Not true actually: in the US, ADS-B isn’t required until January 1, 2020 .
Also, FR24 uses radar data in the US (probably because not all aircraft has ADS-B) .
There are also sites, such as ADS-B Exchange  that provide unfiltered flight data...very helpful for tracking military flights and such.
Basically, it's optional in most uncontrolled airspace and for older aircraft.
Also I have an open source Mac app  to act a network server for the USB device. It contains a copy of dump1090 with everything statically linked so you don't need to build anything yourself. Just plug in the dongle and launch the app. It is codesigned, sandboxed and notorized.
You can also use the prebuilt dump1090 binary included inside the App.
EDIT: Also, do you support MLAT?
For those that don't know, OpenADSB is an iPhone/iPad app that connects to any Virtual Radar Server and dump1090 server. ADSBexchange runs on VRS and dump1090 is the de facto Raspberry Pi ADS-B decoder. OpenADSB is not affiliated with but uses ADSBexchange as the default datasource.
Page above also have a similar guide to this submission.
I mainly started contributing with data only because you'll be able to get a free business account with Flightradar24 if you contribute, which gives you longer history to view, and bunch of more map layers to use.
ADSB Exchange on the other hand is built with an open premise, runs off donations, and encourages third-party app and value add to build off their API.
Their API is actually a bit more open than adsbexchange's
There's also no delay on the data, although I think Flightradar and Flightaware dropped the 5 minute delay they used to have. Flightradar censors a lot of corporate jets and military/law enforcement aircraft but I don't think Opensky does. In fact one of either Opensky or adsbexchange even has a special flag in their REST API for "interesting" aircraft
Yes, this is disappointing. In the past I had seen military planes on there. I even saw fighters practising dogfighting over the North Sea. But more recently I've seen interesting aircraft fly over, such as large four-engine planes at altitude outside of normal commercial flight paths, but they just don't appear on flightradar. It's stupid because I can see the damn thing. I need to figure out an alternative to flightradar, it seems.
* No data
* No ADS-B Emitter Category Information
* Light (<15500 lbs)
* Small (15500 to 75000 lbs)
* Large (75500 to 300000 lbs)
* High Vortex Large (aircraft such as B-757
* Heavy (> 300000 lbs)
* High Performance (> 5g acceleration and 400 kts)
* Glider / sailplane
* Parachutist / Skydiver
* Ultralight / hang-glider / paraglider
* Unmanned Aerial Vehicle
* Space / Trans-atmospheric vehicle
* Surface Vehicle – Emergency Vehicle
* Surface Vehicle – Service Vehicle
* Point Obstacle (includes tethered balloons)
* Cluster Obstacle
* Line Obstacle
I was using Flightradar yesterday and visually tracking planes, seems like about a 10 second delay.
Building an app, maintaining a website (that has something like 2 million daily users iirc) and building out backend infra to support the huge amount of incoming data and turn it into something greater than the sum of its parts costs money. What many people don't realise is the data you see on FR24 is not simply derived from ADS-B broadcasts. Data like fight numbers comes from other licensed sources; MLAT triangulation is done at FR24's end; telemetry data for areas without community ADS-B coverage comes from partnerships with radar operators, airports (and soon satellite, when Aireon is active) etc.
If you're curious to know what raw info is included in a typical broadcast, this is a good link: https://www.adsbexchange.com/datafields/
Except the TOS, if you're using one of their receiver kits.
They are only a “data monopoly” because they are good at what they do.
In any case, being good at what they do definitely helps, but network effects is also a factor. They have the best data coverage, therefore new contributors will mainly chose them over a hypothetical competitor with a slightly better support and user interface.
This discourages new competitors to even try entering the market, which has the usual downsides of a monopoly market such as less innovation.
Someone else already asked this question before:
If you want to send data to multiple services from one receiver all you need is to install the feeder for each service. Most uses dump1090 , but Flightradar24 uses their own. Dump1090 sends data in different formats to various local ports by default, and ADS-b Exchange uses netcat to send it to their server. You can use the ADS-B Receiver Project  to install everything needed.
MarineTraffic has a more comprehensive monitoring network but they keep the data to themselves. Details at https://www.marinetraffic.com/en/p/expand-coverage
As noted by another comment, AIS signals are being broadcast line-of-sight from the ground so you need more receivers than you do to track airplanes. OTOH you only need the receivers on the coastlines and on major inland waterways, not over the whole earth's surface. (If you want to track a ship mid-ocean, you'll need a satellite. Those exist but cost $$.)
BTW new Iridiums are capturing AIS and ADS-B from satelite.
In Finland receiving as such is not illegal, but forwarding the information is.
In both cases the reasoning is that this information is not directed to the public. Whether anybody has ever been prosecuted I have no idea.
Moreover - when you finally get caught, on which scale do you have to be doing it to get caught in the first place? Remember - laws don't exist outside reality.
And let's be honest - the recording of the presence of a car is also quite illegal in certain jurisdictions. e.g. Germany.
> It looks like it was legalized a while ago
Interesting enough the law has not been changed. The article tells how officials forbade a trader to sell ADS-B receivers to the public. The trader went into court and won. The reasoning of the court was that the law forbids only listening. But because the ADS-B signal is not made audible, but visualized on a PC screen, the law is not applicable.
This was only a medium court. Another one or a higher one might decide differently. Probably you should start lobbying that lawmakers will not "adapt the law to the digital age" when revising it the next time.
In Finnish law the construction is different. All radio communication is considered confidential unless otherwise stated, like e.g. for radio and TV programs. Receiving such confidential information is not criminalized, but sharing it further is.
Just filled their forms. Slightly concerned about running a blackbox on my network so I'll have to do some isolation, but this'll be a fun contribution.
Lee (CTO @ Plane Finder)
Just took a look at your website, I was looking for some kind of historical flight data provider.
Clicked on the "Historical Flight Data" link and it just links to a couple popular flights which in turn link to pages with a few pieces of flight data visualized/available.
Clicked on the "Commercial Services" link and it details a few commercial services including "Historical Flight Data" which says
> Looking for historical flight data? Plane Finder historical flight data is available in 5 minute or 1 minute intervals dating back to 2011 and is delivered as flat files in CSV format.
"Historical Flight Data" isn't clickable, and I don't want to fill out a form ("Contact Us"), so I click on "View Products" which just links me to your downloadable apps.
Apologies if there's something I'm missing.
I'm trying to get a look at API docs and pricing, and sign up and get started without having to "contact your team."
> for non-commercial use, all of this data is freely accessible to anyone!
> Any commercial users are required to license the data from ADSBexchange, contact here for terms.
Commercial use is a thing very hard to define so I avoid that even for personal projects (which could be consider advertisements for my commercial offers).
For a more DIY approach, there's these two:
My guess is that FR24 just looks up the flight path from the flight number, and then once an airplane goes “off the radar” it just assumes it goes the shortest/great circle path towards its destination airport - at which point it will again be in a “known” spot? If this is how it’s done then one should see lots of planes approaching e.g the US east coast suddenly “shift” from their estimate position to their transponder positions, as they are picked up by receivers.
This may change soon -- at least for the North Atlantic -- now that Aireon is using satellites to pick up ADS-B data. It's just a question of whether or not this info gets included in the FAA's ASDI feed.
Fortunately there is https://www.adsbexchange.com which offers unfiltered data. You can set up a receiver so that it runs dump1090 separately and forwards it to both using Beast protocol. You can also participate in adsbexchange M-LAT.
HN thread here: https://news.ycombinator.com/item?id=10969447
It’s also worth noting that FlightAware has partnered with Aireon (owned by Iridium according to Wikipedia) to put ADSB receivers on satelites that were launched with Iridum’s NEXT satelite constellation in low-earth orbit. Sounds like that data is not yet included in the free data FlightAware provides on its website, but is available commercially. https://flightaware.com/commercial/aireon
Would be to specifially watch all the planes that fly in and out of a large notable event; such as the superbowl, or davos, g-20 summit etc - and see where all thise private jets come from to get to that event...
The only API i found exclude all freight trains. (Netherlands) https://spoorkaart.mwnn.nl/
(Though this does seem spoofable.)
The hardware is often proprietary, but they must allow you to re-purpouse the data received by the antenna (it's public domain).