Observation 513126: METEOR-M 2 (40069)


#1

Regarding Observation 513126

So I am curious as to how M-2 works, and if the decoder works automatically, etc… so I scheduled a few observations on my 2m station. Dimitris has marked it good, and honestly I cannot see anything there. Am I missing something? Can somebody point me to a really good waterfall image of M-2?

It should be worth noting that generally my station has no hope to pick up a 0° pass, and this one was only scheduled because it was lumped in with all passes over my station (with no minimum elevation).

–Roy


#2

Hi,

I would have personally marked it as bad.

For a really good, I am not sure, but this one shows a typical M2 observation:
https://network.satnogs.org/observations/424190/

For the decoder, I have never seen it work automatically under SatNOGS.

There is a lot of references about M2 on this site.
I found this one particularly interesting for decoding M2:

73,


#3

Ok, that’s what I thought (regarding the decoder). However, I am still curious about the waterfall: Is the observation you linked above really what the downlink looks like (a 50kHz wide fuzzy cloud)?


#4

I have seen this on numerous observations.

You can compare with this:


#5

So that waterfall does look bad to me.

Something to note is if you are not running the custom meteor-m2 flowgraph, the default waterfall bandwidth used is only 48 khz wide. The Meteor-m2 signal is about 50 kHz wide, so you only see it as an apparent rise in the noise floor, just like what you see in observation #424190.

However, if you look at an observation from a station running the meteor-m2 flowgraph, the signal is clearly band-limited: https://network.satnogs.org/observations/496269/

I suspect a recent update may have broken the flowgraph, so I need to go have another look when I get time…


#6

@surligas have a look at this ^^


#7

More my problem than anyones… The flowgraph i’m talking about is not in gr-satnogs - it’s an extra one in https://github.com/darksidelemm/satnogs-extras which does the meteor-m2 QPSK decoding.

The actual processing of the QPSK soft-bits into imagery doesn’t run in real-time, so that part is done as a post-processing script. Hence, it hasn’t ever been included in gr-satnogs as it doesn’t fit the real-time processing aims. I believe someone was working on a ‘live’ meteor m-2 decoder, but I don’t know the status of it.