spkw18_c

Index Page spkw18_c
A B C D E F G H I J K L M N O P Q R S T U V W X
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
       void spkw18_c ( SpiceInt             handle,
                       SpiceSPK18Subtype    subtyp,
                       SpiceInt             body,
                       SpiceInt             center,
                       ConstSpiceChar     * frame,
                       SpiceDouble          first,
                       SpiceDouble          last,
                       ConstSpiceChar     * segid,
                       SpiceInt             degree,
                       SpiceInt             n,
                       const void         * packts,
                       ConstSpiceDouble     epochs[]     )
#### Abstract
       Write a type 18 segment to an SPK file.
#### Required_Reading
       NAIF_IDS
       SPC
       SPK
       TIME
#### Keywords
       EPHEMERIS
       FILES
#### Brief_I/O
       Variable  I/O  Description
       --------  ---  --------------------------------------------------
       handle     I   Handle of an SPK file open for writing.
       subtyp     I   SPK type 18 subtype code.
       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.
       degree     I   Degree of interpolating polynomials.
       n          I   Number of states.
       states     I   Array of states.
       epochs     I   Array of epochs corresponding to states.
       MAXDEG     P   Maximum allowed degree of interpolating polynomial.
#### Detailed_Input
       handle         is the file handle of an SPK file that has been
                      opened for writing.

       subtyp         is an integer code indicating the subtype of the
                      the segment to be created.

       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.

       degree         is the nominal degree of the polynomials used to
                      interpolate the states contained in the input
                      packets.  All components of the state vectors are
                      interpolated by polynomials of the specified
                      degree, except near the segment boundaries,
                      or if the total number of states in the segment
                      is too few to allow interpolation using the
                      specified degree.

       n              is the number of packets in the input packet
                      array.

       packts         contains a time-ordered array of data packets
                      representing geometric states of body relative
                      to center, specified relative to frame.  The
                      packet structure depends on the segment subtype
                      as follows:

                         Type 0 (indicated by code S18TP0):

                             x,  y,  z,  dx/dt,  dy/dt,  dz/dt,
                             vx, vy, vz, dvx/dt, dvy/dt, dvz/dt

                         where x, y, z represent Cartesian position
                         components and  vx, vy, vz represent Cartesian
                         velocity components.  Note well:  vx, vy, and
                         vz *are not necessarily equal* to the time
                         derivatives of x, y, and z.  This packet
                         structure mimics that of the Rosetta/MEX orbit
                         file from which the data are taken.

                         Type 1 (indicated by code S18TP1):

                             x,  y,  z,  dx/dt,  dy/dt,  dz/dt

                         where x, y, z represent Cartesian position
                         components and  vx, vy, vz represent Cartesian
                         velocity components.

                      Position units are kilometers, velocity units
                      are kilometers per second, and acceleration units
                      are kilometers per second per second.

       epochs         is an array of epochs corresponding to the members
                      of the packets array.  The epochs are specified as
                      seconds past J2000, TDB.
#### Detailed_Output
       None.  See $Particulars for a description of the effect of this
       routine.
#### Parameters
       MAXDEG         is the maximum allowed degree of the interpolating
                      polynomial.  If the value of MAXDEG is increased,
                      the CSPICE routine spkpvn_ must be changed
                      accordingly.  In particular, the size of the
                      record passed to SPKRnn and SPKEnn must be
                      increased, and comments describing the record size
                      must be changed.
#### 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 degree is not at least 1 or is greater than MAXDEG, the
           error SPICE(INVALIDDEGREE) is signaled.

       5)  If the window size implied by DEGREE is odd, the error
           SPICE(INVALIDDEGREE) is signaled.

       6)  If the number of packets n is not at least 1,
           the error SPICE(TOOFEWSTATES) will be signaled.

       7)  If first is greater than or equal to last then the error
           SPICE(BADDESCRTIMES) will be signaled.

       8)  If the elements of the array epochs are not in strictly
           increasing order, the error SPICE(TIMESOUTOFORDER) will be
           signaled.

       9)  If the first epoch epochs[0] is greater than first, the error
           SPICE(BADDESCRTIMES) will be signaled.

       10) If the last epoch epochs[n-1] is less than last, the error
           SPICE(BADDESCRTIMES) will be signaled.

       11) If either the input frame or segment ID string pointer is null,
           the error SPICE(NULLPOINTER) is signaled.

       12) If either the input frame or segment ID string is empty,
           the error SPICE(EMPTYSTRING) is signaled.
#### Files
       A new type 18 SPK segment is written to the SPK file attached
       to HANDLE.
#### Particulars
       This routine writes an SPK type 18 data segment to the open SPK
       file according to the format described in the type 18 section of
       the SPK Required Reading. The SPK file must have been opened with
       write access.
#### Examples
      Suppose that you have states and are prepared to produce
       a segment of type 18 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.

          #include "SpiceUsr.h"
               .
               .
               .

          /.
          Create a segment identifier.
          ./
          #define  SEGID  "MY_SAMPLE_SPK_TYPE_18_SEGMENT"

          /.
          Write the segment.
          ./
          spkw18_c ( handle,  subtyp,  body,    center,
                     frame,   first,   last,    segid,
                     degree,  n,       states,  epochs );
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman   (JPL)
#### Version
       -CSPICE Version 1.0.1, 29-APR-2003 (NJB)

           Description of error condition arising from invalid window
           size was corrected.

       -CSPICE Version 1.0.0, 16-AUG-2002 (NJB)
#### Index_Entries
       write spk type_18 ephemeris data segment
#### Link to routine spkw18_c source file spkw18_c.c

    Thu Apr 16 08:59:18 2009