Definition
A free service within the FAA's ADS-B system that retransmits traffic information between aircraft equipped on different ADS-B frequencies. Aircraft in the United States use one of two ADS-B data links: 1090 MHz Extended Squitter (used mostly by airliners and high-altitude traffic) or 978 MHz Universal Access Transceiver (used mostly by general aviation). ADS-R takes traffic reports from one frequency, processes them through ground stations, and rebroadcasts them on the other frequency so that aircraft on either link can see each other on their cockpit traffic display.
Plain English
A ground-based service that lets aircraft using different ADS-B radio frequencies still see each other on their traffic displays. It listens on one frequency and re-sends the information on the other.
Context Anchor
Seen in ADS-B traffic display, datalink, and NextGen surveillance discussions.
Derivation
Rebroadcast literally means 'broadcast again.' The ground network receives ADS-B reports on one frequency and broadcasts them again on the other, which is exactly what the name describes.
Why Pilots Care
It ensures pilots using different ADS-B frequencies receive traffic information about each other, improving situational awareness.
Analogy
Think of it like a translator at a meeting. One aircraft sends a message in one electronic “language,” and the ground station repeats it in another so more aircraft can understand it.
Intuition Check
“Dependent” does not mean the system is weak or unreliable; it means the report depends on the aircraft’s own position source. “Rebroadcast” does not mean the ground station creates a new position report; it repeats a report it received.
Example Sentence 1
Because the airliner above us was on 1090ES and we were on 978 UAT, ADS-R was what let us see each other on the traffic display.
Example Sentence 2
Ground stations use Automatic Dependent Surveillance–Rebroadcast to forward position data between aircraft on incompatible links.