[Kstars-devel] Re : Satellites in KStars

[Akarsh Simha]

Hi Bernard

> The SGP4 C library used by KStars to handle TLEs was developed by
> Jean-Baptiste BUTET , Patrick Chevalley and Vincent Suck based on
> NORAD Spacecraft Report #3 (a very old document that you can find on
> the web).
> The SGP4 routine returns position, velocity of thew spacecraft in the
> TEME (True Equator Mean Equinox) frame of epoch (if I remember
> correctly). The library also converts to azimuth/elevation in the
> topocentric frame of the observer. I think the library has been
> successfully checked standalone against other libraries and against
> data from Heavens Above.
> 
> However, there were problems in Kstars. Among them :
> - longitude sign convention in the interface of the routines
> - graphical problems :  ticks on the orbit pass being drawn ... far
> from the orbit path
> 
> You should read all the previous e-mail in the archive containing the
> words satellites, SGP, SGP4, TLE, NORAD, heavens above...
> 
> In the long term, the C library has to be replaced by the new SGP4
> algorithm that you can find here :
> http://www.centerforspace.com/downloads/files/pubs/AIAA-2006-6753.pdf
> I wanted to do this but I really don't have time at the moment.
> 
> You can also find the C++ code for the new algorithm on Vallado's website :
> http://celestrak.com/software/vallado-sw.asp
> 
> If you need more info about TLEs, have a look at Kelso's website :
> http://celestrak.com/

I guess this is enough information. Thanks a lot. I hope to work on
this in my vacation in May - but I could use help if anyone wishes to
work on this.

Regards
Akarsh