Publications
Development and performance of a CW coherent laser radar for detecting wake vortices
July 23, 1995
Journal Article
Published in:
Optical Society of America, Coherent Laser Radar Topical Mtg., 1995 Technical Digest Series, Vol. 19, 23-27 July 1995, pp. 186-189
Summary
A CW-coherent laser radar using a 20-Watt CO2 laser has been constructed and deployed for the measurement of wake-vortext turbulence. This is part of a larger effort to understand the motion and decay of wake vortices as a function of the local atmospheric conditions. The construction and operation of the lidar and the initial fielding at Memphis International Airport are described.
Summary
A CW-coherent laser radar using a 20-Watt CO2 laser has been constructed and deployed for the measurement of wake-vortext turbulence. This is part of a larger effort to understand the motion and decay of wake vortices as a function of the local atmospheric conditions. The construction and operation of the...
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Controller-human interface design for the final approach spacing tool
June 17, 1995
Conference Paper
Published in:
Proc. IFAC Man-Machine Systems Conf., 27-29 June 1995, pp. 559-564.
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The Federal Aviation Administration is developing a set of software tools, known as the Center-TRACON Automation System (CTAS) to assist air traffic controllers in their management and control tasks. CTAS originated at National Aeronautics and Space Administration (NASA) Ames Research Center, where prototypes continue to evolve. In parallel, Massachusetts Institute of Technology/Lincoln Laboratory (MIT/LL) is refining and testing the software, including the Computer-Human Interface (CHI). This paper focuses on the CHI designed by MIT/LL for the Final Approach Spacing Tool (FAST) part of CTAS. The FAST design approach, CHI development and operational concept is presented.
Summary
The Federal Aviation Administration is developing a set of software tools, known as the Center-TRACON Automation System (CTAS) to assist air traffic controllers in their management and control tasks. CTAS originated at National Aeronautics and Space Administration (NASA) Ames Research Center, where prototypes continue to evolve. In parallel, Massachusetts Institute...
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Data processing techniques for airport surveillance radar weather sensing
May 8, 1995
Conference Paper
Published in:
Proc. IEEE 1995 Int. Radar Conf., 8-11 May 1995, pp. 521-528.
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Summary
Discusses data processing techniques that can provide high quality, automated weather information using the FAA's existing Airport Surveillance Radars (ASR-9). The cost of modifying the ASR-9 is significantly less than that for deployment of the dedicated terminal Doppler weather radar. These techniques have been implemented on a prototype ASR-9 weather surveillance processor (WSP) and have been tested operationally at the Orlando, FL and Albuquerque, NM air traffic control towers. The key to the success of this system has been the development of innovative data processing techniques that accommodate the non-optimum parameters of the ASR as a weather sensor. The authors motivate the development of the ASR-9 WSP system and describe in detail the data processing techniques that have been employed to achieve an operationally useful capability. They provide an overview of the WSP and the ongoing system development and test program. They provide specifics on the data processing algorithms that have been key to successful implementation of this capability.
Summary
Discusses data processing techniques that can provide high quality, automated weather information using the FAA's existing Airport Surveillance Radars (ASR-9). The cost of modifying the ASR-9 is significantly less than that for deployment of the dedicated terminal Doppler weather radar. These techniques have been implemented on a prototype ASR-9 weather...
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Comparative analysis of ground-based wind shear detection radars
May 8, 1995
Conference Paper
Published in:
Proc. IEEE 1995 Int. Radar Conf., 8-11 May 1995, pp. 486-495.
Summary
The UNISYS Corporation has developed a microburst prediction radar (MBPR) to provide detection and short-term predictions of the most hazardous form of low altitude wind shear in the vicinity of an airport. The MBPR is intended for deployment on- or near-airport so as to minimize range coverage (and associated radar power-aperture) requirements. Like the airport surveillance radar wind shear processor (ASR-WSP), the cost of the MBPR is significantly less than that of the terminal Doppler weather radar (TDWR) so that its deployment at smaller airports might be economically justified if the performance is operationally acceptable. Field tests of engineering prototypes of the MBPR have been conducted in conjunction with FAA-sponsored TDWR and WSP demonstration programs. We assess the capabilities and limitations of each of these systems using a consistent methodology that emphasizes the comparative analysis of the significant parameters of each radar in relation to wind shear phenomenology. An extensive database on wind shear event radar cross section, spatial structure and intensity distribution-derived through our FAA-sponsored testing of TDWR and ASR-WSP prototypes is an important asset in developing this comparison.
Summary
The UNISYS Corporation has developed a microburst prediction radar (MBPR) to provide detection and short-term predictions of the most hazardous form of low altitude wind shear in the vicinity of an airport. The MBPR is intended for deployment on- or near-airport so as to minimize range coverage (and associated radar...
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Terminal Weather Information for Pilots (TWIP) Test Report for 1994 Memphis and Orlando Demonstrations
April 28, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-227
Summary
Demonstrations of delivering the Terminal Weather Information for Pilots (TWIP) products to air carrier pilots via the Aircraft Communications Addressing and Reporting System (ACARS) data link were carried out at Memphis and Orlando during the summer of 1994. Six airlines participated in the demonstrations at both airports. The Terminal Weather Text Message and the Terminal Weather Character Graphics Depiction were evaluated using request/reply and forced update approaches. In the first case, the pilot needed to make a request in order to obtain the TWIP products. In the second case, the TWIP message was sent to the aircraft automatically when certain criteria were met (e.g., the aircraft was within 20 minutes of landing and wind shear alerts began at the airport). Five of the airlines used the request/reply approach, and one airline used the forced update approach. Pilot and contoller response to the TWIP products were evaluated using questionnaires. Statistics on message traffic and content were analyzed, and some cases were analyzed in detail to compare the TWIP products with the existing Surface Aviation Observation (SAO) reports. Recorded radio traffic also was analyzed to determine if there was any effect on the number of requests for terminal weather information. Pilots rated the TWIP products favorably, with most indicating that the messages provided improved situational awareness of terminal weather hazards without substantially increased cockpit workload. Controller reaction to the TWIP demonstration was generally neutral, indicating that providing these messages to pilots caused no substantial increase in contoller workload. Further results of the demonstration are discussed in the report, along with recommendations for subsequent TWIP demonstrations.
Summary
Demonstrations of delivering the Terminal Weather Information for Pilots (TWIP) products to air carrier pilots via the Aircraft Communications Addressing and Reporting System (ACARS) data link were carried out at Memphis and Orlando during the summer of 1994. Six airlines participated in the demonstrations at both airports. The Terminal Weather...
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Initial evaluation of the Oregon State University Planetary Boundary Layer Column Model for ITWS applications
April 13, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-233
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products important for air traffic control in the terminal area. Some ITWS is supporting the development of products important for air traffic control in the terminal area. Some ITWS products will allow air traffic managers to anticipate operationally significant short-term (0-30 min) changes in ceiling and visibility (C&V) and aircraft separations necessary to avoid encounters with wake vortices. Development of such products exploits data that will be available from new FAA terminal area sensor systems. These sensor systems include Terminal Doppler Weather Radar (TDWR), Next Generation Weather Radar (NEXRAD), the Meteorological Data Collection and Reporting System (MDCRS), and the Automated Surface Observing System (ASOS). A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to ITWS by providing current analyses and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. This report summarizes the initial evaluation of the Oregon State University one-dimensional boundary layer model for its potential role within a DAVS-NS.
Summary
The Federal Aviation Administration (FAA) Integrated Terminal Weather System (ITWS) is supporting the development of products important for air traffic control in the terminal area. Some ITWS is supporting the development of products important for air traffic control in the terminal area. Some ITWS products will allow air traffic managers...
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Integrated Terminal Weather System (ITWS) demonstration and validation operational test and evaluation
April 13, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-234
Summary
During summer 1994, MIT Lincoln Laboratory conducted the Operational Test and Evaluation Demonstration and Validation (Dem Val) of the Federal Aviation Administration's Integrated Terminal Weather System (ITWS). The purpose of the demonstration was to obtain user feedback on products and to prove that the ITWS products and concept were sufficiently mature to proceed with procurement. Dem Val was conducted at the Memphis International Airport from 23 May through 22 July and at the Orlando International Airport from 11 July through 19 August. Products were delivered to users at the Memphis Airport Traffic Control Tower (ATCT) and TRACON (Terminal Radar Approach Control), at the Memphis Air Route Traffic Control Center (ARTCC), at the Orlando International ATCT and TRACON, and at the Jacksonville ARTCC. In addition, ITWS displays were available to the National Weather Service forecast offices at Memphis, TN, and Melbourne, FL; to Northwest Airlines in Minneapolis, MN; and to Delta Airlines in Orlando, FL. This report documents the technical performance of the product generation algorithms. Each algorithm is described briefly, including the product operational and display concepts. The techniques by which the technical performance is assessed and the results of the assessment are presented. The performance of the algorithms is measured against the Minimum Operational Performance Requirements (MOPR), which products must meet to be considered operationally useful by the ATC user community.
Summary
During summer 1994, MIT Lincoln Laboratory conducted the Operational Test and Evaluation Demonstration and Validation (Dem Val) of the Federal Aviation Administration's Integrated Terminal Weather System (ITWS). The purpose of the demonstration was to obtain user feedback on products and to prove that the ITWS products and concept were sufficiently...
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An advanced weather surveillance processor for airport surveillance radars
January 15, 1995
Conference Paper
Published in:
Proc. Sixth Conf. on Aviation Weather Systems, 15-20 January 1995, pp. 396-401.
Summary
This paper describes an enhanced weather processor for the Federal Aviation Administration's Airport Surveillance Radar (ASR-9) that will include Doppler wind estimation for the detection of low altitude wind shear, scan-to-scan tracking to provide estimates of the speed and direction of storm movement and suppression of spurious weather reports currently generated by the ASR-9's six-level weather channel during episodes of anamalous radar energy propagation (AP). This ASR-9 Wind Shear Processor (WSP) will be implemented as a retrofit to the ASR-9 through the addition of interfaces, receiving chain hardware and high-speed digital processing and display equipment. Thunderstorm activity in terminal airspace (the volume extending approximately 30 nmi from an airport and to 15,000 feet altitude) is an obvious safety issue and makes a significant overall contribution to delay in the United States commercial aviation industry. Associated low-altitude wind shear has been identified as the primary cause of a number of air carrier accidents, involving almost 600 fatalities. Correlations of aircraft arrival and takeoff delay with associated weather conditions suggest that thunderstorm activity may account for 40 to 50 percent of serious delay within the United States. The WSP modification to the ASR-9 will provide the functional capabilities of the Terminal Doppler Weather Radar (TDWR) at airports whose operation levels and/or thunderstorm exposures do not justify the costs of the dedicated radar. Field testing of a prototype version of the ASR-9 WSP has confirmed that the weather information products it generates are accurate and are operationally useful in an Air Traffic Control (ATC) environment.
Summary
This paper describes an enhanced weather processor for the Federal Aviation Administration's Airport Surveillance Radar (ASR-9) that will include Doppler wind estimation for the detection of low altitude wind shear, scan-to-scan tracking to provide estimates of the speed and direction of storm movement and suppression of spurious weather reports currently...
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An algorithm to remove anomalous propagation clutter returns from ASR-9 weather channel data using pencil beam radar data
January 15, 1995
Conference Paper
Published in:
Sixth Conf. on Aviation Weather Systems, 15-20 January 1995, pp. 366-371.
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Summary
The Integrated Terminal Weather System (ITWS), currently under development by the Federal Aviation Administration (FAA), will produce a fully automated, integrated terminal weather information system to improve the safety, efficiency and capacity of terminal area aviation operations. The ITWS will acquire data from FAA and National Weather Service sensors as well as from aircraft in flight in the terminal area. The ITWS will provide products to Air Traffic personnel that are immediately usable without further meteorological interpretation. These products include current terminal-area weather and short-term (0-30 minute) predictions of significant weather phenomena. The ASR (Airport Surveillance Radar)-9 radar is used in the terminal area to control aircraft. This radar has a weather channel that provides the location and intensity of precipitation (6-level) on the air traffic controllers' radar screen. Controllers use the weather information to aid aircraft in avoiding weather. The ASR-9 radar data are often contaminated by anomalous propagation (AP). Due to the smoothing process used in the ASR-9, controllers are unable to distinguish between AP and valid weather returns. As a result controllers may attempt to vector aircraft around AP, resulting in increased controller workload and decreased terminal airspace capacity. The ITWS product suite includes two precipitation products: ITWS Precipitation (AP removed) and the ASR-9 Precipitation (AP flagged in black). The basis for these products is the ASR-9 weather channel output. Both of these products are created by an algorithm called AP-edit. The ITWS precipitation product is a representation of the location and intensity of precipitation in the TRACON (Terminal Radar Approach Control) area and may be used for situational awareness and as a planning aid for air traffic managers by showing where weather is located relative to traffic flow patterns. The ASR-9 precipitation product explicitly shows where AP clutter is located relative to any ASR-9 radar. Since the ITWS precipitation product docs not replace the ASR-9 weather display on any controllers' displays, the Air Traffic Control (ATC) supervisor or traffic manager may use the ASR-9 precipitation product to indicate the location of AP clutter to any individual controller. The products were demonstrated during the ITWS Demonstration and Validation Operational Test and Evaluation (OT&E) conducted at Memphis and Orlando International Airports during the summer of 1994. This paper describes the AP-edit algorithm and provides a preliminary evaluation of the performance of the algorithm.
Summary
The Integrated Terminal Weather System (ITWS), currently under development by the Federal Aviation Administration (FAA), will produce a fully automated, integrated terminal weather information system to improve the safety, efficiency and capacity of terminal area aviation operations. The ITWS will acquire data from FAA and National Weather Service sensors as...
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Applications of column models for terminal weather nowcasts
January 15, 1995
Conference Paper
Published in:
Sixth Conf. on Aviation Weather Systems, 15-20 January 1995, pp. 66-71.
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The Planetary Boundary Layer (PBL) is that part of the atmosphere, which is directly influenced by the presence of the earth's surface, and which responds to surface forcing with a time-scale of an hour or less. The Residual Layer (RL) is the portion of the lower atmosphere, which was part of the PBL within the past several hours, and which has become separated from the influence of short-term surface forcing, usually by the formation of a cooler layer at the surface. In the mid-latitudes, the height of the combined PBL and RL is usually 1-2 kilometers. A column model is a one-dimensional prognostic model for the state of a single column of the atmosphere, with special attention to the processes in the lowest few kilometers. It is designed to diagnose and nowcast the vertical structure of the PBL. Important information for ITWS1 nowcast products are the vertical profiles of horizontal wind velocity, temperature, humidity, and turbulent kinetic energy (TKE) in the lowest few kilometers (Sankey, 1994). Traditionally, operational meteorologists have obtained estimates of these quantities by balloon soundings, a measurement process that is not well-suited for continuous updates. We are investigating the possibility of developing an operational column model to obtain this vertical structure information for use in the ITWS. Our approach involves using a combination of sensing technology and analysis techniques that have proven successful in several research programs. Column models are designed to mimic the processes by which the surface forces the processes in the low atmosphere at times when local radiation is a dominant factor. Fluxes are measures of the net rates of these transport processes. The widely used Oregon State University column model (OSUlDPBL) parameterizes the fluxes by gradient transfer techniques (Troen and Mahr!, 1986). This model has provided dependable service in several field experiments, providing information with a vertical resolution of tens of meters. It is not designed to provide a fine-scale description of the stable nocturnal PBL. The French model COB EL has been developed to forecast the occurrence of radiation fog, and therefore concentrates on modeling the stable nocturnal PBL (Bergot and Guedalia, 1994). It uses a prognostic equation to estimate TKE in the stable boundary layer and parameterizes the fluxes in tern1s of the TKE (Duynkerke, 1991). A discussion of the potential uses of the column model in the ITWS is followed by the considerations that motivate the design of an operational column model. The prototype design is described. We conclude with the results of a preliminary evaluation using STORMFEST data (STORM Project Office, 1992) and a discussion of plans for a more comprehensive evaluation.
Summary
The Planetary Boundary Layer (PBL) is that part of the atmosphere, which is directly influenced by the presence of the earth's surface, and which responds to surface forcing with a time-scale of an hour or less. The Residual Layer (RL) is the portion of the lower atmosphere, which was part...
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