Procedure

     SPKR01 ( Read SPK record from segment, type 1 )

     SUBROUTINE SPKR01 ( HANDLE, DESCR, ET, RECORD )

Abstract

     Read a single SPK data record from a segment of type 1
     (Difference Lines).

Required_Reading

     SPK

Keywords

     EPHEMERIS

Declarations

     IMPLICIT NONE

     INTEGER               HANDLE
     DOUBLE PRECISION      DESCR    ( 5 )
     DOUBLE PRECISION      ET
     DOUBLE PRECISION      RECORD   ( * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     HANDLE     I   File handle.
     DESCR      I   Segment descriptor.
     ET         I   Target epoch.
     RECORD     O   Data record.

Detailed_Input

     HANDLE,
     DESCR    are the file handle and segment descriptor for
              a SPK segment of type 1.

     ET       is a target epoch, for which a data record from
              a specific segment is required.

Detailed_Output

     RECORD   is the record from the specified segment which,
              when evaluated at epoch ET, will give the state
              (position and velocity) of some body, relative
              to some center, in some inertial reference frame.

Parameters

     None.

Exceptions

     1)  If an error occurs while looking up SPK data, the error is
         signaled by a routine in the call tree of this routine.

Files

     See argument HANDLE.

Particulars

     See the SPK Required Reading file for a description of the
     structure of a data type 1 segment.

Examples

     The data returned by the SPKRnn routine is in its rawest form,
     taken directly from the segment. As such, it will be meaningless
     to a user unless he/she understands the structure of the data type
     completely. Given that understanding, however, the SPKRxx
     routines might be used to "dump" and check segment data for a
     particular epoch.


     C
     C     Get a segment applicable to a specified body and epoch.
     C
           CALL SPKSFS ( BODY, ET, HANDLE, DESCR, IDENT, FOUND )

     C
     C     Look at parts of the descriptor.
     C
           CALL DAFUS ( DESCR, 2, 6, DCD, ICD )
           CENTER = ICD( 2 )
           REF    = ICD( 3 )
           TYPE   = ICD( 4 )

           IF ( TYPE .EQ. 1 ) THEN
              CALL SPKR01 ( HANDLE, DESCR, ET, RECORD )
                  .
                  .  Look at the RECORD data.
                  .
           END IF

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     H.A. Neilan        (JPL)
     W.L. Taber         (JPL)
     I.M. Underwood     (JPL)
     E.D. Wright        (JPL)

Version

    SPICELIB Version 1.1.1, 14-APR-2021 (JDR)

        Edited the header to comply with NAIF standard. Added entry #1
        to $Exceptions section. Moved SPK required reading from
        $Literature_References to $Required_Reading section.

    SPICELIB Version 1.1.0, 07-SEP-2001 (EDW)

        Replaced DAFRDA call with DAFGDA.

    SPICELIB Version 1.0.3, 10-MAR-1992 (WLT)

        Comment section for permuted index source lines was added
        following the header.

    SPICELIB Version 1.0.2, 23-AUG-1991 (HAN)

        SPK01 was removed from the $Required_Reading section of the
        header. The information in the SPK01 Required Reading file
        is now part of the SPK Required Reading file.

    SPICELIB Version 1.0.1, 22-MAR-1990 (HAN)

        Literature references added to the header.

    SPICELIB Version 1.0.0, 31-JAN-1990 (IMU)