CCSD3ZF0000100000001NJPL3IF0PDS200000001 = SFDU_LABEL
/* Detached PDS label for the Pioneer Venus ORAD database file */
RECORD_TYPE                    = FIXED_LENGTH
RECORD_BYTES                   = 186
FILE_RECORDS                   = 144129
^TABLE                         = "PVEN001S.DAT"
OBJECT                         = TABLE
  INTERCHANGE_FORMAT           = ASCII
  ROWS                         = 144129
  COLUMNS                      = 25
/* Dataset descriptive parameters */
  DATA_SET_ID                  = "P12-V-ORAD-4-ALT/RAD-V1.0"
  TARGET_NAME                  = VENUS
  EVENT_START_TIME             = 1978-12-05
  EVENT_STOP_TIME              = 1981-03-23
  SPACECRAFT_NAME              = "PIONEER VENUS ORBITER"
  INSTRUMENT_NAME              = "ORBITING RADAR"
  TRANSMITTED_POLARIZATION     = "LINEAR"
  RECEIVED_POLARIZATION        = "SAME SENSE LINEAR"
  WAVELENGTH                   = 17. <CENTIMETERS>
  PRODUCER_FULL_NAME           = "GORDON H. PETTENGILL"
  NOTE                         = "This data set consists of measurements
        made by the Radar Mapper Experiment on the Pioneer Venus Orbiter
        spacecraft.  The measurements were made during each 12-second
        spacecraft rotation period for a period of 32 minutes either
        side of periapsis, when the range to the surface was less that
        about 4500 km.  This data set contains results from the
        altimetry and radiometry measurements.  Each record describes
        the data collected during a single 12-second roll period.  If
        multiple altimetry measurements were made at that time, the
        individual results have been averaged.  This data set includes
        corrections for timing errors, orbit determination errors, and
        for atmospheric delay and attenuation.  There remain severe
        systematic errors in the planetary radius and Fresnel
        reflectivity parameters, the former due to a combination of
        spacecraft timing and orbit determination errors, the latter to
        spacecraft timing errors alone.  All fields are separated by
        commas.  For reference, see Pettengill, G.H., E. Eliason, P.G.
        Ford, G.B. Loriot, H. Masursky, and G.E. McGill, Pioneer Venus
        radar results: Altimetry and surface properties, J. Geophys.
        Res., 85, 8261-8270, 1980."

/* Descriptions of each column in the file */
  OBJECT                       = COLUMN
     NAME                      = DATE
     DATA_TYPE                 = INTEGER
     UNIT                      = DAYS
     START_BYTE                = 1
     BYTES                     = 8
     FORMAT                    = 'I8'
     DESCRIPTION               = "The year and day-of-year of the
        observation, as supplied by the Pioneer project.  The year
        occupies the first 5 bytes, the day the remaining 3 bytes.  This
        field may be used to correlate this radar observation record
        with data from other Pioneer Venus instruments, but the
        RADAR_DATE field should be used for radar mapping purposes.  A
        value of 0 for this field means the field is undefined for this
        record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = TIME
     DATA_TYPE                 = INTEGER
     UNIT                      = MILLISECONDS
     START_BYTE                = 10
     BYTES                     = 9
     FORMAT                    = 'I9'
     DESCRIPTION               = "The time of the observation, in
        milliseconds from midnight UT, as supplied by the Pioneer
        project.  As with the Date field, this should only be used for
        comparison purposes.  The accurate radar observation time is
        contained in the RADAR_TIME field.  A value of 0 for this field
        means the field is undefined for this record and should be
        ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = ORBIT_NUMBER
     DATA_TYPE                 = INTEGER
     UNIT                      = "N/A"
     START_BYTE                = 20
     BYTES                     = 5
     FORMAT                    = 'I5'
     DESCRIPTION               = "The Pioneer Venus orbit number.  The
        spacecraft maintained a nearly 24-hour orbit.  Radar data was
        taken from orbit 3 on December 7, 1978 through orbit 834 on
        March 19, 1981.  A value of 0 for this field means the field is
        undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = ROLL_TIME
     DATA_TYPE                 = INTEGER
     UNIT                      = SECONDS
     START_BYTE                = 26
     BYTES                     = 6
     FORMAT                    = 'I6'
     DESCRIPTION               = "The time from periapsis, in seconds,
        supplied by the Pioneer project.  Negative values represent
        pre-periapsis measurements.  This time field is specified in
        precisely 12 second intervals from the periapsis time derived
        from spacecraft doppler tracking.  The 12-second interval was
        chosen to closely approximate the spacecraft spin period.  Radar
        data were taken once per spacecraft rotation, and therefore not
        at exactly 12-second intervals.  In addition, the radar
        altimeter was able to refine the measurement of UT of periapsis.
        Each radar observation was therefore assigned to a particular
        12-second interval by counting spacecraft revolutions before or
        after the true periapsis, assigning the last radar measurement
        before periapsis to the Roll field with value 0.  A value of 0
        for this field means the field is undefined for this record and
        should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADAR_DATE
     DATA_TYPE                 = INTEGER
     UNITS                     = DAYS
     START_BYTE                = 33
     BYTES                     = 8
     FORMAT                    = 'I8'
     DESCRIPTION               = "The year and day-of-year of the
        observation.  The year occupies the first 5 bytes, the day the
        remaining 3 bytes.  A value of 99999999 for this field means the
        field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADAR_TIME
     DATA_TYPE                 = INTEGER
     UNITS                     = MILLISECONDS
     START_BYTE                = 42
     BYTES                     = 9
     FORMAT                    = 'I9'
     DESCRIPTION               = "The time that the first altimeter
        pulse left the transmitter, measured in milliseconds from
        midnight UT.  A value of 999999999 for this field means the
        field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIOMETER_LATITUDE
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 52
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The latitude of the radiometric
        brightness measurement.  Latitudes are expressed in degrees,
        positive in the northern hemisphere, negative in the southern.
        The body-fixed 1985 IAU coordinate system (VBF85) is used.  A
        value of 999.999 for this field means the field is undefined for
        this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIOMETER_LONGITUDE
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 60
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The longitude of the radiometric
        brightness measurement.  Longitudes are expressed in degrees, in
        the range 0 through 360.  Longitudes increase eastward of the
        prime meridian, and the (retrograde) planetary rotation is from
        east to west.  The body-fixed 1985 IAU coordinate system (VBF85)
        is used.  A value of 999.999 for this field means the field is
        undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = PLANET_RADIANCE
     DATA_TYPE                 = REAL
     UNITS                     = CENTIVOLTS
     START_BYTE                = 68
     BYTES                     = 6
     FORMAT                    = 'F6.1'
     DESCRIPTION               = "The voltage reading from the radar
        receiver during the radiometry period, when the transmitter was
        turned off and the antenna pointed within about 5 degrees of the
        plane defined by the spacecraft spin-axis and the nadir.  A
        value of 9999.9 for this field means the field is undefined for
        this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = SPACE_RADIANCE
     DATA_TYPE                 = REAL
     UNITS                     = CENTIVOLTS
     START_BYTE                = 75
     BYTES                     = 6
     FORMAT                    = 'F6.1'
     DESCRIPTION               = "The voltage reading from the radar
        receiver during the radiometry-background period, when the
        transmitter was turned off and the antenna pointed within about
        5 degrees of the plane defined by the spacecraft spin-axis and
        the zenith.  A value of 9999.9 for this field means the field is
        undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = BRIGHTNESS_TEMPERATURE
     DATA_TYPE                 = REAL
     UNITS                     = "DEGREES KELVIN"
     START_BYTE                = 82
     BYTES                     = 6
     FORMAT                    = 'F6.1'
     DESCRIPTION               = "The microwave brightness temperature
        of the planet, in degrees Kelvin, derived from the
        PLANET_RADIANCE (PC) and SPACE_RADIANCE (SC) measurements, as
        follows: the data set was divided into 1 degree latitude
        intervals.  For each interval, the average SC reading <SC> was
        taken to represent a measurement of the 3K cold sky.  The
        average PC values <PC> from lowland regions were interpreted as
        measuring an average temperature of 735K with an emissivity of
        88%.  BRIGHTNESS_TEMPERATURE is therefore obtained by
        (735*0.88*(PC-<SC>)+3*(<PC>-PC))/(<PC>-<SC>).  This formula may
        occasionally predict a negative brightness temperature value, a
        result of the large random noise component in PC and SC along
        with the assumption of linear temperature response.  A value of
        9999.9 for this field means the field is undefined for this
        record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADAR_LATITUDE
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 89
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The latitude of the average radar
        altimeter footprint for this observation.  Because of the delay
        and doppler filtering applied by the on-board data processing
        electronics, the footprint is not necessarily centered about the
        sub-spacecraft point, nor is it symmetric with respect to the
        antenna axis.  In addition, some observations are, in fact,
        averaged over up to 4 measurements taken at varying doppler
        frequency offsets, corresponding to 4 separated footprints
        spaced along the spacecraft ground track.  Latitudes are
        expressed in degrees, positive in the northern hemisphere,
        negative in the southern.  The body-fixed 1985 IAU coordinate
        system (VBF85) is used.  A value of 999.999 for this field means
        the field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADAR_LONGITUDE
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 97
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The longitude of the average radar
        altimeter footprint.  Longitudes are expressed in degrees, in
        the range 0 through 360.  Longitudes increase eastward of the
        prime meridian, and the (retrograde) planetary rotation is from
        east to west.  The body-fixed 1985 IAU coordinate system (VBF85)
        is used.  A value of 999.999 for this field means the field is
        undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = CROSS_TRACK_FOOTPRINT_SIZE
     DATA_TYPE                 = REAL
     UNITS                     = KILOMETERS
     START_BYTE                = 105
     BYTES                     = 5
     FORMAT                    = 'F5.1'
     DESCRIPTION               = "The average cross-track dimension of
        the altimeter footprint.  This is determined by the
        delay-resolution of the radar receiver.  A value of 9999. for
        this field means the field is undefined for this record and
        should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = ALONG_TRACK_FOOTPRINT_SIZE
     DATA_TYPE                 = REAL
     UNITS                     = KILOMETERS
     START_BYTE                = 111
     BYTES                     = 5
     FORMAT                    = 'F5.1'
     DESCRIPTION               = "The average along-track dimension of
        the altimeter footprint.  For spacecraft altitudes above about
        500 km, this is also determined by the delay-resolution of the
        radar receiver.  Below this altitude, it is determined by the
        frequency resolution.  The high altitude footprints are
        therefore circular, and the low altitude ones are approximately
        elliptical with ALONG_TRACK_FOOTPRINT_SIZE <
        CROSS_TRACK_FOOTPRINT_SIZE.  A value of 9999. for this field
        means the field is undefined for this record and should be
        ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIUS
     DATA_TYPE                 = REAL
     UNITS                     = KILOMETERS
     START_BYTE                = 117
     BYTES                     = 8
     FORMAT                    = 'F8.3'
     DESCRIPTION               = "The planetary radius measured by the
        radar altimeter.  A correction has been made for atmospheric
        delay, using the results of Kliore et al., 1985.  A value of
        9999.999 for this field means the field is undefined for this
        record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIUS_ERROR
     DATA_TYPE                 = REAL
     UNITS                     = KILOMETERS
     START_BYTE                = 126
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The formal error in planetary radius,
        derived from the statistics of the time-sampled altimetry
        echo-power profile.  A value of 999.999 for this field means the
        field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RMS_SLOPE
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 134
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The RMS average surface slope at meter
        scale, from the altimeter measurement.  The slope is derived by
        analyzing the time-sampled profile according to Hagfors' Law of
        near-normal-incidence scattering from a quasi-specular surface,
        where the specific radar cross-section varies with the
        scattering angle t according to
        0.5*R*C*(cos(t)**4+C*sin(t)**2)**(-1.5), where R is the
        FRESNEL_REFLECTIVITY and the Hagfors constant C is
        RMS_SLOPE**(-2) in radians.  A value of 999.999 for this field
        means the field is undefined for this record and should be
        ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = SLOPE_ERROR
     DATA_TYPE                 = REAL
     UNITS                     = DEGREES
     START_BYTE                = 142
     BYTES                     = 7
     FORMAT                    = 'F7.3'
     DESCRIPTION               = "The formal error in surface slope,
        derived during the process of fitting the returned time-sampled
        radar echo to a set of Hagfors Law templates.  A value of
        999.999 for this field means the field is undefined for this
        record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = FRESNEL_REFLECTIVITY
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 150
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "The Fresnel reflectivity of the
        surface.  This is related to the (complex) surface bulk
        dielectric constant E by ((sqrt(E)-1)/(sqrt(E)+1))**2.  A value
        of 99.99 for this field means the field is undefined for this
        record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = FRESNEL_REFLECTIVITY_ERROR
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 156
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "The formal error in Fresnel
        reflectivity, derived during the process of fitting the returned
        time-sampled radar echo to a set of theoretical templates
        derived from Hagfors Law."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = FRESNEL_REFLECTIVITY_CORRECTION
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 162
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "A correction to the Fresnel
        reflectivity to account for that fraction of the incident radar
        beam that is reflected by sub-wavelength-sized scatterers.  This
        component was estimated, where possible, from the ORAD side
        looking radar imaging mode, and modeled by the phenomenological
        function g*a*Rf*cos(t)**1.5, where t is the scattering angle, g
        = 2.69 is a fitted geometrical factor, and a is the fraction of
        the surface covered by diffusely-scattering material.  Rf is the
        true Fresnel reflectivity, and may be reconstructed from
        FRESNEL_REFLECTIVITY+FRESNEL_REFLECTIVITY_CORRECTION.  This
        correction is only available for that portion of the altimetric
        data set that is also covered by side-looking imaging data, i.e.
        from about 15 degrees south to 45 degrees north latitude.  A
        value of 99.99 for this field means the field is undefined for
        this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIUS_SLOPE_CORRELATION
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 168
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "The formal correlation coefficient
        between the planetary radius and the surface slope, derived
        while fitting the observed echo-power profile to Hagfors Law
        derived templates.  A value of 99.99 for this field means the
        field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = RADIUS_REFLECTIVITY_CORRELATION
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 174
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "The formal correlation coefficient
        between the planetary radius and the Fresnel reflectivity,
        derived while fitting the observed echo-power profile to Hagfors
        Law derived templates.  A value of 99.99 for this field means
        the field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN

  OBJECT                       = COLUMN
     NAME                      = SLOPE_REFLECTIVITY_CORRELATION
     DATA_TYPE                 = REAL
     UNITS                     = "N/A"
     START_BYTE                = 180
     BYTES                     = 5
     FORMAT                    = 'F5.2'
     DESCRIPTION               = "The formal correlation coefficient
        between the surface slope and the Fresnel reflectivity, derived
        while fitting the observed echo-power profile to Hagfors Law
        derived templates.   A value of 99.99 for this field means the
        field is undefined for this record and should be ignored."
  END_OBJECT                   = COLUMN
END_OBJECT                     = PV_RADAR_TABLE
END