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Journal of Advanced Transportation
Volume 2018, Article ID 7905140, 10 pages
Research Article

Trajectory Specification Language for Air Traffic Control

NASA Ames Research Center, Moffett Field, CA 94035, USA

Correspondence should be addressed to Russell A. Paielli; vog.asan@illeiap.ssur

Received 10 August 2017; Revised 8 January 2018; Accepted 21 January 2018; Published 7 March 2018

Academic Editor: Rodrigo Carlson

Copyright © 2018 Russell A. Paielli. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Trajectory Specification is a method of specifying aircraft trajectories with tolerances such that the position at any given time in flight is constrained to a precisely defined bounding space. The bounding space is defined by tolerances relative to a reference trajectory that specifies position as a function of time. The tolerances are dynamic and are based on the aircraft navigation capabilities and the traffic situation. This paper proposes a standard Trajectory Specification Language (TSL) based on the Extensible Markup Language (XML) to represent these specifications and to communicate them by datalink. The language can be used to downlink trajectory requests from air to ground and to uplink trajectory assignments from ground to air. The XML format can be converted to binary for operational use, if necessary, using Efficient XML Interchange (EXI) or Abstract Syntax Notation (ASN.1).