Data Set Overview
      =================
      This data set contains magnetic-field data acquired during the
      cruise and tour phases of the Cassini mission to Saturn.
      On 16 August, 1999 two days before the spacecraft commenced Earth
      swingby, the magnetometer boom was unfurled into its extended
      position; a  configuration it maintained for the remainder of the
      mission.  Magnetic-field data acquired prior to boom deployment are
      limited and are significantly affected by spacecraft noise. These
      data are of no scientific value and, consequently, do not form part
      of this data set.

      Cassini carried two magnetometers: a fluxgate magnetometer (FGM)
      and a vector-helium magnetometer capable of operating in both
      vector and scalar mode (V/SHM). This data set contains calibrated,
      and averaged magnetic-field data recorded by the FGM instrument.
      The data are provided in 1 minute averages.  The 1 minute data are
      provided in year files. The data are provided in RTN coordinates
      throughout the mission. After arrival at Saturn, the Saturn-centered
      KRTP, KSO, and KSM coordinates are also provided. Earth-centered,
      and Jupiter-centered coordinates are provided for the flybys of
      those two planets. All data files are ASCII.

      These data were calibrated, and rotated into geophysical coordinates
      by the Cassini MAG team at Imperial College (IC), and provided to
      the PDS/PPI node via the Cassini MAG team Co-I at UCLA. In other
      words these data use the same calibration as the data routinely
      delivered to the Cassini MAG team. The data were also averaged at
      IC. The data were reformatted into their current ASCII format,
      add trajectory information was added at PDS/PPI.

      Processing
      ==========


      Coordinate Systems
      ==================
      The coordinate systems in which the data are provided in vary by
      mission phase, and are designed to support both solar wind and
      planetary magnetospheric studies.


      Solar Wind Coordinates
      ----------------------

         Radial-Tangential-Normal Coordinates (RTN)
         ------------------------------------------
         RTN coordinates consist of R (radial component, Sun to the
         spacecraft), T (tangential component, parallel to the Solar
         Equatorial plane and perpendicular to R), and N (normal component,
         completes right handed set).

      Saturn-Centered Coordinates
      ---------------------------

         Kronocentric body-fixed, J2000 spherical Coordinates (KRTP)
         -----------------------------------------------------------
         KRTP magnetic field vector components form the standard right-handed
         spherical triad (R, Theta, Phi) for a planet-centered system.
         Namely, R is radial (along the line from the center of Saturn to the
         center of the spacecraft), and positive away from Saturn. Phi, the
         azimuthal component, is parallel to the Kronographic equator (Omega
         x R) and positive in the direction of corotation. Theta, the
         'southward' component, completes the right-handed set.

         Kronocentric Solar Magnetospheric Coordinates (KSM)
         ---------------------------------------------------
         KSM is a cartesian Saturn-center coordinate system where X points
         from Saturn to the Sun, the X-Z plane contains Saturn's centered
         magnetic dipole axis, M, and Y completes right handed set.

         Kronocentric Solar Orbital Coordinates (KSO)
         --------------------------------------------
         KSO is a cartesian Saturn-centered coordinate system where X points
         from Saturn to the Sun, Z is parallel to Saturn's orbital plane
         upward normal, and Y completes the right handed set.

      Earth-Centered Coordinates
      --------------------------

      Jupiter-Centered Coordinates
      ----------------------------

         Jovicentric Body-Fixed (IAU_JUPITER) Coordinates (J3)
         -----------------------------------------------------
         J3 is a body-fixed Jovicentric cartesian coordinate system
         consistent with the IAU 1997 definition of the System 3 prime
         meridian where X is in the Jovian equatorial plane, along S3
         1997 Prime Meridian, Z is parallel to the Jovian spin axis,
         and Y completes right-handed set.

         Jovicentric Body-Fixed Magnetospheric Coordinates (JMXYZ)
         ---------------------------------------------------------
         JMAG XYZ is a body-fixed Jovicentric cartesian coordinate system
         where X is in the plane containing Z and the S3 1997 Prime Meridian,
         Z is the Jupiter magnetic dipole, and Y completes right handed set.


      SPICE
      =====
      The data product labels associated with the data set include the name of
      a SPICE metakerenls which contains a list of the SPICE kernels that were
      used in calibrating the magnetic-field data, coverting them to physical
      coordinates, and generating the associated trajectory information.
      Copies of these metakernels are included in the GEOMETRY directory of
      the archive volume on which the data are located. While the SPICE
      kernels themselves are not part of this data set, they are archived at
      the PDS-NAIF node on the volume cosp_1000. Note that the SPICE kernels
      listed in the metakernels may be uniquely identified by their file name.

Product Versions
      ================
      PRODUCT_VERSION_ID 1 data were calibrated at the PDS/PPI node at
      UCLA using software (CAL02), and calibration data provided by the
      Cassini MAG team. The process used the same calibration data that
      was provided with the Raw Magnetometer data archive (Data Set ID:
      CO-E/SW/J/S-MAG-2-REDR-RAW-DATA-V1.0). The data were then rotated
      into geophysical coordinates using additonal code provided by the
      MAG team (TRANSCAL) and spice kernels obtained from NAIF.
      Additional processing, including averaging, reformatting to ASCII,
      and the addition of trajectory to the 1 minute data was performed
      using code developed at PDS/PPI.

      PRODUCT_VERSION_ID 2 data were calibrated, and rotated into
      geophysical coordinates by the Cassini MAG team at Imperial
      College, and provided to the PDS/PPI node via the MAG team Co-I at
      UCLA. The 1 minute data were also averaged at IC. Averaging for the
      1 second data was performed at PDS/PPI. The data were reformatted
      at PDS/PPI to match the format used for the version 1 data.

      PRODUCT_VERSION_ID 3 data were processed following the same
      procedure that was followed for the version 2 data. However,
      subsequent to the release of the version 2 data it was discovered
      that the coordinate system trasformation for some of those data had
      been performed using predict SPICE kernels, rather than
      reconstructions. The version 3 were reprocessed using reconstructed
      ephemeris kernels for all of the data.

      PRODUCT_VERSION_ID 4 data were processed following the same
      procedure that was followed for the version 2 and 3 data. These
      data, however, were processed using only reconstructed SPK's to
      generate the trajectory data, thus correcting the errors which
      were present in the version 3 data. The MAG data do not differ
      between versions 3 and 4.

      PRODUCT_VERSION_ID 5 data were processed following the same
      procedure that was followed for the version 3 and 4 data.  These data
      include corrections to the NPTS column data values, and some updates
      to the label files. The MAG data were unchanged from the previous
      version.

      PRODUCT_VERSION_ID 6 for RTN data files - The DATA/ *_FGM_RTN_1M.TAB
      files, Version 5, and older versions, had assigned a width to the Sun
      to Spacecraft distance column (RANGE) that was insufficient to
      accommodate values of 10 AU or greater. This resulted in inconsistent
      record structures and lengths. The version 6 RTN files correct this
      error by allocating an additional byte to the RANGE column width and
      adjusting the start position of the subsequent columns accordingly.
      The MAG data were unchanged from the previous version.

      PRODUCT_VERSION_ID 6 for KRTP, KSO, and KSM and PRODUCT_VERSION_ID 7
      for RTN data files were processed using an updated calibration that
      was produced by the MAG team using data from the Cassini Proximal
      Orbits.

      PRODUCT_VERSION_ID 7 for KRTP, KSO, and KSM and PRODUCT_VERSION_ID 8
      for RTN data products were updated to provide greater precision for
      the trajectory parameters provided in units of AU and satellite
      radii. The MAG data were unchanged from the previous version.