Orlando-The Mode S Beacon Radar System Air Traffic Control Radar Beacon System

Air traffic controllers rely on primary and secondary radars to locate and identifY aircraft. Secondary, or beacon, radars require aircraft to carry devices called transponders that enhance surveillance echoes and provide data links. Airports currently use a secondary-radar system known as the Air Traffic Control Radar Beacon System (ATCRBS). However, ATCRBS has limitations in dense-traffic conditions, and the system's air-to-ground data link is limited. In response to these shortcomings, Lincoln Laboratory has developed the Mode Select Beacon System (referred to as Mode S), a nextgeneration system that extensive laboratory and field testing has validated. In addition to significant surveillance improvements, Mode S provides the general-purpose groundair-ground data link necessary to support the future automation of air traffic control (ATC). The Federal Aviation Administration (FAA) is currently installing the system with initial operation scheduled for 1991.