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Microburst recognition performance of TDWR operational testbed

February 3, 1989
  |
Conference Paper
Author:
Steven D. Campbell
…
Published in:
Proc. Third Int. Conf. on the Aviation Weather System, 30 January - 3 February 1989, pp. 25-30.
Topic:
air traffic control
R&D area:
R&D group:

Summary

This paper describes current work in assessing the microburst recognition performance of the Terminal Doppler Weather Radar (TDWR) operational testbed. The paper is divided into three main sections: microburst recognition algorithm, performance assessment methodology and results. The first section provides an overview of the prototype TDWR microburst recognition algorithm The algorithm uses radar data from both surface scans and scans aloft to identify microburst events. The surface scan is used to identify microburst outflows, and the scans aloft provide information concerning reflectivity and velocity structures associated with microbursts to improve recognition rate and timeliness. The second section of the paper describes the methodology for assessing the recognition performance of the system. The performance of the testbed system is addressed from two viewpoints: radar detectability and pattern recognition capability. The issue of radar detectability is examined by comparing radar and mesonet data to determine if any events observed by the mesonet fail to be observed by the radar. The issue of pattern recognition performance is assessed by comparing microburst recognition algorithm outputs with truth as determined by expert radar meteorologists. The final section of the paper provides performance results for data collected by the testbed radar at Huntsville, AL and Denver, CO.
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Summary

This paper describes current work in assessing the microburst recognition performance of the Terminal Doppler Weather Radar (TDWR) operational testbed. The paper is divided into three main sections: microburst recognition algorithm, performance assessment methodology and results. The first section provides an overview of the prototype TDWR microburst recognition algorithm The...

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Microburst recognition performance of TDWR operational testbed

The FAA Terminal Doppler Weather (TDWR) Program

February 3, 1989
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Conference Paper
Author:
Donald H. Turnbull
…
Published in:
Proc. Third Int. Conf. on the Aviation Weather Systems, 30 January - 3 February 1989, pp. 414-419.
Topic:
air traffic control
R&D area:
R&D group:

Summary

The Federal Aviation Administration (FAA) initiated the Terminal Doppler Weather Radar (TDWR) program in the mid-1980s in response to overwhelming scientific evidence that low-altitude wind shear had caused a number of major air-carrier accidents. The program is designed to develop a reliable automated system for detecting low-altitude wind shear in the terminal area and providing warnings that will help pilots successfully avoid it on approach and departure. Wind shear has caused more U.S. air-carrier fatalities than any other weather hazard. A 1983 National Research Council (NRC) study (National Research Council, 1983) identified low-altitude wind shear as the cause of 27 aircraft accidents and incidents between 1964 and 1982. A total of 488 people died in seven of these accidents, 112 of them in the 1975 crash of Eastern Flight 66 at New York and 153 in the crash of Pan American Flight 759 at New Orleans in 1982. Since the NRC study was completed, the National Transportation Safety Board (NTSB) has investigated at least three more wind-shear incidents. One of these, the crash of Delta Flight 191 at Dallas/Fort Worth on August 2, 1985, took another 137 lives. Wind shear is not a serious hazard for aircraft enroute between airports at normal cruising altitudes, but low-level wind shear in the terminal area can be deadly for an aircraft on approach or departure. The most hazardous form of wind shear is the microburst, an outflow of air from a small-scale but powerful downward gush of cold, heavy air that can occur beneath a thunderstorm or rain shower or even in rain-free air under a harmless-looking cumulus cloud. As this downdraft reaches the earth's surface, it spreads out horizontally, like a stream of water sprayed straight down on a concrete driveway from a garden hose. An aircraft that flies through a microburst at low altitude first encounters a strong headwind, then a downdraft, and finally a tailwind that produces a sharp reduction in airspeed and a sudden loss of lift. This deadly sequence of events caused the fatal crash at Dallas/Fort Worth in 1985, as well as a number of other serious air-carrier accidents. Wind shear can also be associated with gust fronts, warm and cold fronts, and strong winds near the ground. It is important for pilots to be trained in recovery techniques to use if they are caught in wind shear. But a sudden windspeed change of at least 40 to 50 knots, which is not uncommon in microbursts, presents a serious hazard to jet airliners, and some microbursts simply are non-survivable. The only sure way to survive wind shear in the terminal area is to avoid it. However, flight crews do not have adequate information available today to predict or detect wind shear. The primary goal of the IDWR program is to provide pilots with an objective, quantitative assessment of the wind-shear hazard. The TDWR system also will improve operational efficiency and reduce delays in the terminal area by providing air traffic control supervisors with timely warnings of impending wind shifts resulting from gust fronts.
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Summary

The Federal Aviation Administration (FAA) initiated the Terminal Doppler Weather Radar (TDWR) program in the mid-1980s in response to overwhelming scientific evidence that low-altitude wind shear had caused a number of major air-carrier accidents. The program is designed to develop a reliable automated system for detecting low-altitude wind shear in...

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The FAA Terminal Doppler Weather (TDWR) Program

Weather sensing with airport surveillance radars

February 3, 1989
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Conference Paper
Author:
Mark E. Weber
Published in:
Proc. Third Int. Conf. on the Aviation Weather System, 30 January - 3 February 1989, pp. 68-74.
Topic:
aviation weather
R&D area:
R&D group:

Summary

Modern airport surveillance radars (ASR) are coherent, pulsed-Doppler radars used for detection and tracking of aircraft in terminal area air space. The Federal Aviation Agency (FAA is procuring over 100 next-generation ASR-9 radars for major US. airports while relocating existing ASR-8s to secondary terminals. Thus within the next five years, almost every U.S. airport that supports commercial operations will be equipped with one of these sensitive, highly stable S-band radars. In view of their on- or near-airport location, rapid scan rate and direct data link to air traffic control personnel, it has been recognized that ASRs can also provide flight controllers with timely information on weather conditions that are hazardous to aircraft. An ASR's transmitted frequency, power, pulse-to-pulse stability and receiver sensitivity are well suited for weather sensing. Conversely, its broad elevation beamwidth, rapid antenna scan rate and non-uniform pulse transmission sequence introduce significant complications for the quantitative interpretation of echoes returned from weather. This paper reviews principal results of a four-year, FAA-sponsored program to evaluate the capabilities and limitations of ASRs for measuring storm severity.
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Summary

Modern airport surveillance radars (ASR) are coherent, pulsed-Doppler radars used for detection and tracking of aircraft in terminal area air space. The Federal Aviation Agency (FAA is procuring over 100 next-generation ASR-9 radars for major US. airports while relocating existing ASR-8s to secondary terminals. Thus within the next five years...

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Weather sensing with airport surveillance radars

Advances in primary-radar technology

January 1, 1989
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Journal Article
Author:
Melvin L. Stone
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Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 363-380.
Topic:
surveillance
R&D area:
R&D group:

Summary

Current primary radars have difficulty detecting aircraft when ground clutter, rain, or birds interfere. To overcome such interference, the Moving Target Detector (MTD) uses adaptive digital signal and data processing techniques. MTD has provided the foundation for a new generation of primary radars called Airport Surveillance Radar-9 (ASR-9). In addition to achieving near-optimal target-detection performance, ASR-9 also provides timely weather information. The Federal Aviation Administration (FAA) is installing ASR- 9 systems at more than 100 airports across the United States.
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Summary

Current primary radars have difficulty detecting aircraft when ground clutter, rain, or birds interfere. To overcome such interference, the Moving Target Detector (MTD) uses adaptive digital signal and data processing techniques. MTD has provided the foundation for a new generation of primary radars called Airport Surveillance Radar-9 (ASR-9). In addition...

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Advances in primary-radar technology

Applying artificial intelligence techniques to air traffic control automation

January 1, 1989
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Journal Article
Author:
David A. Spencer
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 537-554.
Topic:
air traffic control
R&D area:
R&D group:

Summary

We have developed a computer program that automates rudimentary air traffic control (ATC) planning and decision-making functions. The ability to plan, make decisions, and act on them makes this experimental program qualitatively different from the more clerical ATC software currently in use. Encouraging results were obtained from tests involving simple scenarios used to train air traffic controllers.
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Summary

We have developed a computer program that automates rudimentary air traffic control (ATC) planning and decision-making functions. The ability to plan, make decisions, and act on them makes this experimental program qualitatively different from the more clerical ATC software currently in use. Encouraging results were obtained from tests involving simple...

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Applying artificial intelligence techniques to air traffic control automation

Experimental examination of the benefits of improved terminal air traffic control planning

January 1, 1989
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Journal Article
Author:
David A. Spencer
…
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 527-536.
Topic:
air traffic control
R&D area:
R&D group:

Summary

Airport capacity can be improved significantly-by precisely controlling the sequence and timing of traffic flow-even when airspace usage and procedures remain fixed. In a preliminary experiment, a plan for such sequencing and timing was applied in a simulation to a 70-min traffic sample observed at Boston's Logan Airport, and the result was a 13% increase in terminal throughput. A total of 2.2 aircraft flight hours were saved. Delays imposed upon arriving traffic in the simulation were much more equitably distributed than in the actual traffic sample. An even greater improvement may be possible if controllers are able to space aircraft more precisely on final approach than was achieved in the simulation. If the plan had been followed precisely, the throughput increase would have been 23%.
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Summary

Airport capacity can be improved significantly-by precisely controlling the sequence and timing of traffic flow-even when airspace usage and procedures remain fixed. In a preliminary experiment, a plan for such sequencing and timing was applied in a simulation to a 70-min traffic sample observed at Boston's Logan Airport, and the...

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Experimental examination of the benefits of improved terminal air traffic control planning

Propagation of mode S beacon signals on the airport surface

January 1, 1989
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Journal Article
Author:
M. Loren Wood Jr
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 397-410.
Topic:
air traffic control
R&D area:
R&D group:

Summary

Many airports across the United States will soon be equipped with Mode S, a next generation beacon (or secondary) radar system. One feature of Mode S is that it provides a data link between airborne aircraft and air traffic controllers. If Mode S could be used to communicate with aircraft on the airport surface, the radar system would improve airport safety and efficiency on runways and taxiways. The airport surface, however, is a hostile propagation environment. This article outlines a candidate design for the propagation of Mode-S beacon signals on the airport surface. Data that support the feasibility of Mode S for surveilling runways and taxiways are presented.
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Summary

Many airports across the United States will soon be equipped with Mode S, a next generation beacon (or secondary) radar system. One feature of Mode S is that it provides a data link between airborne aircraft and air traffic controllers. If Mode S could be used to communicate with aircraft...

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Propagation of mode S beacon signals on the airport surface

Multipath modeling for simulating the performance of the Microwave Landing System

January 1, 1989
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Journal Article
Author:
James E. Evans
…
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 459-474.
Topic:
aviation weather
R&D area:
R&D group:

Summary

The Microwave Landing System (MLS) will be deployed throughout the world in the 1990s to provide precision guidance to aircraft for approach and landing at airports. At Lincoln Laboratory, we have developed a computer-based simulation that models the performance of MLS and takes into account the multipath effects of buildings, the surrounding terrain, and other aircraft in the vicinity. The simulation has provided useful information about the effects of multipath on MLS performance.
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Summary

The Microwave Landing System (MLS) will be deployed throughout the world in the 1990s to provide precision guidance to aircraft for approach and landing at airports. At Lincoln Laboratory, we have developed a computer-based simulation that models the performance of MLS and takes into account the multipath effects of buildings...

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Multipath modeling for simulating the performance of the Microwave Landing System

TCAS: a system for preventing midair collisions

January 1, 1989
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Journal Article
Author:
William H. Harman III
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 437-458.
Topic:
air traffic control
R&D area:
R&D group:

Summary

To reduce the possibility of midair collisions, the Federal Aviation Administration has developed the Traffic Alert and Collision Avoidance System, or TCAS. This airborne system senses the presence of nearby aircraft by interrogating the transponders carried by these aircraft. When TCAS senses that a nearby aircraft is a possible collision threat, TCAS issues a traffic advisory to the pilot, indicating the presence and location of the other aircraft. If the encounter becomes hazardous, TCAS issues a maneuver advisory.
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Summary

To reduce the possibility of midair collisions, the Federal Aviation Administration has developed the Traffic Alert and Collision Avoidance System, or TCAS. This airborne system senses the presence of nearby aircraft by interrogating the transponders carried by these aircraft. When TCAS senses that a nearby aircraft is a possible collision...

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TCAS: a system for preventing midair collisions

Using aircraft radar tracks to estimate winds aloft

January 1, 1989
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Journal Article
Author:
Walter M. Hollister
…
Published in:
Lincoln Laboratory Journal, Vol. 2, No. 3, Fall 1989, pp. 555-565.
Topic:
aviation weather
R&D area:
R&D group:

Summary

In air traffic control, the wind is a critical factor because it affects, among other important variables, the amount of time an aircraft will take to reach its destination. The authors have developed a method for estimating winds aloft in which the radar tracks of aircraft are used; i.e., data beyond what are already available to terminal air traffic control are not required. The method, which has been implemented at Lincoln Laboratory, gives a useful estimate of wind fields.
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Summary

In air traffic control, the wind is a critical factor because it affects, among other important variables, the amount of time an aircraft will take to reach its destination. The authors have developed a method for estimating winds aloft in which the radar tracks of aircraft are used; i.e., data...

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Using aircraft radar tracks to estimate winds aloft
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