Publications
U.S. Department of Transportation Federal Aviation Administration Field Demonstration #2: Final Report for Staffed NextGen Tower (SNT)
March 1, 2012
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-389
Topic:
R&D area:
Summary
Staffed NextGen Towers (SNT), a research concept being developed and validated by the Federal Aviation Administration (FAA), is a paradigm shift to providing air traffic control services primarily via surface surveillance approved for operational use by controllers instead of the existing out-the-window (OTW) view at high-density airports. SNT was exercised as a prototype installed at the Dallas-Fortworth International Airport (DFW) during a two-week demonstration in the spring of 2011. MIT Lincoln Laboratory conducted this demonstration for the FAA in coordination with DFW air traffic control (ATC) and the DFW airport authority. This proof-of-concept demonstration used live traffic and was conducted by shadowing East tower operations from the DFW center tower, which is a back-up facility currently not typically used for air traffic control. The objective of this SNT field demonstration was to validate the supplemental SNT concept, to assess the operational suitability of the Tower Information Display System (TIDS) display for surface surveillance, and to evaluate the first iteration of prototype cameras in providing visual augmentation. TIDS provided surface surveillance information using an updated user interface that was integrated with electronic flight data. The cameras provided both fixed and scanning views of traffic to augment the OTW view. These objectives were met during the two-week field demonstration. DFW air traffic provided twelve controllers, three front line manager (FLMs), and three traffic management coordinators (TMCs) as test subjects. The twelve National Air Traffic Controllers Association (NATCA) DFW controllers "worked" the traffic according to their own techniques, using new hardware and software that included high resolution displays of surveillance data augmented by camera views. This equipment was designed to provide enhanced situational awareness to allow controllers to manage increased traffic volume during poor visibility conditions, leading to increased throughput. Results indicated that the likelihood of user acceptance and operational suitability is high for TIDS as a primary means for control, given surface surveillance that is approved for operational use. Human factors data indicated that TIDS could be beneficial. However, major technical issues included two display freezes, some incorrectly depicted targets, and display inconsistencies on TIDS. The cameras experienced numerous technical limitations that negatively influenced the human factors assessment of them. This report includes the percentages of human factors and technical success criteria that passed at DFW-2.
Summary
Staffed NextGen Towers (SNT), a research concept being developed and validated by the Federal Aviation Administration (FAA), is a paradigm shift to providing air traffic control services primarily via surface surveillance approved for operational use by controllers instead of the existing out-the-window (OTW) view at high-density airports. SNT was exercised...
READ MORE
Estimation of New York departure fix capacities in fair and convective weather
January 23, 2012
Conference Paper
Published in:
3rd Aviation, Range, and Aerospace Meteorology, 23 January 2012.
Topic:
R&D area:
R&D group:
Summary
When convective weather impacts the New York Metro airspace, traffic managers may employ several tactics to mitigate weather impacts and maintain manageable and efficient flow of traffic to and from the airports. These tactics, which include maneuvering individual flights through weather, merging and redirecting traffic flows to avoid storms, and rerouting traffic from blocked routes onto unimpacted or less-impacted routes, all affect the capacity of the affected airspace resources (departure fixes, routes, or gates). Furthermore, the location of the weather impacts can have a great influence on the amount of leeway that traffic managers have in applying these tactics. In New York, departure fixes, the gateways to en route airspace where departure traffic from several metroplex airports are merged onto en route airways, are particularly critical. When congestion (volume of traffic in excess of capacity) occurs near departure fixes as a result of weather impacts, traffic managers must resort to airborne holding or unplanned departure stops to quickly reduce traffic over the fix to manageable levels. Nonetheless, when convective weather impacts densely packed and busy metroplex airspaces, it is inevitable that traffic will need to use impacted departure fixes and routes to keep delays in check. For this reason, predictions of the weather-impacted capacity of critical airspace resources like departure fixes that are based in the reality of commonly used impact mitigation tactics, are needed to help traffic managers anticipate and avoid disruptive congestion at weather-impacted departure fixes. The Route Availability Planning Tool (RAPT) is a departure management decision support tool that has been used in the New York operations since 2003. It predicts the weather impact on departure fixes and routes based on departure times. RAPT assigns a departure status (RED, YELLOW, or GREEN) to individual departure routes based on the departure time, the predicted severity of the convective weather that will impact the route, the likelihood that a pilot will deviate to avoid the weather along the route, and the operational sensitivity to deviations in the departure airspace that the route traverses. These blockages assist traffic managers in prompt route reopening of routes closed by convective weather impacts, as well as providing situational awareness for impeding impacts on routes. RAPT also identifies the location of weather impacts along the departure route. This paper presents an analysis of observed fair weather and convective weather impacted throughput on New York departure fixes. RAPT departure status and impact location are used to characterize the severity of departure fix weather impacts, and weather-impacted fix capacity ranges are estimated as a function of RAPT impacts. The use of traffic flow merging is identified, and weather impacted capacity ranges for commonly used merged flows are also estimated.
Summary
When convective weather impacts the New York Metro airspace, traffic managers may employ several tactics to mitigate weather impacts and maintain manageable and efficient flow of traffic to and from the airports. These tactics, which include maneuvering individual flights through weather, merging and redirecting traffic flows to avoid storms, and...
READ MORE
A tree-based ensemble method of the prediction and uncertainty quantification of aircraft landing times
January 22, 2012
Conference Paper
Published in:
10th Conf. on Artificial and Computational Intelligence, 22 January 2012.
Topic:
R&D area:
R&D group:
Summary
Accurate aircraft landing time predictions provide situational awareness for air traffic controllers, enable decision support algorithms and gate management planning. This paper presents a new approach for estimation of landing times using a tree-based ensemble method, namely Quantile Regression Forests. This method is suitable for real-time applications, provides robust and accurate predictions of landing times, and yields prediction intervals for individual flights, which provide a natural way of quantifying uncertainty. The approach was tested for arrivals at Dallas/Fort Worth International Airport over a range of days with a variety of operational conditions.
Summary
Accurate aircraft landing time predictions provide situational awareness for air traffic controllers, enable decision support algorithms and gate management planning. This paper presents a new approach for estimation of landing times using a tree-based ensemble method, namely Quantile Regression Forests. This method is suitable for real-time applications, provides robust and...
READ MORE
A new approach for designing safer collision avoidance systems
January 1, 2012
Journal Article
Published in:
Air Traffic Control Q., Vol. 20, No. 1, January 2012, pp. 27-45.
Topic:
R&D area:
R&D group:
Summary
The Traffic Alert and Collision Avoidance System significantly reduces the risk of mid-air collision and is mandated worldwide on transport aircraft. Engineering the avoidance logic was costly and spanned decades. The development followed an iterative process where the logic was specified using pseudocode, evaluated in simulation, and revised based on performance against a set of metrics. Modifying the logic is difficult because the pseudocode contains many heuristic rules that interact in complex ways. With the introduction of next-generation air traffic control procedures and surveillance systems, the logic will require significant revision to prevent unnecessary alerts. Recent work has explored an approach for designing collision avoidance systems that will shorten the development cycle, improve maintainability, and enhance safety with fewer false alerts. The approach involves computationally deriving optimized logic from encounter models and performance metrics. This paper outlines the approach and discusses the anticipated impact on development, safety, and operation.
Summary
The Traffic Alert and Collision Avoidance System significantly reduces the risk of mid-air collision and is mandated worldwide on transport aircraft. Engineering the avoidance logic was costly and spanned decades. The development followed an iterative process where the logic was specified using pseudocode, evaluated in simulation, and revised based on...
READ MORE
Lincoln Laboratory 1030/1090 MHz monitoring, March-June 2010
November 15, 2011
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-372
Topic:
R&D area:
R&D group:
Summary
Traffic Alert and Collision Avoidance System (TCAS) behavior in New England airspace is being monitored and analyzed, making use of an omni-directional 1030/1090 MHz receiver. The receiver system, located in Lexington, Massachusetts, and operated by MIT Lincoln Laboratory, is used to record data for subsequent analysis in non-real-time. This is the second report of MIT Lincoln Laboratory 1030/1090 MHz monitoring, covering the period March through June 2010. There are three main areas of study: 1. 1030 MHz data related to TCAS air-to-air coordination and other communications, 2. 1030 and 1090 MHz data related to TCAS surveillance, and 3. 1090 MHZ Extended Squitter data, i.e., the Mode S implementation of Automatic Dependent Surveillance-Broadcast (ADS-B). In addition to a summary of results, this report answers specific questions raised during the previous 2009 analysis and attempts to provide insights into the meaning of the data with respect to TCAS operation. This four-month period will be used to baseline 1030/1090 MHz activity in the New England area. Future plans call for the 1030/1090 MHz receiver to be moved so that limited data recording can be performed at various TCAS RA monitoring system (TRAMS) sites throughout the NAS.
Summary
Traffic Alert and Collision Avoidance System (TCAS) behavior in New England airspace is being monitored and analyzed, making use of an omni-directional 1030/1090 MHz receiver. The receiver system, located in Lexington, Massachusetts, and operated by MIT Lincoln Laboratory, is used to record data for subsequent analysis in non-real-time. This is...
READ MORE
Evaluation of Consolidated Storm Prediction for Aviation (CoSPA) 0-8 hour convective weather forecast using the airspace flow program blockage-based capacity forecast ("The Matrix")
November 9, 2011
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-385
Topic:
R&D area:
R&D group:
Summary
The CoSPA 0-8 hour convective weather forecast provides deterministic forecast products that can be used by strategic traffic management planners, and can be readily translated into forecasts of aviation capacity impacts for use in automated decision support tools. An operational CoSPA prototype was evaluated at several FAA Air Traffic Control facilities during the summer of 2010. As part of this evaluation, CoSPA forecasts were translated into forecasts of capacity impacts on traffic flows through two Flow Constrained Areas (FCAA05 and FCAA08) commonly used to control arrival traffic into the highly congested northeastern United States. This report describes an objective and operationally relevant evaluation of the accurancy of CoSPA-based forecasts of FCA capacity.
Summary
The CoSPA 0-8 hour convective weather forecast provides deterministic forecast products that can be used by strategic traffic management planners, and can be readily translated into forecasts of aviation capacity impacts for use in automated decision support tools. An operational CoSPA prototype was evaluated at several FAA Air Traffic Control...
READ MORE
Decomposition methods for optimized collision avoidance with multiple threats
October 16, 2011
Conference Paper
Published in:
DASC 2011, 30th IEEE/AIAA Digital Avionics Systems Conference, 16-20 October 2011, pp. 1D2.
Topic:
R&D area:
R&D group:
Summary
Aircraft collision avoidance systems assist in the resolution of collision threats from nearby aircraft by issuing avoidance maneuvers to pilots. Encounters where multiple aircraft pose a threat, though rare, can be difficult to resolve because a maneuver that might resolve a conflict with one aircraft might induce conflicts with others. Recent efforts to develop robust collision avoidance systems for single-threat encounters have involved modeling the problem as a Markov decision process and applying dynamic programming to solve for the optimal avoidance strategy. Because this methodology does not scale well to multiple threats, this paper evaluates a variety of decomposition methods that leverage the optimal avoidance strategy for single-threat encounters.
Summary
Aircraft collision avoidance systems assist in the resolution of collision threats from nearby aircraft by issuing avoidance maneuvers to pilots. Encounters where multiple aircraft pose a threat, though rare, can be difficult to resolve because a maneuver that might resolve a conflict with one aircraft might induce conflicts with others...
READ MORE
Collision avoidance for general aviation
October 16, 2011
Conference Paper
Published in:
30th AIAA/IEEE Digital Avionics Systems Conf., 16-20 October 2011.
Topic:
R&D area:
Summary
The Traffic Alert and Collision Avoidance System (TCAS) is mandated on all large transport aircraft to reduce mid-air collision risk. Since its introduction, no mid-air collisions between TCAS-equipped aircraft have occurred in the United States. However, General Aviation (GA) aircraft are generally not equipped with TCAS and experience collisions several times per year. There is interest in low-cost collision avoidance systems for GA aircraft to reduce collision risk with other GA aircraft as well as with TCAS-equipped aircraft. Since TCAS was designed for large aircraft that can achieve greater vertical rates, the assumptions made by the system and the associated advisories are not always appropriate for GA aircraft. Modifying the TCAS logic to accommodate GA aircraft is far from straightforward. Even minor changes to TCAS to correct operational issues are difficult to implement due to the interaction of the complex rules defining the logic. Recent work has explored an alternative to the TCAS logic based on optimization with respect to a probabilistic model of aircraft behavior. The model encodes performance constraints of GA aircraft, and a computational technique called dynamic programming allows the optimal collision avoidance strategy to be computed efficiently. Prior work has focused on systems that meet the performance assumptions of the existing TCAS logic. However, these assumptions are not always appropriate for GA aircraft. This paper will present simulation results comparing the existing logic to logic that has been optimized to operate onboard GA aircraft. If both aircraft are equipped with collision avoidance logic, it is important that the advisories be coordinated to prevent both aircraft from climbing or descending. The TCAS logic has a built-in coordination mechanism with which a GA system must maintain compatibility. Several coordination strategies, both with the optimized logic and the current logic, are evaluated in simulation.
Summary
The Traffic Alert and Collision Avoidance System (TCAS) is mandated on all large transport aircraft to reduce mid-air collision risk. Since its introduction, no mid-air collisions between TCAS-equipped aircraft have occurred in the United States. However, General Aviation (GA) aircraft are generally not equipped with TCAS and experience collisions several...
READ MORE
Estimating the likelihood of success in departure management strategies during convective weather
October 16, 2011
Conference Paper
Published in:
Proc. 30th IEEE/AIAA Digital Avionics Systems Conference, DASC, 16-20 October 2011, pp. 6D4.
Topic:
R&D area:
R&D group:
Summary
The presence of convective weather (thunderstorms) in terminal and nearby en route airspace of major metroplex areas can have significant impacts on departure operations. Traffic on departure routes impacted by convective weather may be constrained by miles-in-trail (MIT) restrictions, to allow controllers the time needed to maneuver individual flights around thunderstorms that pilots wish to avoid. When the workload required to manage traffic flows becomes too great, departure routes may be closed. Departures still on the ground that are filed on closed or restricted routes may face significant delays as they wait for clearance on their filed route, or for a viable reroute to be implemented. The solution proposed in concepts such as the Integrated Departure Route Planning tool (IDRP) [1] is the use of weather and departure demand forecasts to plan and implement reroutes to avoid weather and volume congestion proactively, well in advance of route restrictions or closures.
Summary
The presence of convective weather (thunderstorms) in terminal and nearby en route airspace of major metroplex areas can have significant impacts on departure operations. Traffic on departure routes impacted by convective weather may be constrained by miles-in-trail (MIT) restrictions, to allow controllers the time needed to maneuver individual flights around...
READ MORE
Initial validation of a convective weather avoidance model (CWAM) in departure airspace
October 16, 2011
Conference Paper
Published in:
DASC 2011, 30th IEEE/AIAA Digital Avionics Systems Conference, 16-20 October 2011, pp. 3A2.
Topic:
R&D area:
R&D group:
Summary
The Convective Weather Avoidance Model (CWAM) translates gridded, deterministic weather observations and forecasts into Weather Avoidance Fields (WAF). The WAF gives the probability, at each point in the grid, that a pilot will choose to deviate around convective weather at that location. CWAM have been developed and validated for en route, high altitude, level flight, low altitude level flight, and for descending arrivals. A heuristic CWAM for departures was also developed and deployed as part of the Route Availability Planning Tool (RAPT) prototype development in New York and Chicago. This paper presents an evaluation of the departure CWAM that is currently deployed as part of RAPT, based on an analysis of departure traffic in the Chicago terminal area during convective weather events.
Summary
The Convective Weather Avoidance Model (CWAM) translates gridded, deterministic weather observations and forecasts into Weather Avoidance Fields (WAF). The WAF gives the probability, at each point in the grid, that a pilot will choose to deviate around convective weather at that location. CWAM have been developed and validated for en...
READ MORE