Receiving images of Earth from satellites with software defined radio | Hacker News Reader

Receiving images of Earth from satellites with software defined radio

l-o-o-s-e-d.net

235 pointsl00sed79 comments

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/ but is better explored at 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

NorthEast US: https://twitter.com/satellite_NE

It's amazing to see storm formation visually.

Very cool!

github link to source? would live to build one for PNW

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.

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...

Yes, there is also a Reddit https://www.reddit.com/r/RTLSDR/

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.

> 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.

> 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...

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.

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.

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

>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.

Like any hobby?

This confused me. I swear I thought i wrote 'like any good hobby' at the end of the sentence. Totally agree!

Congrats, you made me purchase another gizmo. :)

Anyway, I'm a licensed HAM and I've played with electronics since forever. I was thinking to get a small SDR module to tinker with.

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!

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.

For those who are interested in submitting airplane data to the non-commercial ADSB-Exchange project, here are my extensive installation instructions: https://tomverbeure.github.io/2019/05/11/ADSB-Exchange-Feede....

Also note that Flightradar allows rich/famous people to pay to have their airplanes omitted from the display on the website.

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)

You can also look into receiving weather forecast from the sky: https://forums.othernet.is/t/wiki-pages-for-the-othernet-dre...

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

Buy this 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 - 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/

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/ , 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... (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/ (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.)

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

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

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

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

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/ I'm looking forward to the public release of the exercises from the qualifying round which will be on June 19.

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).

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

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.

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

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.

> images obtained from Soviet spy satellites

How did they obtain them? Were they not encrypted?

Sigint means - it is mentioned in the book GCHQ by Richard Aldrich.

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.

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)

Hug of Death? Couldn't find it in archive, so google cache it is https://webcache.googleusercontent.com/search?q=cache:https:...

Though I haven't read the article yet

https://archive.ph/o9YC3

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?

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

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.

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.

Look for "Full Disc" at https://www.star.nesdis.noaa.gov/GOES/

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.

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.

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.

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/

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...

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.

Even if the satellites are private, it is intercepting, not stealing.

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

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

Also (especially if it’s got sufficiently high resolution) it is almost certainly encrypted with Aes-256 or similar.

Early satellites, of which there may still be a few active, had analogue sensors and analogue modulation.

Can't AES encrypt analogue... Sure, various analogue scrambling schemes are possible, but they degrade the signal and add a lot of risk to the mission so theres a good chance they weren't used.

Hmmm. When someone steals another person’s notes or homework, I guess it could be called interception, but really it’s taking someone else’s work who hasn’t volunteered to give it to you and stealing is more appropriate.

Now, if it’s public, that’s different.

Legally, theft is taking some physical object from the legitimate owner through dishonest means. I don't think you're describing the theft of some pieces of paper here.

Colloquially, people use the word more loosely.

There is nothing inherently wrong with either use. The problem happens when there is confusion about which sense is being used. The legacy copyright rentiers of course do this deliberately.

What is taking IP?

You discover an antiviral for SARS-Cov2. Someone takes it without consent or permission? What is that, legally?

A big damn hero.

If they have deprived you of your discovery, then theft. If you retain your discovery, then copyright or possibly patent law.

Don't want your work intercepted? Just keep your radio signals out of my yard. Simple.

I remember being awestruck in about 1992, when our science teacher at school used an antenna and, I think a BBC micro, although it may have been an acorn, to receive images from weather satellites passing overhead. It was a brilliant educational experience.

Edit: looks like it was a BBC Micro, using AMSAT software and an ASTRID receiver. https://amsat-uk.org/2011/12/11/bbc-micro-and-amsat-uk-softw...

Wow. Thanks for this.

A teacher I had told a story about using this (or something very similar) with students in the 80s - they were asked (by the U.K. govt he said iirc) to destroy pics they’d got of the Chernobyl area around the time of the disaster.

That sounds apocryphal. Why would the UK ask them to destroy images of Chernobyl?

Why would that be? Because of the infrared? What would it have shown? Glowing reactor building?

I think its just a figure of speech here.

What is the figure of speech? Maybe I'm missing something, but 'stealing' is completely wrong in every sense of the word here IMO.

Stealing hearts is also horribly wrong, from the medical standpoint.

I think 'stealing' is a sensitive term in IT because of all the propaganda of the copyright cartels, conjuring visions of struggle, imprisonment and financial ruin.

"stealing hearts" is consistent with proper usage of "stealing". Stealing deprives the original owner, stealing hearts means that the person's "heart" belongs to you, they don't have a choice, they love you too the exclusion of all else. Sure, it's hyperbolic, but the usage is consistent within that context.

"The Great Imaging Satellite Heist Using SDR!"

Ok, we've s/Steal/Receiv/'d the title above.

+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

It still would not be stealing.

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

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

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

it's not stealing if they broadcast it unencrypted.

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.

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.

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