This bundle contains open-loop radio receiver raw data collected using 
the Parkes Observatory (Australia) 64-m antenna, temporarily assigned
to the NASA Deep Space Network (as DSS-49) during the Voyager 2 
encounter with Uranus on January 24-25, 1986. The data include samples
from an X-band receiver (3.6 cm) in right-circular polarization.  Also
included are calibration measurements collected within a few hours of
the Uranus observations.  The data supported investigations of the 
structure of Uranus' neutral atmosphere, ionosphere, and rings.

56 original data tapes -- known as Parkes Original Data Records (PODRs)
-- were delivered to the Voyager Radio Science Team in the format
specified by the 1982 version of the DSN RSC-11-9 Software Interface 
Specification (SIS).  Original tape identifiers (UL0304 through UL0359,
which were delivered in sequence but not in chronological order) have
been converted to a form (see below) that allows sorting by start time.

Each original PODR tape forms the basis for a PDS4 product in the bundle.
The binary file is the first part of the product; but the binary data
are in an archaic binary format, so they have been converted to ASCII
for easier reading.  There is one ASCII table with record header data,
and one ASCII file with the X-band receiver samples; these are the second
and third parts of each PDS4 product.  Future users will likely prefer
to work with the ASCII files.  Each product also includes a detached
PDS4 label file written in XML and a small ASCII file with terse titles
for the fields in the header table.  For example, the following five
files constitute one PDS4 product (from original tape UL0356):

  vg2u_49xr_1986024t033501.dat     original PODR file (binary)
  vg2u_49xr_1986024t033501.hdr     record header data (ASCII)
  vg2u_49xr_1986024t033501.tab     X-band receiver samples (ASCII)
  vg2u_49xr_1986024t033501.xml     PDS4 XML label (ASCII)
  vg2u_49xr_1986024t033501.txt     field headers for the hdr file (ASCII)

In two cases (UL0305 and UL0355, or vg2u_49xr_1986024t212141.dat and
vg2u_49xr_1986024t174101.dat, respectively, in the PDS4 archive), one 
record could not be read from the PODR tape that was delivered to the 
Voyager Radio Science Team.  A replacement record has been substituted;
its record header is valid, but some of the receiver samples are not.  
In these cases, a flag has been set in the record header. This should 
have negligible effect on most types of data processing.  See the 
archive SIS for details.

Each PODR has been processed to give a 'browse' product -- a plot in 
JPEG format.  Each plot contains a histogram of data sample values, a
line drawing of average sample power versus time, a waterfall plot of
time-averaged power spectra, and labeling information.

Also included in the bundle are reconstructions of the spacecraft
trajectory (in the Celestial Reference System) and spacecraft high-gain
antenna (HGA) pointing, which was offset during the Uranus atmospheric 
occultation to compensate for refraction.  These files are included 
primarily for historical interest; for reanalysis of the data, users should
consider obtaining the latest reconstructions from the PDS Navigation and 
Ancillary Information Facility (NAIF).  

Receiver tuning data, included in the PODR header, and estimated frequency
of the spacecraft ultrastable oscillator (USO) allow calculation of the 
exact received frequency at the ground station.

The document collection includes a description of the Voyager mission,
a SIS for the archive bundle, a description of the HGA pointing 
reconstruction procedure, a description of the ephemeris file, and a 
listing of selected software used to process the data.  The archive
SIS (sis_vgr_rs) describes in more detail how the products in this archive
were constructed from the original raw data files.  The software listing 
is intended for documentation; there is no expectation that the programs
and subroutines would run in arbitrary environments. Documentation of the 
binary formats in the PODR, which has been archived elsewhere in PDS, has 
been included by reference.  

The archive SIS provides more description of the archive than can be 
included here.

Dick Simpson
2025-04-11