Real-Time decoding of Meteor-M2 on Linux
Recently RTL-SDR.com reader Mark wrote in and wanted to share his modified version of otti-soft’s GNU Radio flowgraph for decoding Meteor-M2 weather satellite images on Linux. The modified version allows for real time decoding, whereas the original version requires several offline decoding steps to be performed after recording the signal.
I have modified one of otti-soft’s gnuradio flowgraphs so that they work with RTL-SDR and output the demodulated symbols to a TCP socket, from which the new version of LRPT Analizer (from robonuka.ru) can decode the data in real-time.
First, one needs to download and extract the AMIGOS version of the LRPT analyzer from robonuka.ru: ftp://meteor2soft:[email protected]/AMIGOS/AMIGOS2.zip.
(AFAIK, only the AMIGOS version is able to decode the data from a socket, which is required for real-time decoding).
The program is to be run under a 32-bit version of Wine.
When the satellite is overhead, open and run the flowgraph (attached) in gnuradio-companion and leave it running. You might need to adjust the gain.
Then, run the LRPToffLineDecoder.exe executable from the extracted archive.
It should display a constantly-updating constellation diagram. When the data is decoded, the channel images will start to appear in each section of the window.
That’s it, when the image is decoded, one can save it and close the windows of gnuradio-companion and the decoder.
Notes: when running the flowgraph, no other processes (rtl_sdr, rtl_power, gqrx, …) should use the SDR device.
The modified GRC file is available here.
Hello colleagues. Please help to understand this diagram. When trying to repeat can’t put the gain in the RTL-SDR receiver. When you run the command rtl_test -t shows the gain values, but putting them in the box RF Gain (block RTL-SDR Source) accepted levels do not change. Use RTL-SDR v.3. At the same receiver when operating in SDR# the values are changing correctly. When receiving the signal from the NOAA levels reach 0 dB, when receiving the signal of the METEOR to -10 dB. Thanks in advance for your help. PS Tested on a Raspberry Pi3.
Worked great here.
Smooth meteor also works to correct the aspect ratio of the channels.
Can you tell me the path you use in the .ini for saving the files, when using Wine?
A few minutes of capture:
OMG I’ve been looking for that socket based LRPT client for ages! Tried the tutorial a while back for M2 but had difficulties locating software. Bookmarking for when I I get more time to play with GNURadio.
A small correction: I accidentally left the Throttle block in the flowgraph (while experimenting with an I/Q recording). It’s harmless, but if you find GRC running rather slowly, try bypassing it.