AUTOMATIC DEPENDENT SURVEILLANCE (ADS)

Probably the most significant development in air traffic control over the next 20 years will be the introduction of precise navigation and position reporting through Global Navigation Satellite Systems (GNSS).

Future Air Navigation Systems (FANS) cover three principal areas: voice and datalinks, global navigation and automatic dependent surveillance.

Global navigation relies or constellations of satellites covering virtually every part of the globe. Two systems are in operation: the US Global Positioning System (GPS) and the Russian Glonass System (Global Orbiting Navigation Satellite System). Both of these are currently available to the civil aviation authorities at no charge.

British Airways is one airline currently undertaking trials of satellite-based air traffic control using one of its fleet of Boeing 747-400 aircraft. In 1993 a flight from Osaka in Japan to Heathrow used the system to test communications, navigation and aircraft surveillance ready to use on the North Atlantic routes.

Ground stations were able to trigger position reports and other information from the onboard computers via a land-based satellite station at Goonhilly in Conwall to an Inmarsat communications satellite and then to the ADS unit on the flight deck. Within a matter of seconds the aircraft position was relayed back to ATC together with information as the flight passed over particular waypoints on the journey. The systems will be used to report position instead of the current method which relies on HF radio. During a period of 5 1/2 hours of the flight, more than 1,700 reports were received.

2. Answer the questions to the text.

a) What will the most significant development in air traffic control be over the next 20 years?

b) What principal areas do Future Air Navigation Systems cover?

c) What does global navigation rely on?

d) Name the two global navigation systems now in operation.

e) Which airline is currently undertaking trials of satellite-based air traffic control?

f) What does the current positioning method rely on?