Index of Functions: A B C D E F G H I J K L M N O P Q R S T U V W X
Index Page scs2e_c

Table of contents

Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries

#### Procedure

       scs2e_c ( SCLK string to ET )

       void scs2e_c ( SpiceInt          sc,
                      ConstSpiceChar  * sclkch,
                      SpiceDouble     * et      )

#### Abstract

       Convert a spacecraft clock string to ephemeris seconds past
       J2000 (ET).

#### Required_Reading

       CK
       SCLK
       SPK
       TIME

#### Keywords

       CONVERSION
       TIME

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       sc         I   NAIF integer code for a spacecraft.
       sclkch     I   An SCLK string.
       et         O   Ephemeris time, seconds past J2000.

#### Detailed_Input

       sc          is a NAIF ID code for a spacecraft, one of whose
                   clock values is represented by `sclkch'. The set of
                   supported spacecraft clocks is listed in the SCLK
                   Required Reading.

       sclkch      is a character string representation of the
                   spacecraft clock value that corresponds to `et', for
                   the spacecraft specified by the input argument `sc'.
                   `sclkch' is an absolute spacecraft clock time, so
                   partition information should be included in this
                   string. The precise format of `sclkch' is specified
                   in the SCLK Required Reading.

#### Detailed_Output

       et          is the epoch, specified as ephemeris seconds past
                   J2000, that corresponds to `sclkch'.

#### Parameters

       None.

#### Exceptions

       1)  If an SCLK kernel has not been loaded, does not contain all of
           the required data, or contains invalid data, an error is
           signaled by a routine in the call tree of this routine. The
           output argument `et' will not be modified. This routine assumes
           that that an SCLK kernel appropriate to the spacecraft clock
           identified by the input argument `sc' has been loaded.

       2)  If a leapseconds kernel is required for conversion between
           SCLK and ET but is not loaded, an error is signaled by a
           routine in the call tree of this routine. The output argument
           `et' will not be modified. When using SCLK kernels that map SCLK
           to a time system other than ET (also called barycentric
           dynamical time---`TDB'), it is necessary to have a leapseconds
           kernel loaded at the time this routine is called.

           The time system that an SCLK kernel maps SCLK to is indicated
           by the variable SCLK_TIME_SYSTEM_nn in the kernel, where nn
           is the negative of the NAIF integer code for the spacecraft.
           The time system used in a kernel is TDB if and only if the
           variable is assigned the value 1.

       3)  If the value of `sclkch' is invalid, an error is signaled by a
           routine in the call tree of this routine. The output argument
           `et' will not be modified.

       4)  If the `sclkch' input string pointer is null, the error
           SPICE(NULLPOINTER) is signaled.

       5)  If the `sclkch' input string has zero length, the error
           SPICE(EMPTYSTRING) is signaled.

#### Files

       None.

#### Particulars

       This routine is provided as a convenience; it is simply shorthand
       for the code fragment

          scencd_c ( sc, sclkch, &sclkdp );
          sct2e_c  ( sc, sclkdp, &et     );

       See the SCLK Required Reading for a list of the entire set of
       SCLK conversion routines.

#### Examples

       1)  Find the state (position and velocity) of Jupiter, as seen
           from the Galileo spacecraft, at the epoch corresponding to
           the SCLK value

              2 / 3110578:89:09

           The digit "2", followed by the forward slash, indicates that
           the time value is in the second mission partition.

           During program initialization, load the leapseconds and
           SCLK kernels. We will pretend that these files are named
           "leapseconds.ker" and "gllsclk.ker".  To use this code
           fragment, you must substitute the actual names of these
           kernel files for the names used here.

              /.
              Load leapseconds and SCLK kernels:
              ./
              furnsh_c ( "leapseconds.ker" );
              furnsh_c ( "gllsclk.ker"     );

              /.
              Load an SPK file (again, a fictitious file)
              containing an ephemeris for Jupiter and the
              GLL orbiter's trajectory.
              ./
              spklef_c ( "gllspk.ker", &handle );

              /.
              The Galileo spacecraft ID is -77. Convert our SCLK
              string to ephemeris seconds past J2000, which is the
              time representation expected by spkez_c.
              ./
              scs2e_c ( -77, "2 / 3110578:89:09", &et );

              /.
              Find the state of Jupiter (body 599) as seen from Galileo
              at time et. To use spkez_c, you must first load an SPK
              kernel, using the routine spklef_c.
              ./
              spkez_c ( 599, et, refsys, corr, -77, state, &lt );

       2)  Convert a Voyager 2 SCLK value to UTC, using calendar format,
           with 3 digits of precision in the seconds component.

           Again, your initialization code must load the leapseconds
           and SCLK kernels:

              /.
              Load leapseconds and SCLK kernels:
              ./
              furnsh_c ( "leapseconds.ker" );
              furnsh_c ( "vgr2sclk.ker"    );

           To find the UTC value corresponding to Voyager 2 SCLK
           string

              11389.20.768

           you can use the code fragment

              scs2e_c  ( -32,  "11389.29.768",          &et  );
              et2utc_c (  et,  "c",      3,    UTCLEN,  utc  );

           where UTCLEN is a constant indicating the available
           room in the string utc. A value of 25 characters suffices.

#### Restrictions

       1)  An SCLK kernel appropriate to the spacecraft clock identified
           by `sc' must be loaded at the time this routine is called.

       2)  If the SCLK kernel used with this routine does not map SCLK
           directly to barycentric dynamical time, a leapseconds kernel
           must be loaded at the time this routine is called.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       E.D. Wright         (JPL)

#### Version

       -CSPICE Version 1.1.2, 05-AUG-2021 (JDR)

           Edited the header to comply with NAIF standard. Moved CK and SPK
           required readings from -Literature_References to -Required_Reading
           section.

           Added entries #4 and #5 to -Exceptions section. Extended -Particulars.

       -CSPICE Version 1.1.1, 14-AUG-2006 (EDW)

           Replace mention of ldpool_c with furnsh_c.

       -CSPICE Version 1.1.0, 08-FEB-1998 (NJB)

            References to C2F_CreateStr_Sig were removed; code was
            cleaned up accordingly. String checks are now done using
            the macro CHKFSTR.

       -CSPICE Version 1.0.0, 25-OCT-1997 (NJB)

           Based on SPICELIB Version 1.0.2, 10-APR-1992 (NJB) (WLT)

#### Index_Entries

       spacecraft_clock string to ephemeris time

#### Link to routine scs2e_c source file scs2e_c.c

    Fri Dec 31 18:41:12 2021