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Beam filling loss adjustments for ASR-9 weather channel reflectivity estimates

October 22, 1990
  |
Project Report
Author:
Cynthia D. Engholm
…
Published in:
MIT Lincoln Laboratory Report ATC-177
Topic:
radar
R&D area:
R&D group:

Summary

The FAA is deploying over 100 new ariport surveillance radars (ASR-9) across the country. In contrast to earlier ASRs, the ASR-9 utilized a separate digital weather processing channel to provide air traffic controllers with timely, calibrated displays of precipitation intensity. The ASR-9 utilizes dual selectable fan-shaped elevation beams designed to track aircraft over a large volume. As a consequence, weather echoes received from these fan-shaped beams represent vertically-averaged quantities. If the precipitation only partially or nonuniformly fills the beam, then the vertically integrated reflectivity may underestimate the actual intensity of the storm. The ASR-9 weather channel corrects for this by adjusting the range-dependent six-level relfectivity thresholds. The appropriateness of the currently implemented correction has not been carefully examined and may require modification to take into account regional and morphological variability in storm structure. This report discusses the method used to derive new beam filling loss adjustments. An extensive database of volumetric pencil-beam radar data were used in conjunction with our ASR-9 simulation facility to derive adjustments aimed at calibrating the precipitation intensity reports to the maximum perceived hazard. The new corrections yield substantially improved results over the current corrections in producing these reflectivity reports.
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Summary

The FAA is deploying over 100 new ariport surveillance radars (ASR-9) across the country. In contrast to earlier ASRs, the ASR-9 utilized a separate digital weather processing channel to provide air traffic controllers with timely, calibrated displays of precipitation intensity. The ASR-9 utilizes dual selectable fan-shaped elevation beams designed to...

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Beam filling loss adjustments for ASR-9 weather channel reflectivity estimates

Divergence detection in wind fields estimated by an airport surveillance radar

October 15, 1990
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Project Report
Author:
Terri A. Noyes
Published in:
MIT Lincoln Laboratory Report ATC-172
Topic:
wind shear
R&D area:
R&D group:

Summary

This report assesses a technique for automatic detection of hazardous divergence in velocity fields estimated by an Airport Surveillance Radar (SAR). We evaluate a least-squares approach to radial divergence estimation through a performance analysis based on simulated data. That approach is compared to an existing decision-based radial shear finding method used for the Terminal Doppler Weather Radar (TDWR). Empirical results derived by the application of two techniques to data collected at ASR testbeds in Huntsville, Alabama and in Kansas City, Missouri are presented. Results indicate that a simple, least-squares divergence estimator combined with time association logic to increase temporal continuity of algorithm output is an equally effective means of detecting divergent wind shear in velocity fields estimated from ASR signals.
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Summary

This report assesses a technique for automatic detection of hazardous divergence in velocity fields estimated by an Airport Surveillance Radar (SAR). We evaluate a least-squares approach to radial divergence estimation through a performance analysis based on simulated data. That approach is compared to an existing decision-based radial shear finding method...

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Divergence detection in wind fields estimated by an airport surveillance radar

Planning horizon requirements for automated terminal scheduling

October 1, 1990
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Conference Paper
Author:
Herman F. Vandevenne
…
Published in:
Proc. 35th Annual Air Traffic Control Association Mtg., 16-20 September 1990, pp. 438-451.
Topic:
air traffic control
R&D area:
R&D group:

Summary

This paper presents the results of an engineering analysis of the ability of an automated terminal scheduling process to achieve efficient use of runways. The motivation for the analysis is the need to understand possible architectures for an implementation of the proposed Terminal Air Traffic Automation (TATCA) system. The performance of TATCA is dependent upon metering precision and the controllability that TATCA can apply to aircraft entering the scheduling process. Controllability refers to the amount of time by which the flight time of an aircraft can be lengthened or shortened between the scheduling horizon and the chosen runway. The analysis concludes that when current en route metering mechanisms are used to deliver traffic to the terminal, the terminal scheduler meets a controllability window of 300 seconds or so in order to achieve full runway utilization. Because this amount of controllability is often achievable within the terminal area itself, a TATCA system can provide significant benefits prior to the implementation of further improvements in the en route metering process.
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Summary

This paper presents the results of an engineering analysis of the ability of an automated terminal scheduling process to achieve efficient use of runways. The motivation for the analysis is the need to understand possible architectures for an implementation of the proposed Terminal Air Traffic Automation (TATCA) system. The performance...

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Planning horizon requirements for automated terminal scheduling

Real-time simulation for air traffic control research and development

September 1, 1990
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Conference Paper
Author:
Steven R. Bussolari
…
Published in:
Proc. 1990 Air Traffic Control Association Conf., September 1990, pp. 378-384.
Topic:
air traffic control
R&D area:
R&D group:

Summary

An approach is suggested for the incremental use of real-time ATC simulations for concept development and human factors evaluation of automation systems. Emphasis is placed on the characteristics that distinguish research simulators from those used primarily for training. Four general levels of simulator fidelity are identified for two ATC environments of interest: the radar room and the control tower. Fidelity requirements are generated by the specific needs of the particular human factors study to be conducted, ranging from part-task single-controller simulation used for concept demonstration to full-mission simulation of multiple ATC facilities to examine issues of interaction among automation systems. This approach is applicable to smaller simulations performed at an R&D contractor site as well as large-scale system integration studies conducted at a high-fidelity, centralized, simulation facility. It has been applied to the design of simulations of ATCT and TRACON environments that are being used for the evaluation of displays, controls, and procedures for the Airport Surface Traffic Automation (ASTA) and Terminal ATC Automation (TATCA) projects.
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Summary

An approach is suggested for the incremental use of real-time ATC simulations for concept development and human factors evaluation of automation systems. Emphasis is placed on the characteristics that distinguish research simulators from those used primarily for training. Four general levels of simulator fidelity are identified for two ATC environments...

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Real-time simulation for air traffic control research and development

Results of the Kansas City 1989 Terminal Doppler Weather Radar (TDWR) operational evaluation testing

August 17, 1990
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Project Report
Author:
James E. Evans
Published in:
MIT Lincoln Laboratory Report ATC-171
Topic:
weather
R&D area:
R&D group:

Summary

The Lincoln Laboratory Terminal Doppler Weather Radar (TDWR) testbed was used to carry out an experimental and operational hazardous weather product evaluation program for the Federal Aviation Administration (FAA) at the Kansas City International (KCI) Airport during the summer of 1989. The objective of the program was to test and refine previously tested techniques for the automatic detection of low-altitude wind shear phenomena (specifically microbursts and gust fronts) and heavy precipitation in a midwest weather environment, as well as to assess possible new products such as storm movement predictions. A successful operational evaluation of the TDWR products took place at the KCI tower and terminal radar control room (TRACON) from 15 July to 15 August 1989 and from 15 to 30 September 1989. Several supervisor and controller display refinements that had been determined from the 1988 operational evaluation at Denver were assessed as effective. The system was successful in terms of aircraft at KCI avoiding wind shear encounters during the operational period, and it was assessed as "very good" in usefulness for continuing operation by the KCI air traffic control (ATC) personnel.
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Summary

The Lincoln Laboratory Terminal Doppler Weather Radar (TDWR) testbed was used to carry out an experimental and operational hazardous weather product evaluation program for the Federal Aviation Administration (FAA) at the Kansas City International (KCI) Airport during the summer of 1989. The objective of the program was to test and...

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Results of the Kansas City 1989 Terminal Doppler Weather Radar (TDWR) operational evaluation testing

Contributions to the American Meterorological Society 16th Conference on Severe Local Storms

August 15, 1990
  |
Project Report
Author:
Marilyn M. Wolfson
Published in:
MIT Lincoln Laboratory Report ATC-173
Topic:
weather
R&D area:
R&D group:

Summary

Eight papers contributed by the Lincoln Laboratory Weather Sensing Group to the American Meteorological Society's 16th Conference on Severe Local Storms, to be held October 22-26, 1990 in Kananaskis Provincial Park, Alberta, Canada, are compiled in this volume. The FAA sponsored the summer 1989 field test of the Terminal Doppler Weather Radar (TDWR) system in Kansas City, Missouri to detect wind shear aviation hazards at or near the airport. The papers are based on data collected through the summer 1989 field test and on subsequent analyses and product evaluation. The staff members of Group 43, Weather Sensing, have documented their studies of the following topics: a severe microburst; a prototype microburst prediction product; average summer microburst threat prediction at an airport; microburst asymmetry; the effect of radar viewing angle on the performance of the gust front detection algorithm; a comparison of Low-Level Wind Shear Alert System (LLWAS) anemometer-measured winds and Doppler-measured winds; and ASR-9 (Airport Surveillance Radar) adjustment of range-dependent storm reflectivity levels. The final paper is an invited paper for the Conference on microbursts. This paper discusses the precipitation-driven downdraft and the downdraft associated with the "vortex," or gust front, at the leading edge of an expanding thunderstorm outflow as two primary forms of low altitude downdraft phenomena in the microburst problem.
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Summary

Eight papers contributed by the Lincoln Laboratory Weather Sensing Group to the American Meteorological Society's 16th Conference on Severe Local Storms, to be held October 22-26, 1990 in Kananaskis Provincial Park, Alberta, Canada, are compiled in this volume. The FAA sponsored the summer 1989 field test of the Terminal Doppler...

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Contributions to the American Meterorological Society 16th Conference on Severe Local Storms

Clutter rejection in Doppler weather radars used for airport wind shear detection

June 1, 1990
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Conference Paper
Author:
James E. Evans
…
Published in:
Proc. Second Int. Symp. on Noise & Clutter Rejection in Radars & Imaging Sensors (ISNCR-89), 14-16 November 1989, PP. 275-280.
Topic:
aviation weather
R&D area:
R&D group:

Summary

Techniques for the suppression of ground and storm clutter to permit the detection of low altitude windshear by pulse Doppler radars are described. Novel features of the system include the use of clutter residue and range aliased weather echo editing maps which edit out the range-azimuth cells on a "data adaptive" basis.
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Summary

Techniques for the suppression of ground and storm clutter to permit the detection of low altitude windshear by pulse Doppler radars are described. Novel features of the system include the use of clutter residue and range aliased weather echo editing maps which edit out the range-azimuth cells on a "data...

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Clutter rejection in Doppler weather radars used for airport wind shear detection

Analysis of the potential benefits of Terminal Air Traffic Control Automation (TATCA)

May 23, 1990
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Conference Paper
Author:
Steven B. Boswell
…
Published in:
Proc. 1990 American Control Conf., Vol. 1, 23-25 May 1990, pp.535-542
Topic:
air traffic control
R&D area:
R&D group:

Summary

Terminal Air Traffic Control Automation (TATCA) is an FAA research and development program to provide computer-aided sequencing, spacing, and management of air traffic flows in terminal areas. This paper discusses technical and national economic benefits that are attainable with such a terminal automation program.
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Summary

Terminal Air Traffic Control Automation (TATCA) is an FAA research and development program to provide computer-aided sequencing, spacing, and management of air traffic flows in terminal areas. This paper discusses technical and national economic benefits that are attainable with such a terminal automation program.

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Analysis of the potential benefits of Terminal Air Traffic Control Automation (TATCA)

Microburst observability and frequency during 1988 in Denver, CO

May 14, 1990
  |
Project Report
Author:
John T. DiStefano
…
Published in:
MIT Lincoln Laboratory Report ATC-170
Topic:
weather
R&D area:
R&D group:

Summary

The observability of microbursts with single-Doppler radar is investigated through comparison of radar data and surface weather sensor data. The data were collected during 1988 in Denver, CO as part of the FAA Terminal Doppler Weather Radar measurement program. Radar data were collected by both and S-band and C-band radar, while surface data were taken from a mesoscale network of 42 weather sensors in the vicinity of Denver's Stapleton International Airport. Results are compared with previous similar studies of observability using data from 1987 in Denver, and 1986 in Huntsville, AL. A total of 184 microbursts impacting the surface mesonet were identified. For those microbursts for which both radar and surface data were available, 97% were observable by single-Doppler radar. This compares to 94% observability during 1987 in Denver, and 98% during 1986 in Huntsville. Two strong microbursts (at lease 20 m/s differential velocity) were unobservable by radar throughout their lifetime: one due to low signal-to-noise ratio, and the other due initially to an asymmetric outflow with low signal-to-noise ratio also a contributing factor. Two other microbursts, with differential velocities from 10-19 m/s, were unobservable by radar: one due to shallow outflow with a depth limited to a height below that of the radar beam, and one due to asymmetric outflow oriented unfavorably with respect to the radar viewing angle. Consistent with previous observations, microburst occurrence was most frequent during June and July, when 94 microbursts were identified on 20 days. An anomalously high frequency was also seen in April, although the strength of these events was relatively modest. As expected, the diurnal distribution shows the late afternoon to be the most favorable time for microburst development; more than half of all events reached their maximum strength between the hours of 2-5 p.m. local time.
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Summary

The observability of microbursts with single-Doppler radar is investigated through comparison of radar data and surface weather sensor data. The data were collected during 1988 in Denver, CO as part of the FAA Terminal Doppler Weather Radar measurement program. Radar data were collected by both and S-band and C-band radar...

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Microburst observability and frequency during 1988 in Denver, CO

Terminal Doppler Weather Radar clutter control

May 10, 1990
  |
Conference Paper
Author:
James E. Evans
…
Published in:
Proc. IEEE 1990 Int. Radar Conf., 7-10 May 1990, pp. 12-16.
Topic:
aviation weather
R&D area:
R&D group:

Summary

The FAA is developing the Terminal Doppler Weather Radar system to automatically detect low altitude wind shear due to microbursts and gust fronts. Detection of this phenomenon presents a significant radar engineering challenge due to the need to observe low reflectivity events in the presence of strong clutter from ground objects and range aliased weather returns. This paper describes a number of unique approaches to clutter recognition which have been validated with the TDWR test bed radar.
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Summary

The FAA is developing the Terminal Doppler Weather Radar system to automatically detect low altitude wind shear due to microbursts and gust fronts. Detection of this phenomenon presents a significant radar engineering challenge due to the need to observe low reflectivity events in the presence of strong clutter from ground...

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Terminal Doppler Weather Radar clutter control
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