meteor.md

Meteor M2 Decoding

The Meteor M2 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. This framework uses rtl_fm @ 288k and sox to capture the raw stream. Most likely, the 288k bandwidth may be lower.

Decoding Steps

Below are the steps used to decode the signal:

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. Some changes were made to rectify to export to compressed JPG and remove some prints