Performance Analysis of a Horizontal Miss Distance Filter for TCAS II

Abstract

This paper describes the performance of a filter for reducing unnecessary alerts from the Traffic Alert and Collision Avoidance System (TCAS). The filter uses range and bearing measurements to estimate miss distance for potential threat aircraft. When the estimated miss distance is high, TCAS resolution advisories are suppressed. The filter has been prototyped and extensively tested in MITRE’s TCAS simulation test bed. When implemented, the filter is expected to reduce TCAS resolution advisories by about 25% in US airspace and by about 40% in European airspace, while having a negligible effect on system safety. The filter will be included in the next fielded version of TCAS.