How Flight Tracking Works: ADS-B Technology Explained

The Technology Behind Real-Time Flight Tracking

Every day, over 100,000 commercial flights crisscross the globe. The ability to track each one in real-time is made possible by a technology called ADS-B — Automatic Dependent Surveillance-Broadcast. Here is how it works.

What is ADS-B?

ADS-B stands for Automatic Dependent Surveillance-Broadcast. It is a surveillance technology where aircraft determine their position via satellite navigation (GPS) and periodically broadcast it, enabling ground stations and other aircraft to track them.

The system has two main components:

How Flight Tracking Services Work

Services like flyingradar24 aggregate data from thousands of ADS-B receivers positioned around the world. Here is the data flow:

1. 1.Aircraft GPS determines the plane's exact position
2. 2.ADS-B transponder broadcasts this data on 1090 MHz
3. 3.Ground receivers (often operated by volunteers) pick up the signal
4. 4.Data aggregation servers combine feeds from thousands of receivers
5. 5.Web interface displays the aircraft on an interactive map in near real-time

The typical delay between an aircraft's actual position and what you see on screen is just 1-5 seconds.

What Data Does ADS-B Transmit?

Each ADS-B message contains:

Why Some Flights Cannot Be Tracked

Not all aircraft are visible on flight tracking services:

The Future of Flight Tracking

Space-based ADS-B, using satellite constellations like Aireon's system on Iridium NEXT satellites, now provides global coverage including over oceans and polar regions. This means virtually every commercial flight on Earth can be tracked in real-time, a significant safety improvement over the previous radar-based system.