Data Set Overview
  =================
    This data set consists of magnetic field vector data recorded by
    the Vector Helium Magnetometer onboard the Pioneer 10 spacecraft,
    during the close encounter to Jupiter (inside 7 RJ). The vector
    data are provided in a Jupiter-centered JG coordinates (see
    descriptions in Sections of Data Format and Coordinate System for
    Data). Also included are the spacecraft trajectory data (distance
    from Jupiter, latitude, and longitude) in the same coordinates.


  Data Sampling
  ==============
    These data are provided in 1 minute averages. The resolution from
    which the 1 minute averages were generated is unknown. The
    magnetometer measures the three field components over a frequency
    range from 0 to 10 Hz. At encounter the data rate was 1024 bits/sec
    and the magnetometer sampling rate was one vector measurement every
    3/16 second, corresponding to 5.33 samples/sec.


  Data Format
  ============
    The Pioneer 10 magnetometer data for the close encounter to Jupiter
    were originally written on a 9-track, 1600 bpi, ASCII encoded
    magnetic tape. The original file was re-formatted into ASCII. The
    data file contains the following data columns:
    --------------------------------------------------------------------
    Column  Column   Column
    Name    Format   Description
    --------------------------------------------------------------------
    TIME    A24      Ground received time in yyyy-mm-ddThh:mm:ss.sss
    R       F12.4    Distance of Pioneer 10 from Jupiter in Rj
    LAT     F12.4    Latitude of Pioneer 10 in JG coordinates
    LON     F12.4    Longitude of Pioneer 10 in JG coordinates
    BX      F12.4    X component of the magnetic field in JG coordinates
    BY      F12.4    Y component of the magnetic field in JG coordinates
    Bz      F12.4    Z component of the magnetic field in JG coordinates
    --------------------------------------------------------------------


  Coordinate System for Data
  ===========================
    JG coordinates is defined as the X axis in the direction of G, the
    equatorial vector lying in the System III (1957.0) Prime Meridian;
    the Z axis in the direction of J, the spin axis of Jupiter;  and
    the Y axis parallel to Jupiter's equatorial plane and completing
    the right-handed orthogonal system.


  Instrument Calibration
  ======================
    The in-flight calibration consists of impressing eight precisely
    known currents on the sensor coil system and measuring the resulting
    fields with the magnetometer. The instrument is designed to carry
    out a nominal mission with only one instrument-on command. The
    instrument comes on in the automatic ranging/spectrum analyzer
    mode and automatically ranges to the proper scale by comparing
    the +X and |Z| axis outputs with fixed reference voltages. The
    only function commands sent to this instrument during the Pioneer
    F&G missions were those to initiate the in-flight calibration
    sequence periodically during the cruise phase. At the conclusion
    of this sequence the instrument automatically returned to the
    automatic ranging mode. A 6-bit digital house-keeping word
    indicates the operating mode of the instrument.

    The in-flight calibration onboard the Pioneer spacecraft was done
    by ground command once or twice a week. The low range sensors were
    calibrated at field magnitude of 13 GAMMA and 26 GAMMA during the
    interplanetary cruise period. While the high range sensors were
    calibrated near planetary encounter where the field magnitude was
    as high as +/-43,000 GAMMA and 86,800 GAMMA. There are two kind of
    instrument calibration parameters, sensor scale factor (gain) and
    offset.

    The conventional approach to checking the magnetometer scale
    factors in flight is to apply calibration field changes, dB to
    the sensors so that the corresponding voltage change dV can be
    determined. Normally several step changes are applied sequentially
    so that the linearity can be tested directly. After two years of
    in-flight calibrations, no change has been detected in the Pioneer
    10 or 11 scale factors which were then known to an accuracy of
    1 percent or better.

    The sensor offsets were determined in-flight using two different
    techniques.  For the two sensors in the spin plane, the offset
    was calculated by averaging the spinning data in a time interval
    of an integral number of spin period. The offset of the spin axis
    sensor was determined by an adaptation of a variance technique
    developed by L. Davis [BELCHER1973]. The essential assumption
    was made that over short intervals of time (5 minutes), the
    fluctuations in the interplanetary field are principally changes
    in direction and tend to conserve the magnitude of the field.

Confidence Level Overview
  =========================
    The vector helium magnetometer noise spectrum is independent of
    frequency (white) with a field equivalent power spectral density
    of 10**-4 GAMMA**2/HZ. For signal bandwidths less than 1 Hz,
    corresponding for example to values averaged over a few seconds
    or more, fields smaller than 0.01 GAMMA can be detected.

    The maximum relative error of the magnetometer sensors is given by
               dB/B <= dB0/B + dk/k
    where B0 is the total offset error and dk is the scale factor error.
    The scale factor accuracy is as good as 1%. And the total offset
    error is mainly caused by the spin axis sensor error because it
    is not readily determined as the two in spin-plane sensors. The
    ratio of the standard deviation of the offset in spinning axis
    to the field magnitude is about 0.05. Thus, the maximum relative
    error in the magnetic field measurement is 0.06.


  Data Coverage and Quality
  =========================
    This data set has a nearly 2-hour data gap between
    1973-12-04T04:08:58 and 1973-12-04T05:51:05 in this data set, on top
    of sporadic missing data points after 1973-12-04T06:18:00.000.

    There are no flagged values in this data set.