Sources, reliability… How the FlightRadar24 air tracking site works

From the curious to aviation enthusiasts and professionals: FlightRadar24 draws the crowd. The site broke its audience record on Tuesday: more than 708,000 Internet users connected to follow the flight to Taiwan of Nancy Pelosi, president of the US House of Representatives.

FlightRadar24 allows you to follow the movements of aircraft in real time around the world, but also to consult various flight data: numbers, airlines or their origins and destinations.

However, the site, which has 2 million users per day and more than 40 million downloads for its application, was born a bit by chance. In 2006, two Swedish friends, Mikael Robertsson and Olov Lindberg, launched an airline ticket comparison website. To stand out, they add real-time travel tracking. Quickly, they notice with surprise the enthusiasm of netizens, says the Wall Street Journal.

Almost exhaustive coverage of air traffic

FlightRadar24 claims the daily monitoring of 180,000 flights, operated by more than 1,200 companies in a network of 4,000 airports. Among the routes analyzed, those of “commercial flights, executive jet flights, private flights, gliders, most helicopter flights, (…) government flights, some military flights and drones,” the company lists on its site.

Enough to guarantee complete coverage of air traffic, with some exceptions.

And to continue: “Some high-profile aircraft, such as Air Force One (Editor’s note: US presidential fleet), are not shown. Most other aircraft subject to restrictions are shown anonymously.”

A more precise technology than radar

To track aircraft, the site collects a large amount of information. It retrieves airline and airport databases, including flight times and status, but also other structures, such as the Federal Aviation Administration.

The heart of its activity, however, is based on the data provided by the aircraft themselves thanks to ADS-B technology (for “automatic dependent surveillance in transmission mode”, in French). This technology, in the process of being implemented for about fifteen years, allows aircraft equipped with it to send a signal to satellites in real time, including their position, altitude, speed or even their flight direction.

If requested by air traffic controllers, ADS-B can also provide data such as cockpit instrument settings and the amount of fuel remaining. Wall Street Journal.

The satellites that have received the signals, in turn, send them back to ground stations, such as those at airports.

ADS-B technology was developed with modern aircraft to replace the considered inaccurate radar ground control system. The objective: to prevent the planes from disappearing in mid-flight, as happened with the MH370, considered the greatest mystery in civil aviation. In March 2014, the Malaysia Airlines plane and its 239 passengers on board disappeared from radar over the Indian Ocean before crashing.

A global community of volunteers

FlightRadar24 anticipated the development of the technology by early on implementing a cooperative global network of receivers capable of collecting signals from aircraft.

The company now has a network of 30,000 receivers, thanks to a community of volunteers. It is possible to apply online at the site to receive a free receiver to install at home.

For the requirements to be fulfilled, to provide a logement permettant d’offrir “d’excellentes conditions de réception” car une “antenne doit être placée à l’extérieur, sur un toit, et avoir une vue dégagée du ciel à 360 degrés”, detail the place. Then the antenna is connected by cable to the receiver, located inside the house. This receiver must be connected to the Internet “24/7” to transmit data to FlightRadar24.

The site is working to strengthen the mesh of its receiver network to improve its coverage, which is still imperfect depending on the geographical area.

This makes it “very difficult to cover the oceans” in particular.

For aircraft not yet equipped with ADS-B, the site calculates their position using the multilateration method. This calculates a location by measuring the distance between several known points.