Over a period of 18 months from February 2018, although airline passengers generally won't be aware of it, air traffic control in the world's busiest oceanic airspace and huge volumes of remote territorial airspace in Africa and elsewhere will be revolutionised. Today, primary and secondary (transponder-interrogating) radar and GPS-reliant ground- technologies can't reliably detect aircraft in flight at ranges beyond 250 nautical miles (460km). Broadcasting signals from and receiving them at facilities on the ground, radars and ground-based ADS-B receivers can only detect aircraft in their line of sight - which for an airliner flying at cruising altitudes of 31,000ft (9,450m) to 43,000ft (13,105m) is from 200nm to 250nm (370km-460km).
展开▼
