What is the purpose of this project?

Dear community,

I got introduced with the SatNOGS project because of FOSDEM, and I would like to understand what is the real goal of this project?
I am reading the websites (SatNOGS, SatNOGS Network, SatNOGS DB), but I just cannot put this together.
It is okay that individuals can create/setup ground stations (with dedicated hardware and software), and these ground stations are connected together, but what is deal with these stations? What can you do with them?

If you are a sattelite operator/owner, what can you gain from this network of ground stations? Can you use any of these ground stations to send commands to your satellite, for example? Or you only will be able to get telemetry data from the satellite through the ground station? How would the satellite know that you are expecting it to download its data to a particular ground station within the SatNOGS network?

I would really appreciate some enlightenment about this.

Thanks and regards,
Tamas

I’m just getting started building a rotator for my ground station.

With that being said (and someone correct me if I’m wrong) in a normal situation, you may only have a few ground stations scattered across the globe, so getting that telemetry and data from the satellite, you will have dead spots where you aren’t able to receive as much information however if you use a networked group of ground stations, more data and telemetry is available, and in satnogs case, it’s stored as a collective on the db.satnogs.org website.

In my case, i’m going to dual purpose the rotator I’m building (at least until I build two of these) I’ll be participating to the ground station network, but also, I plan on building a seperate antenna to communicate via ham radio (I’m a licensed ham) to talk to other ham radio operators or even the international space station (to the ham radio operators / astronauts on the space station)

Others chime in if I’m wrong on the first part of this reply, just my two cents.

Folks who are part of the project can correct me, but here are my answers to these questions (which are a small expansion of @ka4jwb’s answer) .

  • Sending commands to satellites is done through dedicated stations run by the satellite owners, not through SatNOGS; SatNOGS is receive-only.
  • Satellites will usually broadcast telemetry data continously, or at least often; this helps the operators, because others (like SatNOGS or other interested amateurs) can receive, decode and forward that data.
  • One of the aims of the SatNOGS project is to encourage satellite builders (especially cubesat builders, which are often university or other non-profit organizations) to use open-source protocols for data. One way of encouraging this is to show add capability to SatNOGS to decode those open-source protocols, which will allow cubesat builders to collect telemetry from their satellite from lots of different ground stations. In other words: if you use an open-source protocol, you (the satellite builder) will have a worldwide network of ground stations to collect telemetry; if you use something proprietary, all you’ll have is your own ground stations.

HTH!

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Thank you guys for the replies. Now it makes lot more sense.
I’ve also found this, which also helps to understand the idea (and possibilities) behind the project.

Some random follow up questions:

  1. If you are a satellite/cubesat owner, can you directly connect to a specific ground station to get telemetry from your satellite? Or it is rather like a cloud: you have access to telemetry data (through SatNOGS DB I suppose), which has been collected by all ground stations out there. But you cannot directly ‘login’ to a ground station to get data.

  2. I see that you can setup a groundstation with or without antenna rotator. Suppose your ground station has a rotator, who or what is deciding which satellite is your station is ‘tracking’?

Regards,
Tamas

Hi @toma

  1. Data (audio, waterfall, decoded data if there’s support for it in the SatNOGS project) is uploaded to the SatNOGS network, and can be downloaded there; you don’t log in to particular ground stations to get it, but download it from the observation page (example).

  2. Observations are scheduled for particular satellites over particular ground stations (“Oh look, NOAA 18 will be over station #23 at 10:18 UTC!”). They can be scheduled by (I believe) anyone with a SatNOGS account. A station doesn’t require a rotator in order to observe a particular satellite (though it will help); instead, it’s the combination of time and frequency that determines which satellite is being observed (“That NOAA 18 observation will start at 10:18 UTC / 137.504 MHz, peak at 10:25 UTC / 137.530 MHz, and end at 10:33 UTC / 137.485 MHz.”)

Thanks for the reply.
Do I understand you properly that the rotator is just pre-positioning the antenna (system) for better downlinking? So it is not dynamically following a bypass of a satellite, but rather positioning to a certain direction, and after that is stays in that position for a certain amount of time, and start ‘tracking’ and ‘receiving’ from the fixed position. Followed by another repositioning (turning into another direction), etc, etc.

I am sorry if this is obvious to you guys, but I am quite a noob on this subject.

And also I am getting a bit off topic. If that is a problem I can continue in a new thread…

My understanding is it uses Keplerian downloaded satellite data and the location of your ground station to make calculations about what Azimuth and Elevation it needs to track. It doesnt “lock” into the signal, it knows what it’s track is based on Keplerian data and where your ground station is (and your elevation you enter into your ground station info)

No, it is dynamically moving to follow a satellite across the sky; this can take anywhere from 5 minutes (or less) to 20 minutes, depending on the orbit of the satellite and how high the particular pass is. You can see a demonstration in this video (which shows an older version of the rotator). The video is about 8 minutes long, but if you speed it up you’ll see the movement a little more clearly.

Don’t worry about being a noob – I’m one as well! :slight_smile: Feel free to start a new thread if you’d like.