Publications
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Frequency of ADS-B equipped manned aircraft observed by the OpenSky Network
November 12, 2020
Conference Paper
Published in:
8th OpenSky Symp. 2020, Online, 12–13 November 2020.
Summary
To support integration of unmanned aerial systems into the airspace, the low altitude airspace needs to be characterized. Identifying the frequency of different aircraft types, such as rotorcraft or fixed wing single engine, given criteria such as altitude, airspace class, or quantity of seats can inform surveillance requirements, flight test campaigns, or simulation safety thresholds for detect and avoid systems. We leveraged observations of Automatic Dependent Surveillance-Broadcast (ADS-B) equipped aircraft by the OpenSky Network for this characterization.
Summary
To support integration of unmanned aerial systems into the airspace, the low altitude airspace needs to be characterized. Identifying the frequency of different aircraft types, such as rotorcraft or fixed wing single engine, given criteria such as altitude, airspace class, or quantity of seats can inform surveillance requirements, flight test...
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Processing of crowdsourced observations of aircraft in a high performance computing environment
September 22, 2020
Conference Paper
Published in:
2020 IEEE High Performance Extreme Computing Conf., HPEC, 22-24 September 2020.
Summary
As unmanned aircraft systems (UASs) continue to integrate into the U.S. National Airspace System (NAS), there is a need to quantify the risk of airborne collisions between unmanned and manned aircraft to support regulation and standards development. Both regulators and standards developing organizations have made extensive use of Monte Carlo collision risk analysis simulations using probabilistic models of aircraft flight. We've previously determined that the observations of manned aircraft by the OpenSky Network, a community network of ground-based sensors, are appropriate to develop models of the low altitude environment. This works overviews the high performance computing workflow designed and deployed on the Lincoln Laboratory Supercomputing Center to process 3.9 billion observations of aircraft. We then trained the aircraft models using more than 250,000 flight hours at 5,000 feet above ground level or below. A key feature of the workflow is that all the aircraft observations and supporting datasets are available as open source technologies or been released to the public domain.
Summary
As unmanned aircraft systems (UASs) continue to integrate into the U.S. National Airspace System (NAS), there is a need to quantify the risk of airborne collisions between unmanned and manned aircraft to support regulation and standards development. Both regulators and standards developing organizations have made extensive use of Monte Carlo...
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Detect-and-avoid closed-loop evaluation of noncooperative well clear definitions
July 12, 2020
Journal Article
Published in:
J. Air Transp., Vol. 28, No. 4, 12 July 2020, pp. 195-206.
Topic:
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Summary
Four candidate detect-and-avoid well clear definitions for unmanned aircraft systems encountering noncooperative aircraft are evaluated using safety and operational suitability metrics. These candidates were proposed in previous research based on unmitigated collision risk, maneuver initiation ranges, and other considerations. Noncooperative aircraft refer to aircraft without a functioning transponder. One million encounters representative of the assumed operational environment for the detect-and-avoid system are simulated using a benchmark alerting and guidance algorithm as well as a pilot response model. Results demonstrate sensitivity of the safety metrics to the unmanned aircraft’s speed and the detect-and-avoid system's surveillance volume. The only candidate without a horizontal time threshold, named modified tau, outperforms the other three candidates in avoiding losses of detect and avoid well clear. Furthermore, this candidate's alerting timeline lowers the required surveillance range. This can help reduce the barrier of enabling unmanned aircraft systems' operations with low size, weight, and power sensors.
Summary
Four candidate detect-and-avoid well clear definitions for unmanned aircraft systems encountering noncooperative aircraft are evaluated using safety and operational suitability metrics. These candidates were proposed in previous research based on unmitigated collision risk, maneuver initiation ranges, and other considerations. Noncooperative aircraft refer to aircraft without a functioning transponder. One million...
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Aircraft laser strike geolocation system
June 5, 2017
Conference Paper
Published in:
17th AIAA Aviation Technology, Integration, and Operations Conf., 5-9 June 2017.
Topic:
R&D area:
Summary
Laser strikes against aircraft are increasing at an alarming rate, driven by the availability of cheap powerful lasers and a lack of deterrence due to the challenges of locating and apprehending perpetrators. Although window coatings and pilot goggles effectively block laser light, uptake has been low due to high cost and pilot reluctance. This paper describes the development and testing of a proof-of-concept ground based sensor system to rapidly geolocate the origin of a laser beam in a protected region of airspace and disseminate this information to law enforcement to allow a timely and targeted response. Geolocation estimates with accuracies of better than 20 m have been demonstrated within 30 seconds of an event at a range of 8.9 nmi with a 450 mW laser. Recommendations for an operational prototype at an airport are also described.
Summary
Laser strikes against aircraft are increasing at an alarming rate, driven by the availability of cheap powerful lasers and a lack of deterrence due to the challenges of locating and apprehending perpetrators. Although window coatings and pilot goggles effectively block laser light, uptake has been low due to high cost...
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Revised multifunction phased array radar (MPAR) network siting analysis
May 26, 2015
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-425
Summary
As part of the NextGen Surveillance and Weather Radar Capability (NSWRC) program, the Federal Aviation Administration (FAA) is currently developing the solution for aircraft and meteorological surveillance in the future National Airspace System (NAS). A potential solution is a multifunction phased array radar (MPAR) that would replace some or all of the single-purpose radar types used in the NAS today. One attractive aspect of MPAR is that the number of radars deployed would decrease, because redundancy in coverage by single-mission sensors would be reduced with a multifunction system. The lower radar count might then result in overall life cycle cost savings, but in order to estimate costs, a reliable estimate of the number of MPARs is needed. Thus this report addresses the question, "If today's weather and aircraft surveillance radars are replaced by a single class of multimission radars, how many would be needed to replicate the current air space coverage over the United States and its territories?" Various replacement scenarios must be considered, since it is not yet determined which of the organizations that own today's radars (the FAA, the National Weather Service (NWS), the different branches of the U.S. military) would join in an MPAR program. It updates a previous study using a revised set of legacy systems, including 81 additional military airbase radars. Six replacement scenarios were considered, depending on the radar mission categories. Scenario 1 would replace terminal radars only, i.e., the Airport Surveillance Radars (ASRs) and the Terminal Doppler Weather Radar (TDWR). Scenario 2 would include the Scenario 1 radars plus the long-range weather radar, commonly known as NEXRAD. Scenario 3 would add the long-range aircraft surveillance radars, i.e., the Air Route Surveillance Radars (ARSRs), to the Scenario 2 radars. To each of these three scenarios, we then add the military's Ground Position Navigation (GPN) airbase radars for Scenarios 1G, 2G, and 3G. We assumed that the new multimission radar would be available in two sizes--a full-size MPAR and a scaled-down terminal MPAR (TMPAR). Furthermore, we assumed that the new radar antennas would have four sides that could be populated by one, two, three, or four phased array faces, such that the azimuthal coverage provided could be scaled from 90 degrees to 360 degrees. Radars in the 50 United States, Guam, Puerto Rico, U.S. Virgin Islands, Guantanamo Bay (Cuba), and Kwajalein (Marshall Islands) were included in the study.
Summary
As part of the NextGen Surveillance and Weather Radar Capability (NSWRC) program, the Federal Aviation Administration (FAA) is currently developing the solution for aircraft and meteorological surveillance in the future National Airspace System (NAS). A potential solution is a multifunction phased array radar (MPAR) that would replace some or all...
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A statistical learning approach to the modeling of aircraft taxi time
October 3, 2010
Conference Paper
Published in:
29th Digital Avionics Systems Conf., 3 October 2010.
Summary
Modeling aircraft taxi operations is an important element in understanding current airport performance and where opportunities may lie for improvements. A statistical learning approach to modeling aircraft taxi time is presented in this paper. This approach allows efficient identification of relatively simple and easily interpretable models of aircraft taxi time, which are shown to yield remarkably accurate predictions when tested on actual data.
Summary
Modeling aircraft taxi operations is an important element in understanding current airport performance and where opportunities may lie for improvements. A statistical learning approach to modeling aircraft taxi time is presented in this paper. This approach allows efficient identification of relatively simple and easily interpretable models of aircraft taxi time...
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Comment on "Reinterpreting aircraft measurement in anisotropic scaling turbulence" by Lovejoy et al. (2009)
January 1, 2010
Journal Article
Published in:
Atmos. Chem. Phys., Vol. 10, No. 3, 2010, pp. 1401-1402.
Summary
Recently, Lovejoy et al. (2009) argued that the steep ~k-3 atmospheric kinetic energy spectrum at synoptic scales (>~1000km) observed by aircraft is a spurious artefact of aircraft following isobars instead of isoheights. Without taking into account the earth's rotation they hypothesize that the horizontal atmospheric energy spectrum should scale as k?5/3 at all scales. We point out that the approximate k?3- spectrum at synoptic scales has been observed by a number of non-aircraft means since the 1960s and that general circulation models and other current models have successfully produced this spectrum. We also argue that the vertical movements of the aircraft are far too small to cause any strong effect on the measured spectrum at synoptic scales.
Summary
Recently, Lovejoy et al. (2009) argued that the steep ~k-3 atmospheric kinetic energy spectrum at synoptic scales (>~1000km) observed by aircraft is a spurious artefact of aircraft following isobars instead of isoheights. Without taking into account the earth's rotation they hypothesize that the horizontal atmospheric energy spectrum should scale as...
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Encounter models for unconventional aircraft version 1.0
April 10, 2009
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-348
Topic:
R&D area:
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Summary
Airspace encounter models, covering close encounter situations that may occur after standard separation assurance has been lost, are a critical component in the safety assessment of aviation procedures and collision avoidance systems. Of particular relevance to Unmanned Aircraft Systems (UAS) is the potential for encountering general aviation aircraft that are flying under Visual Flight Rules (VFR) and are not in contact with air traffic control. In response to the need to develop a model of these types of encounters, Lincoln Laboratory undertook an extensive data collection and modeling effort involving more than 96,000 unconventional aircraft tracks. The outcome of this effort was nine individual models encompassing ultralights, gliders, balloons, and airships. The models use Bayesian networks to represent relationships between dynamic variables and to construct random trajectories that are statistically similar to those observed in the data. The intruder trajectories can be used in fast-time Monte Carlo simulations to estimate collision risk. The model described in this report is one of three developed by Lincoln Laboratory. A correlated encounter model has been developed to represent situations in which it is likely that there would b e air traffic control intervention prior to a close enounter. The correlated model applies to encounters involving aircraft receiving Air Traffic Control (ATC) services and with transponders. TAn encounter with an intruder that does not have a transponder is uncorrelated in the sense that it is unlikely that there would be prior intervention by air traffic control. The uncorrelated model described in this report is based on global databases of pilot-submitted track data. This work is a follow-on to an uncorrelated conventional model developed from recorded radar tracks from aircraft using a 1200 transponder code. A byproduct of this encounter modeling effort was the extraction of feature distributions for unconventional aircraft. This provides an extensive collection of unconventional aircraft behavior in the airspace.
Summary
Airspace encounter models, covering close encounter situations that may occur after standard separation assurance has been lost, are a critical component in the safety assessment of aviation procedures and collision avoidance systems. Of particular relevance to Unmanned Aircraft Systems (UAS) is the potential for encountering general aviation aircraft that are...
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Enhanced regional situational awareness
June 1, 2007
Journal Article
Published in:
Lincoln Laboratory Journal, Vol. 16, No. 2, June 2007, pp. 355-380.
Summary
Airspace protection in the capital area is provided by an Integrated Air Defense System (IADS) created through the coordinated response of U.S. government and local law-enforcement agencies, including the Department of Defense, the Department of Homeland Security, the Federal Aviation Administration, and the Capitol Police. The IADS includes U.S. Coast Guard helicopters, fighter aircraft, and airborne early-warning aircraft cued by surveillance radars. Under Operation Noble Eagle, the response to a threat includes warning flares deployed from fighter aircraft and, ultimately, the use of surface and air-launched missiles. Selecting the appropriate response requires a means for rapidly assessing the aircraft threat. New and existing sensors must be simultaneously cued to the target of interest and integrated with existing sources of information to display a common-air-picture display to support the decision makers. This article describes the development of an Enhanced Regional Situation Awareness system, an integrated sensing and decision support system developed for the complex and busy airspace surrounding the National Capital Region.
Summary
Airspace protection in the capital area is provided by an Integrated Air Defense System (IADS) created through the coordinated response of U.S. government and local law-enforcement agencies, including the Department of Defense, the Department of Homeland Security, the Federal Aviation Administration, and the Capitol Police. The IADS includes U.S. Coast...
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Commercial aviation encounters with severe low altitude turbulence
October 4, 2004
Conference Paper
Published in:
11th Conf. on Aviation, Range and Aerospace Meteorology, 4-8 October 2004.
Summary
Turbulence encounters continue to be one of the largest sources of personal injury in both commercial and general aviation. A significant percentage of these encounters occur without warning, at low altitudes, and have been observed to occur outside of the strong reflectivity storm cores where pilots typically anticipate severe wind shear and/or turbulence. In this paper, statistics illustrating the altitude distributions of specific turbulence encounters are presented. These results suggest that a significant percentage of the moderate and greater turbulence encounters occur at low altitudes. One particularly dangerous form of low altitude turbulence, often associated with convective storms, is the buoyancy wave (BW). Observational evidence of commercial airline encounters with these phenomena indicates that they can cause an impairment of aircraft control that results in significant attitude and altitude fluctuations. Over the past two years several serious aircraft incidents involving low altitude turbulence have been reported. In our investigation of the meteorological conditions surrounding these incidents, there are strong indications that buoyancy waves played a major role in initiating the turbulence. While encounters with this type of buoyancy wave-induced turbulence can be as severe as microburst wind shear encounters, they are typically not detected by current wind shear detection systems. However, these phenomena do have detectable signatures. We suggest two modifications to existing wind shear detection systems that would make it possible to detect these potentially dangerous phenomena.
Summary
Turbulence encounters continue to be one of the largest sources of personal injury in both commercial and general aviation. A significant percentage of these encounters occur without warning, at low altitudes, and have been observed to occur outside of the strong reflectivity storm cores where pilots typically anticipate severe wind...
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