
What’s Flying Above Us? - zuhayeer
https://skycircl.es/donate/
======
jjwiseman
Hi! I made this.

A few points I wanted to make, specific to the HN context (and a lot of this
is in the "nerd mode" donation page at [https://skycircl.es/donate-nerd-
mode/](https://skycircl.es/donate-nerd-mode/)):

1\. This seems like a classic "low effort, high impact" project. It's super
easy to detect aircraft flying in circles, in real-time, and post it to
twitter. But it turns out to be an entry-point into a "strangely interesting"
(according to pg) world of aircraft activity.

The current #1 comment sadly only gets to see general aviation pilots
practicing, but my bots have tweeted military aerial refueling, STOL practice
in the wilderness, float-planes practicing on rivers and lakes, military
drones flying over the desert, planes dropping sterile fruit flies as a way to
reduce the fruit fly population, news helicopters following a highway pursuit,
U.S. Forest Service AH-1Z Viper attack helicopters fighting fires, helicopters
dropping mosquito pesticide, aerial tankers over Manhattan for the president's
combat air patrol, FBI surveillance planes registered to front companies,
Coast Guard helicopters doing search & rescue, crop dusters, scientists
observing sea life over the ocean, planes doing Gorgon Stare-style persistent
surveillance over Baltimore, sheriff's helicopters rescuing hikers, power line
inspections, pipeline inspections, military aircraft doing surveillance over
protestors, stealth jet test flights, a Grumman HU-16 Albatross seaplane that
belongs to the USAF over the Mojave desert, a U-2 test flight, and a B-29.
That is not even close to a complete list.

2\. All the code is open source. See [https://gitlab.com/jjwiseman/advisory-
circular/](https://gitlab.com/jjwiseman/advisory-circular/) and
[https://gitlab.com/jjwiseman/whatsoverhead](https://gitlab.com/jjwiseman/whatsoverhead)

3\. As far as I know, this comment on HN is the first time anyone published
any significant detail about the FBI's secret aerial surveillance program:
[https://news.ycombinator.com/item?id=9508812](https://news.ycombinator.com/item?id=9508812)

~~~
neop1x
Interesting project, thanks! But it is also important to mention AdsbExchange
as the data source. They have quite a big expenses on AWS to keep it running
and unlike FlightRadar24 or similar they doesn't censor any aircraft or take
blocking requests by aircraft owners which is reasonable considering this data
is public an anyone with sdr-compatible dvb-t dongle can receive them.

~~~
Aeolun
That is a very unfortunate name. I don’t think I’d ever click a link called
adsbexchange if I didn’t already know what it was.

------
reaperducer
I have a flight tracking app for my phone and see aircraft flying in circles
over where I live all the time. Dozens and dozens of times each day.

They're people in small planes practicing.

Also, I live near several military bases. The interesting and loud stuff that
I see flying by out my window NEVER shows up on any app. I expect this web
site is similarly, deliberately, incomplete.

~~~
nja
> I expect this web site is similarly, deliberately, incomplete.

Perhaps less incomplete than you think (and certainly more complete than the
standard tracking websites, which outside of hiding planes also must honor a
5-minute data delay requested by the FAA).

The advisory circular bots the author runs link to
[https://tar1090.adsbexchange.com/](https://tar1090.adsbexchange.com/) , which
is run from a home-grown network of SDRs. It makes a point of not hiding
anything that reports its position with ADS-B -- which all aircraft (over a
certain size) must report by law. I've even seen Air Force One and its escorts
on this service, something that is always absent from other flight tracking
services.

~~~
jakub_g
> 5-minute data delay requested by the FAA

Can you expand on this for the noobs in the subject?

~~~
dmitrygr
so you cannot trivially go hit something with a ground-to-air missile.

why the downvotes? this was the actual stated reason when this was requested

~~~
jaywalk
Umm, well, there is this issue that you can actually _see_ the plane without a
delay, so...

~~~
kingbirdy
Requiring a line of site makes it much more difficult than giving real-time
tracking data away

~~~
TerrorKing
That's why The Rurists (Terrorists) try to hit a plane when it takes off or
lands. Easier to hit. Even with a stinger. Just hang out by the airport with
your favourite Stinger Launcher and you're good to go. No need to hit it at
30,000 feets. I'd hit it at landing takeoof the ground taxiing etc. Works for
me.

~~~
rfrey
No wonder that’s why 9/10 of the weekly terrorist takedowns of aircraft I read
about are near airports.

------
swalsh
Reminds me of a program I read about a while ago in Iraq. Planes would circle
cities with a camera and some huge hard drives installed. If an IED went off
they would rewind the tapes, and watch every stop the people who planted it
went through before and after planting the bomb. From that they could unwind
very complex networks of insurgent activity. The equipment was mostly off the
shelf, and relatively cheap.

~~~
avh02
"In Iraq" \- they did it over US cities as well [0]. To be fair, I read that
link a long time ago and don't remember the specifics of how long it ran and
if it ran in more cities.

[0] - [https://www.bloomberg.com/features/2016-baltimore-secret-
sur...](https://www.bloomberg.com/features/2016-baltimore-secret-
surveillance/)

~~~
coldpie
Yes, such drones have been flying over US cities with unrest this year as
well[1]. It's likely surveillance in the form of ARGUS-IS[2], as it was
reported to be on the platform used by the Gorgon Stare project[3].

[1] [https://www.forbes.com/sites/krisholt/2020/05/29/cbp-
predato...](https://www.forbes.com/sites/krisholt/2020/05/29/cbp-predator-
drone-minneapolis-george-floyd-aclu/)

[2] [https://en.wikipedia.org/wiki/ARGUS-
IS](https://en.wikipedia.org/wiki/ARGUS-IS)

[3]
[https://en.wikipedia.org/wiki/Gorgon_Stare](https://en.wikipedia.org/wiki/Gorgon_Stare)

------
kanobo
The most interesting reading is in the 'tracking police helicopters' slidedeck
linked in the site: [https://docs.google.com/presentation/d/1sowJrQQfgxnLCErb-
CvU...](https://docs.google.com/presentation/d/1sowJrQQfgxnLCErb-
CvUV8VGXdtca6SWYWWLRPZgaHI/edit#slide=id.g5086fd3e26_0_51)

------
salex89
To those who notices planes flying in circles, it doesn't have to be anything
sinister. Those might be planes calibrating avionics or ground/airport
equipment or doing test flights after maintenance. I have agencies in the
region doing both, so you can sometimes find planes doing strange patterns
which are their clients.

~~~
spyspy
Commercial flights will also enter a circular holding pattern around airports
if they're not allowed to land for some reason.

This video is a really cool example:
[https://www.youtube.com/watch?v=SdfVIdsufI8](https://www.youtube.com/watch?v=SdfVIdsufI8)

------
motohagiography
When I was tracking flights some years ago (use case was determining whether
speed monitoring aircraft were in the air, and a prediction model of their
schedule) I learned that the ADS-B transmitters didn't need to broadcast GPS
co-ordinates below a certain ceiling. You could get the signal that a given
tail number was in the air, but if it stayed below a certain altitude, you
couldn't always receive its location.

The FAA has guidelines on what kind of data you can receive:
[https://www.faa.gov/nextgen/equipadsb/research/airspace/](https://www.faa.gov/nextgen/equipadsb/research/airspace/)

I lost interest in it because I just don't speed that much and I don't have a
sport bike fast enough for it to matter, but useful to know that ADS-B doesn't
cover all aircraft.

~~~
Scoundreller
> You could get the signal that a given tail number was in the air, but if it
> stayed below a certain altitude, you couldn't always receive its location.

I believe trackers (like ADS-B exchange) will estimate location using
mutlilateration. IE: enough receivers with GPS-sync’d time and knowing where
they are can estimate origin with the differences in receipt timing.

With good enough equipment, even one ground station might be able to tell a
lot with Doppler shifts. Unsure if that’s don’t in practice though.

~~~
sorenjan
They use multilateration, but there's no GPS synced clocks needed. They use
ADS-B messages with position as reference and uses the relative arrival times
of those messages to model the clock characteristics of each receiver. That
way all you need is an inexpensive receiver (like a RTL-SDR) and with enough
receivers in an area you'll get pretty good position estimates of aircraft
only transmitting Mode S messages.

This is the most popular mlat server software, used by ADS-B Exchange among
others: [https://github.com/adsbxchange/mlat-
server](https://github.com/adsbxchange/mlat-server)

------
sbisson
I ended up using some lockdown time to put together a Pi-based ADS-B receiver,
as I live close to the main low-flying helicopter route through London. I've
chosen to feed data to a mix of services, including ADSBexchange which powers
those bots, so some of the data there comes from my receiver; which has a
surprisingly long range with a decent antenna: I'm regularly tracking aircraft
190 or so miles away...

You can set up a system for under $120 with a good antenna and a 1090MHz-
filtered software defined radio stick. I use the Piaware distribution, which
sets up the basic software needed to feed data and to generate your own maps.
An added bonus of being a feeder is that you can get free access to commercial
ADS-B networks like Flightradar...

------
zobzu
it seem cool but it bothers me that this is a link to a donation page and that
its been obviously made to request money, rather than show the service
provided

------
shanecleveland
I find it oddly satisfying to be able to use an app on my phone to identify
planes above me. Do it all the time. I live across the Puget Sound from
Seattle and I occasionally end up spotting a Boeing plane clearly on a test
flight based on the route it has flown (geometric shapes, circles, take-off
and return same airport).

Also had an interesting occurrence when I awoke to the sound of a plane dive-
bombing my house. We happened to be located in an area designated to be
sprayed for some sort of moth. The plane was just about scraping the tops of
trees. But I was able to track and see the pattern it flew to spray our area
and other areas it had visited that morning.

------
gentleman11
I hope visitors are able to donate. Things have been tight this summer for a
lot of people

------
irrational
TIL about iOS shortcuts. This shortcut is pretty cool. But the nearest
airplane comes up as private and now I’m paranoid it is an FBI surveillance
plane when it is probably just going to/from the local small field airport.

~~~
FBI4Life5
Why worry about the FBI if you're not in any of the categories where they have
a reason to act? I doubt they care about your legal activities. They've
probably got better things to do.

~~~
zingplex
"Arguing that you don't care about the right to privacy because you have
nothing to hide is no different than saying you don't care about free speech
because you have nothing to say."

\-- Edward Snowden

With regards to the FBI not caring about your legal activities, I recommend
you look into the FBI blackmailing of Martin Luther King Jr. and COINTELPRO
more generally. Their historic behavior doesn't exactly warrant trust.

~~~
purplerabbit
Hiding something and expressing something are so nearly opposite that I don't
see how Snowden's analogy holds

~~~
zingplex
What he is doing is simply restating the "I have nothing to hide" argument in
the context of a different right, in this case the right to free speech. He is
doing so to illustrate that the argument is not presenting a justification for
the systemic violation of a human right but instead relying on an unstated
assertion that the a given persons disinterest in a specific legal protection
is an adequate pretext for its removal.

~~~
purplerabbit
That actually makes sense. Thank you for your reply.

~~~
zingplex
My pleasure

------
EvRev
Recently we had a suspect run through the yard. It was terrifying and had I
not been hanging out on the back room I would not have been able to lock the
door before he got in. The initial tip off that something was off was the CHP
plane flying in circles above.

Now when I hear the aircraft above us I instantly check its pattern and lock
all the doors.

------
bengotow
Oh jeez this is cool. The least we can do is get this guy a working Macbook
Pro to continue his work. Donated!

------
arkanciscan
I love what you're doing, but where's your website? You've got Twitter bots,
but I'm not on Twitter, and a Siri integration but I don't own AAPL products.
It makes me sad to see such useful data siloed in closed platforms.

~~~
jjwiseman
I'm not happy about the dependence on twitter, either, but that's the platform
that people are on, so that was my priority. Eventually I would like to run a
Mastodon instance or other ActivityPub system.

~~~
arkanciscan
But why no website?

------
bhaile
I've also used Wolfram Alpha for similar information.
[https://www.wolframalpha.com/input/?i=what+planes+are+overhe...](https://www.wolframalpha.com/input/?i=what+planes+are+overhead+now)

------
shruubi
How can this claim to be "all over the world" when your examples are "Los
Angeles, Baltimore, Portland, Minneapolis, and London."

Last I counted, four of those five are in the same country. The world does not
begin and end in America.

~~~
jjwiseman
Oh my goodness, Mr. literal over here. There are currently 3 continents
covered by Advisory Circular bots. There are actually more Australian cities
than American cities covered.

You can see the complete list of bots here:
[https://twitter.com/i/lists/1263724487435890688/members](https://twitter.com/i/lists/1263724487435890688/members)

------
iNerdier
Maybe a link to the actual bots in the page rather than to a tweet with a
twitter list that doesn’t seem to work would be helpful to, you know, actually
see what’s going on?

~~~
jjwiseman
This is the first I've heard that the twitter list doesn't work. What's the
issue?

------
ShradhaSingh
“Hey, Siri, what's overhead?”

------
pps43
Will probably see TACAMO relay aircraft with VLF trailing wire antennas.

------
linhchi
hey, in the slide there was a part that says that surveillance planes
typically flight in a couterclockwise circle. does anybody know why and can
explain to me? thanks

~~~
wheaties
Pilots are in the left seat, you get more visibility that way if you're
"leaning" the plane to fly left circles.

~~~
linhchi
ohh, thanks a lot

------
thatsillyqaguy
How would you feel when criminals use this?

~~~
jjwiseman
Criminals can go to any of the commercial flight trackers and see most of this
stuff, or to adsbexchange.com.

------
think_about_it
Someone needs to mention xkcd.com/1910/.

------
tekkiweb
Nothing!

------
microcolonel
Cute, though I suspect the FBI have known the public knew about this, and
alter their patterns for the most sensitive investigations. The real deal
would be detecting when aircraft are in any cycle, regular or irregular, with
similar visibility of a set of likely “targets”.

~~~
toomuchtodo
You might reach out to this author. Such a feature would be trivial to
implement.

~~~
microcolonel
I might just do that; though you should see my list of side projects. There
only so many hours in the day.

