Publications
Multifunction phased array radar: technical synopsis, cost implications, and operational capabilities
January 14, 2007
Conference Paper
Published in:
87th Annual American Meteorological Society Meeting, 14-18 January 2007.
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Summary
Current U.S. weather and aircraft surveillance radar networks vary in age from 10 to more than 40 years. Ongoing sustainment and upgrade programs can keep these operating in the near to mid term, but the responsible agencies (FAA, NWS and DoD/DHS) recognize that large-scale replacement activities must begin during the next decade. In addition, these agencies are re-evaluating their operational requirements for radar surveillance. FAA has announced that next generation air traffic control (ATC) will be based on Automatic Dependent Surveillance - Broadcast (ADS-B) (Scardina, 2002) rather than current primary and secondary radars. ADS-B, however, requires verification and back-up services which could be provided by retaining or replacing primary ATC radars.
Summary
Current U.S. weather and aircraft surveillance radar networks vary in age from 10 to more than 40 years. Ongoing sustainment and upgrade programs can keep these operating in the near to mid term, but the responsible agencies (FAA, NWS and DoD/DHS) recognize that large-scale replacement activities must begin during the...
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An automated visibility detection algorithm utilizing camera imagery
January 14, 2007
Conference Paper
Published in:
87Th AMS Annual Meeting, 14-18 January 2007.
Summary
The Federal Highway Administration (FHWA) has had a focused program to improve the integration of weather decision support systems into surface transportation operations since 1999. Clarus (Latin for clear) is the FHWA's most recent surface transportation weather initiative. The Clarus concept is to develop and demonstrate an integrated surface transportation weather observing, forecasting and data management system (Pisano, 2006a). As part of this effort, the FHWA is also promoting research into methods for applying new and existing sensor or probe data. These efforts include utilizing new in-vehicle sensor data that will be part of the vehicle infrastructure initiative (VII) (Pisano, 2006b), and finding innovative ways to use existing camera imagery. MIT Lincoln Laboratory (MIT/LL) was tasked to evaluate the usefulness of camera imagery for sensing ambient and road weather conditions and the feasibility for creating a portable visibility estimation algorithm. This paper gives a general background on the current utilization of camera imagery, including past and ongoing research of automated weather/condition algorithms. This is followed by a description of the MIT/LL camera test site, the analyses performed and the resultant prototype visibility estimation algorithm. In addition, the paper details application of the prototype algorithm to existing state DOT cameras in Utah. The final section discusses the future possibilities of camera-based weather and road condition algorithms.
Summary
The Federal Highway Administration (FHWA) has had a focused program to improve the integration of weather decision support systems into surface transportation operations since 1999. Clarus (Latin for clear) is the FHWA's most recent surface transportation weather initiative. The Clarus concept is to develop and demonstrate an integrated surface transportation...
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ASR-9 refractivity measurements using ground targets
November 13, 2006
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-328
Summary
Weather radars rely on the presence of radiowave scattering entities such as hydrometeors and insects to sense the dynamic evolution of the atmosphere. Under clear-air, low-reflectivity conditions, when no such "visible" tracers are present, air mass boundaries such as the outflow edge of a dry microburst may go undetected. Recently, a radar data processing technique was developed to estimate the near-ground atmospheric refractivity field using ground targets. Refractivity is dependent on the moist thermodynamic variables of the atmosphere and, thus, can be used to detect air mass changes and boundaries. In this study, we apply this technique for the first time to Airport Surveillance Radar-9 (ASR-9) Weather Systems Processor (WSP) data. Comparisons with measurements from a meteorological station show good consistency. The potential exists for improving the capability of the WSP to detect low-reflectivity wind-shear phenomena by adding interest information provided by the estimated refractivity field. Adequate computational power is the sole requirement for implementing this scheme; aside from that, no alteration or addition is necessary to the ASR-9 hardware. Its primary weakness is the sensitivity to vertical variation in refractivity and variance of target height. It also has a limited range of coverage (~20 km), but that is acceptable for terminal-area coverage. Further testing is needed during more appropriate meteorological conditions and at other sites to prove that dry wind-shear events can really be detected in the derived refractivity field by this class of radar, and that the technique is robust under various topographical settings.
Summary
Weather radars rely on the presence of radiowave scattering entities such as hydrometeors and insects to sense the dynamic evolution of the atmosphere. Under clear-air, low-reflectivity conditions, when no such "visible" tracers are present, air mass boundaries such as the outflow edge of a dry microburst may go undetected. Recently...
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Required surveillance performance accuracy to support 3-mile and 5-mile separation in the National Airspace System
November 1, 2006
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-323
Summary
The Federal Aviation Administration is modernizing the Air Traffic Control system to improve flight efficiency, to increase capacity, to reduce flight delays, and to control operating costs as the demand for air travel continues to grow. Promising new surveillance technologies such as Automatic Dependent Surveillance Broadcast, (ADS-B), multisensor track fusion, and multifunction phased array radar offer the potential for increased efficiency in the National Airspace System (NAS). However, the introduction of these surveillance systems into the NAS is hampered because the FAA Order containing the surveillance requirements to support separation services assumes surveillance is provided by radar technology. The requirements are stated in terms that don't apply to new surveillance technologies. In order to take advantage of new surveillance technologies, the surveillance requirements to support separation services in the NAS must be articulated from a performance perspective that is not technology specific. This will allow the FAA to make the investment and performance trade-off analysis necessary to support the introduction of new surveillance technologies. [not complete]
Summary
The Federal Aviation Administration is modernizing the Air Traffic Control system to improve flight efficiency, to increase capacity, to reduce flight delays, and to control operating costs as the demand for air travel continues to grow. Promising new surveillance technologies such as Automatic Dependent Surveillance Broadcast, (ADS-B), multisensor track fusion...
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SFO marine stratus forecast system documentation
October 17, 2006
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-319
Summary
San Francisco International Airport (SFO) experiences frequent low ceiling conditions during the summer season due to marine stratus clouds. Stratus in the approach zone prevents dual approaches to the airport??s closely spaced parallel runways, effectively reducing arrival capacity by half. The stratus typically behaves on a daily cycle, with dissipation occurring during the hours following sunrise. Often the low ceiling conditions persist throughout the morning hours and interfere with the high rate of air traffic scheduled into SFO from mid-morning to early afternoon. Air traffic managers require accurate forecasts of clearing time to efficiently administer Ground Delay Programs (GDPs) to match the rate of arriving aircraft with expected capacity. The San Francisco Marine Stratus Forecast System was developed as a tool for anticipating the time of stratus clearing. The system relies on field-deployed sensors as well as routinely available regional surface observations and satellite data from the Geostationary Operational Environmental Satellite (GOES-West). Data are collected, processed, and input to a suite of forecast models to predict the time that the approach zone will be sufficiently clear to perform dual approaches. Data observations and model forecasts are delivered to users on an interactive display accessible via the Internet. The system prototype was developed under the sponsorship of the FAA Aviation Weather Research Program (AWRP). MIT Lincoln Laboratory served as technical lead for the project, in collaboration with San Jose State University, the University of Quebec at Montreal, and the Center Weather Service Unit (CWSU) at the Oakland Air Route Traffic Control Center (ARTCC). The National Weather Service (NWS), under the direction of the NWS Forecast Office in Monterey, assumed responsibility for operation and maintenance of the system following technical transfer in 2004. This document was compiled as a resource to support continuing system operation and maintenance.
Summary
San Francisco International Airport (SFO) experiences frequent low ceiling conditions during the summer season due to marine stratus clouds. Stratus in the approach zone prevents dual approaches to the airport??s closely spaced parallel runways, effectively reducing arrival capacity by half. The stratus typically behaves on a daily cycle, with dissipation...
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Improving the resolution advisory reversal logic of the traffic alert and collision avoidance system
October 15, 2006
Conference Paper
Published in:
25th IEEE/AIAA Digital Avionics Systems Conf., 15-18 October 2006, pp. 561-570.
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Summary
The Traffic Alert and Collision Avoidance System (TCAS II) is the worldwide standard system for manned aircraft to avoid collisions with airborne transponder-equipped traffic. A safety vulnerability of the collision avoidance logic was reported by European analysts, who also proposed a change to correct it. The safety issue concerns limitations in the ability of TCAS to reverse the sense of a Resolution Advisory (RA) during an encounter. The issue was addressed by a team of experts1 in the Requirements Working Group (RWG) of RTCA Special Committee 147 [1]. This paper discusses the problem, the metrics and methods used in the analysis, and presents results that quantify the effectiveness of the proposed solution. Finally, recommendations are presented for implementing the change.
Summary
The Traffic Alert and Collision Avoidance System (TCAS II) is the worldwide standard system for manned aircraft to avoid collisions with airborne transponder-equipped traffic. A safety vulnerability of the collision avoidance logic was reported by European analysts, who also proposed a change to correct it. The safety issue concerns limitations...
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Assessment of air traffic control productivity enhancements from the Corridor Integrated Weather System (CIWS)
June 30, 2006
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-325
Summary
The Air Traffic Control (ATC) productivity benefits attributed to the Corridor Integrated Weather System (CIWS) were assessed using real-time observations of CIWS product usage during three multi-day thunderstorm events in 2005 at eight U.S. Air Route Traffic Control Centers (ARTCCs). CIWS improved ATC productivity by: reducing the time required to develop, coordinate, and implement weather impact mitigation plans; increasing the number of safety and capacity-enhancing plans that were executed (e.g., more efficient, proactive rerouting and greater ability to keep routes open; [and] assisting with FAA staffing decisions. Time savings per consecutive weather day for Traffic Management Coordinators (TMCs) in an ARTCC typically were 20-95 minutes. The overall frequency of capacity-enhancing decisions increased by 177% relative to the CIWS benefits study conducted in 2003. The annual CIWS delay savings are in excess of 92,000 hours. Corresponding airline direct operations cost (DOC) savings exceeded $94M and passenger value of time (PVT) savings exceeded $201M. Annual jet fuel savings exceeded 11M gallons. The ability of the Cleveland ARTCC to develop and execute weather impact mitigation plans improved significantly (e.g., by 50-80%) when CIWS products were available to Area Supervisors as well as to the TMCs.
Summary
The Air Traffic Control (ATC) productivity benefits attributed to the Corridor Integrated Weather System (CIWS) were assessed using real-time observations of CIWS product usage during three multi-day thunderstorm events in 2005 at eight U.S. Air Route Traffic Control Centers (ARTCCs). CIWS improved ATC productivity by: reducing the time required to...
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Assessment of air traffic control productivity enhancements from the Corridor Integrated Weather System (CIWS) - executive summary
June 27, 2006
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-325-1
Summary
In an era of significant federal government budget austerity for civil aviation operations, it has become essential to improve Air Traffic Control (ATC) productivity. This report summarizes the results of an exploratory field measurement program conducted during summer 2005 to assess ATC productivity benefits of the Corridor Integrated Weather System (CIWS). Real-time observations of CIWS product usage during multi-day thunderstorm events were carried out at eight U.S. Air Route Traffic Control Centers (ARTCC). The real time observations data were used in conjunction with specific in-depth case study analyses to assess the CIWS productivity enhancements associated with convective weather impact mitigation plan development and implementation. Comparisons of ARTCC operations between facilities with and without access to CIWS were alos made to further identify CIWS contributions to improved ATC productivity.
Summary
In an era of significant federal government budget austerity for civil aviation operations, it has become essential to improve Air Traffic Control (ATC) productivity. This report summarizes the results of an exploratory field measurement program conducted during summer 2005 to assess ATC productivity benefits of the Corridor Integrated Weather System...
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Surveillance accuracy requirements in support of separation services
June 1, 2006
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 16, No. 1, June 2006, pp. 97-122.
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Summary
The Federal Aviation Administration is modernizing the Air Traffic Control system to improve flight efficiency, to increase airspace capacity, to reduce flight delays, and to control operating costs as the demand for air travel continues to grow. Promising new surveillance technologies such as Automatic Dependent Surveillance Broadcast and multisensor track fusion offer the potential to augment the ground-based surveillance and controller-display systems by providing more timely and complete information about aircraft. The resulting improvement in surveillance accuracy may potentially allow the expanded use of the minimum safe-separation distance between aircraft. However, these new technologies cannot be introduced with today's radar-separation standards, because they assume surveillance will be provided only through radar technology. In this article, we review the background of aircraft surveillance and the establishment of radar separation standards. The required surveillance accuracy to safely support aircraft separation with National Airspace System technologies is then derived from currently widely used surveillance systems. We end with flight test validation of the derived results, which can be used to evaluate new technologies.
Summary
The Federal Aviation Administration is modernizing the Air Traffic Control system to improve flight efficiency, to increase airspace capacity, to reduce flight delays, and to control operating costs as the demand for air travel continues to grow. Promising new surveillance technologies such as Automatic Dependent Surveillance Broadcast and multisensor track...
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Corridor Integrated Weather System
June 1, 2006
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 16, No. 1, June 2006, pp. 59-80.
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Summary
Flight delays are now a major problem in the U.S. National Airspace System. A significant fraction of these delays are caused by reductions in en route capacity due to severe convective weather. The Corridor Integrated Weather System (CIWS) is a fully automated weather analysis and forecasting system designed to support the development and execution of convective weather impact mitigation plans for congested en route airspace. The CIWS combines data from dozens of weather radars with satellite data, surface observations, and numerical weather models to dramatically improve the accuracy and timeliness of the storm severity information and to provide state-of-the-art, accurate, automated, high-resolution, animated three-dimensional forecasts of storms (including explicit detection of storm growth and decay). Real-time observations of the Federal Aviation Administration (FAA) decision making process during convective weather at Air Route Traffic Control Centers in the Midwest and Northeast have shown that the CIWS enables the FAA users to achieve more efficient tactical use of the airspace, reduce traffic manager workload, and significantly reduce delays. A real-time data-fusion architecture to assist in national deployment of CIWS is under development, and the CIWS products are being used in integrated air traffic management decision support systems.
Summary
Flight delays are now a major problem in the U.S. National Airspace System. A significant fraction of these delays are caused by reductions in en route capacity due to severe convective weather. The Corridor Integrated Weather System (CIWS) is a fully automated weather analysis and forecasting system designed to support...
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