Air traffic control systems gradually evolved from the old sweeping radar to modern computer-driven systems showing maps, weather information, aircraft routes, and digitized radar tracks on an ergonomically designed console.[2]
The development of radar technology during World War II revolutionized air traffic control, allowing controllers to detect and track aircraft in real-time.[3] Whereas in the past information came only from radar, current systems use inputs from a variety of sources. Radar remains central but is now complemented by transponder data (aircraft sending out information regarding altitude and identification) and increasingly by satellite data for more accurate positioning and navigation.[2]
As most data is now digital, advanced digital functionalities are now embedded in modern Operational Display Systems. Those technologies include trajectory prediction, conflict warnings, traffic flow management, and arrival optimization.[4] Two separate competing systems are currently operating within the US, Common ARTS (Automated Radar Terminal System (Lockheed Martin)) and STARS (Raytheon), with Common ARTS operating at the busiest facilities (New York, Dallas, Atlanta, Southern California, Chicago, Washington D.C. area, Denver, St. Louis, Minneapolis and San Francisco area) within the US.[5]