GNSS FK files
===========================================================================

   This ``aareadme.txt'' file describes the contents of the kernels/fk
   directory of the GNSS SPICE Kernel Dataset.

   It was last modified on November 23, 2022 by Ricardo Valles Blanco ESAC/ESA.


Brief Summary
------------------------------------------------------------------------

   This directory contains the SPICE Frames Definition Kernel files for the
   GNSS spacecrafts.


File naming conventions
------------------------------------------------------------------------

   The following table provides information on which file contains which
   frames, their file naming conventions and some particular details:

      File                         Contents
     ---------------------------  -----------------------------------------
      estrack_vNN.tf               ESA Ground Stations topocentric frames.

      earth_topo_050714.tf         NASA DSN Ground Stations topocentric
                                   frames.

      gnss_vNN.tf                  GNSS spacecrafts frames.

   where

           NN       version number -- two digits (required)

                    If multiple versions of a Frames Kernel file are
                    provided, always use the latest version (unless
                    earlier version is needed for some special reasons.)


 Current FK Kernels Set
------------------------------------------------------------------------

   estrack_vNN.tf

      SPICE FK file that provides topocentric frames for the ESA Ground
      Stations. Created by the ESA SPICE Service.


   earth_topo_050714.tf

      SPICE FK kernel for the topocentric reference frames for the Deep Space
      Network (DSN) stations. This kernel was released on the date indicated
      in the filename.


   gnss_vNN.tf

      SPICE FK file that provides GNSS spacecrafts frames.
      Created by the ESA SPICE Service.


Other directory contents
------------------------------------------------------------------------

    aareadme.txt         This file.


Kernel File Details
------------------------------------------------------------------------

   The most detailed description of the data in an FK file is provided in
   metadata included inside the descriptive text areas of the file. This
   information can be viewed using any text editor.


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

   If you have any questions regarding this file contact the
   ESA SPICE Service (ESS) at ESAC:

           Alfredo Escalante Lopez
           (+34) 91-8131-429
           spice@sciops.esa.int


References and required readings
------------------------------------------------------------------------

   1. ``Frames Required Reading'', NAIF Document

   2. ``Kernel Pool Required Reading'', NAIF

   3. ``C-Kernel Required Reading'', NAIF


End of aareadme file.