Tracking the ISS

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Quick_Nick
2009-02-20
2012-10-09
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  • Quick_Nick
    Quick_Nick
    2009-02-20

    I don't know if anyone has mentioned doing it before(is there a search function here? :P), but I've managed to use Stellarium to 'track' the International Space Station by adding a small moon to Earth with updated elements from Heavens-Above. (some elements derived from other formulas based on other elements) I can view fairly accurate satellite passes within a day or two of the elements' epoch. Unfortunately I haven't yet got things accurate enough to do any better than this(if that's possible with Stellarium) and I can't get the brightness(magnitude) to be correct all the time.(it's usually FAR off with my current settings) If anyone has also done this before, I'd like to hear about it. Also, I may show a working example(script + modified planets) sooner or later.

     
    • barrykgerdes
      barrykgerdes
      2009-02-21

      Hi Quick_Nick

      I wrote a little filter program in Qbasic some time ago for version 0.9.1 that reads a two line orbital elements text file

      ISS (ZARYA)
      1 25544U 98067A 09051.15793981 .00007935 00000-0 66564-4 0 3087
      2 25544 051.6391 186.2851 0009266 044.7396 323.5179 15.70992814587549

      and writes it out as an entry for the ssystem.ini file. It is still suitable for the current version

      The comet_orbit algorithm used to display comets etc. is not really suitable for displaying fast moving near earth satellites so the display is really only a sample representation of one of these satellites and lacks accuracy because it does not take into account all the relevant parameters.

      Below is the ssystem.ini generation for todays (22/02/09) parameters from Heavens Above. To get a reasonable sized display the size has been increased about 10 times. Compare it with yours and let me know any differences.

      [ISS]
      name = Space Station
      parent = Earth
      radius = .592

      oblateness = 0.0

      albedo = 0.423

      rot_periode = 1.0

      rot_rotation_offset = 0

      rot_obliquity = 29

      sidereal_period = 0.0633384

      halo = true
      color = 1.0,1.0,1.0
      tex_halo = star16x16.png
      tex_map = nomap.png
      coord_func = comet_orbit
      orbit_Epoch = 2454881.907939807
      orbit_MeanAnomaly = 323.5179
      orbit_Period = 0.063654012
      orbit_SemiMajorAxis = 0.0000448399
      orbit_Eccentricity = .0009266
      orbit_ArgOfPericenter = 44.7396
      orbit_AscendingNode = 186.2851
      orbit_Inclination = 51.6391

      Barry

       
    • Fetz
      Fetz
      2009-03-18

      Hi Barry,

      I am very interested in this solution, but I can't make it on my own. I didn't find all parameters in the two line orbital elements text file.

      Where do I get orbit_epoch, orbit_Period and orbit_SemiMajorAxis?

      orbit_SemiMajorAxis seems to be the Parameter "A" in the M50 Keplerian table on http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/JavaSSOP/orbit/ISS/SVPOST.html, but the value is totally different from yours.

      Can you give a hint?

      Thanks in advance,

      Stefan

       
    • barrykgerdes
      barrykgerdes
      2009-03-18

      Hi Stefan

      I don't remember all the calculations. I would have to do them all again. It would be much easier for me to send the little Conv2lin.exe program to you to run youself.

      Barry

       
    • Fetz
      Fetz
      2009-03-19

      Hi Barry,

      I've done some researches before and found some documents on http://www.celestrak.com/publications/AIAA/2006-6753/
      I think it is possible to work with these dacouments, but they were too difficult for me to understand. Does your program work with these calculations?
      If there is a possibility, to download the file, I will do it.
      In case not, I've sent you my email adress.

      Thank you for your help.

      Stefan

       
    • barrykgerdes
      barrykgerdes
      2009-03-20

      Hi Stefan

      I checked the TLE data in that reference and it will work with the little filter program I have sent to you.

      Barry

       
    • Rich Messeder
      Rich Messeder
      2009-03-20

      This is great! This is exactly what I want to do - in part. I also want to track ham satellites, and I have this data

      Decode 2-line elsets with the following key:
      1 AAAAAU 00 0 0 BBBBB.BBBBBBBB .CCCCCCCC 00000-0 00000-0 0 DDDZ
      2 AAAAA EEE.EEEE FFF.FFFF GGGGGGG HHH.HHHH III.IIII JJ.JJJJJJJJKKKKKZ
      KEY: A-CATALOGNUM B-EPOCHTIME C-DECAY D-ELSETNUM E-INCLINATION F-RAAN
      G-ECCENTRICITY H-ARGPERIGEE I-MNANOM J-MNMOTION K-ORBITNUM Z-CHECKSUM

      AO-07
      1 07530U 74089B 09076.15182494 -.00000027 00000-0 10000-3 0 4280
      2 07530 101.4361 104.1787 0012071 089.0486 271.1968 12.53575523571181

      I looks to me like a conversion is possible?

      Of course, heavens-above.com has the ISS stuff to display, but I'd still like to have it all in one place.

      Even if you no longer have the source code, I'll bet that it would not be difficult to reproduce - with a little help from a friend where need be. I am a programmer of sorts and will be happy to dev the code and post it.

      ~R~

       
    • barrykgerdes
      barrykgerdes
      2009-03-20

      Hi Rich
      I sent a copy of the little program to Stefan with source in Qbasic. It is a bit messy but should work on any TLE data in that form to print out an insert to the ssystem.ini file.

      If you want a copy tell me where to send it. If I get a chance to clean it up I will place the copy on my web site.

      [AO-O7]
      name = AO-O7
      parent = Earth
      radius = .01

      oblateness = 0.0

      albedo = 0.423

      rot_periode = 1.0

      rot_rotation_offset = 0

      rot_obliquity = 29

      sidereal_period = 0.079771824

      halo = true
      color = 1.0,1.0,1.0
      tex_halo = star16x16.png
      tex_map = nomap.png
      coord_func = comet_orbit
      orbit_Epoch = 2454906.901824936
      orbit_MeanAnomaly = 271.1968
      orbit_Period = 0.079771824
      orbit_SemiMajorAxis = 0.0000448399
      orbit_Eccentricity = .0012071
      orbit_ArgOfPericenter = 89.0486
      orbit_AscendingNode = 104.1787
      orbit_Inclination = 1.4361

      Barry

       
    • Matthew Gates
      Matthew Gates
      2009-03-20

      I may soon have something which does the proper modeling directly from the TLEs... stay posted.

      Matthew

       
      • Matthew Gates
        Matthew Gates
        2009-03-21

        • Rich Messeder
          Rich Messeder
          2009-03-21

          Well, Matthew, you certainly are good at teasers ;-) Did you get the data from AMSAT.ORG?

          I am new to this forum, so have a few questions:

          Are the satellite icons part of Stellarium?

          Does "plugin" mean that it will work with Stellarium?

          Will the plugin automatically access AMSAT.ORG and get updates?

          Will Stellarium update the s/c postions on a regular basis?

          Thanks,
          ~R~

           
          • Matthew Gates
            Matthew Gates
            2009-03-21

            > Well, Matthew, you certainly are good at teasers ;-)
            > Did you get the data from AMSAT.ORG?

            I used google, and found:

            http://celestrak.com/NORAD/elements/noaa.txt
            http://celestrak.com/NORAD/elements/goes.txt
            http://celestrak.com/NORAD/elements/gps-ops.txt
            http://celestrak.com/NORAD/elements/galileo.txt
            http://celestrak.com/NORAD/elements/visual.txt
            http://celestrak.com/NORAD/elements/amateur.txt
            http://celestrak.com/NORAD/elements/iridium.txt

            So here's a nice task for volunteers: find me the best (most up to date, reliable) site, which explicitly gives permission for people to use their data and re-distribute it. Maybe celestrak is it, maybe not.

            > I am new to this forum, so have a few questions:
            > Are the satellite icons part of Stellarium?

            Well, for the plugin, as you can see in the screnshots, the icons were drawn by me and are in the Satellite part of the SVN tree. It's not "core" Stellarium, but it's all part of the same sourcecode repo.

            > Does "plugin" mean that it will work with Stellarium?

            It's a good question. The plugin functionality is quite new, and I'm learning as I go. Essentially, a plugin is a run-time linkable library (i.e. .dll on windows, .so on ELF based linker systems). There may be a few other files too, like graphics, settings files and so on.

            A plugin must be compiled, and is specific to one platform - you can't use the windows version of the plugin on an OSX machine and so on. Once installed in the right place, Stellarium will detect installed plugins when it starts, and load them if there is the appropriate setting in the corresponding module.ini file. Assuming the plugin is the right platform, and for the right version of Stellarium, it should work, barring bugs.

            > Will the plugin automatically access AMSAT.ORG and get updates?
            > Will Stellarium update the s/c postions on a regular basis?

            It doesn't yet. I would like to add an auto-update feature in the future. Certainly the TLEs should be fairly easy to auto-update since there are lots of sites which offer a consistent format. For non-TLE data like beacon / communication frequencies I don't know how easy it will be. It depends on the availability of information and the format in which it is available. If AMSAT make this data available in a computer-program-parsing-it-friendly format, I would like to do it.

            Matthew

             
        • Bogdan Marinov
          Bogdan Marinov
          2009-03-21

          LOL. Cool. It definitely has a NORAD feel to it. :)

          Is this a plug-in, or?

           
          • Matthew Gates
            Matthew Gates
            2009-03-21

            Another teaser:

            http://porpoisehead.net/misc/stellarium-more-satellites.png

            And finally some code:

            http://porpoisehead.net/misc/Satellites-0.1.0.tar.gz

            I'm pretty pleased with it so far, although it's not finished.

            I added the GPS constellation, and the positions match those which my little garmin handheld GPS shows me while it is trying to get a signal.

            I didn't do a test build against the 0.10.2 release code - just the development code, and then only for Linux. I hope it is possible to build a binary which will work with the 0.10.2 release for Windows, what with there being so many Windows users out there. I have a few more things to do before I check it into SVN, but when I do I'll play about with the windows build and create an installer generation script for it.

            Cheers,
            Matthew

             
            • Rich Messeder
              Rich Messeder
              2009-03-21

              Very nice work! Windows user waiting...waiting...still waiting ;-) Still, it's great to see such a response to user comments from all of you, and I have so much to look forward to...

              I like the "canned" approach to the plugin AND all the extra ham specs on the page AND the GPS locations. Coupla times I actually clicked on your image thinking that is was the real thing!

              'Course I also like the option of adding any s/c to the ssystem.ini file, as in Barry's code, because I also want to track other s/c. Check out http://sscweb.gsfc.nasa.gov/tipsod/

              ~R~

               
              • Matthew Gates
                Matthew Gates
                2009-03-21

                Seems to work OK on XP with 0.10.2 release:

                http://porpoisehead.net/misc/stellarium-satellites-plugin.exe

                Enjoy
                Matthew

                 
                • Rich Messeder
                  Rich Messeder
                  2009-03-21

                  Very cool. I like the blue better than the red, and also like the way they all change to night vision. I think I better pare down the s/c list, though; I can hardly find those I want! I get regular Keplerian data for those I am interested in, so it should be easy to update the module.ini (which I might have called satellites.ini) because it already uses TLE data.

                  ~R~

                   
              • Matthew Gates
                Matthew Gates
                2009-03-21

                Sorry, I don't understand what s/c means?

                 
          • Matthew Gates
            Matthew Gates
            2009-03-21

            It's a plugin. Lots of stuff still to do, but I might commit to SVN sometime soon since the basics are more or less working.

            Matthew

             
    • barrykgerdes
      barrykgerdes
      2009-03-21

      Hi Rich
      I have placed my updated cov2lin.zip on my web site. It is still not perfect but does have all the correct algoritms to make a ssystem.ini file that works.

      Its main problem is that the TLE file must match the sample in the readme.txt file because of the simplified filtering of the parameters that I use. Qbasic source is also provided.

      www.geocities.com/wendygblyde

      Barry

       
      • Rich Messeder
        Rich Messeder
        2009-03-21

        Thanks much for posting the file and the source code, Barry. We'll see how this all plays out.

        ~R~

         
        • Matthew Gates
          Matthew Gates
          2009-03-21

          I did the check in to SVN. Much better to use that version... has bug fixes over the one I posed to my site.

          Matthew

           
    • Fetz
      Fetz
      2009-03-21

      Hi,

      it's really amazing, how this topic developed the last days. I like to see the lights fading when ISS reaches the shadow of the earth with Barry's solution.
      I'm really excited to see, what maybe will be implemented in stellarium.

      Stefan

       
    • barrykgerdes
      barrykgerdes
      2009-03-21

      Hi Matthew

      I just got the satellites tarball from the svn, unzipped it, put the files into my windows build area, compiled it and placed the results into the modules area and ran the program. Looks great some of those satelllites move pretty fast.

      I will add a windows compiled version to my web site later this morning.

      Barry

       
      • Matthew Gates
        Matthew Gates
        2009-03-21

        I did it already, and there is a serious bug which was fixed too... see the .exe installer I posed somewhere in this thread.

        :-)

        Matthew

         
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