Review and Analysis of Some Collision Avoidance Algorithms with Particular Reference to ANTC-117.
INSTITUTE FOR DEFENSE ANALYSES ARLINGTON VA
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Since 1971, Revision 10 of ANTC Report 117, issued by the Air Transport Association of America, has served as the unofficial standard for cooperative mid-air collision avoidance systems. This paper presents the results of an assessment of those parts of ANTC-117 that deal with threat and maneuver selection logics. Of primary concern were two questions 1 whether the threat evaluation logics of ANTC-117 provide sufficient time for performing maneuvers necessary to achieve safe separation and 2 whether in dense traffic the expected number of alarms occur infrequently enough for the CAS to be practical. The answers to both questions were found to be negative. The possibility of modifying the threat-evaluation techniques to achieve safe separation was investigated and found to be feasible. However, attempts to reduce the expected alarm rate to tolerable levels proved unsuccessful. It is postualted that existing ATC procedures or modifications thereof can substantially reduce the alarm rates by altering the aircraft range and range rate distributions that were assumed and which are the source of the excessive alarm rate.
- Military Aircraft Operations