist in the avoidance of severe weather areas and implementation of Traffic Flow Management flow initiatives.
Eliminating the Altitude-for-Direction Rule Implementing Reduced Vertical
September 1, 2001
Alvin McFarland, David Maroney
View abstract [+]
This paper discusses the feasibility of eliminating the Altitude-for-Direction (AFD) rule and implementing Reduced Vertical Separation Minimum (RVSM) at higher altitudes in the United States. Both actions would provide meaningful benefits to airspace users: eliminating the AFD rule permits more efficient altitude profiles, while RVSM would provide more altitudes for traffic management, potentially reducing the number of traffic flow restrictions in congested airspace. Implementation of automation as part of the Federal Aviation Administrations Free Flight Phase 1 and 2 programs, and development of procedures as part of the Operational Evolution Plan, are expected to facilitate these changes. Simulation scenarios were derived from real traffic scenarios to represent eliminating the AFD rule and implementing RVSM. The numbers of URET conflicts (predicted separation less than roughly 1700 feet vertical (with 2000-foot vertical minimum) and 12 nmi lateral) occurring in high altitude sectors are compared to assess the feasibility of the changes. Eliminating the AFD rule in large contiguous areas of less dense airspace is promising and warrants further study. The number of additional conflicts generated by eliminating the rule in dense airspace makes elimination there uncertain. In contrast, there was a significant drop in the number of conflicts observed in dense airspace when the runs were made with RVSM. There were indications that the additional altitudes from RVSM greatly facilitate the handling of traffic in dense airspace.
US Civil - Military Airspace Sharing: Collaboration Tools and Trials [2,068k]
April 1, 2001
View abstract [+]
This briefing accomplishes three objectives. First, it highlights the need for civil-military airspace sharing, while accounting for military needs and increasing civil and commercial traffic. Secondly, it identifies some of the procedures and automated Special Use Airspace (SUA) tools that facilitate civil-military information sharing and collaboration, including a number that use the Internet. Third, it discusses some of the initiatives that have been undertaken to improve civil access to SUA when it is not being use by the military. On a case by case basis, it has proven beneficial for civil and military entities to work out arrangements for sharing airspace to meet the needs of those desiring to use it.
Analysis of Fifth STAR Proposal for Runway Expansion at Minneapolis/St. Paul International Airport [1MB]
March 1, 2001
Robert S. Conker, Patricia A. Massimini, Debra A. Moch-Mooney, Michael J. Yablonski
View abstract [+]
The MITRE Corporation's Center for Advanced Aviation System Development (MITRE/CAASD) has investigated the effects of a new runway currently being constructed at Minneapolis/St. Paul International Airport (MSP). The principal focus of the analysis was to study the effects of adding a fifth Standard Terminal Arrival Route (STAR). The new STAR would accept approximately half the traffic approaching MSP from the east to relieve the existing TWINZ STAR. The results show the new STAR will not reduce delays at MSP and, because of the extra miles flown, is not justified under the conditions of the study.
Validation of the Feasibility of Coexistence of the New Civil GPS Signal (L5) with Existing Systems [1.1MB]
February 1, 2001
Dr. Michael Tran, Taehwan Kim, Dr. Christopher J. Hegarty, John Devincentis, Jr., Swen D. Ericson
View abstract [+]
The United States plans to implement a third civil Global Positioning System (GPS) frequency (L5) at 1176.45 MHz beginning with GPS satellites to be launched in 2005. This frequency is located within the 960-1215 MHz frequency band already used worldwide for aeronautical radionavigation services such as Distance Measuring Equipment (DME), Tactical Air Navigation (TACAN), and Secondary Surveillance Radar, as well as by the Department of Defense's Link 16. In November 1999, the interagency GPS Executive Board endorsed a set of recommendations on implementing L5 that included certain measures to be taken within the United States to ensure that L5 can coexist with government systems operating at the same or nearby frequencies. This report describes a series of activities that have been conducted by CAASD towards validating the ability of L5 to coexist with existing systems including: DME/TACAN, Link 16, and radar measurements; and GPS L5 receiver performance simulations in the presence of digitally synthesized pulsed interference.
A Comparison of LAAS Error Bounding Concepts [63k]
January 1, 2001
Curtis A. Shively
View abstract [+]
The FAA's Local Area Augmentation System (LAAS) broadcasts a parameter spr_gnd to describe the errors in the differential corrections caused by the ground facility. An aircraft using LAAS computes an upper bound with high probability on the resulting error in the position domain based on spr_gnd assuming that the errors are Gaussian distributed. This paper compares five bounding methods in terms of assumptions and resulting performance. Assumptions regarding the tails of the error distribution range from a Gaussian model to an exponential model. Performance is compared in terms of the factor by which the estimated value of spr_gnd must be inflated before broadcast to ensure the bound is provided with known confidence. For fixed, desired confidence the inflation factor varies with the number of independent samples used to estimate spr_gnd. Results show that using the same number of samples, methods assuming Gaussian tails give significantly smaller inflation factors than does the exponential tail method. Between these two extremes, is a more recently conceived method that assumes the error distribution is a mixture of Gaussian distributions with different standard deviations. The Gaussian mixture method gives inflation factors that are smaller than for the exponential tail method and may most closely correspond to the manner in which errors are present in real data.
An Ionospheric Grid Algorithm for WAAS Based on the Minimum Mean Square Error Estimator [63k]
December 1, 2000
Roland Lejeune, M. Bakry El-Arini
View abstract [+]
The Wide Area Augmentation System (WAAS) is a major component of the future air-navigation infrastructure of the United States. One of its functions is to provide corrections that can be used to reduce the errors inherent in the basic Global Positioning System (GPS) navigation solution available to civilian users. Among these are ionospheric delay corrections. WAAS also provides bounds on the post-correction residual errors from which the accuracy of the corrected navigation solution can be evaluated. The conservatism of the ionospheric estimation algorithm developed for WAAS Phase 1 is believed to limit the availability of the Precision Approach (PA) service delivered by the system more than necessary. MITREs Center for Advanced Aviation System Development (CAASD) investigated an alternative algorithm based on the Minimum Mean Square Error (MMSE) technique. Preliminary performance results obtained from processing a limited amount of recorded GPS data with the MMSE Algorithm are presented in this paper. Given the amount and quality of these data, these initial results do not provide a good indication of expected performance under operational conditions. However, compared to the results of a Reference Algorithm somewhat similar to the WAAS Phase 1 algorithm, the MMSE Algorithm results suggest that a significant improvement in performance could be obtained from an operational system using this technique.
Limited Dynamic Resectorization Casebook [1.5 MB]
November 14, 2000
Norma J. Taber, Floyd Woodward and Duane Small
View abstract [+]
The goal of the Limited Dynamic Resectorization Casebook is to educate and train facility personnel on Limited Dynamic Resectorization (LDR) so they can propose/develop an approach and action plan to practice LDR more effectively. The Casebook describes how LDR is implemented and (potentially) practiced in the current en route environment. The Casebook includes generic descriptions of LDR with several real world examples. The generic cases are classified according to certain operational characteristics (for example, weather, traffic volume, special use airspace). These cases are mapped to actual facilities that practice LDR today. The casebook also provides details on LDR procedures, processes, automation, and techniques used by automation and airspace staff.
Simulation Analysis of Dual CRDA Arrival Streams to Runways 27 and 33L at Boston Logan International Airport [214k]
November 1, 2000
Brian Simmons, Linda Boan, Dr. Patricia Massimini,
View abstract [+]
For much of the winter, northwest winds at Logan International Airport preclude the use of parallel runways 4L/4R and 22L/22R. Under these conditions, the standard configuration is to use 27 as the primary departure runway and 33L as the arrival runway. Since these runways intersect, the arrival and departure operations cannot be run independently, which results in substantial arrival delays that often accumulate to several hours by the evening arrival pushes. Consequently, there is a desire to increase arrival capacity and reduce arrival delay in this configuration by implementing a Converging Runway Display Aid (CRDA) dual arrive stream procedure to Runways 27 and 33L.
This document presents the results of a capacity and delay analysis using the Total Airspace and Airport Modeler (TAAM), and a subsequent communications workload analysis based upon the simulation model output. The simulation and communication models were developed and validated at CAASD under the guidance of a study team made up of Boston Tower controllers, managers, and representatives from the Air Transport Association. This analysis quantifies the expected impacts of the procedure in terms of arrival capacity, arrival delay, ground congestion, and communication frequency demand.
Enhanced Trial Planning and Problem Resolution Tools to Support Free Flight Operations [36k]
October 15, 2000
Daniel B. Kirk
View abstract [+]
This paper reports on research into providing enhanced trial planning and problem resolution capabilites to the en route sector controller. The goal of this research is to assist the controller in handling the more complex traffic patterns that can result from a less structured free flight environment, and in maintaining an efficient, strategic mode of air traffic control operation in heavy traffic situations.
FAA Data Register (FDR) Concepts of Use and Implementation [739k]
September 1, 2000
Dr. Nels A. Broste, Ronald G. Rhoades, Ronald A. Schwartz
View abstract [+]
As part of its plan to develop a National Airspace System (NAS)-wide Information Service, the Federal Aviation Administration (FAA) is in the process of developing a resource to manage NAS-wide metadata, data standards, and, eventually, data element models. Called the FAA Data Registry (FDR), this capability will give FAA managers and staff across the NAS the ability to manage metadata from multiple systems in a single, integrated tool as well as to define, store, and disseminate its developing data standards. To be developed in concert with the Metadata Repository, this effort is a fundamental step in the development of configuration management for NAS data elements over their life cycle. The creation of the FDR is a step towards configuration management of NAS data elements that support a wide range of interoperable systems. This activity is also expected to benefit modernization of the NAS and support international data harmonization efforts.
This document describes a concept of use, or vision, for the FDR as a tool in the technical architecture evolution. The subject includes a brief description of the FDR and its functionality; how it would be deployed, fielded, and maintained; who its users might be; and the anticipated benefits. In total, it will support the larger strategic goals of the FAA, facilitate work process improvement, and provide benefits to the engineers and managers guiding change to the NAS.
Modeling the Effects of Ionospheric Scintillation on GPS/SBAS Availability [887k]
August 15, 2000
Dr. Robert S. Conker, Dr. M. Bakry El-Arini, Dr. Christopher J. Hegarty, Tzong-Yang Hsiao
View abstract [+]
Ionospheric scintillation is a rapid change in the amplitude and phase of a radio signal as it passes through small-scale plasma density irregularities in the ionosphere. These scintillations not only can reduce the accuracy of GPS/SBAS receiver pseudorange and carrier phase measurements but can result in a complete loss of lock on a satellite. In a worst-case scenario, lock on enough satellites could result in lost positioning service. Scintillation has not had a major effect on mid-latitude regions (e.g., CONUS) since most severe scintillation occurs in a band approximately 20 degrees (deg) on either side of the magnetic equator and to a lesser extent in the polar and auroral regions. Most scintillation occurs for a few hours after sunset during the peak years of the solar cycle. Typical delay locked loop (DLL) / phase locked loop (PLL) designs of GPS/SBAS receivers enable them to handle moderate amounts of scintillation. Consequently, any attempt to determine the effects of scintillation on GPS/SBAS must consider both predictions of scintillation activity in the ionosphere, and the residual effect of this activity after processing by a receiver. This paper estimates the effects of scintillation on the availability on GPS and SBAS for L1 C/A and L2 semicodeless receivers. These effects are described in terms of loss of lock and degradation of accuracy and are related to different times, ionospheric conditions, and positions on the Earth. Sample results are presented using WAAS in the Western Hemisphere.
User Request Evaluation Tool (URET) Benefits During Free Flight Phase 1 [124k]
July 1, 2000
Joseph C. Celio, Marilyn G. Walker, Alvin L. McFarland
View abstract [+]
In the Free Flight Phase 1 (FFP1) Implementation Program a limited deployment of the core capabilities of several decision support systems will be evaluated at a number of operational sites. One component is the User Request Evaluation Tool (URET). URET will be implemented at seven Air Route Traffic Control Centers (ARTCCs) as part of FFP1. This document presents a detailed description of the URET benefits. Summaries of studies show the benefits in each of three areas: safety, FAA productivity, and airspace user cost savings. The plan for benefits measurement during FFP1 is also discussed.
A URET prototype is currently being used daily at the Indianapolis and Memphis ARTCCs. Much of what is described in this report comes from the operational use of the prototype at these centers.
Transition Airspace Controller Tools (TACT) Visualization Aids for Radar Controllers: Concepts for Cognitive Assistance With Flow Control Tasks in Transition Airspace [139k]
July 1, 2000
Christopher T. DeSenti
View abstract [+]
This document introduces and describes concepts being explored under the Transition Airspace Controller Tools (TACT) research effort at the MITRE Corporation's Center for Advanced Aviation System Development (CAASD). These concepts address identified difficulties radar controllers face while meeting flow restrictions in transition airspace. The tools provide controllers with cognitive assistance, through intuitive visualization, for complex tasks such as accurately meeting time-based metering schedules. This document serves as a primer for decision makers and stakeholders who seek to understand the functional value of TACT concepts; their applicability considering current National Airspace System (NAS) modernization activities; and the postulated effect of their use in an operational environment. KEYWORDS: Transition Airspace, Metering, Time based, Spatial, Visual, Visualization, Cognitive, Marker, Ghosting
Suppression of Pulsed Interference through Blanking
June 26, 2000
Christopher Hegart, FAA; A.J. Van Dierendonck, A.J. Systmes; Dan Bobyn, Dan Boby Engineering Ltd.; Michael Tran, Taehwan Kim, MITRE Corporation; Joe Grabpwski, Zeta Associates
View abstract [+]
In November 1999, the Interagency GPS Executive Board endorsed a set of recommendations on implementing the third civil GPS frequency (L5) that included certain measures to be taken within the United States to ensure that L5 can coexist with government systems operating at the same or nearby frequencies. These recommendations were based on analyses conducted in 1999 that assumed that pulse blanking is employed by GPS L5 user equipment. This paper describes the impact of pulsed interference on GPS user equipment and presents the results of simulation and hardware tests that were conducted this year to validate the assumed performance of L5 user equipment with blanking.
Methodology for Determining Compatibility of GPS L5 With Existing Systems and Preliminary Results
June 26, 2000
Christopher Hegarty; Taehwan Kim; Swen Ericson of CAASD; Patrick Reddan, Thomas Morrissey of Zeta Associates; A.J. Van Dierendonck of A.J. Systems
View abstract [+]
This paper describes the methodology being used by an ad hoc working group of the Interagency GPS Executive Board Third Civil Signal Implementation Steering Group to address the feasibility of coexistence between the third civil GPS signal and existing sytems at or near 1176.45 MHz. The paper also describes preliminary results of applying this methodoly to known emitters in the United States and other regions of the world.
An Agent-Based Model of the Airline Industry
June 15, 2000
William Niedringhaus
View abstract [+]
The Air Carrier Service Evolution Model (ACSEM) is an agent-based model that explores the evolution of the airline industry and its interactions with the US National Airspace System (NAS). ACSEM models airline decisions such as markets (what airports to serve and where to establish hubs), fleet mix, schedules, fares, and airline responses to delays, congestion and missed connections. ACSEM also models decisions by the Federal Aviation Administration (FAA) or individual airports, related to airport hourly capacities and possible reductions imposed due to weather or congestion.
Mining Aviation Safety Data: A Hybrid Approach
April 15, 2000
Eric Bloedorn
View abstract [+]
Data mining is broadly defined as the search for interesting patterns from large amounts of data. Techniques for performing data mining come from a wide variety of disciplines including traditional statistics, machine learning, and information retrieval. While this means that for any given application there is probably some "data mining" technique for finding interesting patterns, it also means there exists a confusing array of possible data mining tools and approaches for any given application. This problem is exacerbated when the available data contains both structured as well as unstructured (free-text) data. For example, the aviation safety data used in the reported experiments contains records which include both free text event descriptions as well as structured fields for phase-of-flight and location. Performing separate analysis on these different sources of data does not fully exploit the available information (e.g. clustering records without regard to narratives can match reports of total electrical failure with human factors problems). Unfortunately currently available tools provide little support. This paper describes one approach to combining the information available from all of these different types of data together to get a single 'similarity' score. The importance of picking tools appropriate to the types of data in hand is also stressed.
Aviation System Performance Metrics: Airport Utilization [47.4k]
April 1, 2000
Dr. Ellen A.Cherniavsky, Thor R. Abrahamsen
View abstract [+]
Airport utilization metrics are a subset of Aviation system performance Metrics which are currently being reported by the Federal Aviation Administration on the Internet. These airport utilization metrics were developed by CAASD under the sponsorship and direction of the Air Traffic control System Command Center. This paper describes how the metrics are defined and calculated, and provides example results.
Free Flight Phase 1 Conflict Probe Operational Description [483k]
March 1, 2000
Joseph C. Celio, Karen C. Bowen, David J. Winokur, Kenneth S. Lindsay, Edwin C. Newberger, Dolores Sicenavage
View abstract [+]
As part of the modernization of the National Airspace System (NAS) program, the Federal Aviation Administration (FAA) in collaboration with the aviation community, has developed a comprehensive plan, known as the NAS Architecture. The plan defines methods for modernizing the NAS well into the 21st Century through effective and efficient use of equipment, software, services, facilities, procedures, and resources. Included in the plan is the aviation concept called Free Flight.
Free Flight is a concept of air traffic management that permits pilots and controllers to share information and work together to manage air traffic from pre-flight through arrival without compromising safety. The first step in the evolution of capabilities is called Free Flight Phase 1 (FFP1).
This document describes the operational capabilities and concept of operations for the FFP1 Conflict Probe. Emphasis is placed on the functional capabilities and the operational context in which these capabilities are used. How the automation supports the use of these capabilities in accomplishing the tasks that provide the anticipated benefits to the user community is also described. Conflict Probe capabilities are discussed in sufficient detail to permit the reader to understand the automation concepts, to provide a framework for understanding the operational concept, and to enable the reader to understand how the benefits associated with Conflict Probe may be achieved.
Analysis of Triple Arrivals to Hartsfield Atlanta International Airport [346k]
March 1, 2000
Carla X. Gladstone, Graham K. Glover, Patricia A. Massimini, S.V. Massimini, Camille Shiotsuki, Brian T. Simmons
View abstract [+]
CAASD investigated new procedures that would improve arrival throughput at Hartsfield Atlanta International Airport in marginal visual weather. The analysis focused on adding a third arrival stream to closely spaced parallel runways during periods of peak arrivals and measuring the impacts on operations and delays. Two of the procedures investigated in this study show promise for being implemented in a short timeframe and have the potential for reducing arrival delay at the expense of some increase in departure delay. Two other procedures will require more equipment or development and are not likely to be available for implementation in the near future.
User Request Evaluation Tool (URET) Interfacility Conflict Probe Performance Assessment
December 15, 1999
W. C. Arthur, M. P. McLaughlin
View abstract [+]
The Federal Aviation Administration (FAA) and The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) have developed a set of en route decision support capabilities known as the User Request Evaluation Tool (URET) prototype. These capabilities include a flight plan based conflict probe that continuously checks for strategic conflicts, a trial planning function that allows a controller to evaluate resolutions or pilot requests before they are issued as clearances, and electronic flight data displays that provide an effective means of managing flight information at the sector. The URET prototype is the basis for the Free Flight Phase I (FFP1) conflict probe that will be deployed for large-scale national trials. The prototype has been in daily use at Radar Associate sector positions since 1997 in the Indianapolis (ZID) and Memphis (ZME) Air Route Traffic Control Centers (ARTCCs). Daily use is defined as controllers using URET on a regular scheduled basis (currently 12 hours per day, five days per week). Beginning in 1998, an interfacility (IFA) capability that provides data exchange between multiple ARTCCs was added to the daily use system. IFA operation allows controllers to have more accurate and timely trajectory and conflict data beyond the center boundary, and provides a capability for automated coordination of trial plans between centers. This paper describes quantitative metrics and models that can be used to determine FFPl conflict probe accuracy requirements as well as to evaluate the prototype system upgrades. The metrics herein are technical performance measures to evaluate functional performance. Operational performance metrics that are based on controller assessments are outside the scope of this paper. However, the operational consensus that has emerged from the URET field evaluations to date is that the URET information is perceived to be "highly accurate" in the context of (1) the sector operations that it supports and (2) its relative value as compared to the current automation system capabilities in supporting those same operations. Technical performance measures, however quantified, also need to be interpreted in that context to ensure analytically complete and consistent conclusions with respect to the net contribution of the tools to operational performance This paper presents the results of the particular methodology currently being used at CAASD to quantify technical performance of the URET conflict probe. Technical performance is shown to vary over a range determined by a number of factors in the ATC operational environment, but the experience to date has been that the tolerance on suitable operational performance is consistent with the technical performance that has been achievable. Any specific instances of performance outside the tolerances for operational suitability are pursued for the purpose of understanding and correcting such variances.
Conflict Probe Operational Evaluation and Benefits Assessment
November 15, 1999
K. Kerns, A. L. McFarland
View abstract [+]
Air traffic controllers currently rely on structured routes and traffic organization for managing separation problems. However, even in today's structured air traffic control environment, human limitations in the rate and accuracy with which they can extrapolate aircraft positions can result in late or unnecessary ATC interventions to resolve conflicts. To meet the additional demands that will be placed on controllers operating in the unstructured routing environment introduced as part of Free Flight, the FAA and the MITRE Center for Advanced Aviation System Development (CAASD) have been researching and developing a strategic conflict probe capability for the en route controller team called the User Request Evaluation Tool (URET). This paper presents results from (a) recent field evaluations of URET, (b) analysis activities using real traffic scenarios from Indianapolis Center, and (c) a controller-in-the-loop simulation study of the URET being used in a traffic environment with reduced structure relative to current practice. The paper analyzes these results to describe how Conflict Probe can help reduce the restrictions that are imposed on flights.
The Concept of Path Objects : Making the FMS More Useful [595k]
November 15, 1999
Dr. John N. Barrer
View abstract [+]
The utility of the FMS can be increased significantly by addressing problems associated with; the complexity of the pilot-FMS interface, the increasing size of the FMS database and limitations on the flexibility of RNAV routes. The Concept of Path Objects offers a simple path language for expressing FMS/RNAV routes, which should simplify the pilot-FMS interface, reduce the size of the pre-stored database, and offer a means to have dynamically generated random 3D RNAV capability (primarily) for terminal area operations.
Conflict Probe Benefits to Controllers and Users Indications from Field Evaluations
August 15, 1999
Daniel J. Brudnicki, Alvin L. McFarland, Susan M. Schultheis
View abstract [+]
A prototype version of an automated, flight plan-based conflict probe has been built and installed at Indianapolis Center. This capability is called User Request Evaluation Tool (URET). It was derived from laboratory versions of Automated En Route Air Traffic Control (AERA). URET receives track, flight plans, and flight plan amendments from the Host computer in real time and maintains current flight plan-based trajectories for all aircraft in the center. It predicts aircraft into the future along their flight plans for up to 20 minutes, and alerts the controller to any conflicts found between two or more aircraft, or between an aircraft and a special use airspace. URET also permits a controller to enter a proposed new clearance into the system, and to check it for conflicts prior to issuing it to the pilot. Controllers at Indianapolis Center have evaluated URET on the control room floor during live air traffic control operations. These evaluations began in February, 1996 and continue to present. URET has been favorably received by the controllers, who described various ways in which it could help them carry out their air traffic control duties more safely and more efficiently. The controllers suggested that use of conflict probe could also enable them to provide concrete benefits to users, and they mentioned specific situations that could be impacted. This paper describes the URET prototype and the field evaluations conducted. It summarizes the feedback from the controllers and indicates the types of benefits URET provides to controllers. It also provides quantitative indications and anecdotal examples of the two major types of benefits to users.
An Introduction to WAAS and Its Predicted Performance [396k]
August 1, 1999
Dr. M. Bakry El-Arini, Dr. Walter A. Poor, Roland O. Lejeune, Dr. Robert S. Conker, James (J.P. ) Fernow, Kelly R. Markin
View abstract [+]
The FAA is developing a Wide-Area Augmentation System (WAAS) to GPS that will broadcast clock, ephemeris, and ionospheric corrections. Aviation user equipment will apply the corrections to GPS measurements and also convert error bounds into the position domain. Flight operations can be conducted using WAAS guidance only when the horizontal, and in some cases also the vertical, position error bound is less than a threshold that depends on the phase of flight. The expected fraction of time that a given flight operation can be conducted is termed its availability. Geomagnetic storms sometimes are accompanied by large spatial and temporal gradients in ionospheric delay that result in an increase in ionospheric and position error bounds, which reduces availability. The paper estimates availability of precision approach operations under various scenarios.
An Object Oriented Analysis Of Air Traffic Control [1.8MB]
August 1, 1999
Celesta Ball, Rebecca Kim
View abstract [+]
The Integration and Interaction Laboratory (I-Lab) project is a development program undertaken by the Center for Advanced Aviation System Development of The MITRE Corporation and sponsored by the Federal Aviation Administration (FAA) Operations Research Service, AOR-1. A first step towards development of an Air Traffic Control (ATC) National Simulation Laboratory (NSL), the I-Lab project has been established by the FAA as a means of incrementally developing the operational and architectural concepts and the requirements for the NSL. The software and architecture of the I-Lab testbed will be used as the basis for establishment of the initial baseline system at the NSL.
Air Traffic Control System Command Center Report Card [751k]
July 15, 1999
Thor R. Abrahamsen, Catherine N. Bolczak, Dr. Ellen A. Cherniavsky
View abstract [+]
This document summarizes work done to explore the concept of a "report card" that assesses the performance of that National Airspace System. This document covers three main areas: the purpose and approach used to explore the report card; a summary of the metrics explored to date; and recommended next steps. The goal of the report card is to assess NAS performance by capturing air carrier concerns while also considering the circumstances under which the system was operating.
Integrating the Flight Management System with Air Traffic Control Functions [566k]
July 1, 1999
Dr. John N. Barrer
View abstract [+]
The concept of path objects (POs) is to store in aircrafts' flight management computers the instructions on how to create the shapes of frequently flown flight paths. The instructions for creating these paths are called path objects (POs). A particular PO is the definition of a shape, independent of its location. A specific aircraft's trajectory can then be specified by setting a few parameters and the starting and ending points of the PO, using universal latitude/longitude/altitude coordinates. This paper develops the concept, specifies a basic set of POs, and discusses many applications to air traffic control (ATC) situations. The PO concept offers a common language that can compactly express complete information about the aircraftâs intended path, which in turn offers potential benefits to both the ground control system and the aircraft operator. Using POs, most aircraft flight paths can be expressed with only the path's name and its starting and ending points. By simplifying the expression of flight paths, the PO concept potentially solves many practical problems related to ATC and offers increased flexibility to ATC functions. It addresses the issues of the integrity of aircraft intent information, the maintenance of navigation databases, the commonality of procedures for the pilot, the charting and cockpit display of information, and the efficiency of transmission. Implementation of the concept requires that PO processing be incorporated into the aircraft's flight management computer system and into the ground ATC systems. However, once both sides of the system are aware of POs, any manufacturer's flight management system (FMS) that contains POs can communicate with any ATC system that also uses POs. This means that the development of air traffic management (ATM) functionality can proceed independently of FMS development. Any civil aviation system in the world can independently develop its proprietary ATM functions and incorporate the capabilities of the FMS by communicating in the language of POs. While the use of POs does not require data link (thereby allowing a transition from today's voice communication system to a full data-link system), the use of data link would enable the use of more complex POs. KEYWORDS: Path Objects, Path Object Processing, Flight Management Systems, Air Traffic Control.
The Concept of Path Objects
June 15, 1999
John Barrer
View abstract [+]
Path Objects are instructions stored in a computer such as the FMS (or any area navigation system) for constructing a flight path based on a few inputs in the form of fixes and parameters. For example, if we wanted to have the aircraft fly a circle, we would store (in the FMS) the instructions for how to construct the circle given just the center (a geographical fix) and the radius (a parameter). By sending the values of only those two arguments to the aircraft, we could locate the circle over the White House or the Kremlin by merely changing the center. We could change the radius by changing only one number. Furthermore, anyone could reconstruct the identical circle by just knowing the center and radius.
National Airspace System Report Card [13.4MB]
June 15, 1999
Dr. Ellen A. Cherniavsky, Thor R. Abrahamsen
View abstract [+]
This document summarizes the work that has been done since July 1998 in developing a Report Card that assesses the performance of the National Airspace System. The work was done in support of efforts by Air Traffic Services to measure system performance and develop strategies to improve that performance. The report contains some background on the project and its current status is provided. The bulk of the effort has been devoted to airport utilization metrics, which are described next including how the metrics are defined and calculated, and showing example results. Data quality and validation issues are discussed. Two other metrics, Arrival Times and Relationship to Miles-in-Trail Restrictions, have been investigated and are documented in succeeding section. The conclusion highlights what has been learned from this years work.
User Request Evaluation Tool (URET) Conflict Probe Performance and Benefits Assessment
June 1, 1999
D. J. Brudnicki, A. L. McFarland
View abstract [+]
In order to respond to rising demands for services from the National Airspace System (NAS), the Federal Aviation Administration (FAA) and The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) have developed and evaluated a set of en route air traffic control (ATC) decision support capabilities based on many years of earlier work on the Advanced En Route ATC (AERA) program. The component capabilities, embodied in a prototype referred to as the User Request Evaluation Tool (URET), include a conflict probe that continuously checks current flight plan trajectories for strategic conflicts, and a Trial Planning function that allows a controller to expeditiously evaluate problem resolutions before they are issued as clearances. These capabilities are intended to provide the flexibility and decision support needed to allow more user preferences while continuing to maintain or enhance today's level of safety. The URET prototype was deployed to the Indianapolis Air Route Traffic Control Center (ARTCC) for January 1996. This paper presents key findings from the field trials and related activities that have occurred since. It includes a summary of the evaluation results, algorithmic performance assessment of URET's conflict probe and component capabilities and a discussion of the projected benefits that can be expected with a national deployment of the system. The field trials have strongly indicated thus far that URET capabilities are operationally acceptable for both planning and clearance decision making purposes at the en route sector. The algorithmic analyses quantify those results in terms of conflict likelihood and warning time to effectively define the performance levels needed to support that degree of utility and acceptability. Finally, the benefits analyses focus on contrasting today's operations with expected increases in system flexibility, efficiency, and of projected annual savings to the aviation community.
Impact of Regional Jets on Congestion in the NAS [131k]
February 15, 1999
Dr. W. W. Trigeiro
View abstract [+]
This briefing summarizes the results of an analysis performed by The MITRE Corporation's Center for Advanced Aviation System Development (CAASD) to examine the potential effects of regional jets (RJs) on the performance of the National Airspace System (NAS). The study was part of a Mission Oriented Investigation and Experimentation (MOIE) project conducted in fiscal years (FY) 1998 - 1999. The intent was to provide a "heads up" to aviation planners about the ability of the NAS to accommodate the significant changes anticipated in the regional airline fleet through 2003. The study was conducted in two phases. First, an analysis of the airline industry was performed to determine the degree to which RJs are now in use and the plans of the airlines for expanding their deployment in the future. The final result of the first phase was a scenario reflecting expected RJ usage at the end of 2003. Second, that scenario was used to create a prototype airline schedule (format-compatible with the Official Airline Guide, or OAG). This, in turn, served as the basis of a simulation of air traffic flows at the end of 2003. In turn, this model produced results that suggest the expected influence of RJs on congestion in the NAS at the end of 2003. The analysis considered only traffic within the continental United States (CONUS).
Controller Perspective of AERA 2 [548k]
February 1, 1999
J.C. Celio
View abstract [+]
This Controller Perspective of AERA 2 describes a proposed role for the controllers in the Air Traffic Control (ATC) system as it is envisioned to exist once the AERA 2 automation capabilities are deployed. The effects of other systems, scheduled for installation prior to AERA 2, are also included. A view of the integration of the automation capabilities and human operators into a workable ATC system is presented. The focus is on the controller's role, tasks, and priorities, how these change because of AERA 2 automation, and how the entire ATC system with AERA 2 will improve upon the current system.
Conflict Probe Operational Evaluation and Benefits Assessment
November 1, 1998
Dr. Karols Kerns and Dr. Alvin L McFarland
A Conflict Probe to Provide Early Benefits for Airspace Users and Controllers
August 27, 1997
Alvin L. McFarland
View abstract [+]
Current Air Traffic Control (ATC) operations in many areas of the United States are highly structured and restrictive. Increasing structure imposed on flight operations over the years allowed controllers to safely manage rising traffic levels. This structure conflicts with users desires for more freedom to fly preferred routes and altitudes from origin to destination. Airspace users have made a unified call for a less structured environment they call Free Flight. Analyses performed to date indicate that airspace users would realize substantial savings in operating costs with free flight.
Full AERA Services Operational Description [654k]
September 1, 1993
Bruce, Wetherby, Joseph C. Celio, Sonya M. Kidman, Margaret A. Stanley
View abstract [+]
The operational characteristics of Full AERA Services (FAS) are described. This includes a background description of the program and its Air Traffic Control (ATC) system benefits, a discussion of the environment for FAS and its key automation features, and a description of FAS capabilities. Major FAS capabilities include automated problem detection and resolution, including automation processing support and planning and replanning aids, and enhanced operational capabilities in the controller-to-controller coordination and controller to-pilot communication areas. To facilitate an understanding of the application of FAS, military and air carrier scenario incorporating the use of this system are illustrated. Finally, an appendix is provided which delineates the differences between FAS and Introductory AERA Services (IAS), an interim step in the transition to FAS.
Evaluation of the Proposed Signal Structure for the New Civil GPS Signal at 1176.45 MHz
June 1, 1990
Dr. Christopher J. Hegarty
View abstract [+]
A signal structure for the third civil GPS signal (L5) at 1176.45 MHz has been proposed by Drs. J. J. Spilker and A.J. Van Dierendonck. This paper evaluates the performance of this signal proposal in the presence of wideband Gaussian noise (e.g. thermal noise or wideband interference) and multipath.
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