[Spice_discussion] spkezr question

[Aimee Mostella]

Thanks for everyone's help.

Aimee Mostella

On Jul 20, 2005, at 1:58 PM, William Thompson wrote:

> 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
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>>
>
> -- 
> 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
>



~~~~~~~~~~~~~~~~~~~~~~~
Aimee Mostella
Research Analyst
Southwest Research Institute
Space Science Division
(210) 522-6735

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