rasoberry-noaa/METEOR.md

Meteor M2 decoding

The satellite uses a 72k QPSK 120hz carrier to send very high quality images

Receiving

Currently, the satellite is using 137.1Mhz as the center frequency, Wide-FM @ 120Khz. I’m using rtl_fm @ 288k and sox to capture the raw stream. Most likely, the 288k bandwidth may be lower

Decoding steps

1. Normalize audio stream with sox gain -n
2. Use dbdexter’s meteor_demod to convert the audio stream to QPSK symbols at a 72k rate
3. Use artlav’s medet_arm to generate a decoded dump and then a false color image
4. Use dbdexter’s meteor_rectify to correct the visible deformation on Meteor images (wrong aspect ratio)
   1. I made some changes to rectify to export to compressed JPG and remove some prints