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An assessment of the communications, navigation, surveillance (CNS) capabilities needed to support the future Air Traffic Management System
January 10, 2001
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-295
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Summary
The purpose of this study was to assess the Communications, Navigation, and Surveillance (CNS) capabilities needed to support future Air Traffic Management (ATM) functionality in the National Airspace System (NAS). The goal was to determine the most effective areas for research and technical development in the CNS field and to make sure the decision support tools under development match future CNS capabilities. The requirements for future ATM functions were derived from high level operational concepts designed to provide more freedom and flexibility in flight operations and from the Joint Research Project Descriptions (JRPDs) that are listed in the Integrated Plan for Air Traffic Management Research and Technology Development. This work was performed for the FAA/NASA Interagency Air Traffic Management Integrated Product Team.
Summary
The purpose of this study was to assess the Communications, Navigation, and Surveillance (CNS) capabilities needed to support future Air Traffic Management (ATM) functionality in the National Airspace System (NAS). The goal was to determine the most effective areas for research and technical development in the CNS field and to...
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An operational concept for the Smart Landing Facility (SLF)
January 1, 2001
Conference Paper
Published in:
20th AIAA/IEEE Digital Avionics Systems Conf., 14-18 October 2001, pp. 6.C.2-1 - 6.C.2-8.
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This paper describes an operational concept for the Smart Landing Facility (SLF). The SLF is proposed as a component of the Small Aircraft Transportation System (SATS) and is envisioned to utilize Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies to support higher-volume air traffic operations in a wider variety of weather conditions than are currently possible at airports without an Air Traffic Control Tower (ATCT) or Terminal Radar Approach Control (TRACON). In order to accomplish this, the SLF will provide aircraft sequencing and separation within its terminal airspace (the SLF traffic area) and on the airport surface. The SLF infrastructure will provide timely and accurate weather and other flight information as well as traffic advisories. The SLF will provide a means to coordinate with nearby TRACONs or Air Route Traffic Control Centers (ARTCCs) to ensure proper integration of its traffic flows with those of adjacent airspace.
Summary
This paper describes an operational concept for the Smart Landing Facility (SLF). The SLF is proposed as a component of the Small Aircraft Transportation System (SATS) and is envisioned to utilize Communication, Navigation, Surveillance and Air Traffic Management (CNS/ATM) technologies to support higher-volume air traffic operations in a wider variety...
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Comparison of active TCAS slant range measurements with interpolated passive position reports for use in hybrid surveillance applications - measurements from the June 1999 Los Angeles Basin flight tests
October 17, 2000
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-294
Summary
Traffic Alert and Collision Avoidance System (TCAS) hybrid surveillance is a technique that makes use of both active surveillance data from the interrogation reply sequence and passive position estimates received from Mode S extended squitters. This technique allows TCAS to use passive surveillance once the data have been validated by comparison with active data. The maximum allowable range difference for validation specified by the International Civil Aviation Organization (ICAO) is 200 meters. Data from twenty encounters recorded during flight tests conducted in the Los Angeles Basin in June 1999 were analyzed. The results show that the ICAO specified limits were never exceeded and serve to validate the 200 meter limit.
Summary
Traffic Alert and Collision Avoidance System (TCAS) hybrid surveillance is a technique that makes use of both active surveillance data from the interrogation reply sequence and passive position estimates received from Mode S extended squitters. This technique allows TCAS to use passive surveillance once the data have been validated by...
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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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The Beacon Target Detector (BTD) algorithms deployed in the ASR-9 Processor Augmentation Card (9-PAC)
September 5, 2000
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-288
Summary
This project report describes the Beacon Target Detector (BTD) algorithms implemented in the ASR-9 Processor Augmentation Card (9-PAC). The BTD function combines replies that arise from the same aircraft to form beacon targets, and sends these beacon targets to the 9-PAC merge process where they are combined with primary radar targets. The 9-PAC BTD algorithm was designed to solve two problems with the ASR-9 Array Signal Processor (ASP) BTD: identifying and removing false beacon targets due to reflections, and preventing merging or splitting of targets due to reply overlap and garble. The BTD reflection processing algorithm marks each beacon target as either real or false, and provides this information to the 9-PAC merge process. Discrete Mode 3/A reflection false targets are identified when duplicate code reports satisfying stringent conditions are located. In order to find non-discrete Mode 3/A code reflection false targets, the BTD builds an automated, dynamic reflector database based on the geography of real and false targets with discrete Mode 3/A codes. This report supersedes an earlier report (ATC-220) which described the 9-PAC BTD algorithms prior to the operational field testing effort conducted by the FAA in 1995 and 1996. Nationwide deployment of 9-PAC on production hardware was approved in April 1999. To date, more than 60 installations have been performed, and hardware has been procured to update all 134 ASR-9s in the National Airspace System.
Summary
This project report describes the Beacon Target Detector (BTD) algorithms implemented in the ASR-9 Processor Augmentation Card (9-PAC). The BTD function combines replies that arise from the same aircraft to form beacon targets, and sends these beacon targets to the 9-PAC merge process where they are combined with primary radar...
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Wind shear detection using the Next Generation Airport Surveillance Radar
July 12, 1999
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-266
Summary
The Federal Aviation Administration (FAA) is deploying a Weather Systems Processor (WSP) for the current-generation Airport Surveillance Radar - ASR-9. This modification exploits the coherency of the ASR-9 to perform Doppler wind measurement. Signature recognition algorithms then automatically detect low altitude wind shear phenomena, track thunderstorm motion and display appropriate graphical and alphanumeric alerts to air traffic control (ATC) personnel. The FAA and U.S. Air Force are now procuring an ASR-11 to replace older terminal surveillance radars at facilities that did not receive the ASR-9. Although the antenna pattern, scan rate and energy-on-target of the ASR-11 match the corresponding parameters of the ASR-9, two other characteristics are markedly different. It utilizes a low peak power solid state transmitter that requires transmission of long, coded waveforms and a pulse compression receiver. Secondly, its pulse transmission sequence consists of short (five-pulse) bursts at both different pulse-repetition frequencies (PRF) and different RF frequencies. In this report, we assess the technical and operational issues associated with adding a WSP to the ASR-11. The existing WSP data processing and display technology are largely re-usable for the ASR-11 based WSP. Ground clutter filter coefficients and the length and number of coherent processing intervals would need to be changed to conform to the ASR-11 pulse transmission strategy, and straightforward adaptations to the equations used in the pulse-pair weather reflectivity and Doppler velocity estimation would be required. With these changes, the ASR-11 could host the WSP, subject to performance degradations for low reflectivity wind shear phenomena such as dry microbursts and gust fronts. A benefits assessment waas performed to evaluate the operational requirements for an ASR-11 based WSP. Given that the FAA has already committed to deploy improved Low Level Wind Shear Alert Systems (LLWAS) at most ASR-11 airports, the incremental safety benefits for the ASR-11 WSP appear to be less than the cost of the equipment. A case can be made for deployment based on "situational awareness" benefits that the WSP has been demonstrated to provide to air traffic controllers. We estimate that the value to the public and airline industry of reductions in aircraft delay, and avoidance of unnecessary diversions, would be in excess of eight million dollars per year tallied across 18 of the larger ASR-11 equipped airports.
Summary
The Federal Aviation Administration (FAA) is deploying a Weather Systems Processor (WSP) for the current-generation Airport Surveillance Radar - ASR-9. This modification exploits the coherency of the ASR-9 to perform Doppler wind measurement. Signature recognition algorithms then automatically detect low altitude wind shear phenomena, track thunderstorm motion and display appropriate...
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TCAS II use of ADS-B surveillance data through hybrid surveillance
January 1, 1999
Journal Article
Published in:
Air Traffic Control Q., Vol. 7, No. 2, 1999, pp. 109-121.
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This paper describes a technique that enables TCAS II to use passive surveillance data obtained via extended squitter, an implementation of automatic dependent surveillance broadcast (ADS-B). The technique, known as hybrid surveillance, is based upon the use of TCAS active surveillance to perform validation of the reported ADS-B position at track acquisition. Aircraft that pass initial validation are maintained on passive surveillance until they become a near threat. At that time, TCAS begins regular active surveillance and thus uses its current surveillance techniques for traffic and resolution advisories. In this way, TCAS is able to use passive extended squitter data while retaining its role as an independent monitor. Simulation results show that the use of passive information for non-threatening aircraft results in a significant decrease in TCAS interrogation rate. This enables TCAS to delay or avoid the range reduction that is now required in order for TCAS to remain within its interference budget in high traffic density airspace. Maintaining TCAS operating range in high density air-space enhances TCAS ability to support situational awareness for the flight crew.
Summary
This paper describes a technique that enables TCAS II to use passive surveillance data obtained via extended squitter, an implementation of automatic dependent surveillance broadcast (ADS-B). The technique, known as hybrid surveillance, is based upon the use of TCAS active surveillance to perform validation of the reported ADS-B position at...
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Techniques for improved reception of 1090 MHz ADS-B signals
October 31, 1998
Conference Paper
Published in:
17th DASC: Proc. of the 17th. Digital Avionics Systems Conf., 31 October - 7 November 1998, Vol. 2, pp. G25-1 - G25-9.
Summary
The recent development of ADS-B (Automatic Dependent Surveillance-Broadcast) is based on the use of the Mode S transponders now carried by all air carrier and commuter aircraft. ADS-B aircraft broadcast aircraft positions, identity, and other information via semi-random Mode S transponder squitters. Other aircraft or ground facilities receive the squitters and the associated position and status. Squitter reception includes the detection of the Mode S 1090 MHz waveform preamble, declaration of the bit and confidence values, error detection, and (if necessary) error correction. The current techniques for squitter reception are based upon methods developed for use in Mode S narrow-beam interrogators and for ACAS. In both of these applications, the rate of Mode NC fruit that is stronger than the Mode S waveform is relatively low, nominally less than 4,000 fruit per second. Extended squitter applications now include long range (up to 100 nmi) air-air surveillance in support of free flight. This type of surveillance is sometimes referred to as Cockpit Display of Traffic Information (CDTI). In high density environments, it is possible to operate with fruit rates of 40,000 fruit per second and higher. Operation of extended squitter in very high ModeNC fruit environments has led to the need to re-evaluate squitter reception techniques to determine if improved performance is achievable. The purpose of this paper is to provide a summary of work in progress to investigate improved squitter reception techniques. Elements of improved squitter reception being investigated include (1) the use of amplitude to improve bit and confidence declaration accuracy, (2) more capable error correction algorithms, and (3) more selective preamble detection approaches.
Summary
The recent development of ADS-B (Automatic Dependent Surveillance-Broadcast) is based on the use of the Mode S transponders now carried by all air carrier and commuter aircraft. ADS-B aircraft broadcast aircraft positions, identity, and other information via semi-random Mode S transponder squitters. Other aircraft or ground facilities receive the squitters...
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Multilateration on Mode S and ATCRBS signals at Atlanta's Hartsfield Airport
January 8, 1998
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-260
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The ATC community is seeking a way to obtain aircraft ID and improved surveillance on the airport movement area. Surface radars provide good surveillance data, but do not provide ID, may not cover the whole movement area, and suffer from false reflection targets and performance degradations in rain. This report describes an evolutionary technique employing multilateration, TCAS technology, and existing ATCBI transponders to provide the desired surface surveillance information. Five multilateration receiver/transmitters (RTs) based on TCAS units, and a central multilateration computer processor were procured and installed on the highest available buildings on the perimeter of the north side of Atlanta's Hartsfield airport. The resulting coverage was such that there was a 93% probability that a multilateration position would be computed on a given Mode S short squitter emitted from a a target at a randomly selected position on the movement area. Multilateration was performed on ATCRBS targets using replies elicited by whisper shout methods originally developed for TCAS. Measurements showed that whisper shout was successful in degarbling targets that were in close proximity on the movement area. The probability of obtaining an ATCRBS multilateration position in a given one second interval depended on the number of whisper shout interrogations transmitted. The equipment required over 10 interrogations per target per second to obtain per second multilateration update rates on two typical targets of 58% and 83% respectively. This less than anticipated performance was primarily due to the inefficient whisper shout interrogation technique that was used in the test equipment. This can be corrected in next generation equipment. The multilateration accuracy was about 20 feet one sigma, as anticipated from theoretical considerations and previous experience with other equipment. By combining the multilateration data with ASDE data and tracking the results, it would be possible to obtain track reliabilities on the airport surface similar to that obtained elsewhere in the ATC system but update rates of 1Hz as required for surface surveillance and control purposes. The RTs were also capable of receiving Mode S long squitters containing GPS position information. The probability of at least one of the 5RTs receiving a given long squitter was essentially 100% on the movement area.
Summary
The ATC community is seeking a way to obtain aircraft ID and improved surveillance on the airport movement area. Surface radars provide good surveillance data, but do not provide ID, may not cover the whole movement area, and suffer from false reflection targets and performance degradations in rain. This report...
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A description of the interfaces between the Weather Systems Processor (WSP) and the Airport Surveillance Radar (ASR-9)
June 16, 1997
Project Report
Published in:
MIT Lincoln Laboratory Report ATC-259
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Summary
The Weather Systems Processor (WSP) is an enhancement for the Federal Aviation Administration's (FAA) current generation Airport Surveillance Radars (ASR-9) that provides fully automated detection of microburst and gust front wind shear phenomena, estimates of storm cell movement and extrapolated future postion, and 10- and 20-minute predictions of the future postion of gust fronts. The WSP also generates six-level weather reflectivity free of anomalous propagation induced ground clutter breakthrough. Alphanumeric and graphical displays provide WSP-generated weather information to air traffic controllers and their supervisors. This report describes the hardware, interfaces, timing and digital signal extraction from the ASR-9 necessary to support the WSP. The digital interface circuitry between the WSP and the ASR-9, the control functions associated with the WSP, and the strategies for performing system test functions are described
Summary
The Weather Systems Processor (WSP) is an enhancement for the Federal Aviation Administration's (FAA) current generation Airport Surveillance Radars (ASR-9) that provides fully automated detection of microburst and gust front wind shear phenomena, estimates of storm cell movement and extrapolated future postion, and 10- and 20-minute predictions of the future...
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