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What is ADS-B?

Automatic Dependent Surveillance-Broadcast is a primary technology supporting the FAA’s Next Generation Air Traffic Control System, or NextGen, which will shift aircraft separation and air traffic control from ground-based radar to satellite-derived positions. ADS-B Out broadcasts an aircraft’s WAAS-enhanced GPS position to the ground, where it is displayed to air traffic controllers. It’s also transmitted to aircraft with ADS-B receivers, either directly or relayed by ground stations, to allow self-separation and increase situational awareness. An aircraft equipped with ADS-B In can display this data, increasing the pilot’s situational awareness.

Getting to know the mandate

AOPA has significant concerns about the FAA’s implementation of Automatic Dependent Surveillance-Broadcast (ADS-B)—especially with respect to its cost, which AOPA believes is too high for many GA aircraft owners. To learn more about AOPA’s position on this issue, see the Air Traffic Services Brief on ADS-B.

If you’re ready to equip your aircraft now, or just want to determine which options make sense, our online tool will consider the kind of flying you do and help steer you to the appropriate solution(s). Links on this page offer more information about a wide array of ADS-B topics.

ADS-B Out—which will be required beginning January 1, 2020, in airspace where transponders are mandatory today—broadcasts GPS position to ground stations and directly to equipped aircraft. 

ADS-B In—which is optional—generally refers to transmission of weather and traffic information from ground stations into the cockpit, where it can be displayed on panel-mounted avionics or a tablet, like an iPad.

Two Technologies

There are two paths to compliance, 978UAT or 1090ES. A Universal Access Transceiver, or UAT, operates on 978 MHz (978UAT). UAT equipment costs generally are lower, and this frequency receives free weather information (not all UATs support the optional ADS-B In).

The 1090ES datalink uses a Mode S Extended Squitter transponder (1090 MHz; “ES” refers to ADS-B information appended to the Mode S data). 1090ES is required above 18,000 feet, outside of the United States, and for Part 135 operations. However, 1090ES does not receive weather data.

ADS-B News