ADS-B Exchange explained: unfiltered flight tracking for spotters

The tanker has been circling over the North Sea for an hour, the government aircraft has just taken off, and your usual flight tracker app shows none of it. At the latest then, many spotters open ADS-B Exchange. The service has made a name for itself as an unfiltered map: whatever the community’s receivers pick up is displayed. This guide explains what is behind ADS-B Exchange, how to really get the most out of the interface at globe.adsbexchange.com and where even the unfiltered map stays blind.

ADS-B Exchange: the short answer

ADS-B Exchange is a worldwide reception network for aircraft signals that gets its data from volunteers. People all over the world run small receivers with antennas that pick up the transmissions of aircraft transponders and forward them to the service. From that comes a live map on which you follow aircraft with identification, altitude, speed and track.

The difference from the big commercial services lies in its attitude toward filtering: ADS-B Exchange describes itself as a platform that shows flight movements without censorship or targeted filtering. According to its own statements, specific flights or aircraft types are not hidden, and military traffic is explicitly included. For spotters looking for tankers, transports, reconnaissance aircraft or business jets, that is the decisive point.

Where the data comes from

The basis is ADS-B: modern airliners broadcast, at regular intervals, their satellite-navigation-derived position, altitude, speed and identification on 1090 MHz. Anyone with a suitable antenna and receiver can passively listen in on these signals – the receiver does not query anything, it only listens. How this works technically is explained in the basics article Flight tracking with ADS-B for spotters.

Not every aircraft delivers a finished position. Many military aircraft and older airplanes do send Mode S replies with identification and altitude, but no position of their own. For them ADS-B Exchange uses multilateration (MLAT): several receivers measure when the same signal arrives at them, and the position is calculated from the tiny time differences. That only works where enough stations stand close enough together. You will find the details under MLAT explained, and the differences between the transponder modes in the article Transponder Mode A, C and S.

Every aircraft also transmits a fixed 24-bit address, the so-called hex code. Through it the map assigns a registration and type to a transmission. What this address is all about is in the article ICAO 24-bit address (hex code).

What “unfiltered” actually means

Commercial flight tracker services hide part of the traffic or show it only anonymously. The reasons are owners’ requests, security concerns or blocking programs such as the US LADD program. In the US, operators can additionally use a changing 24-bit address through the PIA program, so the aircraft stays visible but can no longer easily be matched to a registration.

ADS-B Exchange goes a different way and, according to its own statements, does without targeted filters. For you at the screen that means:

• Military traffic stays visible, provided it transmits at all and is received.
• Government and business aircraft appear with their identifications, even when they are missing on other services. More on this in Spotting government aircraft and Spotting business jets.
• Changing addresses remain changing addresses. Even an unfiltered map cannot automatically match an aircraft with a PIA address to a registration. You then often see only type and position, not the identity.

Unfiltered is therefore not magic but the absence of after-the-fact hiding. What the receivers do not hear, ADS-B Exchange cannot show either.

From hobby project to company

ADS-B Exchange began in 2016 as the project of an aviation enthusiast with an IT background. The project grew into one of the largest community maps in the world. In January 2023, the US aviation data provider JETNET took over the service. At the announcement, the founder continued to appear as president of ADS-B Exchange, and it was said that the data would stay unfiltered.

In parts of the feeder community the acquisition did not go down well. The main criticism was that a network built by volunteers now belongs to a commercial data provider. As a result, further community maps working with the same map software gained importance. An overview of these alternatives is given in the article Unfiltered community trackers compared.

Today, besides the free map, which carries ads, ADS-B Exchange sells data products for businesses: live data, daily data packages, an API, a streaming service and archive data. For the private spotter, one thing matters most: the map in the browser remains free to use.

Using the globe.adsbexchange.com map properly

The web interface at globe.adsbexchange.com is based on tar1090, an open-source map software that many spotters also use for their own receiver. Once you have understood it, you find your way around several unfiltered maps. How to run tar1090 at home is covered in the guide Flight tracking on a PC.

Search, list and colors

With the search you find any aircraft: you enter a hex code, a registration or a type and jump straight to the hit. How to reliably find a specific aircraft again is described in Tracking an aircraft by registration.

The aircraft symbols are colored by altitude, with a gradient from orange through violet to red. Aircraft shown in gray are on the ground; their transponder reports ground mode. For spotters that is handy: a gray symbol at your airport has landed or is still taxiing. What the other symbols and data fields on flight tracker maps mean is explained in the article Flight tracker symbols and colors.

The aircraft list in the sidebar shows about 100 entries. If an aircraft you are looking for is missing there, zoom in closer on the region.

The most important keys

Almost every button on the map carries a letter – you can click, or simply press the key.

Key	Function	What you use it for as a spotter
U	Military/interesting filter	Tankers, transports, reconnaissance aircraft at a glance
T	Tracks for all aircraft	Make approach routes and holding patterns visible
I	Isolate selected aircraft	Follow one aircraft without others getting in the way
F	Follow aircraft	The map moves along, ideal for the approach
P	Persistence mode	Aircraft stay put after signal loss
M	Multi-select	Watch several aircraft at once
L / K	Labels / track labels	Altitude and identification right on the map
H	Reset map	Quickly back to the initial view

Two combinations come on top: Shift + S temporarily hides all buttons, Shift + L switches between the estimated last flight path and the full track.

Filters: the underrated tool

In the right sidebar you filter by altitude range, callsign, squawk, type and type description. The filters understand simple patterns: a dot stands for any character, a vertical bar joins several patterns. Spaces must not appear, otherwise the filter does not work.

• By type code: B73. shows the 737 family, A32. the A320 family, B73.|B3.M the 737 including MAX. How the codes are structured is explained in ICAO type codes explained.
• By type description: H.. shows helicopters, L2J twin-engine jet landplanes, ..T turboprops, .4. four-engine aircraft.
• By squawk: A filter on 7700 shows you aircraft reporting an emergency. What the special codes mean is covered under Squawk codes 7500, 7600, 7700.

A filter like .4. is worth its weight in gold for spotters: four-engine aircraft have become rare in scheduled service, so you immediately see whether a 747, an A380 or a military four-engine aircraft is currently around in your region.

URL parameters for advanced users

Many settings can be appended directly to the address. The first parameter starts with ?, further ones you append with &. This way you build bookmarks for recurring tasks:

• ?icao= with a hex code appended centers, selects and isolates exactly that aircraft.
• ?airport=EDDM centers the map on an airport.
• ?mil starts directly with the military filter.
• ?replay displays a playback bar for the current map section.
• ?heatmap=200000 draws a heatmap with up to 200,000 points, by default over the last 24 hours.

The heatmap is exciting for spot planning: it shows where approach routes, traffic patterns or practice areas concentrate. You first scroll to your region and then append the parameter.

How to use ADS-B Exchange when spotting

This is especially rewarding at military airfields. At the NATO airbase Geilenkirchen, for example, you can follow whether the AWACS fleet is on the move – tips on the location are in the spot Teveren spotters’ hill and in the guide Plane spotting in Geilenkirchen. How to recognize tankers like the Boeing KC-135 Stratotanker in the field is explained in Recognizing tanker aircraft. A broader overview is offered by Tracking military aircraft online.

The limits of the unfiltered map

As useful as ADS-B Exchange is: the map shows only what a receiver has actually heard. That results in limits you should know about.

• No transponder, no symbol. Military aircraft often switch off their identification on missions. What does not transmit appears on no map, no matter how unfiltered it is. Further causes of missing aircraft are collected in the article Why an aircraft does not show up on Flightradar.
• Coverage is unevenly distributed. In densely populated regions with many feeders the network is tight; over the open sea or in sparsely populated areas there are gaps. Low-flying helicopters and small aircraft quickly disappear behind hills and buildings.
• MLAT needs partners. For aircraft without a position of their own, several stations must receive the signal at the same time. If they are missing, you see the aircraft at best without a position in the list.
• Master data is not infallible. The assignment of hex code to registration and type comes from databases. New, re-registered or sold aircraft are sometimes entered wrongly there or not at all. A look at the photo beats any database.
• No guarantee of completeness. The map shows an image of what the community receives – not an official air situation picture from air traffic control.

The terms of use also set limits: ADS-B Exchange’s policy prohibits, among other things, exporting data on a large scale, reselling it or using it to build a competing offering. For your private spotting planning that does not matter; for your own projects with the data it does.

Becoming a feeder yourself

The network lives on people who run their own receivers. According to ADS-B Exchange, all it takes is a small antenna with a receiver, which under good conditions picks up signals from up to around 250 nautical miles. Feeders see their station on a leaderboard, unlock MLAT functions and can pass a discount on to friends. Anyone who already feeds Flightradar24, FlightAware or other networks can supply ADS-B Exchange with data as well.

How to build the receiver is explained in Build your own ADS-B receiver; the setup for ADS-B Exchange and the community networks is described in Feeding ADS-B Exchange and community networks. What the individual services offer in return is compared in What feeders get in return.

Conclusion

For spotters, ADS-B Exchange is the map for everything that is missing on the big services. Doing without targeted filters makes military, government and business flights visible, and the tar1090 interface offers, with keyboard shortcuts, type filters, replay and heatmap, tools that on commercial apps are often behind a subscription. Since the JETNET acquisition the service is no longer a pure community project, but the map remains free to use. The limits are set by the technology: what does not transmit or is heard by no receiver stays invisible. And as with the Flightradar24 subscription question, the same applies: the best map does not replace the view through the viewfinder.