Aircraft Separation by Synchronized Transponder Interrogation (ASSTI)

Sherman G. Francisco

Abstract:	Aircraft separation can be aided by adopting Precision Time scales for the interrogation of conventional airborne transponders. When the Air Traffic Control (ATC) Radar Beacon System (ATCRBS) is synchronized to a precision frequency standard, bistatic pseudorange is available which conveys the separation between any ATC-transponder equipped aircraft and those aircraft equipped with ASSTI receivers. Dynamic estimates of relative position are generated for conventional ATe-transponder equipped traffic within the overlapping coverage areas. On-board monitoring and guidance data is thus available to the crew for flight separation with respect to essentially all traffic within controlled airspace. The normal Federal Aviation Administration (FAA) traffic monitoring functions are not compromised since no additional transmissions are introduced with the ASSTI concept. Only modest navigation capabilities are required of the ASSTI equipped aircraft to precisely monitor its local traffic for separation. No requirements other than the minimum ATC-transponder are required of the traffic aircraft. A precision interrogator time scale and a published site survey are required of the FAA ATCRBS facilities. This paper introduces the ASSTI concept and presents an analysis of major system error sources which establishes the practicality of this non-interfering aircraft separation aid which can improve safety in the national airspace.
Published in:	Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989) September 27 - 29, 1989 The Broadmoor Hotel Colorado Spring, CO
Pages:	475 - 481
Cite this article:	Francisco, Sherman G., "Aircraft Separation by Synchronized Transponder Interrogation (ASSTI)," Proceedings of the 2nd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1989), Colorado Spring, CO, September 1989, pp. 475-481.
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