Procedure

     CKR05 ( Read CK record from segment, type 05 )

     SUBROUTINE CKR05 ( HANDLE, DESCR, SCLKDP, TOL, NEEDAV,
    .                   RECORD, FOUND                       )

Abstract

     Read a single CK data record from a segment of type 05
     (MEX/Rosetta Attitude file interpolation).

Required_Reading

     CK

Keywords

     POINTING

Declarations

     IMPLICIT NONE

     INCLUDE 'ck05.inc'
     INCLUDE 'ckparam.inc'

     INTEGER               HANDLE
     DOUBLE PRECISION      DESCR    ( 5 )
     DOUBLE PRECISION      SCLKDP
     DOUBLE PRECISION      TOL
     LOGICAL               NEEDAV
     DOUBLE PRECISION      RECORD   ( * )
     LOGICAL               FOUND

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     HANDLE     I   File handle.
     DESCR      I   Segment descriptor.
     SCLKDP     I   Pointing request time.
     TOL        I   Lookup tolerance.
     NEEDAV     I   Angular velocity flag.
     RECORD     O   Data record.
     FOUND      O   Flag indicating whether record was found.

Detailed_Input

     HANDLE,
     DESCR    are the file handle and segment descriptor for
              a CK segment of type 05.

     SCLKDP   is an encoded spacecraft clock time indicating
              the epoch for which pointing is desired.

     TOL      is a time tolerance, measured in the same units as
              encoded spacecraft clock.

              When SCLKDP falls within the bounds of one of the
              interpolation intervals then the tolerance has no
              effect because pointing will be returned at the
              request time.

              However, if the request time is not in one of the
              intervals, then the tolerance is used to determine
              if pointing at one of the interval endpoints should
              be returned.

     NEEDAV   is .TRUE. if angular velocity is requested.

Detailed_Output

     RECORD   is a set of data from the specified segment which,
              when evaluated at epoch SCLKDP, will give the
              attitude and angular velocity of some body, relative
              to the reference frame indicated by DESCR.

              The structure of the record is as follows:

                 +----------------------+
                 | evaluation epoch     |
                 +----------------------+
                 | subtype code         |
                 +----------------------+
                 | number of packets (n)|
                 +----------------------+
                 | nominal SCLK rate    |
                 +----------------------+
                 | packet 1             |
                 +----------------------+
                 | packet 2             |
                 +----------------------+
                             .
                             .
                             .
                 +----------------------+
                 | packet n             |
                 +----------------------+
                 | epochs 1--n          |
                 +----------------------+

              The packet size is a function of the subtype code.
              All packets in a record have the same size.

Parameters

     None.

Exceptions

     This routine follows the pattern established in the lower-numbered
     CK data type readers of not explicitly performing error
     diagnoses. Exceptions are listed below nonetheless.

     1)  If the input HANDLE does not designate a loaded CK file, an
         error is signaled by a routine in the call tree of this
         routine.

     2)  If the segment specified by DESCR is not of data type 05,
         the error SPICE(WRONGCKTYPE) is signaled.

     3)  If the input SCLK value is not within the range specified
         in the segment descriptor, the error SPICE(TIMEOUTOFBOUNDS)
         is signaled.

     4)  If the window size is non-positive or greater than the
         maximum allowed value, the error SPICE(INVALIDVALUE) is
         signaled.

     5)  If the window size is not compatible with the segment
         subtype, the error SPICE(INVALIDVALUE) is signaled.

     6)  If the segment subtype is not recognized, the error
         SPICE(NOTSUPPORTED) is signaled.

     7)  If the tolerance is negative, the error SPICE(VALUEOUTOFRANGE)
         is signaled.

Files

     See argument HANDLE.

Particulars

     See the CK Required Reading file for a description of the
     structure of a data type 05 segment.

Examples

     The data returned by the CKRnn 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 CKRxx
     routines might be used to "dump" and check segment data for a
     particular epoch.

     The search performed here does not mimic the behavior of the CK
     reader APIs CKGP and CKGPAV, which continue searching when an
     applicable segment doesn't satisfy a pointing request. See the CK
     Required reading for details.

     C
     C     Get a segment applicable to a specified body and epoch.
     C
           CALL CKBSS ( INST,   SCLKDP, TOL,   NEEDAV )
           CALL CKSNS ( HANDLE, DESCR,  SEGID, SFND   )

           IF ( .NOT. SFND ) THEN
              [Handle case of pointing not being found]
           END IF

     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. 05 ) THEN

              CALL CKR05 ( HANDLE, DESCR, SCLKDP, TOL, NEEDAV,
          .                RECORD, FOUND                       )

              IF ( .NOT. FOUND ) THEN
                 [Handle case of pointing not being found]
              END IF

              [Look at the RECORD data]
                  .
                  .
                  .
           END IF

Restrictions

     1)  Correctness of inputs must be ensured by the caller of
         this routine.

Literature_References

     None.

Author_and_Institution

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

Version

    SPICELIB Version 2.0.1, 06-JUL-2021 (NJB) (JDR)

        Corrected code example: removed comment character preceding
        CKBSS call. Added note regarding difference between this
        search and those performed by the CK reader APIs CKGP and
        CKGPAV.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 2.0.0, 27-JAN-2014 (NJB)

        Increased MAXDEG to 23 for compatibility with CK type 6.

    SPICELIB Version 1.1.0, 06-SEP-2002 (NJB)