Publications
Operational usage of the Route Availability Planning Tool during the 2007 convective weather season
October 6, 2008
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-339
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Summary
The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance at forecasting route blockage, to assess RAPT operational use during adverse weather, and to evaluate RAPT benefits. The operational test found that RAPT guidance was operationally sound and timely in many circumstances. RAPT applications included increased departure route throughput, more efficient reroute planning, and more timely decision coordination. Estimated annual NY departure delay savings attributed to RAPT in 2007 totaled 2,300 hours, with a cost savings of $7.5 M. The RAPT field study also sought to develop a better understanding of NY traffic flow decision-making during convective weather impacts since the RAPT benefits in 2007 were significantly limited by a number of factors other than direct weather impacts. Observations were made of the multi-facility departure management decision chain, the traffic management concerns and responsibilities at specific FAA facilities, and the procedures and pitfalls of the current process for capturing and disseminating key information such as route/fix availability and restrictions.
Summary
The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance...
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Operational usage of the Route Availability Planning Tool during the 2007 convective weather season : executive summary
October 6, 2008
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-339-1
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Summary
The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance at forecasting route blockage, to assess RAPT operational use during adverse weather, and to evaluate RAPT benefits. The operational test found that RAPT guidance was operationally sound and timely in many circumstances. RAPT applications included increased departure route throughput, more efficient reroute planning, and more timely decision coordination. Estimated annual NY departure delay savings attributed to RAPT in 2007 totaled 2,300 hours, with a cost savings of $7.5 M. The RAPT field study also sought to develop a better understanding of NY traffic flow decision-making during convective weather impacts since the RAPT benefi ts in 2007 were significantly limited by a number of factors other than direct weather impacts. Observations were made of the multi-facility departure management decision chain, the traffic management concerns and responsibilities at specific FAA facilities, and the procedures and pitfalls of the current process for capturing and disseminating key information such as route/fix availability and restrictions.
Summary
The Route Availability Planning Tool (RAPT) is an integrated weather/air traffic management decision support tool that has been designed to help traffic managers better anticipate weather impacts on jet routes and thus improve NY departure route usage efficiency. A field study was conducted in 2007 to evaluate RAPT technical performance...
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Detection probability modeling for airport wind-shear sensors
September 15, 2008
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-340
Summary
An objective wind-shear detection probability estimation model is developed for radar, lidar, and sensor combinations. The model includes effects of system sensitivity, site-specific wind-shear, clutter, and terrain blockage characteristics, range-aliased obscuration statistics, antenna beam filling and attenuation, and signal processing differences which allow a sensor- and site-specific performance analysis of deployed and future systems. A total of 161 sites are analyzed for the study, consisting of airports currently serviced by the Terminal Doppler Weather Radar (TDWR) (46), Airport Surveillance Radar Weather Systems Processor (ASR-9 WSP) (35), Low Altitude Wind Shear Alert System-Relocation/Sustainment (LLWAS-RS) (40), and no wind-shear detection system (40). Sensors considered are the TDWR, WSP, LLWAS, Weather Surveillance Radar 1988-Doppler (WSR-88D, commonly known as NEXRAD), adn the Lockheed Martin Coherent Technologies (LMCT) Doppler lidar and proposed x-band radar. [not complete]
Summary
An objective wind-shear detection probability estimation model is developed for radar, lidar, and sensor combinations. The model includes effects of system sensitivity, site-specific wind-shear, clutter, and terrain blockage characteristics, range-aliased obscuration statistics, antenna beam filling and attenuation, and signal processing differences which allow a sensor- and site-specific performance analysis of...
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Convection diagnosis and nowcasting for oceanic aviation applications
August 25, 2008
Conference Paper
Published in:
Proc. SPIE, Vol. 7088, Remote Sensing Applications for Aviation Weather Hazard Detection and Decision Support, 25 August 2008, 708808.
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Summary
An oceanic convection diagnosis and nowcasting system is described whose domain of interest is the region between the southern continental United States and the northern extent of South America. In this system, geostationary satellite imagery are used to define the locations of deep convective clouds through the weighted combination of three independent algorithms. The resultant output, called the Convective Diagnosis Oceanic (CDO) product, is independently validated against space-borne radar and lightning products from the Tropical Rainfall Measuring Mission (TRMM) satellite to ascertain the ability of the CDO to discriminate hazardous convection. The CDO performed well in this preliminary investigation with some limitations noted. Short-term, 1-hr and 2-hr nowcasts of convection location are performed within the Convective Nowcasting Oceanic (CNO) system using a storm tracker. The CNO was found to have good statistical performance at extrapolating existing storm positions. Current work includes the development and implementation of additional atmospheric features for nowcasting convection initiation and to improve nowcasting of mature convection evolution.
Summary
An oceanic convection diagnosis and nowcasting system is described whose domain of interest is the region between the southern continental United States and the northern extent of South America. In this system, geostationary satellite imagery are used to define the locations of deep convective clouds through the weighted combination of...
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Hazard alerting using line-of-sight rate
August 18, 2008
Conference Paper
Published in:
AIAA Guidance, Navigation, and Control Conf., 18-21 August 2008.
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This paper presents an analysis of an electro-optical hazard alerting system based on intruder line-of-sight rate. We use a recently-developed airspace encounter model to analyze intruder line-of-sight rate behavior prior to near miss. We look at a simple hazard alerting system that alerts whenever the line-of-sight rate drops below some set threshold. Simulations demonstrate that such an approach, regardless of the chosen threshold, leads to frequent false alerts. We explain how the problem of hazard alerting can also be formulated as a partially observable Markov decision process (POMDP) and show how such an approach significantly decreases the false alert rate.
Summary
This paper presents an analysis of an electro-optical hazard alerting system based on intruder line-of-sight rate. We use a recently-developed airspace encounter model to analyze intruder line-of-sight rate behavior prior to near miss. We look at a simple hazard alerting system that alerts whenever the line-of-sight rate drops below some...
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Applications of a macroscopic model for en route sector capacity
August 18, 2008
Conference Paper
Published in:
AIAA Guidance, Navigation and Control Conf. and Exhibit, 18-21 August 2008.
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Airspace capacity estimates are important both for airspace design and for operational air traffic management. Considerable effort has gone into understanding the complexity factors that reduce sector capacity by increasing controller workload. Yet no analytical means is available for accurately estimating the maximum capacity of an en route sector. The Monitor Alert Parameter (MAP) values that determine the operational traffic limit of en route sectors in the United States account only for workload from inter-sector coordination tasks. We propose a more complete sector capacity model that also accounts for workload from conflict avoidance and recurring tasks. We use mean closing speeds and airspace separation standards to estimate aircraft conflict rates. We estimate the mean controller service times for all three task types by fitting the model against observed peak traffic counts for hundreds of en route airspace volumes in the Northeastern United States. This macroscopic approach provides numerical capacity predictions that closely bound peak observed traffic densities for those airspace volumes. This paper reviews recent efforts to improve the accuracy of the bound by replacing certain global parameters with measured data from individual sectors. It also compares the model capacity with MAP values for sectors in the New York Center. It concludes by illustrating the use of the model to predict the capacity benefits of proposed technological and operational improvements to the air traffic management system.
Summary
Airspace capacity estimates are important both for airspace design and for operational air traffic management. Considerable effort has gone into understanding the complexity factors that reduce sector capacity by increasing controller workload. Yet no analytical means is available for accurately estimating the maximum capacity of an en route sector. The...
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Comparing convective weather avoidance models and aircraft-based data
August 4, 2008
Conference Paper
Published in:
89th ARAM Special Symp., 4 August 2008.
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The Convective Weather Avoidance Model (CWAM), developed in collaboration with NASA, translates convective weather information into a Weather Avoidance Field (WAF), to determine if pilots will route around convective regions. The WAF provides an estimate of the probability of pilot deviation around convective weather in en route airspace as a function of time, horizontal location, and flight altitude [1][2]. The results of the WAF can used to create reroutes around regions of convective weather where pilots are more likely to deviate. If reliable WAF information is provided to the cockpit and ground, pilot decisions may become more predictable, simplifying the task of air traffic control in convective weather. The improvement and validation of CWAM requires inference of pilot intent from flight trajectory data, which is challenging. The process currently involves laborious human review of the results of automated deviation detection algorithms. Both previous CWAM studies and a recent validation study [3] illustrate the difficulties and limitations of attempting to infer pilot intent from flight trajectory data. Furthermore, observed flight tracks may not correctly represent pilot preference. In some instances, pilots may have penetrated airspace that they would rather have avoided or they may have avoided airspace that was easily passable. In order to improve and assess the accuracy of the WAF, it is desirable to compare WAF predictions of pilot intent with direct evidence of the airborne experience during weather encounters in en route airspace, such as normal acceleration. To achieve this, a series of flights using a research aircraft was conducted. In the summer of 2008, four research flights (three on 17 July and one on 14 August) were flown in and around convective activity in the upper Midwestern United States to gather aircraft data that could be correlated to the WAF and other remotely-sensed weather data. The aircraft, a Rockwell Sabreliner Model 50 research aircraft (similar to the Sabreliner Model 40 production model) owned by Rockwell-Collins, flew through and around convective activity while recording on-board accelerations for comparison to the WAF deviation probabilities encountered along the flight trajectory. Aircraft state data, on-board weather radar images, video, photographs and pilot narrative from the cockpit were also collected. This paper briefly describes the CWAM model and WAF. Description of the data collection methodology is then presented. Following that section are descriptions of the flights comparing radar data from the flight deck with ground-based weather radar and the WAF. Visual observations and pilot narrative from the flight deck are also presented. Next, the normal acceleration data from on-board accelerometer data are compared with WAF. Finally, conclusions and suggestions for further study are presented.
Summary
The Convective Weather Avoidance Model (CWAM), developed in collaboration with NASA, translates convective weather information into a Weather Avoidance Field (WAF), to determine if pilots will route around convective regions. The WAF provides an estimate of the probability of pilot deviation around convective weather in en route airspace as a...
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Measuring the uncertainty of weather forecasts specific to air traffic management operations
August 4, 2008
Conference Paper
Published in:
89th ARAM Special Symp., 4 August 2008.
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In this paper, we develop a novel way to measure the accuracy of weather forecasts based upon the impact on air traffic flows. This method uses new techniques developed as part of the CWAM that consider the complicated interaction between pilots, air traffic controllers and weather. This technique, known as the blockage model (Martin et al., 2006), differentiates between minor deviations performed by pilots around convective weather and their larger deviations due to fully blocked air routes that require air traffic control interaction. This blockage model is being used by the automated Route Availability Planning Tool (RAPT) to predict route blockage for NYC departures. RAPT integrates the Corridor Integrated Weather Systems (CIWS) deterministic 0-2 hour forecasts of precipitation and echo tops into route specific forecasts of impact on air traffic in the congested east coast corridor. Applying the blockage model to the entire CIWS weather domain as a metric for scoring the performance of the forecast algorithms is shown to be an excellent approach for measuring the adequacy of the forecast in predicting the impact of the convective weather on air traffic operations.
Summary
In this paper, we develop a novel way to measure the accuracy of weather forecasts based upon the impact on air traffic flows. This method uses new techniques developed as part of the CWAM that consider the complicated interaction between pilots, air traffic controllers and weather. This technique, known as...
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Key research issues for near term operational use of integrated convective weather-ATM decision support systems
January 20, 2008
Conference Paper
Published in:
13th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 20-24 January 2008.
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Thunderstorm-related delays dominate the overall U.S. airspace delay statistics and continue to increase, even though a number of new weather information systems and air traffic management (ATM) decision support tools have been deployed since 1999. Operational decision makers must mitigate the network congestion that arises from rapidly varying capacity loss in both en route and terminal airspace. Improving decision making in such an environment requires explicitly considering airspace structure, network impacts, forecast uncertainty and pilot preferences for weather avoidance. To date, the NextGen initiative has focused on envisioning an operational concept and research agenda for 2025 where it is assumed that aircraft separation and weather avoidance is accomplished using a high degree of automation. In this paper, we consider research to achieve significant improvements in the near term (2010-2015) where aircraft separation is provided largely by controllers and hazardous weather avoidance is accomplished by pilots using visual cues, reports from other aircraft, on board weather radar and ATC advisories. We briefly review the current status of work in key areas and then suggest major near term initiatives. Key elements of the research program to be discussed include: 1. Translation of convective weather products into ATC impacts (including handling of uncertainty in the convective weather forecasts). Initial models for en route pilot avoidance of storms and sector capacity in convective weather have shown promising results, but clearly much more research is needed in this area. 2. Determining when and where available capacity was not appropriately utilized during convective events, based on both facility observations during storm events and computations of avoidable delay. Preliminary results suggest that much of today's delay is in fact avoidable. 3. Developing integrated weather-ATM decision support tools (DST) to enable decision makers to more fully utilize available capacity. The accuracy of contemporary convective weather forecasts is a key issue in the design of such systems. Initial operational experience with a departure decision support tool will be discussed to illustrate key points. 4. Explicitly considering the human side of convective weather ATM [e.g., how individuals make real time decisions in collaboration with other decision makers (e.g., ATC, airlines, dispatch, pilots)]. Recent results from field usage of convective weather decision support tools will be interpreted in the context of recent literature on how people actually make decisions and perform cognitively complex functions in demanding situations.
Summary
Thunderstorm-related delays dominate the overall U.S. airspace delay statistics and continue to increase, even though a number of new weather information systems and air traffic management (ATM) decision support tools have been deployed since 1999. Operational decision makers must mitigate the network congestion that arises from rapidly varying capacity loss...
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Improving weather radar data quality for aviation weather needs
January 20, 2008
Conference Paper
Published in:
13th Conf. on Aviation, Range and Aerospace Meteorology, ARAM, 20-24 January 2008.
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Summary
A fundamental function of any aviation weather system is to provide accurate and timely weather information tailored to the specific air traffic situations for which a system is designed. Weather location and intensity are of prime importance to such systems. Knowledge of the weather provides "nowcasting" functionality in the terminal and en route air spaces. It also is used as input into aviation weather forecasting applications for purposes such as storm tracking, storm growth and decay trends, and convective initiation. Weather radar products are the primary source of the weather location and intensity information used by the aviation weather systems. In the United States, the primary radar sources are the Terminal Doppler Weather Radar (TDWR) and the Weather Surveillance Radar 1988 Doppler (WSR-88D, known as NEXRAD). Additional weather radar products from the Canadian network are used by some of the aviation weather systems. Product quality from all these radars directly impacts the quality of the down stream products created by the aviation weather systems and their utility to air traffic controllers. Four FAA weather systems use some combination of products from the aforementioned radars. They are the Corridor Integrated Weather System (CIWS), the Integrated Terminal Weather System (ITWS), the Weather and Radar Processor (WARP), and the Medium Intensity Airport Weather System (MIAWS). This paper focuses on the improvement of weather radar data quality specific to CIWS. The other mentioned FAA aviation weather systems also benefit either directly or indirectly from the improvements noted in this paper. For CIWS, the legacy data quality practices involve two steps. Step one is the creation of weather radar products of highest possible fidelity. The second step involves creating a mosaic from these products. The mosaic creation process takes advantage of inter-radar product comparisons to interject a further level of improved data quality. The new CIWS data quality plan will use a mounting evidence data quality classifier technique currently being developed. The technique applies a multi-tiered approach to weather radar data quality. Its premise is that no single data quality improvement technique is as effective as a collaboration of many. The evidence will be expanded to include data and products from the radars along with data from additional sensing platforms. The mosaic creation process will correspondingly expand to take advantage of the additional evidence. Section 2 covers data quality of products from the single radar perspective. Section 3 focuses on the use of satellite data as the first additional sensing platform to augment removal of problematic radar contamination. Section 4 describes the data quality procedures associated with creation of mosaics from the single radar products augmented with new satellite masking information. Last, Section 5 discusses future plans for the mounting evidence data quality improvement technique.
Summary
A fundamental function of any aviation weather system is to provide accurate and timely weather information tailored to the specific air traffic situations for which a system is designed. Weather location and intensity are of prime importance to such systems. Knowledge of the weather provides "nowcasting" functionality in the terminal...
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