Garmin's Sam Seery (left) explains ADS-B's
UAT to an AOPA member at Sun 'n Fun.
Apr. 22, 2004 - East Coast pilots got their first real chance to see ADS-B (automatic dependent surveillance - broadcast) - a system AOPA has backed virtually since its inception - during this past week at Sun 'n Fun. The FAA set up an ADS-B ground station that transmitted both traffic and weather information via datalink radio to a special receiver at the Garmin display at Sun 'n Fun.
The FAA has been testing ADS-B as part of Alaska's Capstone project since early 2000. Aircraft equipped with ADS-B use a datalink transceiver coupled with a GPS receiver to broadcast their GPS-derived position to other ADS-B equipped aircraft and to ground stations that send that information to air traffic controllers. And because the datalink is a two-way connection, the ground station can send ATC traffic information (TIS-B, or traffic information system - broadcast) as well as limited graphic and text weather information (FIS-B, or flight information system - broadcast) to the aircraft, where the pilot can call it up on a multifunction display.
The breakthrough for general aviation came when the FAA decided on the best performing, extremely robust Universal Access Transceiver (UAT) datalink for most GA aircraft. For its part of the demonstration, Garmin showed off a UAT that incorporates a WAAS-enabled GPS receiver and comes with the necessary antennas for a suggested price of $8,000.
"That's substantially less than the cost of a Mode S transponder (which has datalink capabilities) with traffic, and a second datalink and annual weather data subscriptions," said AOPA Senior Director of Advanced Technology Randy Kenagy. "And there could be economies of scale and competition, like there was with GPS, as more and more UATs reach the market."
Kenagy has been AOPA's point person during ADS-B's development. "ADS-B could also directly replace Mode C transponders without a costly interim transition to Mode S," he said. "It provides all the information air traffic controllers need and, at the same time, provides pilots with the two datalink capabilities that our members tell us are most important to them.