a low cost ground station for weather sat receiving using an oPiZero, sdr dongle, and a home brew antenna

I've been working on a ground station to receive LRPT images from the Russian meteor-m2 satellite for a while now. The scripts for automated recording, decode, and uploading are working reliably now so I thought I'd share.



All of this work is based on haslettj instructables guide, I modified his scripts to work with the tools below to receive and decode LRPT signals.

Tools:



In addition to the tools haslettj uses you'll need to get the following setup and working. Most are pretty self explanatory.



Reception and QPSK decode



I hacked up Otti's gnuRadio flow graphs to work from the command line for easier scheduling. There is a single input variable for the output file name. The output is a .s file which works with artlav's meteor_decoder tools.



You'll want to change the rtl=xxx string on line 52 to work with your rtl device ID.



This py needs gnuRadio 3.7 or newer installed, use your package manager.



Image decode

artlav's meteor_decode handles taking the captured qpsk data and turning it into a bitmap.

Uploader

i'm using prasmussen's gdrive tool to upload the decoded image to my google drive folder.



Scheduler



The github of my modified scripts is here. Create a soft link to schedule_all so that it runs as a cron task daily. You'll need to modify each of the scripts to work with your own home directory location. The qpsk decoder is dumping the received data into a file on a ramdisk. This is to lower latency and prevent gnuRadio from complaining about buffer overruns "OOOO".

