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Modifications to ACAS safety study methods for remotely piloted vehicles (RPV)

Author:
Published in:
Int. Civil Aviation Organization Surveillance and Conflict Resolution Systems Panel Working Group, 3-7 May 2004.
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Summary

Estimating the relative safety of a Remotely Piloted Vehicle (RPV) equipped with ACAS will require several extensions to the methods developed in previous ACAS studies. This paper outlines several of these redesign issues. First, it may be necessary to compute the probability that an RPV will experience a critical encounter relative to that for a conventional aircraft. Performing a safety study on only the incremental impact of equipping an RPV with ACAS would circumvent this need. Additionally, methods are proposed to adapt existing encounter models to better represent the likely characteristics of encounters with RPVs. Finally, modifications to the level of detail included in dynamic simulations and fault trees are discussed. It is proposed to shift all dynamic elements out of the fault tree and into a new more complex Monte Carlo simulation.
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Summary

Estimating the relative safety of a Remotely Piloted Vehicle (RPV) equipped with ACAS will require several extensions to the methods developed in previous ACAS studies. This paper outlines several of these redesign issues. First, it may be necessary to compute the probability that an RPV will experience a critical encounter...

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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

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.
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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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Multilateration system development history and performance at Dallas/Ft. Worth Airport

Published in:
19th AIAA/IEEE Digital Avionics Systems Conf., Vol. 1, 7-13 October 2000, pp. 2.E.1-1 - 2.E.1-8.

Summary

The long search for a method to provide accurate secondary radar beacon surveillance with aircraft ID over the whole airport surface has succeeded, using the Mode S squitter and whisper shout technologies to provide signal sources on which to make multilateration position measurements. The resulting multilateration system will greatly improve the situational awareness of the ground controllers, and provide inputs to automation functions, providing improvements in airport safety and capacity.
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Summary

The long search for a method to provide accurate secondary radar beacon surveillance with aircraft ID over the whole airport surface has succeeded, using the Mode S squitter and whisper shout technologies to provide signal sources on which to make multilateration position measurements. The resulting multilateration system will greatly improve...

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Lincoln Laboratory Evaluation of TCAS II Logic Version 7 Appendices Volume II

Published in:
MIT Lincoln Laboratory Report ATC-268,II

Summary

Volume I described the analysis procedures and inputs. This volume presents tables and figures that were generated during the assessment to the TCAS Logic Performance.
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Summary

Volume I described the analysis procedures and inputs. This volume presents tables and figures that were generated during the assessment to the TCAS Logic Performance.

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Lincoln Laboratory Evaluation of TCAS II Logic Version 7 Volume I

Published in:
MIT Lincoln Laboratory Report ATC-268,I

Summary

This report documents the Lincoln Laboratory evaluation of the Traffic Alert and Collision Avoidance System II (TCAS II) logic version 7. 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 the U.S. airspace. Version 7 is a major revision to the TCAS II logic consisting of more than 300 separately defined changes affecting all majot TCAS areas (surveillance, CAS logic and displays/aurals). Lincoln Laboratory Evaluated the logic by examining approximately two million simulated pairwise TCAS-TCAS encounters, derived from actual tracks recorded in U.S. airspace. The main goals of the evaluation were: (1) to study the performance of the new TCAS-TCAS coordinated reversal logic; (2) to detect and explain any areas of performance; (3) to examine the performance of the version 7 logic for the 30 Representative NMACs identified during the 6.04a logic evaluation; and (4) to understand the limitations of the logic by analyzing every version NMAC. Five Lincoln Laboratory analysis programs written for previous logic evaluation work were updated and new software was written to aid in the evaluation of TCAS-TCAS sense reversals. There were four phases of the evaluation corresponding to the above goals. For each phase the report gives an overview of the evaluation approach taken and a description of the results. An overall summary and perspective on the evolution of the TCAS II logic are given at the end of the report.
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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 7. 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, volume I

Author:
Published in:
MIT Lincoln Laboratory Report ATC-240,I

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.
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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...

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Lincoln Laboratory Evaluation of TCAS II logic version 6.04a, appendices, volume II

Author:
Published in:
MIT Lincoln Laboratory Report ATC-240,II

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.
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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...

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TCAS: maneuvering aircraft in the horizontal plane

Published in:
Lincoln Laboratory Journal, Vol. 7, No. 2, Fall 1994, pp. 295-312.

Summary

The Traffic Alert and Collision Avoidance System (TCAS II) is now operating in all commercial airline aircraft to reduce the risk of midair collisions. TCAS II determines the relative positions of nearby aircraft, called intruders, by interrogating their transponders and receiving their replies. An intruder deemed a potential threat will trigger a resolution advisory (RA) that consists of an audible alert and directive that instructs the pilot to execute a vertical avoidance maneuver. Lincoln Laboratory has investigated the possibility of increasing the capability of TCAS II by incorporating the horizontal maneuvering of aircraft. Horizontal RAs can be computed if the intruder horizontal miss distances at closest approach are known. Horizontal miss distances can be estimated with range and bearing measurements of intruders. With this method, however, large errors in estimating the bearing rates will result in large errors in calculating the horizontal miss distances. An improved method of determining the horizontal miss distances may be to use the Mode S data link to obtain state data (position, velocity, and acceleration) from intruder aircraft.
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Summary

The Traffic Alert and Collision Avoidance System (TCAS II) is now operating in all commercial airline aircraft to reduce the risk of midair collisions. TCAS II determines the relative positions of nearby aircraft, called intruders, by interrogating their transponders and receiving their replies. An intruder deemed a potential threat will...

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GPS-squitter interference analysis

Published in:
MIT Lincoln Laboratory Report ATC-229

Summary

GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent Surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance and data link that permits equipped aircraft to participate in ADS and/or beacon ground environments, offering many possibilities for transition from a beacon to an ADS-based environment. Since GPS-Squitter and its associated data link share the 1030/1090-MHz beacon frequencies with other users (e.g., ground beacon radars and TCAS), there is some level of interaction between the operation of these various systems. One form of interaction is the effect on GPS-Squitter operation caused by the activities of other users. This effect, plus the effect of self-interference of GPS-Squitter operation, determines the operational capacity of GPS-Squitter. The complementary process is the effect of the GPS-Squitter operation on the other users of the beacon frequencies. This report provides an analysis of the interference to the other users of the 1030/1090-MHz beacon frequencies caused by GPS-Squitter operation. The principal interference effect is channel occupancy on the beacon frequencies that prevents the reception of a desired signal by a receiver. The basis for the analysis is to estimate the channel occupancy on the beacon frequencies and its effect on the operation of victim receivers on those frequencies. The analysis is performed separately for the two frequencies. The analysis of 1030-MHz interference estimates the effect of the 1030-MHz data link activity that may be associated with GPS-Squitter (such as differential correction broadcast and two-way data link) on the operation of a transponder receiver. The 1090-MHz analysis estimates similar interference effects on (1) a terminal or en route sensor receiver and (2) a TCAS receiver. The results indicate that the operation of GPS-Squitter and its associated data link will have a negligible effect on the other users of these frequencies.
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Summary

GPS-Squitter is a system concept that merges the capabilities of Automatic Dependent Surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance (ADS) and the Mode S beacon radar. The result is an integrated concept for seamless surveillance and data link that permits...

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Safety analysis of the Traffic Information Service

Published in:
MIT Lincoln Laboratory Report ATC-226

Summary

Traffic Information Service (TIS) is a Mode S data link application being developed for use by general aviation (GA) pilots. Its purpose is to provide a low-cost means of assisting the pilot in visual acquisition of nearby aircraft. The service provides two functions: traffic alerting and threat assessment. These functions are also performed by the Traffic Alert and Collision Avoidance System (TCAS). The purpose of this report is to evaluate the effectiveness and safety of TIS in relation to that of TCAS I. The analysis begins with a conceptual review of Andrews' statistical model of visual acquisition. Next, the surveillance systems and threat-detection logic of TIS and TCAS I are reviewed. Results of a Monte Carlo simulation that modeled the threat-assessment performance of TCAS I and TIS are also presented. The analysis supports the conclusion that, because of the high degree of similarity between TIS and TCAS I, TIS is a safe and effective means of assisting the pilot in visual acquisition of air traffic.
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Summary

Traffic Information Service (TIS) is a Mode S data link application being developed for use by general aviation (GA) pilots. Its purpose is to provide a low-cost means of assisting the pilot in visual acquisition of nearby aircraft. The service provides two functions: traffic alerting and threat assessment. These functions...

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