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Formal Analysis of the Airborne Information for Lateral Spacing (AILS) Algorithm

The Airborne Information for Lateral Spacing (AILS) is a research project within the Reduced Spacing Operations (RSO) element of the Terminal Area Productivity (TAP) Program at NASA. The objective of the AILS research is to increase the ability of aircraft to land on closely-spaced parallel runways in Instrument Meteorological Conditions (IMC). The current minimum runway separation for independent landings during IMC is 4300 feet. Using AILS, independent parallel approaces down to 2500 feet separation are expected to be possible. The AILS system is an airborne alerting system that uses Automatic Dependent Surveillance-Broadcast (ADS-B) datalink and differential GPS.

The AILS concept consists of accurate traffic information visible at the navigation display and an alerting algorithm which warns the crew when one of the aircraft involved in a parallel landing is diverting from the intended flight path. The inhouse project is exploring the use formal methods to analytically demonstrate that the AILS alerting algorithm complies with its requirements for all possible parallel landing scenarios.

The formalization is conducted in the Prototype Verification System (PVS)external link. A PVS dump file of the AILS work is available here.

Note: The link to external site tag identifies links that are outside of the NASA domain.


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last modified: 26 September 2003 (10:10:40)