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Airport surface traffic automation study

May 9, 1988
  |
Project Report
Author:
Walter M. Hollister
Published in:
MIT Lincoln Laboratory Report ATC-156
Topic:
air traffic control
R&D area:
R&D group:

Summary

This report documents a study of requirements for an Airport Surface Traffic Automation (ASTA) system. The objective was to determine the necessary functions, establish the cost and benefits, and outline a modular system design. The highest priority function identified was an improved surface surveillance and communication system. The greatest potential for safety benefits is provided by automatic conflict alert and collision warning for pilots and controllers to prevent runway incursion accidents. Strategic and tactical planning assistance to maximize runway utilization can improve controller productivity while keeping them responsible for final decisions. The report contains a modular design for ASTA and includes specifications for a man-in-the-loop simulation of the system.
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Summary

This report documents a study of requirements for an Airport Surface Traffic Automation (ASTA) system. The objective was to determine the necessary functions, establish the cost and benefits, and outline a modular system design. The highest priority function identified was an improved surface surveillance and communication system. The greatest potential...

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Airport surface traffic automation study

TDWR PRF selection criteria

March 15, 1988
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Project Report
Author:
Sandra C. Crocker
Published in:
MIT Lincoln Laboratory Report ATC-147
Topic:
radar
R&D area:
R&D group:

Summary

The Terminal Doppler Weather Radar (TDWR) system shall provide high quality Doppler radar data on weather phenomena near high traffic airports. These data shall be used in real time by automated TDWR algorithms to detect weather situations which may be hazardous to the safe operation of aircraft within the vicinity of the airport. One of the major factors which could cause the degradation of the quality of these TDWR data is obscuration by 'distant' storm cells. This obscuration is caused by storms located beyond the range interval being sampled by the radar, yet whose radar echo ambiguously folds within the range interval of interest. These range aliased echoes could trigger false detections by the algorithms, and/or cause actual hazardous situations near the airport to remain undetected. By carefully selecting the pulse repetition frequency (PRF) of the radar, range obscuration from distant storms can be minimized over specified airport regions. This document describes techniques for predicting the obscuration as a function of PRF, and details the criteria which shall be used by the TDWR system to automatically and adaptively select an optimal PRF in order to minimize these obscuration effects. Weather radar, Radar range obscuration, TDWR, Radar range aliasing, Radar pulse, Repetition Frequency (PRF).
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Summary

The Terminal Doppler Weather Radar (TDWR) system shall provide high quality Doppler radar data on weather phenomena near high traffic airports. These data shall be used in real time by automated TDWR algorithms to detect weather situations which may be hazardous to the safe operation of aircraft within the vicinity...

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TDWR PRF selection criteria

Characteristics of microbursts observed in the Continental U.S.

February 26, 1988
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Conference Paper
Author:
Marilyn M. Wolfson
Published in:
15th Conf. on Severe Local Storms, 22-26 February 1988, pp. 372-379.
Topic:
aviation weather
R&D area:
R&D group:

Summary

The topic of microbursts is explored in this paper through a historical perspective and review of the studies that have been performed since Fujita (1976) first introduced the concept. Taken as a whole, this body of work actually defines microbursts, and begins to take some of the initial steps toward their understanding. However, a number of dynamically distinct phenomena that give rise to strong surface outflows are being referred to as microbursts. The recent emphasis within the scientific and aviation communities on understanding microbursts makes it particularly important to categorize these various phenomena according to their meteorological nature and true aviation hazard potential. This paper takes some of the first steps toward this categorization, and emphasizes some of the differences in storms that can be expected in different climatological regimes.
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Summary

The topic of microbursts is explored in this paper through a historical perspective and review of the studies that have been performed since Fujita (1976) first introduced the concept. Taken as a whole, this body of work actually defines microbursts, and begins to take some of the initial steps toward...

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Characteristics of microbursts observed in the Continental U.S.

TDWR clutter residue map generation and usage

January 29, 1988
  |
Project Report
Author:
Dwayne R. Mann
Published in:
MIT Lincoln Laboratory Report ATC-148
Topic:
radar
R&D area:
R&D group:

Summary

The Terminal Doppler Weather Radar (TDWR) system is designed to provide high quality low altitude Doppler radar data near airports. Ground clutter suppression will be a major challenge to supplying such high quality Doppler data. To confront this challenge the FAA has specified stringent clutter suppression requirements in the TDWR technical specifications. These specifications are designed to provide an effective clutter suppression system. In particular, the specifications require an antenna with narrow beam width and low side-lobes to minimize ground target illumination. Also, a high pass frequency filter (with a stop attenuation in excess of 50 dB) is required to reduce stationary clutter. FInally, a clutter reisdue map editing system is used to remove remaining clutter. This report describes the algorithms used to generate and use the clutter residue editing system. The major issues are discussed followed by a description of the algorithms designed to address these issues. Finally, preliminary experimental results using a clutter residue map are presented.
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Summary

The Terminal Doppler Weather Radar (TDWR) system is designed to provide high quality low altitude Doppler radar data near airports. Ground clutter suppression will be a major challenge to supplying such high quality Doppler data. To confront this challenge the FAA has specified stringent clutter suppression requirements in the TDWR...

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TDWR clutter residue map generation and usage

Characteristics of microbursts in the continental United States

January 1, 1988
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Journal Article
Author:
Marilyn M. Wolfson
Published in:
Lincoln Laboratory Journal, Vol. 1, No. 1, Spring 1988, pp. 49-74.
Topic:
aviation weather
R&D area:
R&D group:

Summary

Microbursts - powerful downdrafts generally associated with thunderstorms that occur in hot, humid weather - have caused a number of aircraft crashes. To prevent future accidents, air traffic controllers must be able to detect, and predict, microburst events. All microbursts are not alike, however; several distinct weather patterns can produce microbursts. Thus a categorization of the different types of microbursts is an essential part of understanding these hazardous phenomena Using this categorization, the relative hazard to aviation of the various types of microbursts can be assessed.
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Summary

Microbursts - powerful downdrafts generally associated with thunderstorms that occur in hot, humid weather - have caused a number of aircraft crashes. To prevent future accidents, air traffic controllers must be able to detect, and predict, microburst events. All microbursts are not alike, however; several distinct weather patterns can produce...

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Characteristics of microbursts in the continental United States

A comparison of PAM-II and FLOWS mesonet data during COHMEX

December 23, 1987
  |
Project Report
Author:
Marilyn M. Wolfson
…
Published in:
MIT Lincoln Laboratory Report ATC-154
Topic:
weather
R&D area:
R&D group:

Summary

Surface weather stations are being used in the Terminal Doppler Weather Radar program to assess the radar detectibility of wind shear and to help gain an understanding of microburst forcing mechanisms. During 1986, surface station networks operated by Lincoln Laboratory (FLOWS) and the National Center for Atmonspheric Research (PAM-II) were deployed in the Huntsville, AL area. A preliminary assessment of the overall performance of PAM-II and FLOWS networks suggests that they performed with comparable accuracy for those meterological characteristics most important to the detection of microbursts. While differences and discrepancies were noted, especially in the network total precipitation amounts, none would preclude treating PAM-II and FLOWS data together as if they were generated by a single network. We condlcue that the data can be directly combined for microburst detection analyses.
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Summary

Surface weather stations are being used in the Terminal Doppler Weather Radar program to assess the radar detectibility of wind shear and to help gain an understanding of microburst forcing mechanisms. During 1986, surface station networks operated by Lincoln Laboratory (FLOWS) and the National Center for Atmonspheric Research (PAM-II) were...

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A comparison of PAM-II and FLOWS mesonet data during COHMEX

Ground clutter processing for wind measurements with airport surveillance radars

November 4, 1987
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Project Report
Author:
Mark E. Weber
Published in:
MIT Lincoln Laboratory Report ATC-143
Topic:
radar
R&D area:
R&D group:

Summary

Modern airport surveillance radars (ASR) are coherent pulsed-Doppler radars used for detecting and tracking aircraft in terminal area air-space. These radars might serve an additional role by making radial wind measurements in the immediate vicinity of an airport to provide data on low altitude wind shear (LAWS). One factor that will affect their capability in this role is the requirement that intense low-beam ground clutter be filtered from the signals prior to estimation of the reflectivity and radial velocity of weather scatterers. This report describes and analyzes a specific signal processing algorithm for ASR weather parameter measurements. An adaptively selected Finite Impulse Repsonse high-pass filter is used for ground clutter suppression, followed by pulse-pair weather reflectivity and radial velocity estimation. Measurements from a Lincoln Laboratory-developed testbed ASR in Huntsville, Alabama are used to characterize the ground clutter environment under siting ocnditions that are representative of operational ASRs. Temporal fluctuations in ground clutter intensity are analyzed with attention to their impact on the adaptive clutter-filter selection procedure. The performance of the signal processing algorithms is then analyzed using the testbed ASR ground clutter measurements in combination with simulated or real weather signals. We conclude that ground clutter and hte requisite clutter filtering will not severely distort ASR wind shear measurements when the reflectivity factor of the microburst or gust front is approximately 20 dBz or greater. This is typically the case for microbursts ocurring in moist conditions such as prevail over the Eastern United States during summer.
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Summary

Modern airport surveillance radars (ASR) are coherent pulsed-Doppler radars used for detecting and tracking aircraft in terminal area air-space. These radars might serve an additional role by making radial wind measurements in the immediate vicinity of an airport to provide data on low altitude wind shear (LAWS). One factor that...

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Ground clutter processing for wind measurements with airport surveillance radars

Automated detection of microburst windshear for terminal doppler weather radar

October 28, 1987
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Conference Paper
Author:
Mark W. Merritt
Published in:
SPIE, Vol. 846, Digital Image Processing and Visual Communications Technolody in Meteorology, 27-28 October 1987, pp. 61-68.
Topic:
wind shear
R&D area:
R&D group:

Summary

An image analysis method is presented for use in detecting strong windshear events, called microbursts, in Doppler weather radar images. This technique has been developed for use in a completely automated surveil-lance system being procured by the Federal Aviation Administration (FAA) for the protection of airport terminal areas. The detection system must distill the rapidly evolving radar imagery into brief textual warning messages in real time, with high reliability.
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Summary

An image analysis method is presented for use in detecting strong windshear events, called microbursts, in Doppler weather radar images. This technique has been developed for use in a completely automated surveil-lance system being procured by the Federal Aviation Administration (FAA) for the protection of airport terminal areas. The detection...

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Automated detection of microburst windshear for terminal doppler weather radar

Surveillance processing in the Mode S sensor

October 21, 1987
  |
Conference Paper
Author:
Jeffrey L. Gertz
Published in:
Radar-87, IEE Int. Conf., London, U.K., 19-21 October 1987, pp. 189-194.
Topic:
air traffic control
R&D area:
R&D group:

Summary

The principal function of the Mode S sensor (1), an evolutionary upgrade to the current ATCRBS (Air Traffic Control Radar Beacon System) sensor, is the output of one reportper aircraft per antenna scan. This report contains the current aircraft position (range and azimuth), the identity code of its transponder, and the altitude code as supplied by its encoding altimeter. This information is derived from the aircraft transponder replies received at the sensor in response to interrogations transmitted by the sensor. For aircraft equipped with Mode S transponders, a single scheduled interrogation, directed only to that aircraft, elicits a single coding-protected reply containing both identity code and altitude code. For aircraft equipped with ATCRSS transponders, a sequence of interrogations alternately eliclt replies containing un-protected identity code or altitude code from all aircraft in the antenna mainbeam. From this description, it is clear that a Mode S aircraft report can be constructed directly fron the single reply. Surveillance processing, defined as functions that perform scan-to-scan correlation and tracking, are required in general only to predict the next scan position of the aircraft. This information is needed for the proper scheduling of the next interrogation. ATCRBS reports constructed from the aircraft replies, on the other hand, can have a number of deficiencies. The more common such problems are: 1. Either the identity code or altitude code or both can have bits declared either in error or with low confidence by the reply processor due to garbling of overlapping replies. 2. False alarm reports not corresponding to aircraft can be generated from fruit replies (responses to other sensors' interrogations) or reflection replies. 3. Multiple reports for an aircraft can be generited due to incorrect correlation of replies caused by errors in range, azimutn, or code determination. Surveillance processing for ATCRBS aircraft is tasked with correcting these problems prior to report output to the controllers or other users. It does this by correlating raw target reports with, existing track files, and using the information in these files derived from prior scan reports to correct, complete, or reject erroneous reports. This paper presents the major algorithms contained within the Mode S sensor ATCRBS surveillance processing function. It then presents experimental results that demonstrate their effectiveness. Full details of surveillance processing can be obtained by reference to (2) or [3).
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Summary

The principal function of the Mode S sensor (1), an evolutionary upgrade to the current ATCRBS (Air Traffic Control Radar Beacon System) sensor, is the output of one reportper aircraft per antenna scan. This report contains the current aircraft position (range and azimuth), the identity code of its transponder, and...

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Surveillance processing in the Mode S sensor

Study of microburst detection performance during 1985 in Memphis, TN

August 5, 1987
  |
Project Report
Author:
John T. DiStefano
Published in:
MIT Lincoln Laboratory Report ATC-142
Topic:
doppler radar
R&D area:
R&D group:

Summary

This report focuses on the detectability of microbursts using pulse Doppler weather radars and surface anemometers. The data used for this study were collected in the Memphis, TN area during the FLOWS project of 1985. The methods used for declaring a microburst from both Doppler radar and surface anemometer data are described. The main objective of this report was to identify the results that were generated by comparing the 1985 radar detected microbursts (which impacted the surface anemometer system) wit the surface mesonet detected microbursts. In so doing, the issue of missed microburst detections, for which there occurred two (both by the radar), is identified. Possible reasons as to why there two microbursts were not detected are discussed in detail.
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Summary

This report focuses on the detectability of microbursts using pulse Doppler weather radars and surface anemometers. The data used for this study were collected in the Memphis, TN area during the FLOWS project of 1985. The methods used for declaring a microburst from both Doppler radar and surface anemometer data...

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Study of microburst detection performance during 1985 in Memphis, TN
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