DIY Satellite Tracking

Travis Goodspeed has authored a blog post detailing his method of tracking low-earth-orbit satellites. Starting with an old Felcom 82B dish made for use on maritime vessels, he added motors to move it around and a webcam-based homemade calibration system. "For handling the radio input and controlling the motors, I have a BeagleBone wired into a USB hub. These are all mounted on the trunk of the assembly inside of the radome, sending data back to a server indoors. ... In order to operate the dish, I wanted both a flashy GUI and concise scripting, but scripting was the higher priority. Toward that end, I constructed the software as a series of daemons that communicate through a PostgreSQL database on a server inside the house. For example, I can run SELECT * FROM sats WHERE el>0 to select the names and positions of all currently tracked satellites that are above the horizon. To begin tracking the International Space Station if it is in view, I run UPDATE target SET name='ISS';. For predicting satellite locations, I wrote a quick daemon using PyEphem that fetches satellite catalog data from CelesTrak. These positions are held in a database, with duplicates filtered out and positions constantly updated. PyEphem is sophisticated enough to predict in any number of formats, so it's easy to track many of the brighter stars as well as planets and deep-space probes, such as Voyagers 1 and 2."

Ok, maybe

[Brett Buck]

Perhaps you can take and antenna and point it where you think Voyager might be with this sort of equipment. I am extremely skeptical that you can "track" it, that is, lock on to the carrier and then follow it. I bet you can't see the carrier at all, much less see the data.

     

Re:

[Edis Krad]

Maybe you should read the part where it says "low earth orbit"

Re:

[batkiwi]

From the summary:

"so it's easy to track many of the brighter stars as well as planets and deep-space probes, such as Voyagers 1 and 2."

Re:Ok, maybe

[Anonymous Coward]

Maybe "low" is relative... ;)

Comment removed

[account_deleted]

Comment removed based on user account deletion

Re:

[plover]

I have a better question....why? Why would you go to this much trouble when you can use the free Stellarium [stellarium.org] and know where pretty much everything visible (and not visible unless you have a big ass telescope) and just call it a day? It can even control a telescope for you, just slap it on a netbook, wire it to the telescope and there ya go, easy peasy.

Aside from the fact that PyEphem is probably the most ridiculously thorough ephemeris calculator available, and is an optimal tool when you are pointing one piece of equipment at one single target?

I know, let's check with Stellarium's own documentation [stellarium.org] on the subject:

"As of the current version, this plug-in doesn't allow satellite tracking, and is not very suitable for Moon or planetary observations."

I noticed a distinct lack of both easy and peasy in that statement. Does that answer your question of "why?

Re:Ok, maybe

[Ozoner]

The article says right there in the heading ".. so it's easy to track many of the brighter stars as well as planets and deep-space probes, such as Voyagers 1 and 2"

Also there's a big difference between tracking and locking-on. Most big systems (eg NASA) simply track the target (based on precise ephemerals) because extracting the signal from the noise (post processing) takes far to long for locking-on to be practical.

Plus the beam-width of even a huge dish is far to wide to allow locking-on to be of much advantage. You can nod the dish a little and extract revised ephemerals after the event, but that's about all.

Re:

[Flere Imsaho]

Actually, if you'd read TFA you'd have come across the text saying "In the screenshot above, the dish is aimed at GOES 3 and has just been ordered to aim at Voyager 1"

So let me get this straight. You've just publicly called this guy a liar, based on what - did the Force tell you he's full of shit? You bet he can't see the carrier at all? OK, email the guy and make a wager - put your money where your cynical mouth is.

This guy did something geeky and cool. It's not a new idea, but he's been good enough to blo

This is news?

[Ozoner]

Amateur Radio operators have been automatically tracking satellites for decades and the tracking ephemeral's have been published forever.

Searching Google for "amateur satellite tracking" gets around 10 pages of hits.

Never mind. This is Slash Dot...

Re:This is news?

[Anonymous Coward]

This isn't as much tracking them in the sense of figuring out where they are, but rather tracking them by controlling a dish, which is way cooler.

Re:This is news?

[CQDX]

Yes, but computer controlled az/el rotors to track satellites is not new, at least not to ham radio. Just one of many examples: http://www.youtube.com/watch?v=bXWF09gPUSs [youtube.com]

Re:

[Ozoner]

> This isn't as much tracking them in the sense of figuring out where they are, but rather tracking them by controlling a dish.

Idiot. Of course the Hams are automatically steering their Satellite dishes. What on earth do you think they are doing?

It's tragic how some computer geeks live in a bubble hermetically sealed from the rest of the scientific world.

Re:

[Zynder]

You got that wrong. You should have typed:

THIS IS SLASHDOT! Followed by a swift kick to the groin.

Reads like TDWTF material...

[tibit]

Using an SQL database as means of interprocess communication, wow.

Re:Reads like TDWTF material...

[Greyfox]

Hmm. I didn't put a whole lot of effort into mine. I roll a TCP socket server that pretends to be a HTTP daemon and returns a KML file to Google Earth through a network link. Initially it was set up to read a data file with an ephemeris table for a satellite in it and plot a chunk of the satellite's orbit and its current location as a placemark. I'd just feed two or three interesting satellites worth of interesting data into it, running each one on a separate port.

Lately I've been using the same coordinates library to generate static KML files of GPS tracks in Google Earth. These files don't have the same realtime interest that the satellite tracking one does, since the GPS tracks are being gathered earlier and being batched processed. I have several C++ libraries up on Github, [github.com] if you're curious.

Re:

[K. S. Kyosuke]

If the stream of data is slow enough... Such servers as Firebird can post update notifications to interested clients, for example, so it's not like you have to poll for the changes or something.

Re:

[Flere Imsaho]

Then drop him a line and collaborate on something that is "better". It works for him, so what's the big deal?
Honestly, I'm having a hard time getting the nerd-hate this article is garnering.

Re:

[tibit]

I know the value of a hack that works, but there's plenty of such hacks that are TDWTF material at the same time. No hate implied.

Re:

[Flere Imsaho]

Cool - sorry I took your post the wrong way - I was a little pissed at the level of meh this story was generating...

Not SQL!

[lkernan]

Give whole new meaning to the DROP command.

Re:

[RobertLTux]

[fandom type="dresden files"] Only if you are Ebeneezer "Blackstaff" McCoy! [/fandom]

Thirty years ago...

[ctrl-alt-canc]

,,,I tracked NOAA and OSCAR satellites using a polar Earth map upon which I superimposed a orbit-shaped transparent ruler. I then used NASA data, Kepler's equations and a desk calculator to compute the right ascension of the orbits that crossed my reception zone, and I set the ruler accordingly. While I was receiving satellite data I had to read on the ruler the satellite position and move my antennas, while another ruler gave me the amount of Doppler correction. Doing all these tasks alltogether was messy, but it was one of the funniest and more rewarding things I ever did when I was involved with ham radio. I don't think that if I had a computer to automate everything, I would have enjoyed this that much...

Re:Thirty years ago...

[nojayuk]

I worked with the OSCAR Euro command people for a while in the early 80s at the University of Surrey. We had an ex-Navy AA radar X-Y director head on the roof of the building with some Yagis strapped to it to track the satellites and a microcomputer to do the tracking for us as well as sending control commands to the OSCARs as they went by.

The guy in charge was someone you might have heard of, a Ph. D. student name of Martin Sweeting who was busy designing and building cheap satellites; his thesis project was something called UOSAT-1.

And then I'll takeover the world !

[ze_jua]

UPDATE target SET name='ISS'

It sounds like a quote of any James Bond vilain :)