Yesterday we posted about a tutorial showing how to decode Meteor-M2 LRPT weather satellite images in real time with a new QPSK decoder plugin for SDR# and a modified version of Lrptdecoder.
Over on YouTube user max30max31 (a.k.a IZ5RZR) has uploaded a video showing some of the steps in the tutorial as well as the real time result of decoding of the weather satellite image.
Update 02 August 2019: Please use Happysats tutorial which is available here. Happysats tutorial will work for Meteor M-N2-1 and Meteor M-N2-2.
Back in September last year we posted a tutorial written by RTL-SDR.com reader Happysat which showed how to receive and decode high resolution Meteor-M2 LRPT satellite images. The tutorial required several offline manual processing steps to be performed and therefore could not decode the image in real time.
Now Vasili, a SDR# plugins programmer, and Oleg who is the coder of Lrptdecoder have combined ideas to create a new QPSK demodulator plugin for SDR# that allows the real time reception and decoding of Meteor-M2 LRPT images (in Russian use Google translate). The demodulator also offers the advantage of faster and longer signal locking, and also works much better with weak signals compared to the old method.
At the same time Vasili has also released another plugin called DDE Tracker which allows a satellite tracking program such as Orbitron to interface with and control SDR#. The plugin can be downloaded on the same page as the QPSK plugin. This is similar to the already existing DDE plugins, but now also comes with a scheduler which allows users to automatically schedule recordings of Meteor-M2 and NOAA satellite passings.
NOTE: Meteor M1 has come alive again, so the frequency of Meteor M2 was changed from 137.1 MHz to 137.9 MHz. Meteor M1 is now at 137.1 MHz and can be received using the same steps as in this tutorial, though please note that images from Meteor M1 are not perfect since the satellite is tumbling. Meteor M1 is gone again.
To help users get set up with this new method, Happysat has again come forth with another tutorial which can be downloaded here (.pdf) (.docx) (.txt w/ images in .rar). At first glance the tutorial may seem more complicated than the old method, but in the end it is a much faster and more efficient way at decoding LRPT images. The basic steps involve setting up Orbitron and the DDE plugin to automatically track the Meteor-M2 LRPT satellite and signal, and then setting up the QPSK plugin and the new version of Lrptdecoder (if that link is down, try this mirror) to talk to one another in real time via a local TCP connection.
One more Meteor-M2 related thing to look forward to in the future is the AMIGOS project which stands for Amateur Meteor Images Global Observation System. This will be a system where users around the world can contribute LRPT images through the internet to create a worldwide LRPT receiver. Oleg of LrptDecoder writes:
There is an idea to merge LRPT receive amateur radio stations in a network through the Internet and create a super LRPT receiver.
I see the benefit of professionals from the control center in the operational monitoring of the condition of the equipment MSU-MR, and for fans of the fullest reception of images from Meteor-M.
All is in testing phase and need some setup for the servers, data is beeing shared thru a VPN connection to a central server which will have a continous flow of images from all over the world.
Users can join and share in realtime the data more info on:
http://meteor.robonuka.ru/for-experts/amigos/
If you don't understand what all this is about: The Meteor-M N2 is a polar orbiting Russian weather satellite that was launched on July 8, 2014. Its main missions are weather forecasting, climate change monitoring, sea water monitoring/forecasting and space weather analysis/prediction.
The satellite is currently active with a Low Resolution Picture Transmission (LRPT) signal which broadcasts live weather satellite images, similar to the APT images produced by the NOAA satellites. LRPT images are however much better as they are transmitted as a digital signal with an image resolution 12 times greater than the aging analog NOAA APT signals. Some example Meteor weather images can be found on this page and the satellite can be tracked in Orbitron or online.
A software defined radio such as the low cost RTL-SDR, or the higher end Airspy and Funcube dongles can be used to receive these signals.
The DDE plugin can also be used for tracking NOAA satellites. Some people have been having trouble with set up. Happysat writes a solution:
Download TLE from: http://www.celestrak.com/NORAD
/elements/noaa.txt. Make sure the names are the same in DDE Sat Tracking Client schedule. https://dl.dropboxusercontent. com/u/124465398/NOAA_Setup.jpg. Same one as i post in the howto - https://dl.dropboxusercontent. com/u/124465398/DDESchedule.ra r
Over on YouTube user max30max31 aka IZ5RZR has uploaded a video that shows a faster method for decoding Meteor M2 weather satellite images on a Windows system. The Meteor-M N2 is a Russian weather satellite that transmits images using the LRPT protocol at around 137.1 MHz with can be received with an RTL-SDR. Compared to NOAA satellite APT images, LRPT images are much higher in resolution.
Normally, decoding Meteor M2 LRPT images requires a post processing step which involves the use of Audacity, an audio editing suite to reduce the recorded IQ files sample rate. However, with the recently released decimation SDR# drivers the Audacity step can be avoided by using a an appropriate decimation factor (8 at 1.024 MSPS) when recording the LRPT signals IQ data.
Post processing still involves the use of the Lrptrx.exe software, Oleg’s LRPToffLineDecoder to produce the image and SmoothMeteor to remove distortion from the image..
Recently we posted about a tutorial showing how to receive LRPT weather satellite images from the new Russian Meteor M2 satellite. Now over on YouTube user Tom Mladenov has uploaded a tutorial video showing all the tutorial steps.
The reception process is to essentially record an IQ file of an LRPT transmission using SDR#, reduce the sample rate of the IQ file using audacity and then decode the file using LRPTrx.exe. Then finally the decoded data can be imported into LRPTofflineDecoder to produce an image.
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Update 29 June 2023
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With the launch of Meteor M2-3, the loss of all prior Meteor M satellites and the release of new software, this tutorial is now outdated. We will eventually update this tutorial, but for now we will reference this post which has a brief high level overview of how to receive and decode images from the Meteor M2-3.
The current best tutorial for receiving Meteor M2-3 is available from Happysat at https://github.com/happysat/Setup-Meteor-M-N2-3-with-LRPT-Decoder-and-MeteorGIS/blob/main/README.md
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Update 02 August 2019: Please use Happysats tutorial which is available here. Happysats tutorial will work for Meteor M-N2-1 and Meteor M-N2-2.
Update 11 May 2015: There is now a real time method for decoding Meteor-M2 LRPT images. Please also check out the new tutorial available here.
The Meteor-M N2 is a polar orbiting Russian weather satellite that was launched on July 8, 2014. Its main missions are weather forecasting, climate change monitoring, sea water monitoring/forecasting and space weather analysis/prediction.
The satellite is currently active with a Low Resolution Picture Transmission (LRPT) signal which broadcasts live weather satellite images, similar to the APT images produced by the NOAA satellites. LRPT images are however much better as they are transmitted as a digital signal with an image resolution 12 times greater than the aging analog NOAA APT signals. Some example Meteor weather images can be found on this page and the satellite can be tracked in Orbitron or online.
The RTL-SDR and other SDRs like the Funcube along with some free software can be used to receive and decode these images. LRPT images from the Meteor-M N2 are transmitted at around 137.925 MHz, so any satellite antenna like those commonly used with the NOAA weather satellites can be used.
NOTE: Meteor M1 has come alive, (now offline again), so the frequency of Meteor M2 was changed from 137.1 MHz to 137.9 MHz. Meteor M1 is now at 137.1 MHz and can be received using the same steps as in this tutorial, though please note that images from Meteor M1 are not perfect since the satellite is tumbling.
Happysat, a satellite monitoring enthusiast has emailed us with a comprehensive tutorial showing how the RTL-SDR can be used to receive and decode these LRPT images (pdf warning) (txt file). The procedure is not quite as simple as with the NOAA satellites as it involves first pre-recording the transmission as a baseband I/Q file in SDR#, changing the sample rate in Audacity, processing the file with the Lrptrx.exe software, and then using Oleg's LRPToffLineDecoder (now called M2_LRPT_Decoder) to finally produce the image (in case the link is down for LRPToffLineDecoder/M2_LRPT_Decoder), try mirror here or here).
The tutorial also shows an alternative and faster Linux based method using some GNU Radio scripts, but with the final processing still done with Oleg's decoder in Windows.
The tutorial can be downloaded in PDF form from this link or alternatively in a text file here.
Update: This newer post now shows a slightly faster way for receiving and decoding LRPT images on a Windows PC which does not require the use of Audacity.
Check out the new lightweight Meteor M2 demodulator, and the meteor_decoder software.
Basic idea on Linux is to record an IQ wav file using:
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