[Spice_discussion] spkezr question

[William Thompson]

Aimee:

You may be interested in these frame definition files I put together for the 
STEREO project.  The file heliospheric.tf is generic, and can be used for any 
mission.  The stereo_rtn.tf is an implementation of the HGRTN coordinate system 
specific to the two STEREO spacecraft--you can use it as a template for your own 
mission.

http://sohowww.nascom.nasa.gov/solarsoft/stereo/gen/data/spice/gen/heliospheric.tf
http://sohowww.nascom.nasa.gov/solarsoft/stereo/gen/data/spice/gen/stereo_rtn.tf

Bill Thompson


Aimee Mostella wrote:
> Hello, 
> 
> I'm using spkezr to get the position of a spacecraft (target) in the 
> J2000 reference frame with the observer as the Sun.  What coordinate 
> system is this based upon?  Is it Heliocentric Aries Ecliptic HAEJ2000?  
> 
> Ultimately, I need to get the lat and lon of the spacecraft based on the 
> Heliocentric of Date (HCD) coordinate system so that I can convert to 
> Heliocentric RTN (HGRTN).  I thought I could either get the position of 
> the spacecraft in HAEJ2000 and convert to HCD from there or get the 
> position in GEIJ2000 and convert from there.  However, when I tried the 
> GEIJ2000 route, my calculations were more off than they were when I did 
> it from scratch.  I tried the algorithm in the SPK Required Reading but 
> still didn't get a good answer.  Any suggestions?  
> 
> 
> Thanks
> 
> 
> ~~~~~~~~~~~~~~~~~~~~~~~
> 
> Aimee Mostella 
> 
> Research Analyst
> 
> Southwest Research Institute
> 
> Space Science Division
> 
> (210) 522-6735
> 
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> Spice_discussion mailing list
> Spice_discussion at naif.jpl.nasa.gov
> http://naif.jpl.nasa.gov/mailman/listinfo/spice_discussion

-- 
William Thompson
NASA Goddard Space Flight Center
Code 612.1
Greenbelt, MD  20771
USA

301-286-2040
William.T.Thompson.1 at gsfc.nasa.gov