The Cat, The Aircraft, And The Tiny Computer

Sharing your life with a cat is a wonderful and fulfilling experience. Sharing your life with an awake, alert, and bored cat in the early hours when you are trying to sleep, is not. [Simon Aubury] has just this problem, as his cat [Snowy] is woken each morning by a jet passing over. In an attempt to identify the offending aircraft, he’s taken a Raspberry Pi and a software-defined radio, and attempted to isolate it by spotting its ADS-B beacon.

The SDR was the ubiquitous RTL chipset model, and it provided a continuous stream of aircraft data. To process this data he used an Apache Kafka stream processing server into which he also retrieved aircraft identifying data from an online service. Kafka’s SQL interface for interrogating multiple streams allowed him to untangle the mess of ADS-B returns and generate a meaningful feed of aircraft. This in turn was piped into an elasticsearch search engine database, upon which he built a Kibana visualisation.

The result was that any aircraft could be identified at a glance, and potential noise hotspots forecast. Whether all this heavy lifting was worth the end result is for you to decide, however it does provide an interesting introduction to the technologies and software involved. It is however possible to monitor ADS-B traffic considerably more simply.

Thanks [Oleg Anashkin] for the tip.

29 thoughts on “The Cat, The Aircraft, And The Tiny Computer

      1. Most of the ones that are blocked by FR24 are still visible if you have your own ADSB receiver… and starting next year ADSB Out will be mandatory for all planes flying in any kind of controlled airspace. I frequently see private jets leaving town after major sporting events that are not shown on FR24.

  1. It all sounds a lot more technological than when I had to do this as a job in the summer of 1987.
    I had a summer job monitoring aircraft noise around Gatwick airport for the CAA. We basically sat in a field at a sutable distance from the airport while listening to the air traffic control radio and looking at the aircraft. By correlating aircraft type / airline to the radio conversation we were able to determine which aircraft each noise measurement corresponded to.

    The strangest part of the job was a measurement of energy of some point. The measurement hardware would integrate the sound pressure (dB) measurement. So we had to press one button as the nise rose past 80% of the peak SPL and then again as the sound reduced below it. This was obviously a rather imprecise process, as there was no way to determine the peak value at the point of the first press.

    We also did a few measurements at Heathrow, and it was our measurements that saw the last of the 707s banned from there. (Air Zimbabwe). Ironically I was, at the time, living directly under the Heathrow glide path, significantly closer to the end of the runway than the official monitoring points. The highest measurement I took all that summer was taken for fun, in my own back garden.

    1. I’ve noticed that the EU hasn’t been allowing ‘hush kits’ on various aircraft, even if when equipped they bring the noise down to or below restrictions. The FAA and various other countries’ aircraft regulating bodies also tend to make it difficult or impossible to upgrade jetliners to newer, quieter, more efficient engines.

      Smells like collusion between Boeing and Airbus and governments to simply ban older planes so airlines have to buy new planes to meet new regulations.

      It’s the same idiocy that’s been keeping the US Air Force’s B52’s from getting new engines to make them quieter, faster, more fuel efficient, have longer loiter time – and cost a hell of a lot less to maintain. Nevermind the contract would be for around 1,000 engines to replace all the engines on the planes in active use plus have plenty for spares for fast service replacement and to have engines for until the planes my finally be retired – sometime in the 2050’s. With 58 in active service + 18 reserve, it would take 608 engines to refit them all. 1,000 would be an ideal number to order.

      1. Modifying and re-certifying an older aircraft to use new engines is an extremely expensive and time consuming thing to do. For most older planes it is simply not worth the money.
        As for the air force and the B52…. I don’t know why they don’t do it.. except money I suppose.

  2. cats are night active animals, so which countermeasures does this guy plan? a 3.5cm anti aircraft cannon which wakes up the whole lane? i live on the flight path (wind depending) of vienna airport and i dont care at all – even more contrary i couldnt find sleep when there was the vulcanic ash shutdown of flights, because it was so silent…..

    1. Why do you imagine there will be countermeasures against the aircraft? Clearly it’s only [Snowy] who has the trouble sleeping, perhaps [Simon] can find a way to encourage some kitty snores when the aircraft are overhead.

  3. This is a clever build but is unlikely to change the nature of a cat very much – Simon may find that his first assumption (that an un-jetted cat won’t wake up early and won’t decide it’s party/breakfast time) is invalid.

  4. Look you’re not seeing the application…

    When that aircraft transponder is noticed and the location where the noise becomes loud enough to wake the cat…give it a red dot on a treadmill to charge the battery bank for the Pi.

    Aircraft fed perpetual motion, you decide.

  5. I live where lots of small aircraft fly around for tourism. Some fly low over the ocean during heavy fog to keep inside the VFR flight parameters. A few decide to fly directly over my house at sub 500′ to shorten the flightpath to get the tourist to their cruise boats in time. They don’t do that as much anymore. I got a drone and put it up when they are around, Tethered to 400′, and I took photos of the offending planes with registrations and sent them up to the FAA’s headquarters in our state.

    I simply asked the FAA to find a way for both parties to share the airspace over my home. I asked if its ok for them to flow so low if it was ok for me to fly higher? Mind you I don’t mind the aircraft or the fact that the pilots are trying to show some tourists a good time and the money comes into our local economy. All fine. However flying over peoples houses just a few feet above treetop. That’s got problem written all over it.

    My first thought was something like this article. Some way to use ADS-B or something to find the aircraft. That’s when I found that ADS-B for smaller aircraft is on another channel and you enter the rabbit hole from there. Unfortunately I don’t think my solution would work for this poor cat. :)

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