Flight tracking services and websites have brought exciting and valuable changes to
the aviation sector. These provide real-time and historical access to flight information,
including aircraft details, routes, position,
speed, altitude and heading. Today, let’s look at how flight tracking sites work…
Radar, and onboard transponders are the primary method to make aircraft visible to controllers.
However, this data cannot generally be accessed by
others. Automatic Dependent Surveillance-Broadcast, or ADS-B,
has changed this, with the data broadcast by aircraft using unencrypted signals via 1090 MHz.
Indeed, anyone with a receiver and the proper antenna can pick up the data.
This is a relatively new method but it’s already well on its way to mainstream use.
Aircraft determine their position by communicating with satellites, then broadcast
this to air traffic control to enable tracking. ADS-B will also transmit aircraft identification
information, altitude, and speed. It can also receive information such as weather updates,
airspace information or other ADS-B aircraft reports.
Radar tracking remains the long-standing global standard method of aircraft tracking,
but ADS-B is well on the way to replacing it. In the US and Europe,
all commercial aircraft are now required to install ADS-B technology. Upgrade projects for ATC
are underway in both regions - the Next Generation Air Transportation System in the US and the
Single European Sky ATM Research (SESAR) project. ADS-B will ultimately change how ATC and aircraft
tracking works, unlocking coverage in areas where it was previously limited. It’ll allow
for more efficient aircraft routing and spacing too. This technology also makes aircraft data
available to sources other than ATC, and this is how flight tracking websites obtain data.
Indeed, most commercial aircraft are now broadcasting ADS-B data- in fact,
FlightRadar24.com estimates that 70% of all commercial traffic now has an ADS-B transponder),
and this will continue to increase. But this data needs to be collected.
This is done mostly using volunteers to host
and operate ADS-B receivers and feed the data to tracking websites.
These are mostly aviation enthusiasts to agree to install a receiver, aerial,
and connect it to the internet. This then feeds data from that area to the service provider.
For full global coverage, a huge network is needed as each receiver will cover about 250-450
km (150-250 miles) in all directions. FlightRadar24.com claims to have a network of over
20,000 such receivers in place currently. The website claims that it can now cover
100% of airspace above cruising altitude in Europe and the US, and this is increasing
in plenty of other regions. Security and legal implications
are of course a concern and thus data from certain aircraft or operators are blocked from display.
While ADS-B provides the primary source of data for flight tracking,
Multilateration (MLAT) is a technique that uses the data from several receivers to calculate the
position of aircraft without ADS-B transponders. By measuring time differences of standard
transponder signal receipts between multiple receivers, the aircraft
position can be tracked. FlightRadar24.com covers most of Europe and US airspace
between 3,000 feet and 10,000 feet with MLAT. Traditional radar sources can also be used in some
areas. In fact, FlightRadar24.com currently sources standard radar data for commercial
traffic in North America and over parts of the Atlantic and the Pacific oceans.
Do you frequent flight tracking websites? Which site
do you prefer? Let us know more in the comments.