Integrated Aircraft Environment Surveillance System for large civil aircraft

• The Radio Technical Commission for Aeronautics´ (RTCA) Free Flight Selection Committee defines surveillance as “detection, tracking, characterization and observation of aircraft, other vehicles and weather phenomena for the purpose of conducting flight operations in a safe and efficient manner.” • Civil aircraft environment surveillance includes four functions: 1) The ATCRBS/Mode S transponder which includes classic SSR Mode A/C, Mode S, and Extended Squitter (ES) to support the surveillance functions 2) The Aircraft Collision Avoidance System (ACAS) which determines the range, altitude, and bearing of other aircraft equipped with Mode S/ATCRBS transponders, and estimates the separation of other aircraft and provides a vision or an aural advisory to the pilot if a potential conflict exists. ACAS also provides guidance for optimum vertical avoidance maneuver by coordination of mutual intentions with the other ACAS equipped aircraft through Mode S transponder 3) The Weather Radar/Predictive Windshear (WXR/PWS) which provides weather display, predictive windshear advisories, and ground mapping information to aid navigation 4) The Terrain Awareness and Warning System (TAWS)/Reactive Windshear (RWS) which provides terrain display and reactive windshear alerts and cautions