Procedure

     CKBSS ( CK, begin search for segment )

     ENTRY CKBSS ( INST, SCLKDP, TOL, NEEDAV )

Abstract

     Initiate search through loaded files to find segments applicable
     to the spacecraft instrument and time specified.

Required_Reading

     CK
     DAF

Keywords

     POINTING

Declarations

    INTEGER               INST
    DOUBLE PRECISION      SCLKDP
    DOUBLE PRECISION      TOL
    LOGICAL               NEEDAV

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     INST       I   Spacecraft and instrument ID.
     SCLKDP     I   Encoded spacecraft clock time.
     TOL        I   Time tolerance.
     NEEDAV     I   Is there a need for angular velocity?

Detailed_Input

     INST     is the NAIF ID of an instrument.

     SCLKDP   is an encoded spacecraft clock time.

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

     NEEDAV   indicates whether or not angular velocity data is
              required.

              If .TRUE., only segments containing pointing and angular
              velocity data will be checked. If .FALSE., segments
              containing just pointing data will also be considered.

Detailed_Output

     None.

Parameters

     None.

Exceptions

     1)  If no files have been loaded, the error SPICE(NOLOADEDFILES)
         is signaled.

Files

     All files loaded by CKLPF are potential search targets for
     CKSNS.

Particulars

     CKBSS sets up a search for segments by CKSNS. It records the
     instrument and time to be searched for, and whether to require
     segments containing angular velocity data. If angular velocity
     data are required, only segments containing angular velocity
     data will be returned by CKSNS. If angular velocity data are
     not required, segments returned by CKSNS may or may not contain
     angular velocity data.

     CKBSS determines the first task that CKSNS will have to perform
     if it is called to get an applicable segment.

     A segment matches the CKBSS/CKSNS search criteria when the
     following statements are true.

        1) INST matches the instrument number for the segment.

        2) The time interval [SCLKDP - TOL, SCLKDP + TOL] intersects
           the time interval of the segment.

        3) If angular velocity data is required, as indicated by
           NEEDAV, the segment contains angular velocity data.

Examples

     See $Examples in CKBSR.

Restrictions

     None.

Literature_References

     None.

Author_and_Institution

     N.J. Bachman       (JPL)
     J. Diaz del Rio    (ODC Space)
     W.L. Taber         (JPL)
     R.E. Thurman       (JPL)
     I.M. Underwood     (JPL)

Version

    SPICELIB Version 4.1.2, 13-JAN-2021 (JDR)

        Edited the header to comply with NAIF standard.

        Moved details related to search criteria and conditions to meet
        it from the $Detailed_Input to $Particulars.

        Fixed typo in the long error message ('needs must' -> 'must').

    SPICELIB Version 4.1.1, 30-JAN-2017 (NJB)

        Corrected various spelling errors within comments.

    SPICELIB Version 4.1.0, 20-NOV-2001 (NJB)

        Updated to support new doubly-linked list implementation:
        partial segment list that cannot be buffered is now
        deallocated here rather than in CKSNS. Minor changes to
        comments were made as well.

    SPICELIB Version 4.0.0, 17-FEB-2000 (WLT)

        Added the Entry point CKHAVE.

    SPICELIB Version 3.0.0, 03-MAR-1999 (WLT)

        The parameter STSIZE was increased from 1000 to 4000 to
        avoid the buffering error that exists in the CKBSR.

    SPICELIB Version 1.0.1, 10-MAR-1992 (WLT)

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

    SPICELIB Version 1.0.0, 07-SEP-1990 (RET) (IMU)