Publications
The Marine Stratus Initiative at San Francisco International Airport
June 25, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-252
Summary
San Francisco International Airport is one of the busiest airports in the United States and one of the highest delay airports in terms of total aircraft delay hours and number of imposed air traffic delay programs. As with most airports, weather is the primary cause of aircraft delay. In particular, the local airspace is prone to regular occurrences of low cloud ceiling conditions due to intrusion of marine air from the eastern Pacific Ocean from May through September. Typically, this layer of stratus clouds forms in the San Francisco Bay area overnight and dissipates during the middle to late morning. The timing of the stratus cloud dissipation is such that it frequently poses a threat to the morning arrival push of air traffic into San Francisco. Weather forecasters at the Central Weather Service Unit (CWSU) at the Oakland AirRoute Traffic Control Center are responsible for providing a forecast whether or not the cloudiness will impact morning traffic operations. This information is used for decision making by the Traffic Management Unit at Oakland Center in order to optimally match arriving traffic demand to available airport capacity. As part of the FAA's Integrated Terminal Weather System, the Weather Sensing Group at MIT Lincoln Laboratory has begun an effort entitled the "Marine Stratus Initiative." Its objective is to provide improved weather information and forecast guidance to the Oakland CWSU, which is responsible for providing weather forecasts to air traffic managers. During 1995, the main focus of the project was the design and implementation of a data acquisition, communication, and display infrastructure that provides forecasters with new sources of weather data and information. These initial capabilities were tested during an operational demonstration in August and September. As the project continues, the intent is to improve these new data sources and develop an automated or semi-automated algorithm that will process raw information to provide weather forecasters with numerical guidance to assist them in the forecast process. A description of airport operations at San Francisco and the impact of marine stratus are presented. An explanation is given of the marine stratus phenomenology and the primary factors contributing to cloud dissipation. This conceptual model of the dissipation process is used to define system requirements. A description of the hardware, communications, and display subsystems is provided. An overview of the 1995 demonstration, including user comments, is presented, as well as future plans for meeting the longer-term objectives of the project.
Summary
San Francisco International Airport is one of the busiest airports in the United States and one of the highest delay airports in terms of total aircraft delay hours and number of imposed air traffic delay programs. As with most airports, weather is the primary cause of aircraft delay. In particular...
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ASR-9 Weather System Processor (WSP): wind shear algorithms performance assessment
May 7, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-247
Summary
Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP) that has been used for field measurements and operational demonstrations since 1987. Measurements acquired with this prototype provide an extensive data base for development and validation of the algorithms the WSP uses to generate operational wind shear information for Air Traffic Controllers. This report addresses the performance of the current versions of the WSP's microburst and gust front wind shear detection algorithms on available data from each of the WSP's operational sites. Evaluation of the associated environmental characteristics (e.g., storm structure, radar ground clutter environment) allows for generalization of results of the other major U.S. climatic regimes where the production version of WSP will be deployed.
Summary
Lincoln Laboratory has developed a prototype Airport Surveillance Radar Weather Systems Processor (ASR-WSP) that has been used for field measurements and operational demonstrations since 1987. Measurements acquired with this prototype provide an extensive data base for development and validation of the algorithms the WSP uses to generate operational wind shear...
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Anomalous propagation ground clutter suppression with the Airport Surveillance Radar (ASR) Weather Systems Processor (WSP)
March 15, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-244
Summary
Ground-clutter breakthrough caused by anomalous propagation (AP)--ducting of the radar beam when passing through significant atmospheric temperature and/or moisture gradients--is a significant issue for air traffic controllers who use Airport Surveillance Radar (ASR) weather channel data to guide aircraft through the airport terminal area. At present, these data are often contaminated with AP, leaving the controller unsure about the validity of information on storm location and intensity. The Weather System Processor (WSP), which is scheduled for deployment at 33 airports in the U.S., includes an AP-Editing algorithm designed to remove AP based on its Doppler-spectrum characteristics in ASR-9 data. This report provides a description of the algorithm currently used in the FAA/Lincoln Laboratory WSP prototype and a measurement of the performance of the algorithm during nine episodes of AP and/or true weather in Orlando, florida in 1991 and 1992.
Summary
Ground-clutter breakthrough caused by anomalous propagation (AP)--ducting of the radar beam when passing through significant atmospheric temperature and/or moisture gradients--is a significant issue for air traffic controllers who use Airport Surveillance Radar (ASR) weather channel data to guide aircraft through the airport terminal area. At present, these data are often...
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1995 wake vortex program at Memphis, TN
January 5, 1996
Conference Paper
Published in:
AIAA 34th Aerospace Sciences Meeting and Exhibit, 15-18 January 1996.
Summary
This paper describes wake vortex field measurements conducted during August, 1995 at Memphis, TN. The objective of this effort was to record wake vortex behavior for varying atmospheric conditions and aircraft types. Wake vortex behavior was observed using a mobile CW coherent lidar. This lidar features a number of improvements over previous systems, including the first-ever demonstration of an automatic wake vortex detection and tracking algorithm. An extensive meteorological data collection system was deployed in support of the wake vortex measurements, including a 150-ft instrumented tower, wind profiler/RASS (radio acoustic sounding system), sonar and balloon soundings. Aircraft flight plan and beacon data were automatically collected to determine aircraft flight number, type, speed, and descent rate. Additional data was received from airlines in postprocessing to determine aircraft weight and model. Preliminary results from the field measurement program are presented illustrating differences in wake vortex behavior depending on atmospheric conditions and aircraft type.
Summary
This paper describes wake vortex field measurements conducted during August, 1995 at Memphis, TN. The objective of this effort was to record wake vortex behavior for varying atmospheric conditions and aircraft types. Wake vortex behavior was observed using a mobile CW coherent lidar. This lidar features a number of improvements...
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Selected abstracts on aviation weather hazard research
January 2, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-242
Summary
This paper consists of bibliographic information and abstracts for literature on the topics of weather-related aviation hazards. These abstracts were selected from reports written for the ASR-9, ITWS, TDWR programs, sponsored by the Federal Aviation Administration (FAA), and the Wake Vortex program, sponsored by NASA Langley Research Center. All research was performed by MIT Lincoln Laboratory; some research was performed in collaboration with other organizations. These abstracts were compiled to allow participants in the ASR-9 program to conduct research related to their design, development, and production effort. The abstracts and bibliographic information were retrieved from several commercial databases (INSPEC, Ei Compendex*Plus, Aerospace Database, and NTIS) through an open literature search at the Lincoln Laboratory library. Sufficient information is included for readers to obtain documents of interest to them, but documents will not be provided directly by Lincoln Laboratory.
Summary
This paper consists of bibliographic information and abstracts for literature on the topics of weather-related aviation hazards. These abstracts were selected from reports written for the ASR-9, ITWS, TDWR programs, sponsored by the Federal Aviation Administration (FAA), and the Wake Vortex program, sponsored by NASA Langley Research Center. All research...
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Initial evaluation of terminal-area atmospheric vertical structure prediction algorithms using Fall 1994 ITWS/Wake Vortex Programs' meteorological data
November 6, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-237
Summary
A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to the Integrated Terminal Weather System (ITWS) by providing current and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. Operational applications of these estimates of the atmospheric vertical structure include predicting changes in airport operation rates due to ceiling and visibility (C&V) changes and in predicting wake vortex behavior. The core of this system would be a one-dimensional boundary layer column model. This report summarizes the evaluation of a modified Oregon State University (OSU) column model using data collected during the fall 1994 combined National Aeronautics and Space Administration (NASA) wake vortex project and the ITWS site operations at Memphis International Airport (MEM). Further efforts are necessary to develop and test an operational DAVS-NS prototype. The accuracy typically seen in column model predictions of the vertical temperature structure will limit errors in wake vortex dissipation rates to within a factor of two. Given the current working hypothesis for the San Francisco stratus burn-off phenomenon that rests largely on warming of the marine boundary layer by surface heat flux, the OSU model will also appear to be well suited for addressing this particular problem.
Summary
A Dynamic Atmospheric Vertical Structure Nowcast System (DAVS-NS) is being developed that will add value to the Integrated Terminal Weather System (ITWS) by providing current and short-term forecasts of the vertical atmospheric structure focused at specific sites within the terminal domain. Operational applications of these estimates of the atmospheric vertical...
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Description of radar correlation and interpolation algorithms for the ASR-9 Processor Augmentation Card (9-PAC)
October 27, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-236
Topic:
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Summary
MIT Lincoln Laboratory, under sponsorship from the Federal Aviation Adminstration (FAA), is conducting a program to replace/upgrade the existing ASR-9 array signal processor (ASP) and associated algorithms to improve performance and future maintainability. The ASR-9 processor augmentation card (9-PAC) replaces the ASP four-board set with a single card containing three TMS320c40 processors and 32 Megabytes of memory. The resulting increase in both processing speed and memory size allows more sophisticated beacon and radar processing algorithms to be implemented. The majority of the improvement to the radar correlation and interpolation (C&I) function lies in the area of geocensoring and adaptive thresholding, where the larger memory capacity of the 9-PAC allows more detailed maps to be maintained. A dynamic road map mechanism has been implemented to reduce the need for manual tuning of the system when the radars are first installed or when new road construction occurs. The map is twice the resolution of the original geocensormap, resulting in a decrease in total area desensitized to radar-only targets. In addition, the new geocensor mechanism makes use of target amplitude information, allowing aircraft with amplitudes significantly greater than the road traffic returns at a particular cell to pass through uncensored. The adaptive thresholding cell geometry has been modified so that adaptive map cells now overlap one another, eliminating the false target breakthrough that occurs in the present system when regions of false alarms due to birds or weather transition from one cell to the next. The entire C & I function has been recorded in a high-level language (ANSI-C), allowing it to be easily ported between platforms and better facilitating off-line analysis.
Summary
MIT Lincoln Laboratory, under sponsorship from the Federal Aviation Adminstration (FAA), is conducting a program to replace/upgrade the existing ASR-9 array signal processor (ASP) and associated algorithms to improve performance and future maintainability. The ASR-9 processor augmentation card (9-PAC) replaces the ASP four-board set with a single card containing three...
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The ASR-9 Processor Augmentation Card (9-PAC)
October 2, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-232
Topic:
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Summary
Since 1990, the Airport Surveillance Radar-9 (ASR-9) has been commissioned and installed at more than 60 of the largest airports in the United States, and future installations are planned at more than 60 additional airports. After the first several systems were put into daily operation, air traffic controllers began to lodge complaints about the radar's performance. Problems included the detection of "phantom" aircraft caused by the reflection of beacon interrogation signals off buildings and other aircraft, the radar's losing track of targets during parallel approaches and departures, the inability to track highly maneuverable military aircraft through high-G turns, radar clutter caused by highways and weather, and system overloading as a result of signal returns from flocks of migrating birds. An initial investigation of the sources of these problems focused on the radar's post-processor. Nearly all of the problems could be addressed by additions to the post-processor software, but the post-processor was already running near capacity and there was no means for expansion. Thus, a new processor - the ASR-9 Processor Augmentation Card (9-PAC) - was designed to augment the existing system to allow for a significant increase in processing power. New algorithms were developed to run in 9-PAC to address the problems cited by the controllers.
Summary
Since 1990, the Airport Surveillance Radar-9 (ASR-9) has been commissioned and installed at more than 60 of the largest airports in the United States, and future installations are planned at more than 60 additional airports. After the first several systems were put into daily operation, air traffic controllers began to...
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Automated storm tracking for terminal air traffic control
September 1, 1995
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 7, No. 2, Fall 1994, pp. 427-448.
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Summary
Good estimates of storm motion are essential to improved air traffic control operations during times of inclement weather. Automating such a service is a challenge, however, because meteorological phenomena exist as complex distributed systems that exhibit motion across a wide spectrum of scales. Even when viewed from a fixed perspective, these evolving dynamic systems can test the extent of our definition of motion, as well as any attempt at automated tracking of this motion. Image-based motion detection and processing appear to provide the best route toward robust performance of an automated tracking system.
Summary
Good estimates of storm motion are essential to improved air traffic control operations during times of inclement weather. Automating such a service is a challenge, however, because meteorological phenomena exist as complex distributed systems that exhibit motion across a wide spectrum of scales. Even when viewed from a fixed perspective...
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The Integrated Terminal Weather System terminal winds product
September 1, 1995
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 7, No. 2, Fall 1994, pp. 475-502.
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Summary
The wind in the airspace around an airport impacts both airport safety and operational efficiency. Knowledge of the wind helps controllers and automation systems merge streams of traffic; it is also important for the prediction of storm growth and decay, burn-off of fog and lifting of low ceilings, and wake vortex hazards. This knowledge is provided by the Integrated Terminal Weather System (ITWS) gridded wind product, or Terminal Winds. The Terminal Winds product combines data from a national numerical weather-prediction model, called the Rapid Update Cycle, with observations from ground stations, aircraft reports, and Doppler weather radars to provide estimates of the horizontal wind field in the terminal area. The Terminal Winds analysis differs from previous real-time winds-analysis systems in that it is dominated by Doppler weather-radar data. Terminal Winds uses an analysis called cascade of scales and a new winds-analysis technique based on least squares to take full advantage of the information contained in the diverse data set available in an ITWS. The weather radars provide sufficiently fine-scale winds information to support a 2-km horizontal-resolution analysis and a five-minute update rate. A prototype of the Terminal Winds analysis system was tested at Orlando International Airport in 1992, 1993, and 1995, and at Memphis International Airport in 1994. The field operations featured the first real-time winds analysis combining data from the Federal Aviation Administration TDWR radar and the National Weather Service NEXRAD radar. The evaluation plan is designed to capture both the overall system performance and the performance during convective weather, when the fine-scale analysis is expected to show its greatest benefit.
Summary
The wind in the airspace around an airport impacts both airport safety and operational efficiency. Knowledge of the wind helps controllers and automation systems merge streams of traffic; it is also important for the prediction of storm growth and decay, burn-off of fog and lifting of low ceilings, and wake...
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