This forms the basis of present day ATC throughout the world.
A network of control centres based on the RAF’s war-time defensive system was quickly established. But despite its early lead in the development of radar, Britain lagged behind the USA in applying the new technology to civilian use. The US was already well on the way to establishing a system of airways, essentially aerial highways ten miles wide and extending upwards from 3,000 feet and marked by regular radio range beacons. The UK, meanwhile, was making good use of the comprehensive network of 53 beacons installed by the US forces during the war. And from a study of US methods emerged the beginnings of the airways system in the UK in 1951 when the first airway Green One was swiftly followed by Amber One running up the middle of England to Prestwick and then to the Solway Firth. The Manchester Control Zone was set up and Airways Green Two and Red Three, for flights to Dublin and Belfast, were created.
The Ground Controlled Approach (GCA) system, in which a team of controllers using radar (initially installed in a caravan at the end of the runway) vectored incoming aircraft to a safe approach and landing in all weathers, also originated in the USA. GCA led on to Precision Approach Radar, later replaced by today’s Instrument Landing System (ILS). Other war-time inventions also had valuable peace- time applications. The Chain Home network of air defence radar stations, which had played so crucial a role in the Battle of Britain, formed the basis of a civilian ATC system. In fact, the last of the military installations was not superseded by new equipment until the 1970s. During the 1950s, the wartime Identification Friend or Foe (IFF) was developed into Secondary Surveillance Radar (SSR). This meant that by transmitting a signal from the ground, controllers could interrogate an aircraft’s transponder and receive valuable information about its height, route and callsign.