
A Minimal LRIT GOES Receiver - brian-armstrong
https://pietern.github.io/goestools/guides/minimal_receiver.html
======
pietern
Hi everybody, cool to see this submitted on HN. I'm around for questions so
ask away.

Also beware that the guide is a little out of date:

1) the listed antenna is no longer available, but there are comparable ones
for comparable or lower price, and

2) the SAWBird has been generally available for a couple of weeks.

~~~
jonah
Very cool, having some of the parts already, I'd love to build one of these.

A couple (unrelated) questions:

1) GOES _receives_ data from remote terrestrial weather stations too,
right?[1] Is that aggregated and rebroadcast in a way we can receive it?

2) Is data from MODIS available similarly to GOES?

[1] [https://ftsinc.com/fire-weather/products/axiom-
dataloggers/a...](https://ftsinc.com/fire-weather/products/axiom-
dataloggers/axiom-datalogger-features/#1439599320345-26669a70-06b0)

~~~
pietern
Great, if you end up building one, keep us updated (here or on Twitter).

1) Yes, this is DCS (Data Collection System) data. It's a very low bandwidth
signal (300 or 1200 baud) that ground stations uplink to GOES on UHF. I found
there are about 20k separate transmitters in some asset database I once found
somewhere. Every one (or the set that's still active) transmits a tiny packet
every N minutes (some every minute, others every 30 minutes). This data is
also broadcast as part of the LRIT (GOES-15) and HRIT (GOES-16 and GOES-17)
streams. There is no processing for this data in the goestools package yet,
but you can get the originals and walk over the data. When I last looked at
it, the format looked different per receiver, it is possible this is a per-
vendor type of thing. Anyway, yes, you can get a copy of this data with the
receiver described in the OP guide. See
[https://github.com/pietern/goestools/issues/11](https://github.com/pietern/goestools/issues/11)
for some more links.

2) AFAICT MODIS is a product derived from the Aqua and Terra satellites. Both
are polar orbiting sats. You can look them up here [https://www.wmo-
sat.info/oscar/satellites/view/81](https://www.wmo-
sat.info/oscar/satellites/view/81) and it looks like they don't pack a "direct
readout" transmitter, so you wouldn't be able to receive anything directly
yourself. Compare this to the page for GOES-16 at [https://www.wmo-
sat.info/oscar/satellites/view/152](https://www.wmo-
sat.info/oscar/satellites/view/152) and you see there are a bunch of
frequencies with details listed.

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lxe
This guide is what got me diving into the world of software defined radio and
telecommunications in general. Building this thing has been one of the most
rewarding side projects. It really makes you appreciate how many interesting
technologies and ideas are there between "the electromagnetic spectrum" and
"bits per second".

~~~
pietern
That is awesome to hear! Building this has been a fun side project and I'm
happy to hear it sparked interest for you as well.

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lallysingh
So GOES looks to be an imagery satellite, right? And LRIT is some aspect of
it's method of communication?

A few explanatory words in the title here, at the beginning of the article
would really help. I'm surprised it made first page without them. The author's
work is rather cool, though!

~~~
lxe
[GOES-R/GOES-16]([https://en.wikipedia.org/wiki/GOES-16](https://en.wikipedia.org/wiki/GOES-16))
as well as
[GOES-S/GOES-17]([https://en.wikipedia.org/wiki/GOES-17](https://en.wikipedia.org/wiki/GOES-17))
are geostationary weather satellites operated by the NOAA.

They broadcast some of their imagery using a format they call LRIT or HRIT
(High Rate Information Transmission). You can follow this guide to build a
receiver using inexpensive components to tap into that stream.

------
coolspot
Is it possible to receive Solar Ultraviolet Imager (SUVI) images? Didn't find
it in the documentation.

~~~
pietern
It's not. The SUVI data is not broadcast on the HRIT feed, only on the GRB
(GOES ReBroadcast) feed. Receiving GRB requires more effort: minimum 10ft
dish, dual circular polarized feed, DVB-S2 demodulator, and different
software. Never tried this, but would make for a fun project.

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RivieraKid
Is the near-realite GOES imagery available to download over the internet?

Recently I've been looking for a way to download near-realtime Meteosat
imagery. I thought, ok, I'll just download it from their web server. Turns
out, you have to use a satellite antenna, receiver and buy commercial
software... WTH? This is ridiculous in the 21th century. Why not put the
imagery on the internet, for free?

~~~
pietern
Yes, there are multiple interfaces.

This is a nice interactive one: [http://rammb-
slider.cira.colostate.edu/?sat=goes-16](http://rammb-
slider.cira.colostate.edu/?sat=goes-16).

There is also an S3 bucket where you can find all data as soon as it is
available: [https://registry.opendata.aws/noaa-
goes/](https://registry.opendata.aws/noaa-goes/).

But the fun part is receiving it in your backyard, of course ;)

~~~
RivieraKid
Thanks! The S3 bucket is how it should be done.

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guywhocodes
I wonder what a flat-earther would say about this backyard satellite
photography example

~~~
rdtsc
Flat-earthers are fascinating. As long as they are not dangerous to themselves
and others they are a good subject to study on how brainwashing, paranoia, and
reality bubbles work. Also I wonder if some of them are secretly trolls. They
don't believe it, but they spread it around to try to get others to believe
just for fun. Then they also got a nice "mark" that's ripe for other cons and
possibly to profit from ("send me PayPal money to buy this super secret flat
Earth detector for $500"). I imagine their community is a goldmine for con-
artists...

~~~
guywhocodes
About nine years ago I found out a friend of mine was a "flat-earther" online.
He was very much under the impression that it was mostly an insincere and
sarcastic group of people mostly trying to trick people that they actually
believe this.

Today I'm not sure if 1\. He was wrong about the movement. 2\. They succeeded
in convincing me and most of us they believe more than they do. 3\. They
convinced and attracted people and they actually on average do believe that
the earth is flat.

~~~
rdtsc
> Today I'm not sure if 1...2 or 3...

Yeah! That's exactly what's fascinating about it.

I've met a contrails believer and, sadly, I was sure they actually believe it.
But flat earthers are in a whole separate category where it is not clear if
they are just trolling everyone. Your 3. is interesting at first they might
take it up as a joke but then someone out there in the "community" is a better
troll, and makes up a more convincing "evidence" and before they know some of
the trolls start believing.

------
oh_sigh
How many photos do these satellites take/send per day?

~~~
pietern
Depends on the mode the satellite is operating in. Typically: a full disk
image every 15 minutes, the continental USA every 5 minutes, and two selected
"mesoscale" regions (they will move around based on interesting events) every
minute or even 30 seconds. Not all these products are relayed through this
downlink though. On HRIT you'll find a full disk image across 7 different
spectral bands every 30 minutes, and mesoscale images across 3 different
spectral bands every 15 minutes.

Next to this data, it also contains relayed images from GOES-15 (GOES-West),
Himawari-8, EMWIN data, and NWS forecasts and plots.

