RTL-SDR Tutorial: Receiving Meteor-M N2 LRPT Weather Satellite Images with an RTL-SDR

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 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 to finally produce the image.

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.

The Meteor-M2 Satellite
The Meteor-M2 Satellite
An Example LRPT Image Received with an RTL-SDR from the Meteor-2 M2.
An Example LRPT Image Received with an RTL-SDR from the Meteor-2 M2.
Another Sample LRPT Image
Another Sample LRPT Image
What a LRPT signal looks like in SDR#
What a LRPT signal looks like in SDR#

For a comprehensive book about the RTL-SDR you may be interested in our eBook available on Amazon.

The Hobbyist’s Guide to the RTL-SDR: Really Cheap Software Defined radio.

14 comments

  1. Happysat

    Commissioning test phase ends on 09.11.2014.
    LRPT transmission will be declared operational on 10.11.2014.
    The following channels will be available:

    Channel 1 (0.5 0.7 µm; APID64), channel 2 (0,7 1,1 µm; APID65), channel 5 (10,5 µm; APID68).

  2. Reg

    I see the pass over my location using Sdrsharp. Strong signal but there is no audio other than hiss through my speakers. Not sure if I am using the right mode. At the moment it is WFM. This may be wrong. What audio should I hear? Is it something similar to the Noaa satellites.?

  3. Happysat

    VU2IIA from looking @ u’r screenshots it seems that the signal is not strong enough to achieve a proper lock on the signal.
    NOAA’s signal is more powerfull.

    You might consider a pre-amp/retune Qfh or choose a higher pass of Meteor.
    Martin we all have black&white IR Images, Meteor is still in commissioning phase.

    Yes there is a time schedule on Oleg’s website, on mine is the same info also which pid’s are active ect (below).

    29.09.2014 all 3 IR channels will be active Pids: 67,68,69.
    So no color for another week 😉

    Btw when using this nice program http://myweb.tiscali.co.uk/wxsatellite/meteor3m.htm
    The fish eye effect can be edited and stretched to 3000KM view.

    You get this effect:

    http://i.imgur.com/mRDAxxw.jpg

  4. Martin

    With the help of this tutorial I received yesterday and today the first images with my NOAA-equipment (QFH antenna, DVB-T Dongle and SDR#). Unfortunately I could not get such nice colored images, because I received only the first channel in the VIS range and two in the IR range The images in the IR seem to have lower resolution. Is there any time schedule, which channels are used or is this randomly changed during the test phase?

  5. VU2IIA

    PLEASE ADVICE. Strange Problem.
    I tried to receive LRPT signals using my Homebrew QFH antenna, which works perfectly fine with NOAA along with RTL. For LRPT I Noticed a strange problem, signal seems to be jumping up and down(strong and weaker), please see the image. This my third observation all done in the evening with same jumping results.
    https://www.dropbox.com/s/7xeonlef7vgmbam/LRPT.png?dl=0

    LRPTrx doesn’t show required constellation inspite of trying 72k and 80k
    Setup: RTL SDR along with hombrew QFH antenna, Gain-32d, NO PREAM.
    Recieved location: Mumbai, INDIA
    Date: 2014-09-26 Time: 16:10hrs UTC OR 9:40:PM (IST).
    Azm___Elv ___Mag__Range___S.Azm___S.Elv
    258.5__69.4__ecl____879______287.8___-44.9

    Any guidance is very much appreciated.
    VU2IIA

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