Data Set Overview
      =================
      This data set consists of magnetic field vector data recorded
      by the Fluxgate Magnetometer onboard the Pioneer 11 spacecraft,
      during the Jupiter encounter period.  Data include 5 minute
      averages of the magnetic field in both Inertial Heliocentric
      and System III (1957.0) coordinates.  Spacecraft trajectory
      data are also provided, in System I and System III (1957.0)
      coordinates.


      Data Sampling
      ==============
      The fluxgate magnetometer data is multiplexed into one of
      the Science Subcom formats available on the spacecraft.
      Two separate 6-bit words per subcom cycle are assigned
      to the instrument and thus 3 complete cycles are required
      to read out the contents of the output buff.  At a bit rate
      of 2048 bps, a complete subcom cycle requires 6 second and
      a vector measurement is obtained approximately every 18 to
      24 second depending on the actual roll rate of the spacecraft,
      which is nominally 5 revolutions per minute (ACUNA&NESS1974).

      The NSSDC documentation does not contain information about what
      data resolution this data set (5 minute) is averaged from.


      Data Processing
      ===============
      No detailed information of data processing is found in the NSSDC
      documentation pertinent to this data set.

      Pioneer 11 spacecraft was operating under a spin-stablized
      condition and had a spin period of 12 seconds.


      Data Format
      ============
      The Pioneer 11 magnetometer data for Jupiter encounter were
      originally written on a BCD magnetic tape created at NSSDC from
      a card deck supplied by the PI team.  The original file was
      re-formatted into a new ASCII file named P11_FGM_JUP_ENC_5MIN.TAB
      which contains the following data columns:
      --------------------------------------------------------------------
      Column  Column   Column
      Name    Format   Description
      --------------------------------------------------------------------
      TIME    A24      Ground received time in yyyy-mm-ddThh:mm:ss.sssZ
      R       F5.2     Distance of Pioneer 11 from Jupiter in Rj
      LAT     F6.1     Latitude of Pioneer 11 in System III (1957.0)
      LON1    F7.1     Longitude of Pioneer 11 in System I
      LON3    F7.1     Longitude of Pioneer 11 in System III (1957.0)
      BX      F8.4     X component of the magnetic field in Inertial
                           Heliocentric coordinates
      BY      F8.4     Y component of the magnetic field in Inertial
                           Heliocentric coordinates
      Bz      F8.4     Z component of the magnetic field in Inertial
                           Heliocentric coordinates
      BR      F8.4     Radial component of the magnetic field in
                           System III (1957.0)
      BTHETA  F8.4     Polar component of the magnetic field in
                           System III (1957.0)
      BPHI    F8.4     Azimuthal component of the magnetic field in
                           System III (1957.0)
      N       I2       Number of data points used in averaging
      --------------------------------------------------------------------


      Coordinate System for Data
      ===========================
      System I is a planetographic spherical coordinates at Jupiter.  This
      system used a relatively faster Jupiter spin rate (877.90 degree per
      24 hours) to describe cloud features within 10 degree of the equator.
      The Central Meridian Longitude was established at 12:00 Greenwich Mean
      Time on July 14, 1897.

      System III (1957.0) is a planetographic spherical coordinates. In this
      system, the Jovian rotation period is defined to be 9h55m29.37s
      and the Central Meridian Longitude is defined at 00:00 UT on
      January 1, 1957.

      Inertial Heliocentric coordinates is a Cartesian system, defined based
      on two principle directions, the Jupiter spin axis J, and the direction
      from the sun to the first point of Aries, X.  The Y direction is given
      by the cross product of J and X.  The Z direction is defined as the
      cross product of X and Y.


      Ancillary Data
      ==============
      There is no ancillary data associated with this data set.


      Instrument Calibration
      ======================
      The fluxgate magnetometer was calibrated at the GSFC Magnetic
      Test Facility by means of a 2 meter diameter, single axis
      Helmholtz coil system.  Typically hysteresis observed after
      exposure to 2.5 mT fields was less than 1 part in 10**3 (one
      count).  Temperature stability is better than +- 0.5% over the
      temperature range of -20 to +40 degree Celsius in spite of the
      open loop design of the instrument.  This is due to the fact
      that the characteristics of the magnetic material used in the
      sensor cores are fairly independent of temperature over the
      indicated range.  The stability figure includes the A/D converter
      drift and a large portion of it is due to the single ramp design
      of the latter.  Nevertheless, minimum power consumption
      requirements and flight qualified component availability
      precluded the used of more stable A/D converter designs
      (ACUNA&NESS1974).

Confidence Level Overview
      =========================
      No data confidence information is found in the NSSDC documentation
      pertinent to this data set.

      There is no flagged values in this data set.