66% or better

Tracking commercial aircraft with salvaged electronics

ads-b_air_traffic_tracking_station

Early last year, [Edward] started work on an aircraft tracking system using components from old electronics he had sitting around the house. As you may or may not know, most modern aircraft continuously broadcast their current position over the 1090MHz band using the ADS-B protocol. [Edward] found that his old satellite receiver module was able to pick up the signals without too much trouble, and was more than happy to share how he did it.

The whole project cost him just under 5 Euros and requires the aforementioned satellite tuner as well as an ATMega48 microcontroller to decode the ADS-B messages. When the receiver is hooked up to a nice aerial and preamp he can listen in on planes within a 200km radius, but even with a simple piece of wire, he can locate aircraft up to 25 km away.

Raw ADS-B data isn’t terribly useful, so [Edward] put together a small application that plots nearby aircraft on a map for him. We imagine that it wouldn’t be too incredibly difficult to do the same sort of thing with the Google Maps API as well.

If you’re interested in putting together an aircraft tracking receiver of your own, be sure to swing by his site – he has a ton of useful information that will likely be a huge help along the way.

[Thanks, David]

Comments

  1. Gert says:

    Wauw, so add this to the missile guiding system et voila.
    Tool of terror?

    Or just use it with a XY steered laser to “blind” the pilots.

    • mess_maker says:

      or just an awesome project that tested his abilities.

    • macegr says:

      It’s not going to be realtime enough to guide anything that accurately. Tool of terror? If anyone thought so, it would be encrypted. Maybe all airliners should be stealth…that would be pretty cool actually.

      • Marc says:

        ADS-B broadcasts position once per second. Encryption would defeat the whole purpose (unless the keys were widely known, doing little to improve security), which is to provide more accurate real time positioning information to both air traffic control and other aircraft in the vicinity.

        I’m sure it has occurred to various parties that a technology meant to aid in collision avoidance can also be used for collision “optimization”. Keep in mind that international aviation standards take decades to develop, implement, and change…

      • mikuslaw says:

        Why do you think it’s not realtime? I think this data is used at the airport trafic control to guide the planes, so it should be accurate and real time (airports don’t use normal radars for that as they are not good enough/too expensive?). It is a good question why it’s not encrypted.

      • mikuslaw says:

        Very interesting read. Did anybody catch why it’s needed to get the signal level down just above the noise floor? I get it that the demodulator is FM and we need to demodulate PPM signals, but I still don’t get how this helps.
        I remember that I read one day about using USRP to decode data about aircraft or ship possitions and plotting it on google maps, but I can’t find it now.

  2. It could be useful as an add-on to a high altitude balloon to turn on a strobe when aircraft were in the vicinity to avoid a possible collision ?

  3. cozytom says:

    In the US ADS-B isn’t common. In Australia, it is mandated. In Europe, it is similar to the US, not common.

  4. NatureTM says:

    Can the receiver in one of those DTV -> analog converter boxes be used to get things other than tv?

  5. hawkeyeaz1 says:

    Wait for the US government to send a take-down “request” citing “security” concerns due to the aforementioned “terrorist” threat

  6. omegat says:

    Logging ADS-B is acutally not a new thing to do, websites like http://www.flightradar24.com do it more or less in real time. The first receiver commerially availabele which did this was the SBS-1 (http://www.kinetic-avionics.com/sbs-1.php). But Receivers which decoded these ADS-B (Mode-S transponder-) signals were pretty expensive.
    So this is really a cool achievment to do it with some old parts out of the parts bin!
    Great job!!

    • blue carbuncle says:

      Thanks for the info :) Love this project and think I may give this one a go. While I’m a complete amateur at radio, I’ve had a good bit of luck in the area I’m in. Quick question: is there any pc software that you know of that can just decode the “clicks” or fsk or whatever marker and decode them? Maybe I’m going in the wrong direction with this one lol.

  7. z says:

    Here are some realtime plots on the web – see below “Online Daten”: http://www.mikrocontroller.net/articles/1090_MHz-ADS-B-Receiver#Siehe_auch

    There’s also some more ADS-B stuff – in german though

  8. N0LKK says:

    I wasn’t aware such transmissions exist. Perhaps it’s one of those day’s I’m having a difficult time following the write up.Need to come back to it later.I do recall a web page that displayed similar tracks on a map from information gleaned from the web, but it’s more fun to have your own receiver set up, not that it’s particularly useful.

  9. asheets says:

    I may have to build one of these; as I’ve been waiting for something like this since the 1990s; unfortunately, the implementation does not include temperature data, which would be really useful to meteorologists.

    I do notice in the write-up that the software is still a bit buggy — it reads 2 airborne aircraft at FL360, 0 kts.

  10. Roger Wolff says:

    The transmissions need to be unencrypted because all other aircraft need to be able to recieve them.

    Most bigger aircraft are nowadays equipped with the TCAS system: Traffic Collision Avoidance System. If a collision seems imminent (in the next 30 seconds or so) the system will warn of the possibility of a collision and recommend an avoidance strategy (up or down).

    I’m interested in building such a setup. But apparently the guys doing this have much more RF experience than I do. To build an antenna, I would need to measure SWR, which I don’t even know what it means, let alone that I have the equipment to measure it.

    I THINK I need to take apart an old satelite TV reciever, right? My father might have one of those….

  11. Glenn says:

    Actually, there is already several networks of ADS-B receivers hooked up online, that way they can share/combine their data to really useful tools, like getting good arrival times…

    Check-out http://www.flightradar24.com/ as one example.

  12. sariel says:

    you know if google poured some money into this and created a network they could upload the info to a maps function and give users a “real-time” look at where their flights are. would be cool to know if your plane is delayed from your Xg phone before its announced.

    • gw812 says:

      No way the guv’mint would allow it. You can already check out websites (flightaware and others) to see that info and can even find a .kml plug in for Google Earth, but the feds require that the info be delayed 5-15 minutes. Only thing you can get close to real-time is an airport arrival time

  13. Samson says:

    There are already a few commercially built units that receive and decode ADS-B transmissions. Some can be quite up there in price range. I went for a small usb stick one, from microadsb.com . Works great and I share my date with multiple websites that make it very pretty too look at, such as planefinder.net This is nothing new and nothing that the government is trying to crack down on so far.

  14. Adam says:

    Do military and government aircraft also transmit this information. At least once a day there is a fighter jet that flies low to my house and it would be neat to have a “heads up” when it is about to fly over.

  15. mungewell says:

    It’s interesting to note the there’s I2C on VGA output – so you could use that to drive the tuner and feed the received signal direct into a sound card to do a simple decode.

  16. Truth says:

    It would be really nice to see an open source SDR module for 1090MHz that could decode all the 112bit pulse position modulated data and verify the 24bits of parity. From these messages display the position and speed which is broadcast twice a second and the airplane ID which is send every 2.5 or 5 seconds depending on size of plane. And maybe the other status/intent messages sent every 1.7 seconds.

  17. mungewell says:

    Description of the pulse stream:
    http://www.radartutorial.eu/13.ssr/sr24.en.html

  18. liebesiech says:

    There is a website showing the airline traffic over the airport of Zurich, Switzerland on Google maps. For safety reasons there is a slight delay between the real position in the air and the position shown on the map. However, it’s quite cool. Similar to flightradar24.com: http://radar.zhaw.ch/radar.html

  19. bothersaidpooh says:

    Interesting note, it seems that people are repurposing old analogue TV tuners now the digital switchover is here.

    Often, removing the tuner does not affect the TV’s functionality at all and you can build a small transverter that generates baseband video and audio (iirc its 27.3 MHz) to feed into the TV’s chip.
    This means that in theory any TV can be digihacked if you can find a receiver small enough.

    I tried this on an old Sony VCR but had some problems because the tuner kept muting video if it didn’t see a valid signal on the antenna.

  20. bothersaidpooh says:

    Yeah, this is why you need to be very careful with radio projects.
    If your transmitter happens to have a harmonic where it shouldn’t (and many do) then it could disrupt something important.

    Always best to either buy commercial modules which are certified, or test your device at an EMC lab.
    Cost is relatively low compared with the >$10K fine

    • N0LKK says:

      All in all noting the possibility of spurious emissions from any RF device is a good idea, but state consequences should be realistic. QST regularly features RF projects. I have yet to read the suggestion that finished item be sent to a lab to test for spurious emissions outside the amateur radio allocations. Unless any interference is cause by blatant violations of FCC regulations a $10K+ fine is unlikely. At worst there will be knock at the door request that the FCC be allowed to inspect for a source of interference, and if found it will be carted off. In less severe cases you will receive a notice to repair the problem or stop using the equipment. Personally I’m unafraid to work with RF projects.

  21. AndroidCat says:

    The ADS-B data could be combined with ACARS transmissions for a real plane-spotters delight.

  22. kidcrash says:

    first use that comes to mind would be aircraft patrolled highway speed enforcement

  23. John says:

    Someone used to make a unit for purchase, it interfaced with your PC, had an antenna with it, a little black box and it did just what he is doing.

    • John says:

      Btw, this is not saying good job, its awesome he did this, im saying that obviously there not to worried about it, you can still hear planes on scanners, and track them via the internet, by the time you used the data you have they would be gone. And what else are you gonna do with this information. Not a whole lot.

  24. John says:
  25. mungewell says:

    For those looking for ‘out of the box’ hardware to experiment with SDR and/or GnuRadio, check out:
    http://www.funcubedongle.com/

    Intended as a HAM satellite outreach project, they have a ‘pro’ version which is 64K to 1.7GHz (80KHz bandwidth). USB ‘sound card’ providing IQ output direct into PC

    They also community written apps for Windows, Linux and Mac.

    (no affiliation, I just think it’s really cool)

  26. tonto says:

    The picture from the one day of activity looks like a map of the whole world. See all the countries??

    http://www.lll.lu/~edward/edward/adsb/oneday.jpg

  27. Marie Y. says:

    Thanks for sharing

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