Publications
ASR-9 processor augmentation card scan-scan correlator algorithms
April 2, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-245
Summary
This report documents the Scan-Scan correlator algorithms for the ASR-9 Processor Augmentation Card (9-PAC) project. The 9-PAC is a processor card that serves as a processing enhancement to the existing ASR-9's post-processor system. It provides increased speed and memory capabilities to the processor, which allows for the introduction of more complex scan-scan correlator algorithms. These more complex algorithms improve the ASR-9's system performance through decreased false alarms, and increased detection of aircraft. The 9-PAC Scan-Scan correlator, also known as the Tracker, consists of three basic processing tasks: initialization, input/output, and the actual Tracker. The Tracker can be broken down further into four main processing functions: report-to track association, report-to-track correlation, track update, and track initiation.
Summary
This report documents the Scan-Scan correlator algorithms for the ASR-9 Processor Augmentation Card (9-PAC) project. The 9-PAC is a processor card that serves as a processing enhancement to the existing ASR-9's post-processor system. It provides increased speed and memory capabilities to the processor, which allows for the introduction of more...
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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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Lincoln Laboratory Evaluation of TCAS II logic version 6.04a, volume I
February 21, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-240,I
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Summary
This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 6.04a. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in U.S. airspace. Version 6.04a is a logic version mandated by the FAA by 30 December 1994 in order to correct a potential safety problem in earlier versions and to make the TCAS logic more compatible with the air traffic control system. Lincoln Laboratory evaluated the logic by examining approximately two million simulated pairwise TCAS-TCAS encounters, derived from actual aircraft tracks recorded in U.S. airspace. The main goals of the evaluation effort were: (1) to determine if version 6.04a successfully corrected the potential safety problem without introducing new problems; (2) to detect and explain any areas of poor performance; and (3) to understand the performance limits of the logic. Five analysis programs were written to aid in the evaluation, and these programs are described in the report. There were three phases of the evaluation corresponding to the above three goals. For each phase, the report gives an overview of the evaluation approach taken, a description of the results, and a summary. A description of follow-on activities plus overall conclusions and recommendations are given at the end of the report.
Summary
This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 6.04a. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in...
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Lincoln Laboratory Evaluation of TCAS II logic version 6.04a, appendices, volume II
February 15, 1996
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-240,II
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Summary
This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 6.04a. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in U.S. airspace. Version 6.04a is a logic version mandated by the FAA by 30 December 1994 in order to correct a potential safety problem in earlier versions and to make the TCAS logic more compatible with the air traffic control system. Lincoln Laboratory evaluated the logic by examining approximately two million simulated pairwise TCAS-TCAS encounters, derived from actual aircraft tracks recorded in U.S. airspace. The main goals of the evaluation effort were: (1) to determine if version 6.04a successfully corrected the potential safety problem without introducing new problems; (2) to detect and explain any areas of poor performance; and (3) to understand the performance limits of the logic. Five analysis programs were written to aid in the evaluation, and these programs are described in the report. There were three phases of the evaluation corresponding to the above three goals. For each phase, the report gives an overview of the evaluation approach taken, a description of the results, and a summary. A description of follow-on activities plus overall conclusions and recommendations are given at the end of the report.
Summary
This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 6.04a. TCAS II is an airborne collision avoidance system required since 30 December 1993 by the FAA on all air carrier aircraft with more than 30 passenger seats operating in...
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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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A human factors approach to the development and evaluation of the Graphical Weather Service
November 5, 1995
Conference Paper
Published in:
14th AIAA/IEEE Digital Avionics Systems Conf., 5-9 November 1995, pp. 264-269.
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Summary
With the sponsorship of the Federal Aviation Administration, MIT Lincoln Laboratory is developing the Graphical Weather Service (GWS), a data link application that provides near-real-time ground-based weather information to pilots. Through the use of GWS, the pilot will be able to access both graphical and text weather information for any location in the contiguous United States. In-cockpit access to near-real-time weather information may substantially affect the situational awareness and subsequent decision making of pilots. In developing and evaluating this service, a human factors approach has been taken. This paper is an overview of the human factors activities performed in the development and evaluation of GWS.
Summary
With the sponsorship of the Federal Aviation Administration, MIT Lincoln Laboratory is developing the Graphical Weather Service (GWS), a data link application that provides near-real-time ground-based weather information to pilots. Through the use of GWS, the pilot will be able to access both graphical and text weather information for any...
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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
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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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GPS-squitter automatic dependent surveillance broadcast: flight testing in the Gulf of Mexico
October 13, 1995
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-235
Summary
During November - December 1994, MIT Lincoln Laboratory conducted a field evaluation of the air surveillance capabilities of GPS-Squitter in the Gulf of Mexico. Three squitter ground stations were located in the vincinity of Morgan City, Louisiana, for this evaluation: two were located on offshore oil platforms, and the third was located at an onshore heliport. Surveillance coverage tests were flown over the Gulf with three test aircraft - two helicopters and one Cessna 421 fixed wing aircraft. The helicopters flew at altitudes ranging from 100 to 2000 feet above sea level and the Cessna flew at 7500 and 20,000 feet. Extended squitter messages broadcast by each of the test aircraft provided aircraft position and identification. This report documents results of these texts and compares measured coverage to predicted coverage from the ground stations. Based on the good agreement between predicted and measured performance, a description of a possible operational system is included that would provide surveillance of the entire Gulf region serviced by oil platform helicopters. The report concludes that GPS Squitter is a near-term option for providing accurate, real time surveillance of aircraft operating in the offshore airspace in the Gulf of Mexico.
Summary
During November - December 1994, MIT Lincoln Laboratory conducted a field evaluation of the air surveillance capabilities of GPS-Squitter in the Gulf of Mexico. Three squitter ground stations were located in the vincinity of Morgan City, Louisiana, for this evaluation: two were located on offshore oil platforms, and the third...
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