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Analysis and comparison of separation measurement errors in single sensor and multiple radar mosiac display terminal environments
October 21, 2002
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-306
Summary
This paper presents an analyis to estimate and characterize the errors in the measured separation distance between aircraft that are displayed on a radar screen to a controller in a single sensor terminal environment compared to a multiple radar mosiac terminal environment. The error in measured or displayed separation is the difference between the true separation or distance between aircraft in the air and the separation displayed to a controller on a radar screen. In order to eliminate as many variables as possible and to concentrate specifically on the differences between displayed separation errors in the two environments, for the purposes of this analysis, only full operation Mode S secondary beacon surveillance characteristics are considered. A summary of the Mode S secondary radar error sources and characteristics used to model the resultant errors in measured separation between aircraft in single and multi-radar terminal environments is presented. The analysis for average separation errors show that the performance of radars in providing separation services degrades with range. The analysis also shows that when using independent radars in a mosiac display, separation errors will increase, on average, compared to the performance when providing separation with a single radar. The data presented in the section on average separation errors is summarized by plotting the standard deviation of the separation error as a function of range for the single radar case and for the independent mosiac display case. The sections on typical and specific errors in separation measurements illustrate that the separation measurement errors are highly dependent on the geometry of the aircraft and radars. Applying average results to specific geometries can lead to counter intuitive results is illustrated in an example case presented in analysis.
Summary
This paper presents an analyis to estimate and characterize the errors in the measured separation distance between aircraft that are displayed on a radar screen to a controller in a single sensor terminal environment compared to a multiple radar mosiac terminal environment. The error in measured or displayed separation is...
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Machine intelligent gust front algorithm for the WSP
June 10, 2002
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-274
Summary
The Machine Intelligent Gust Front Algorithm (MIGFA) utilizes multi-dimensional image processing and fuzzy logic techniques to identify gust fronts in Doppler radar data generated by the ASR-9 Weather Systems Processor (WSP). The algorithm generates products that support both safety and planning functions for ATC. Outputs include current and predicted locations of gust fronts, as well as estimates of the wind shear and wind shift associated with each gust front. This document provides both high level and detailed functional descriptions of FAA build 2.0 of the WSP MIGFA. The document was written with many explicit references to data structures and routines in the actual software in order that it may serve as a useful algorithm development and programmers reference guide.
Summary
The Machine Intelligent Gust Front Algorithm (MIGFA) utilizes multi-dimensional image processing and fuzzy logic techniques to identify gust fronts in Doppler radar data generated by the ASR-9 Weather Systems Processor (WSP). The algorithm generates products that support both safety and planning functions for ATC. Outputs include current and predicted locations...
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An improved gust front detection capability for the ASR-9 WSP
May 13, 2002
Conference Paper
Published in:
10th Conf. on Aviation, Range, and Aerospace Meteorology, 13-16 May 2002, pp. 379-382.
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Summary
The Weather Systems Processor (WSP) is being deployed by FAA at 35 medium and high-density ASR-9 equipped airports across the United States. The Machine Intelligent Gust Front Algorithm (MIGFA) developed at Lincoln Laboratory provides important gust front detection and tracking capability for this system as well as other FAA systems including Terminal Doppler Weather Radar (TDWR) and Integrated Terminal Weather System (ITWS). The algorithm utilizes multidimensional image processing, data fusion, and fuzzy logic techniques to recognize gust fronts observed in Doppler radar data. Some deficiencies in algorithm performance have been identified through ongoing analysis of data from two initial limited production WSP sites in Austin, TX (AUS) and Albuquerque, NM (ABQ). At AUS, the most common cause of false alarms is bands of low-reflectivity rain echoes having shapes and intensities similar to gust front thin line echoes. Missed or late detections have occasionally occurred when gust fronts are near or embedded in the leading edge of approaching line storms, where direct radar evidence of the gust front (e.g.. thin line echo, velocity convergence) may be fragmented or absent altogether. In ABQ, "canyon wind" events emanating, from mountains located just east of the airport occur with very little lead time, and often with little or no radar signatures, making timely detection on the basis of the radar data alone difficult. MIGFA is equipped with numerous parameters and thresholds that can be adjusted dynamically based on recognition of the local or regional weather context in which it is operating. Through additional contextual weather information processing, this dynamic sensitization capability has been further exploited to address the deficiencies noted above, resulting in an appreciable improvement in performance on data collected at the two WSP sites.
Summary
The Weather Systems Processor (WSP) is being deployed by FAA at 35 medium and high-density ASR-9 equipped airports across the United States. The Machine Intelligent Gust Front Algorithm (MIGFA) developed at Lincoln Laboratory provides important gust front detection and tracking capability for this system as well as other FAA systems...
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The radar Correlation and Interpolation (C&I) algorithms deployed in the ASR-9 Processor Augmentation Card (9PAC)
June 29, 2001
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-299
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Summary
The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board enhancement for the ASR-9 Array Signal Processor (ASP) that provides increases in processing speed, memory size, and programming. The increased capabilities of the 9PAC hardware made it possible for new surveillance algorithms to be developed in software to provide improved primary radar and beacon surveillance performance. The 9PAC project was developed in two phases. Phase I, which addressed the beacon reflection false target problem, was completed, and is currently being deployed nationwide by the FAA on a plug and play basis. Phase II addresses the primary radar surveillance problems, which include automation of the road and ground clutter censoring process, improving the rejection of false targets, and improving the detection and tracking of aircraft targets. The 9PAC also reduces the life-cycle maintenance cost of the ASR-9 in the Phase II configuration, in which a single 9PAC card replaces four ASP cards. This report describes the improvements to the radar Correlation and Interpolation (C&I) process, which is responsible for creating aircraft target reports and filtering out false targets. [Not Complete]
Summary
The Airport Surveillance Radar 9 (ASR-9) is a terminal radar that was deployed by the Federal Aviation Administration (FAA) during the early 1990's at more than 130 of the busiest airports in the United States. The ASR-9 Processor Augmentation Card (9-PAC), developed at MIT Lincoln Laboratory, is a processor board...
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ASR-9 weather systems processor software overview
October 20, 2000
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-264
Summary
The ASR-9 Weather Systems Processor (WSP) augments the weather detection capability of existing ASR-9 radars to include low-level wind shear warnings, storm cell tracking and prediction, and improved immunity to false weather echoes due to anomalous propagation (AP). To economically develop and field an operational system at the 34 WSP sites, the FAA is pursuing a strategy that leverages the software written during the 10-year R&D phase of the project. To that end, the software developed at Lincoln Laboratory has been "hardened" to ensure reliable, continuous operation, and has been ported to a "Phase II" prototype built around the latest generation of COTS hardware. A significant number of the hardened software modules are being used in the production version of the WSP with only minor modifications. This document provides a high-level description of these software modules, with an emphasis on how the modules fit together in the WSP system. Descriptions of the hardware environment in which the software executes are also provided.
Summary
The ASR-9 Weather Systems Processor (WSP) augments the weather detection capability of existing ASR-9 radars to include low-level wind shear warnings, storm cell tracking and prediction, and improved immunity to false weather echoes due to anomalous propagation (AP). To economically develop and field an operational system at the 34 WSP...
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FAA surveillance radar data as a complement to the WSR-88D network
September 11, 2000
Conference Paper
Published in:
Proc. Ninth Conf. on Aviation, Range, and Aerospace Meteorology and 20th Conf. on Severe Local Storms, 11-15 September 2000, pp. J35-J39.
Summary
The U.S. Federal Aviation Administration (FAA) operates over 400 C- to L-band surveillance radars-Airport Surveillance Radars (ASRs), Air Route Surveillance Radars (ARSRs) and Terminal Doppler Weather Radars (TDWRs). Current generation terminal and en route aircraft surveillance radars (ASR-9, ASR-11 and ARSR-4) feature dedicated digital processing channels that measure and display precipitation reflectivity. Some of these "weather channels" will be upgraded to measure Doppler velocity, supporting, for example, wind shear detection at air terminals. The Terminal Doppler Weather Radar is a high quality dedicated meteorological surveillance radar deployed near many of the larger airports in the U.S. In this paper we consider how these radars could complement the WSR-88D network in providing a variety of meteorological services to the U.S. public. Potential benefits from a combined radar network would accrue from significantly increased radar density and the more rapid temporal updates of the FAA radars. Convective weather monitoring and forecasting, hydrological measurements and services to aviation are examples of areas where significant improvements could be expected. Section 2 reviews the status of the FAA radars their parameters, locations and capabilities. We also note the progress of various upgrade programs that will increase their weather surveillance capabilities substantially. In Section 3, we discuss benefits that would result from their usage in conjunction with the WSR-88D network. Finally, we discuss technological developments that will facilitate realization of these benefits.
Summary
The U.S. Federal Aviation Administration (FAA) operates over 400 C- to L-band surveillance radars-Airport Surveillance Radars (ASRs), Air Route Surveillance Radars (ARSRs) and Terminal Doppler Weather Radars (TDWRs). Current generation terminal and en route aircraft surveillance radars (ASR-9, ASR-11 and ARSR-4) feature dedicated digital processing channels that measure and display...
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Operational experience with weather products generated through joint use of FAA and NWS weather radar sensors
September 11, 2000
Conference Paper
Published in:
Ninth Conf. on Aviation, Range, and Aerospace Meteorology and 20th Conf. on Severe Local Storms, 11-15 September 2000, pp. J19-J23.
Summary
In this paper, we describe current joint use of Federal Aviation Administration (FAA) and National Weather Service (NWS) radar sensors to provide operational weather decision support for the FAA, airline operations centers, and NWS forecast offices. The capabilities that have been demonstrated include fully automatic data editing and short term "nowcast" product generation algorithms as well as display of data from the different radars in different windows; direct product distribution to operational decision makers without any intervening meteorologist input; and collaborative decision making between the various parties. The significant use of fully automated product generation algorithms has facilitated flexible, coordinated decision making in real time at many locations simultaneously, without the high personnel costs that would be required to achieve the same weather product generation capability manually through interpretation by experienced radar meteorologist/forecasters. These joint-use capabilities have been demonstrated operationally at the Integrated Terminal Weather System (ITWS) demonstration sites in Memphis, TN, Orlando, FL, Dallas, TX, and Garden City, NY. These sites have provided operational service for the four major terminal areas since 1994.1 Specific capabilities used operationally by FAA- and airline users, which are discussed in the next section, include: 1. Addressing radar data quality issues such as rain attenuation and AP-induced ground clutter contamination, 2. High update rates for detection of rapidly changing weather while also obtaining 3D information on storms, 3. Estimating 3D winds, and 4. Reducing the fraction of phenomena that are not accurately characterized because the radars can directly measure radial velocity only. Section 3 discusses the operational usage of integrated products by NWS forecast offices at the ITVVS demonstration sites. The paper concludes with a summary of the operational uses to date and makes some suggestions for NWS and USAF use of FAA radar sensors in conjunction with NEXt generation weather RADars (NEXRAD).
Summary
In this paper, we describe current joint use of Federal Aviation Administration (FAA) and National Weather Service (NWS) radar sensors to provide operational weather decision support for the FAA, airline operations centers, and NWS forecast offices. The capabilities that have been demonstrated include fully automatic data editing and short term...
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The development of phased-array radar technology
January 1, 2000
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 12, No. 2, 2000, pp. 321-340.
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Summary
Lincoln Laboratory has been involved in the development of phased-array radar technology since the late 1950s. Radar research activities have included theoretical analysis, application studies, hardware design, device fabrication, and system testing. Early phased-array research was centered on improving the national capability in phased-array radars. The Laboratory has developed several test-bed phased arrays, which have been used to demonstrate and evaluate components, beamforming techniques, calibration, and testing methodologies. The Laboratory has also contributed significantly in the area of phased-array antenna radiating elements, phase-shifter technology, solid-state transmit-and-receive modules, and monolithic microwave integrated circuit (MMIC) technology. A number of developmental phased-array radar systems have resulted from this research, as discussed in other articles in this issue. A wide variety of processing techniques and system components have also been developed. This article provides an overview of more than forty years of this phased-array radar research activity.
Summary
Lincoln Laboratory has been involved in the development of phased-array radar technology since the late 1950s. Radar research activities have included theoretical analysis, application studies, hardware design, device fabrication, and system testing. Early phased-array research was centered on improving the national capability in phased-array radars. The Laboratory has developed several...
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An evaluation of the ASR-9 weather channel based on observations from the ITWS prototypes
September 23, 1999
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-270
Summary
The Federal Aviation Administration's (FAA) Airport Surveillance Radar (ASR-9) is a high-scan-rate system which provides a "critical" function in terms of air traffic control (ATC). In addition to its primary role of air traffic surveillance, the system also generates precipitation data for display on air traffic specialists' radar scopes and for use by automated systems such as the Integrated Terminal Weather System (ITWS) and Weather Systems Processor (WSP). Air traffic managers use these data to provide optimum routes for aircraft operating in and near the Terminal Radar Approach Control (TRACON) airspace. The primary advantage of the ASR-9 - as an aviation weather radar - over either the Terminal Doppler Weather Radar (TDWR) or the Next Generation Weather Radar (NEXRAD) is the rapid update rate, i.e., 30 seconds, which provides air traffic managers with a more accurate representation of weather echo location within the sensor's domain. This is far superior toeither the TDWR or NEXRAD, which takes from 2.5 to 6 minutes to create a volume scan, depending on the scan strategy. The sensor is also quite reliable, with limited down time. An analysis of ASR-9 data from the ITWS prototypes has uncovered a number of problems, which impact the quality of the precipitation data. The data quality issues discussed are overly aggressive ground clutter suppression, polarization mode issues, hardware failures associated with high beandlow beam switching, attenuatiodsignal depolarization, beam-filling losses, bright- band contamination, distant weather contamination, calibration issues, and radadantenna failures. The recommendations to address the ASR-9 data quality issues can be grouped into three categories: "Variable Site Parameter (VSP)" adjustments, hardware component maintenance checks, and automated flagging of data quality problems. The report includes discussion of the frequency and characteristics of each degradation, presenting both hardware and non- hardware related problems, and concludes with proposed solutions to the problems and recommendations designed to improve the overall utility of the ASR-9 precipitation data.
Summary
The Federal Aviation Administration's (FAA) Airport Surveillance Radar (ASR-9) is a high-scan-rate system which provides a "critical" function in terms of air traffic control (ATC). In addition to its primary role of air traffic surveillance, the system also generates precipitation data for display on air traffic specialists' radar scopes and...
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Study of Network Expansion LLWAS (LLWAS-NE) fault identification and system warning optimization through joint use of LLWAS-NE and TDWR data
January 10, 1999
Conference Paper
Published in:
8th Conf. on Aviation, Range, and Aerospace Meteorology (ARAM), 10-15 January 1999.
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Summary
Low level wind shear has been identified as an aviation hazard which has caused or contributed to a significant number of aircraft accidents (Soffer, 1990). To protect aircraft from hazardous wind shear, the Federal Aviation Administration (FAA) developed a system called the Low Level Wind Shear Alert System (LLWAS), containing a collection of anemometers as well as data processing logic (Wilson and Gramzow, 1991). The LLWAS has undergone several advancements in both design and algorithmic computation. The latest deployment, known as the Network Expansion Low Level Wind Shear Alert System (LLWAS-NE), consists of additional sensors to the original LLWAS network, providing better coverage of the airfield. In addition, the LLWAS-NE is capable of providing runway-oriented wind shear and microburst alerts with loss and gain values. The alerts from LLWAS-NE will be integrated with those from the Terminal Doppler Weather Radar (TDWR) and the Integrated Terminal Weather System (ITWS) at locations where all systems are available (Cole, 1992; Cole and Todd, 1994). An analysis was undertaken at Orlando (MCO) and Dallas/Ft. Worth (DFW) International Airports to assess the accuracy of wind shear alerts produced by LLWAS-NE and the TDWR/LLWASNE integration algorithm. Identifying improvements that can be made to either system is important, as LLWAS-NE alert information is anticipated to be integrated with ITWS in an ITWS/LLWAS-NE integration algorithm. As currently specified, the ITWS/LLWAS-NE integration algorithm will work the same as the TDWR/LLWAS-NE version. The ITWS/LLWAS-NE algorithm is an area where additional work is necessary to ascertain if the integration parameters should be modified to account for performance differences between the ITWS and TDWR algorithms. We suggest that ongoing assessment of the LLWAS-NE should use both LLWAS-NE data and TDWR base data, when possible. Comparing both data sets also will facilitate optimization of LLWAS-NE parameters used in the computation of the alerts.
Summary
Low level wind shear has been identified as an aviation hazard which has caused or contributed to a significant number of aircraft accidents (Soffer, 1990). To protect aircraft from hazardous wind shear, the Federal Aviation Administration (FAA) developed a system called the Low Level Wind Shear Alert System (LLWAS), containing...
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