 
 
Deep Impact Flyby High Gain Antenna Orientation CK, Based on 'V' Channels
===========================================================================
 
 
Orientation Data in the File
--------------------------------------------------------
 
     This file contains reconstructed orientation of the Deep Impact
     Flyby (DIF) High Gain Antenna (HGA) gimbal frame, DIF_HGA_GIMBAL
     (NAIF ID -140930), relative to DIF spacecraft frame,
     DIF_SPACECRAFT (NAIF ID -140000).
 
 
Status
--------------------------------------------------------
 
     This file was created for archiving in Planetary Data System (PDS)
     after the end of the primary mission using all relevant telemetry
     data available at that time.
 
 
Pedigree
--------------------------------------------------------
 
     This file was generated using MSOPCK program to convert into CK
     format measured DIF HGA gimbal angles sent to the ground in the
     following channels:
 
          V-0001 -- (measured) The Y axis gimbal position (in radians)
          V-0003 -- (measured) The Z axis gimbal position (in radians)
 
     The rotations stored in this CK were generated from the gimbal
     angles as follows:
 
            hgag
          M       = [ 0.0 ]  * [ V-0003 ]  * [ V-0001 ]
            sc             X             Z             Y
 
     All V-0001/V-0003 channel data from both (MASTER and CDR)
     Telemetry Data Systems (TDSs) -- except when only one of the two
     channels was present and when both channel had zero values -- were
     used to make this file.
 
 
Approximate Time Coverage
--------------------------------------------------------
 
     This file covers the following time period:
 
          Coverage Begin UTC       Coverage End UTC
          -----------------------  -----------------------
          2005-01-17T22:39:18.792  2005-08-01T21:31:30.968
 
     This file is a type 3 CK file which provides linear interpolation
     between orientation data points extracted from telemetry. Such
     interpolation is not applied to the whole coverage of the file but
     only inside intervals where enough orientation telemetry data was
     available and orientation data points were close to each other in
     time for such interpolation to make sense.
 
     The nominal gimbal angle time spacing in the telemetry stream
     varied from a few to 32 seconds between adjacent data points.
     Considering that the antenna gimbals cannot rotate very fast and
     that the highest accuracy of the HGA orientation knowledge is
     unlikely to be needed in any application, the duration of the
     longest interval over which the data may be interpolated was set
     to 150 seconds. For all requests for data falling between two
     adjacent data points separated by more than 150 seconds the
     SPICELIB CK readers will return a logical flag stating "POINTING
     NOT FOUND".
 
     A table containing the complete list of valid interpolation
     intervals in the file segments is provided at the end of these
     comments.
 
 
Usage Note
--------------------------------------------------------
 
     In order to use this file a DIF SCLK file, containing coefficients
     mapping DIF on-board time to ET, standard LSK file, providing UTC
     to ET mapping, and DI Frame Definitions file must be loaded into a
     user's program.
 
 
Contacts
--------------------------------------------------------
 
     If you have any questions regarding this data contact NAIF at JPL:
 
        Boris V. Semenov
        (818)-354-8136
        boris.semenov@jpl.nasa.gov
 
 
Appendix -- MSOPCK Setup Parameters and Interpolation Interval Summary
--------------------------------------------------------
 
********************************************************************************
MSOPCK SETUP FILE: dif_hga_050117_050801_vch.msopck
********************************************************************************
 
 
\begindata
 
   LSK_FILE_NAME           = 'naif0007.tls'
   SCLK_FILE_NAME          = 'DIF_SCLKSCET.00015.tsc'
   FRAMES_FILE_NAME        = 'di_v15.tf'
 
   INTERNAL_FILE_NAME      = 'DIF HGA ATTITUDE; MEASURED (V-CHANNELS)'
 
   CK_TYPE                 = 3
   CK_SEGMENT_ID           = 'DIF HGA ATTITUDE; MEASURED (V-CHANNELS)'
   INSTRUMENT_ID           = -140930
   REFERENCE_FRAME_NAME    = 'DIF_SPACECRAFT'
   ANGULAR_RATE_PRESENT    = 'MAKE UP/NO AVERAGING'
 
   MAXIMUM_VALID_INTERVAL  = 150
 
   INPUT_TIME_TYPE         = 'SCLK'
   INPUT_DATA_TYPE         = 'EULER ANGLES'
   EULER_ANGLE_UNITS       = 'RADIANS'
   EULER_ROTATIONS_ORDER   = ( 'X' 'Z' 'Y' )
 
   PRODUCER_ID             = 'Boris Semenov, NAIF'
 
\begintext
 
 
********************************************************************************
RUN-TIME OBTAINED META INFORMATION:
********************************************************************************
 
PRODUCT_CREATION_TIME = 2005-09-09T16:15:28
START_TIME            = 2005-01-17T22:39:18.792
STOP_TIME             = 2005-08-01T21:31:30.968
 
********************************************************************************
INTERPOLATION INTERVALS IN THE FILE SEGMENTS:
********************************************************************************
 
SEG.SUMMARY: ID -140930, COVERG: 2005-01-17T22:39:18.792 2005-02-03T08:23:19.715
--------------------------------------------------------------------------------
      2005-01-17T22:39:18.792    2005-01-17T23:17:30.822
      2005-01-17T23:25:22.829    2005-01-18T01:19:18.017
      2005-01-18T01:24:58.022    2005-01-18T01:29:58.026

      (many lines were skipped to reduce the example size)

      2005-07-30T22:22:41.727    2005-07-30T22:24:41.728
      2005-08-01T13:35:06.759    2005-08-01T21:31:30.968
 
 
********************************************************************************
 
 
