[Spice_discussion] Summarizing CK and SPK files with Icy

William Thompson William.T.Thompson.1 at gsfc.nasa.gov
Thu Jun 16 12:55:34 PDT 2005


I need to be able to document the contents of CK and SPK files, so that I can 
create a database listing what time ranges each file contains.  My original plan 
was to use the "brief" program, and parse the output.  This works okay for SPK 
files, e.g.

> argo:~/kernels> /usr/local/icy/exe/brief behind_2006_114_02.epm.bsp
> Brief.  Version: 2.2.0        (SPICE Toolkit N0058)
>   
>   
> Summary for: behind_2006_114_02.epm.bsp
>   
> Body: STEREO BEHIND (-235)
>       Start of Interval (ET)              End of Interval (ET)
>       --------------------------------    --------------------------------
>       2006 APR 24 11:27:34.470            2007 MAY 01 00:01:04.183

However, this doesn't seem to work properly with CK files.  For those files, the 
"brief" program reports bogus times, evidently because it doesn't have access to 
the corresponding SCLK and LSK files, i.e.

> argo:~/kernels> /usr/local/icy/exe/brief ahead_2006_070_00.ah.bc
> Brief.  Version: 2.2.0        (SPICE Toolkit N0058)
>   
>   
> Summary for: ahead_2006_070_00.ah.bc
>   
> Body: -234000
>       Start of Interval (ET)              End of Interval (ET)
>       --------------------------------    --------------------------------
>       14336 NOV 28 16:05:14.127           14337 JAN 26 01:36:58.127

When I use the "spacit" program, I'm able to load the SCLK and LSK files, and 
get the proper time range, i.e.

> Summary for CK file: ahead_2006_070_00.ah.bc
> Leapseconds File   : naif0007.tls
> SCLK File          : sclk/ahead_science_03.sclk
> Summary Type       : Entire File
>   
> --------------------------------------------------------------------------------
 >    Segment ID     : STEREO Behind spacecraft bus
>    Instrument Code: -234000
>    Spacecraft     : Body -234, STEREO AHEAD
>    Reference Frame: Frame 1, J2000
>    CK Data Type   : Type 3
>       Description : Continuous Pointing: Linear Interpolation
>    Available Data : Pointing and Angular Velocity
>    UTC Start Time : 2006 MAR 11 10:02:49.977
>    UTC Stop Time  : 2006 MAR 11 15:31:18.977
>    SCLK Start Time: 1/1520762569:250
>    SCLK Stop Time : 1/1520782278:250
> --------------------------------------------------------------------------------  

However, spacit is an interactive program, and thus can't be used in cron jobs.

How do I extract the start and end times from a CK file in Icy?

Thank you,

-- 
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


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