Definition
A surveillance service in which aircraft ADS-B Out position broadcasts are received by a constellation of low-earth-orbit satellites and relayed to air traffic control, enabling real-time aircraft tracking in oceanic and remote airspace where ground-based radar and ADS-B receivers cannot reach.
Plain English
Aircraft already broadcast their GPS-derived position through ADS-B. Space-based ADS-B uses satellites to pick up those broadcasts over oceans and remote regions, so controllers can see aircraft in places where ground antennas don't exist.
Context Anchor
Seen in discussions of aircraft tracking, oceanic routes, remote-area surveillance, and modern air traffic control services.
Derivation
Space Based refers to the receivers being on satellites in orbit rather than on the ground. ADS-B itself: Automatic (no pilot action needed), Dependent (relies on the aircraft's own GPS position), Surveillance (used by ATC to track aircraft), Broadcast (sent out continuously for anyone to receive).
Why Pilots Care
It enables radar-like ATC services and reduced separation minima in oceanic and remote airspace, improving safety and route efficiency on long-haul flights.
Intuition Check
Do not read “space based” as a different kind of aircraft equipment. The key point is where the signal is received: by satellites, not just by receivers on the ground.
Example Sentence 1
Thanks to space-based ADS-B, controllers on the North Atlantic tracks can now see aircraft positions in near real time instead of relying on position reports every ten degrees of longitude.
Example Sentence 2
Operators filed routes through the North Atlantic Tracks with confidence once space-based ADS-B coverage was confirmed for the entire crossing.