
Receiving images of Earth from satellites with software defined radio - l00sed
https://l-o-o-s-e-d.net/signs-of-life
======
enginoor
I feel that GOES satellite imagery is a hidden gem, I'm surprised more people
aren't working with it.

The imagery is available at
[https://www.star.nesdis.noaa.gov/GOES/](https://www.star.nesdis.noaa.gov/GOES/)
but is better explored at [https://rammb-
slider.cira.colostate.edu/](https://rammb-slider.cira.colostate.edu/)

I have personally built a Twitter bot to collect and animate imagery
throughout the day. I have it running for two locations currently.

Continental US:
[https://twitter.com/satellite_CONUS](https://twitter.com/satellite_CONUS)

NorthEast US:
[https://twitter.com/satellite_NE](https://twitter.com/satellite_NE)

It's amazing to see storm formation visually.

~~~
Yhippa
That is very cool, thank you. I just sat there and stared at it and had a Pale
Blue Dot moment. This thing is so beautiful and here we are fighting about
everything.

------
leetbulb
This is surprisingly easy to do with some cheap hardware[0]. There is plenty
of information if you just search something like "NOAA RTL-SDR." Building the
antenna is the most labor intensive part, but still very easily done. I
haven't personally, but it's on my to-do list for this summer.

[0] [https://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-
weat...](https://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-weather-
satellite-images/)

~~~
jcims
I would say it's one of those ruses where it's easy to get basic results, but
you can spend (tens of) thousands of dollars and years of learning and
refinement to achieve anything approximating error-free results.

It's a lot of fun though. Diving into SDR really opens up a new dimension of
reality to you and lays bare the magic that can happen when you are able to
directly apply complex mathematical constructs to real data coming out of a
wire attached to, well, nothign.

I got a little obsessed with it actually and had to step away from it for a
while lol.

~~~
leetbulb
> I got a little obsessed with it actually and had to step away from it for a
> while lol.

Same here. I burnt a ton of time just scanning for voice communications and
analyzing ADS-B. Once you start playing around in GNU Radio and decoding more
exotic stuff, you really start going down the RF rabbit hole. It's an amazing
hobby for learning about electronics.

~~~
looklookatme
> Once you start playing around in GNU Radio and decoding more exotic stuff

Do you have any tips or resources on how to get to a competency level where
you get to decode arbitrary digital signals you find from a scan?

I've read through all the GNU Radio documentation, along with the examples on
their wiki and have even written my own blocks but keep finding that opening a
grc file that someone else authored, there will be a critical block I've never
seen before (and likely, never see again) which hampers experimentation. As
soon as I attempt to decode a real-life signal, it feels like I dove in too
fast -- there's too many unknowns, since the end result is [presumably] not
going to be a nice, human-readable string. However, occasionally, I find
challenges like [1] which are great, since you have the expectation that the
signal _can_ be decoded; it's just that I've found examples like these to be
quite rare.

[1] [https://www.gnuradio.org/blog/2018-02-21-gnu-radio-
challenge...](https://www.gnuradio.org/blog/2018-02-21-gnu-radio-
challenge-21-feb-2018/)

~~~
jcims
Not the person you asked but once gnuradio flowgraphs started to function
materially outside of basic flowgraph blocks stitched together, or worse,
wrapped by some python script, I would have to tap out.

It's one thing to demodulate some manchester encoded OOK/FSK signal from some
ISM-band hardware monitor vs. 64-QAM or GMSK. At some point it, to me, becomes
indistinguishable from magic. Fluency in DSP is, IMHO, mandatory to be broadly
effective with GNU Radio.

~~~
timeinput
I'm fairly fluent in both DSP and software, and find GNU radio indecipherable.

A plain C/C++ implementation is often so much clearer than a flow graph built
in python.

~~~
jcims
Copy that. By far the most informative bit of dsp code for me was the core
libraries in SDRSharp.

------
jonpurdy
Somewhat related. For those who are new to SDRs, you can easily view airplane
altitude, heading, speed, and other stats of passing aircraft with a cheap
SDR. Aircraft transmit this using ADS-B and it's totally open and unencrypted.

FlightAware (among other services) work by aggregating data from users around
the world. You can even get a free premium subscription to their service by
contributing. Easiest way is to use a Raspberry Pi, install their software
(much easier now than back in 2013!), and you're good to go!

~~~
mysterydip
I've said this before, but the first time I hooked up an RTL-SDR and tuned it
to 1090 and saw live air traffic, I was awestruck. Sure the same info was
available on flightaware, but something was special about being able to
retrieve it myself.

------
mhh__
Anyone interested in how SDR works/is implemented: the book "Software defined
radio for engineers" is the only book I've come across that combines DSP and
SDR in the right ratios (Proakis's DSP book is bad if you want to build things
straight away)

------
jbj
You can also look into receiving weather forecast from the sky:
[https://forums.othernet.is/t/wiki-pages-for-the-othernet-
dre...](https://forums.othernet.is/t/wiki-pages-for-the-othernet-
dreamcatcher/5314)

------
adwi
A few posters have mentioned this being accessible with inexpensive hardware.
Any tips on how someone starts getting into SDR stuff?

~~~
throwaway3neu94
Buy this [https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/](https://www.rtl-
sdr.com/buy-rtl-sdr-dvb-t-dongles/) (even available on Amazon)

Use gqrx to listen to the radio, public services / air traffic (if legal where
you are. Great fun at airshows), ham radio operators etc
[https://gqrx.dk/download](https://gqrx.dk/download) \- requires minimal
knowledge to get started (select device, put in frequency, mode (AM or FM) and
that's it. Just play). Great time:benefit ratio so far.

There's an excellent video series focusing on SDRs at
[https://greatscottgadgets.com/sdr/](https://greatscottgadgets.com/sdr/)

Then use gnuradio to build your own receiver from predefined blocks.

Start with above cheap receive only SDR, but when you want to transmit, buy a
HackRF. You do need a ham radio license to transmit. It's not hard (not even
highschool level math). Even if you don't do the license, have a look at the
materials linked at
[https://blog.hamstudy.org/links/](https://blog.hamstudy.org/links/) ,
specifically the linked book (free PDF or paid printed). The fundamentals are
excellent and it picks you up where most people are (high school math skills,
no idea about RF). If you speak German, the best resource is
[https://www.darc.de/der-club/referate/ajw/darc-online-
lehrga...](https://www.darc.de/der-club/referate/ajw/darc-online-lehrgang/)
(also available as printed book)

At that point you should have a better idea where to go, and even enough
background to read "real" books like
[http://www.dspguide.com/](http://www.dspguide.com/) (the math is harder of
course). DSP is what SDR is all about in the end. But also other radio related
books, like the ARRL antenna book.

(There are alternatives to everything of course, but with above
recommendations you will not go wrong.)

~~~
dbhattar
Not sure why you would create a throwaway account to post this invaluable
information.

~~~
dewey
It's a 4 month old account, not created to just post this.

------
cushychicken
Can't hack the dense, overly-arty prose.

~~~
l00sed
Haha I do apologize for my writing style. Trying to work on that.

------
7kay
The title first suggested that the article is about a security vulnerability
of a satellite. The DoD actually held a CTF recently focused on the security
of space systems. Information is on
[https://www.hackasat.com/](https://www.hackasat.com/) I'm looking forward to
the public release of the exercises from the qualifying round which will be on
June 19.

------
axegon_
This is incredibly cool!!! Kind of had a similar weekend RTL SDR project in
the back of my mind for quite a while but like a lot of things lately, it's
been a classic case of kicking the can. I really wish I could dig up some
motivation from somewhere(in general, not just this).

~~~
l00sed
It certainly takes time and dedication to go through the steps, but I'd
recommend The Thought Emporium for getting started:
[https://youtu.be/cjClTnZ4Xh4](https://youtu.be/cjClTnZ4Xh4)

------
aasasd
So, if people say here that plenty of folks receive satellite imagery, are
there projects to assemble a complete map of the planet and have it
continually updated? As in, you know, a satellite view for OSM.

~~~
aasasd
Though, if this imagery is the same as what's on [https://rammb-
slider.cira.colostate.edu](https://rammb-slider.cira.colostate.edu) — then its
resolution is apparently on the level of ‘I can see mountains’.

------
arethuza
During the Falklands War the Norwegians gave the UK a constant stream of
images obtained from Soviet spy satellites that gave very good information on
the position of the Argentinian Navy.

~~~
tomato2juice
> images obtained from Soviet spy satellites

How did they obtain them? Were they not encrypted?

~~~
arethuza
Sigint means - it is mentioned in the book _GCHQ_ by Richard Aldrich.

------
dghughes
As a young teen in the early 80s I read about a project that used an FM radio,
a printer, and a bit of code to detect meteoroids. When the meteoroid became a
meteor it gave off a frequency in the FM range.

I liked programming but wasn't good at it and didn't understand what I needed.
I wasn't sure if my Atari 600XL was suitable for the project but I do believe
the code was BASIC which the 600XL could run. And I didn't have a printer
which at the time was like owning a unicorn.

------
ethbro
Also, "How not to optimize a webpage for HN."

(Said with loving snark, as a former architecture student and knowing exactly
why all the bells and formatting whistles were thrown in)

------
zwirbl
Hug of Death? Couldn't find it in archive, so google cache it is
[https://webcache.googleusercontent.com/search?q=cache:https:...](https://webcache.googleusercontent.com/search?q=cache:https://l-o-
o-s-e-d.net/signs-of-life)

Though I haven't read the article yet

~~~
encom
[https://archive.ph/o9YC3](https://archive.ph/o9YC3)

------
praveen9920
This is interesting data. Are there any online services which stream this data
over internet?

AWS has an offering called Ground station. Can we use it to get same data?
Anyone worked on it before?

What kind of license apply to this satellite data? Can we use it for
commercial purposes?

~~~
Spooky23
Work product of the US government is in the public domain.

~~~
l00sed
Something I'm not sure of is whether or not I could legally sell these images,
but as others have noted it's really "intercepting" signals rather than
thieving. With an antenna and a raspberry pi, however, it certainly feels like
a dangerous or exciting thing to be able to "hear" these signals.

~~~
Spooky23
You absolutely can, by design they are open to all.

Major businesses are basically built on this data. So much so that nasty
players like Accuweather want to limit access to public research and shut down
weather.gov so that they can more readily monetize it.

------
jcun4128
Man that's awesome... crazy how your brain is "zoomed in" to your daily
life/forget zoom out on this rock in nothingness like a film of bacteria.

------
jungletime
Are any of those images of earth and space released to public domain, since
NASA is a government agency? Especially video. I would like to use a clip for
Youtube.

------
amelius
Who do we have to thank for not encrypting this data?

PS: Aren't these images available on the web anyway?

Well, if not, perhaps this project could change that.

------
tomato2juice
I wouldn't call this stealing? Maybe "catching"? I've been following a related
subreddit on this topic that might be useful to the hackers here:
[https://www.reddit.com/r/RTLSDR/](https://www.reddit.com/r/RTLSDR/)

------
jrockway
Stealing? The NOAA satellites exist for you to receive the signals; the NOAA
even offers a detailed guide on how to build a receiver:
[https://noaasis.noaa.gov/NOAASIS/pubs/Users_Guide-
Building_R...](https://noaasis.noaa.gov/NOAASIS/pubs/Users_Guide-
Building_Receive_Stations_March_2009.pdf)

The introduction even reads like this art project: "Satellites provide us with
a unique and long-sought after opportunity to look at Earth from space. These
spacecraft now enable us to observe and measure the many forces of nature
which converge on our planet. Mankind can now observe the global nature of the
environmental factors which interact to form the complex systems we call
Earth. From the unique vantage point of space, sophisticated
environmental/weather satellites bring us information about cloud formations
and movements, precipitation amounts, temperatures, ocean currents, sea
surface temperatures, air and water pollutants, drought and floods, severe
weather conditions, vegetation, insect infestations, ozone content of the
atmosphere, volcano eruptions, and other factors that affect our daily lives.
They have also provided us with less tangible aesthetic values which help
shape attitudes about the environment of this planet. This global attitude is,
perhaps, just as important as the hard data that the satellites provide."

I was hoping that this was some security vulnerability that let you receive
images from private satellites.

~~~
globular-toast
Even if the satellites are private, it is intercepting, not stealing.

~~~
gruez
Some call copyright infringement "stealing" as well. Also, "stealing"
someone's idea.

~~~
kube-system
Works by the US government are generally in the public domain and not eligible
for copyright.

------
stjo
+1 for cool project; -1 for baity title

as jrockway said:I was hoping that this was some security vulnerability that
let you receive images from private satellites

~~~
YayamiOmate
It still would not be stealing.

I believe copying information from a commuication channel without autorization
is called eavesdropping.

------
annoyingnoob
Connection timeout. Seems that someone is 'stealing' your bandwidth.

~~~
ASalazarMX
"At the end, Daniel Tompkins revealed that the readers of Hacker News were
tricked into doing the image heist themselves. Brilliant."

------
dekhn
it's not stealing if they broadcast it unencrypted.

~~~
preinheimer
It's interesting that somehow doing math to something sent to your house
unsolicited would make it stealing.

I'm not trying to argue with you, I just think it's a weird place to end up
legally.

~~~
dekhn
The way I think about it is: it's generally accepted that news reporters can
go through the trash you throw in a garbage bin and leave on the street. If
you want to protect your privacy, shred your trash or otherwise deny physical
access to reporters.

The burden is on the transmitter to protect their asset and if they don't,
they're negligent.

