The science and technology of air traffic control | Ars Technica - 6 views
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Alex Lenk on 29 Oct 13Da Woon November 1st Describe the IT system
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Dawoon Jung on 31 Oct 13This article tells us the air traffic controller (ATC) which helps us to have safe fly. ATC has access to sophisticated radar systems that provide an overview of the airspace they control, and they have communication tools to coordinate flight paths with the air crew. When the aircraft travel at higher speed than common modes of transport, the time available for pilots to react to a dangerous situation can be quite short. And ATC helps to aircraft approaching an airfield carefully and it checks the weather conditions for prevent pilots can't see other aircraft. ATC uses radar systems positioned at ATC facility to get a real time overview of the aircraft flying in the airspace they control. Many types of radar equipment are served for traffic on the ground. Primary Surveillance Radars (PSR) - The radar sends a directed pulse into the atmosphere, and when that pulse encounters an object it gets reflected back to the radar station. The bearing of the object with respect to the radar station and its approximate distance can be calculated by this. The radar is typically enclosed in a dome to protect it from adverse weather. Secondary Surveillance Radars (SSR) - the Secondary Surveillance Radar listens for messages from the aircraft's transponder. The radar rotates about the vertical axis, but transmits a specific signal on 1030 MHz. This signal is subsequently received by the aircraft's onboard transponder, which responds with a reply on 1090 MHz. SSR Modes - There are different modes of interrogation that compliant transponders respond to. A - The transponder responds with its squawk code, a unique identifier for the aircraft assigned by ATC comprising of four octal numbers. This code enables ATC to differentiate between the various aircraft being monitored, though it can also be used to discretely communicate the existence of an emergency situation onboard the aircraft. C - the transponder responds with the aircraft's pressure altitude, which is the altitude ab