Procedure

     SPKW01 ( Write SPK segment, type 1 )

     SUBROUTINE SPKW01 (  HANDLE,  BODY,    CENTER,  FRAME,   FIRST,
    .                     LAST,    SEGID,   N,       DLINES,  EPOCHS )

Abstract

     Write a type 1 segment to an SPK file.

Required_Reading

     NAIF_IDS
     SPK
     TIME

Keywords

     EPHEMERIS
     FILES

Declarations

     IMPLICIT NONE

     INTEGER               DLSIZE
     PARAMETER           ( DLSIZE = 71 )

     INTEGER               HANDLE
     INTEGER               BODY
     INTEGER               CENTER
     CHARACTER*(*)         FRAME
     DOUBLE PRECISION      FIRST
     DOUBLE PRECISION      LAST
     CHARACTER*(*)         SEGID
     INTEGER               N
     DOUBLE PRECISION      DLINES ( DLSIZE, * )
     DOUBLE PRECISION      EPOCHS (         * )

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     HANDLE     I   Handle of an SPK file open for writing.
     BODY       I   NAIF code for an ephemeris object.
     CENTER     I   NAIF code for center of motion of BODY.
     FRAME      I   Reference frame name.
     FIRST      I   Start time of interval covered by segment.
     LAST       I   End time of interval covered by segment.
     SEGID      I   Segment identifier.
     N          I   Number of difference lines in segment.
     DLINES     I   Array of difference lines.
     EPOCHS     I   Coverage end times of difference lines.

Detailed_Input

     HANDLE   is the file handle of an SPK file that has been
              opened for writing.

     BODY     is the NAIF integer code for an ephemeris object
              whose state relative to another body is described
              by the segment to be created.

     CENTER   is the NAIF integer code for the center of motion
              of the object identified by BODY.

     FRAME    is the NAIF name for a reference frame relative to
              which the state information for BODY is specified.

     FIRST,
     LAST     are, respectively, the start and stop times of
              the time interval over which the segment defines
              the state of BODY.

     SEGID    is the segment identifier. An SPK segment
              identifier may contain up to 40 characters.

     N        is the number of difference lines in the input
              difference line array.

     DLINES   contains a time-ordered array of difference lines
              The Ith difference line occupies elements (1,I)
              through (71,I) of DLINES. Each difference line
              represents the state (x, y, z, dx/dt, dy/dt,
              dz/dt, in kilometers and kilometers per second)
              of BODY relative to CENTER, specified relative to
              FRAME, for an interval of time. The time interval
              covered by the Ith difference line ends at the
              Ith element of the array EPOCHS (described below).
              The interval covered by the first difference line
              starts at the segment start time.

              The contents of a difference line are as shown
              below:

                 Dimension  Description
                 ---------  ----------------------------------
                 1          Reference epoch of difference line
                 15         Stepsize function vector
                 1          Reference position vector,  x
                 1          Reference velocity vector,  x
                 1          Reference position vector,  y
                 1          Reference velocity vector,  y
                 1          Reference position vector,  z
                 1          Reference velocity vector,  z
                 15,3       Modified divided difference
                            arrays (MDAs)
                 1          Maximum integration order plus 1
                 3          Integration order array

              The reference position and velocity are those of
              BODY relative to CENTER at the reference epoch.
              (A difference line is essentially a polynomial
              expansion of acceleration about the reference
              epoch.)


     EPOCHS   is an array of epochs corresponding to the members
              of the state array. The epochs are specified as
              seconds past J2000, TDB.

              The first difference line covers the time interval
              from the segment start time to EPOCHS(1).  For
              I > 1, the Ith difference line covers the half-open
              time interval from, but not including, EPOCHS(I-1)
              through EPOCHS(I).

              The elements of EPOCHS must be strictly increasing.

Detailed_Output

     None. See $Particulars for a description of the effect of this
     routine.

Parameters

     None.

Exceptions

     If any of the following exceptions occur, this routine will return
     without creating a new segment.

     1)  If FRAME is not a recognized name, the error
         SPICE(INVALIDREFFRAME) is signaled.

     2)  If the last non-blank character of SEGID occurs past index 40,
         the error SPICE(SEGIDTOOLONG) is signaled.

     3)  If SEGID contains any nonprintable characters, the error
         SPICE(NONPRINTABLECHARS) is signaled.

     4)  If the number of difference lines N is not at least one,
         the error SPICE(INVALIDCOUNT) is signaled.

     5)  If FIRST is greater than or equal to LAST, the error
         SPICE(BADDESCRTIMES) is signaled.

     6)  If the elements of the array EPOCHS are not in strictly
         increasing order, the error SPICE(TIMESOUTOFORDER) is
         signaled.

     7)  If the last epoch EPOCHS(N) is less than LAST, the error
         SPICE(BADDESCRTIMES) is signaled.

Files

     A new type 1 SPK segment is written to the SPK file attached
     to HANDLE.

Particulars

     This routine writes an SPK type 1 data segment to the open SPK
     file according to the format described in the type 1 section of
     the SPK Required Reading. The SPK file must have been opened with
     write access.

Examples

     Suppose that you have difference lines and are prepared to
     produce a segment of type 1 in an SPK file.

     The following code fragment could be used to add the new segment
     to a previously opened SPK file attached to HANDLE. The file must
     have been opened with write access.

        C
        C     Create a segment identifier.
        C
                  SEGID = 'MY_SAMPLE_SPK_TYPE_1_SEGMENT'

        C
        C     Write the segment.
        C
              CALL SPKW01 (  HANDLE,  BODY,    CENTER,  FRAME,
             .               FIRST,   LAST,    SEGID,   N,
             .               DLINES,  EPOCHS                  )

Restrictions

     1)  The validity of the difference lines is not checked by
         this routine.

Literature_References

     None.

Author_and_Institution

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

Version

    SPICELIB Version 1.0.2, 03-JUN-2021 (JDR)

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.1, 07-APR-2010 (NJB)

        Updated $Detailed_Input to state that the elements
        of EPOCHS must be strictly increasing. The $Exceptions
        section already described this error condition.

    SPICELIB Version 1.0.0, 30-JAN-2003 (NJB)