Ever wondered how flight radar and live aircraft tracking work? This guide explains the pipeline from aircraft broadcasts to your screen.
The tracking pipeline
Each section below explains one step in this pipeline.
ADS-B (Automatic Dependent Surveillance-Broadcast) is the technology that makes modern aircraft tracking possible. Unlike traditional radar, which bounces radio waves off aircraft, ADS-B relies on planes themselves to broadcast their position.
Aircraft equipped with ADS-B transponders transmit short messages on 1090 MHz. Each message includes position (from GPS), altitude, speed, heading, and identity. These signals go out several times per second—no ground station needs to “ask” where the plane is.
The aircraft’s GPS provides coordinates. The transponder packages this into a compact data packet and broadcasts it on 1090 MHz. Any receiver within line of sight can pick it up—range depends on altitude, so a plane at 35,000 feet can be detected from hundreds of kilometres away.
Thousands of ground-based receivers capture the broadcasts and feed data into central servers. Services like Flightradar24, FlightAware, and OpenSky merge, deduplicate, and enrich it—then apps and displays consume the result via APIs.
Receivers capture broadcasts and send them over the internet to aggregators. Coverage is dense in Europe and North America.
Multiple receivers may see the same aircraft. Aggregators merge, deduplicate, and enrich the data with flight plans and aircraft databases.
Apps like Flightradar24 and dedicated displays consume this data via APIs. They show aircraft on maps, lists, or custom layouts—such as a desk clock that displays flights overhead.
A flight tracker display takes the same ADS-B-derived data and presents it in a format suited to your desk. Instead of a global map, it can filter aircraft by your location and viewing direction—so you see only the planes you can actually look up and spot.
You set your coordinates and compass bearing once. The display then filters live flight data to show only aircraft within that cone of view—for example, aircraft visible from your window. That’s how a dedicated aviation desk display like AvClock turns raw tracking data into a personalised “window to the skies above you.”
The underlying technology is the same: ADS-B data from global networks, enriched with aircraft and route information. The difference is presentation—a clock-style display that’s always on and glanceable, rather than an app you have to open.
AvClock is a dedicated flight tracker display that shows live aircraft visible from your window.
Learn about AvClock