KPL/FK

Viking Lander 1 Frames Definitions Kernel
===============================================================================

   This frames kernel contains the definitions for the Viking Lander 1 (VL1)
   local level frame at the landing site. This file also defines VL1 
   name - ID mapping.


Version and Date
-------------------------------------------------------------------------------

   Ver 1.0a BVS, January 11, 2011
   
      Updated comments to indicate that the file should be used with 
      an IAU 1994 Mars constants PCK. No change to the data or file
      name.

   Ver 1.0 BVS, February 26, 2001
   
      Initial release.
      

Contact Information
-------------------------------------------------------------------------------

   Boris V. Semenov, NAIF/JPL, (818)-354-8136, bsemenov@spice.jpl.nasa.gov


References
-------------------------------------------------------------------------------

   1. ``Frames Required Reading''

   2. ``Kernel Pool Required Reading''

   3. ``C-Kernel Required Reading''
   
   4. Yoder, C.F., and E.M. Standish, Martian Precession and Rotation from
      Viking Lander Range Data, J. Geophys. Res., 102, 4065-4080, 1997. 


Implementation Notes
-------------------------------------------------------------------------------

   This file is used by the SPICE system as follows: programs that make
   use of this frame kernel must `load' the kernel, normally during program
   initialization. The SPICELIB routine FURNSH loads a kernel file into the 
   pool as shown below.

      CALL FURNSH ( frame_kernel_name )

   This file was created and may be updated with a text editor or word
   processor.


Related Kernels
--------------------------------------------------------

   This FK must be used with a PCK containing IAU 1994 Mars rotation
   constants, e.g. pck00007.tpc.


Viking Lander 1 Frames
-------------------------------------------------------------------------------

   The following Viking Lander 1 frames are defined in this kernel file:

           Name                  Relative to           Type       NAIF ID
      ======================  ===================  ============   =======

   Surface frames (-3279xx):
   -------------------------

      VL1_LOCAL_LEVEL         rel.to IAU_MARS      FIXED          -327900


VL1 Frame Hierarchy
-------------------------------------------------------------------------------

   The diagram below shows the VL1 frames hierarchy:
   

                             "J2000" INERTIAL
       +----------------------------+----------------------------+
       |                            |                            |
       | <--pck                     | <--pck                     | <--inertial
       V                            V                            V
   "IAU_EARTH"                 "IAU_MARS"                     "MARSIAU"
   EARTH BFR(*)                MARS BFR(*)                MMEJ2000 Inertial
   ------------                -----------                -----------------
                                    |          
                                    |  <--fixed
                                    V          
                            "VL1_LOCAL_LEVEL"  
                            -----------------

   (*)  BFR -- Body-Fixed Rotating frame, IAU 1994 rotation model based


VL1 Local Level Frame
-------------------------------------------------------------------------------

   This frame defines the z axis as the normal outward at the landing
   site, the x axis points at local north with the y axis completing
   the right handed frame (and pointing west).

   Orientation of the frame is given relative to the Mars fixed rotating
   frame 'IAU_MARS' (x - along the line of zero longitude intersecting
   the equator, z - along the spin axis, y - completing the right hand
   coordinate frame)

   The transformation from 'VL1_LOCAL_LEVEL' frame to 'IAU_MARS' frame 
   is a 3-2-3 rotation with angles defined as the negative of the 
   landing site longitude, the negative of the landing site colatitude, 
   and 180 degrees.

   The landing site coordinates, upon which rotation stored in this file 
   is based, are taken from [4], where they have been provided in as
   cylindrical coordinates with respect to the center of Mars in IAU 1994 
   Mars body-fixed frame provided in [2]:
   
        Rxy = 3136515.5     +/-  1.6    (meters)
        Rz  = 1284456.1     +/- 10.4    (meters)  
        Axz =     311.7359  +/-  0.0011 (degrees, East)
 

   These cylindrical coordinates correspond to the following areodetic 
   coordinates computed for Re=3397/Rp=3375 Mars ellipsoid:

        Lon = 311.736 (degrees East)
        Lat =  22.533 (degrees)
        Alt =  -4.484 (km above 3397 x 3375 ellipsoid)

   The rotation angles, computed from these areodetic coordinates using 
   the rule described above, are:

         iau_mars
        M         =  [ -311.736 ] * [ -67.467 ] * [ 180.000 ]     
         vl1_ll                  Z             Y             Z

   \begindata

      FRAME_VL1_LOCAL_LEVEL        =  -327900
      FRAME_-327900_NAME           = 'VL1_LOCAL_LEVEL'
      FRAME_-327900_CLASS          =  4
      FRAME_-327900_CLASS_ID       =  -327900
      FRAME_-327900_CENTER         =  -327

      TKFRAME_-327900_RELATIVE     = 'IAU_MARS'
      TKFRAME_-327900_SPEC         = 'ANGLES'
      TKFRAME_-327900_UNITS        = 'DEGREES'
      TKFRAME_-327900_AXES         = (    3,        2,       3      )
      TKFRAME_-327900_ANGLES       = ( -311.736,  -67.467, 180.000  )

   \begintext 


VL1 Spacecraft and Instrument NAIF ID <-> Name Mapping
-------------------------------------------------------------------------------

   This section contains mapping needed by SPICE system to support use of 
   the VL1 spacecraft, instrument and structure names in the SPKEZ/SPKEZR 
   calls.
   
   \begindata
      
      NAIF_BODY_NAME += ( 'VL1_LANDER'                   )
      NAIF_BODY_CODE += ( -327                           )
      
      NAIF_BODY_NAME += ( 'VL1'                          )
      NAIF_BODY_CODE += ( -327                           )
      
   \begintext