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OBJECT = DATA_SET
DATA_SET_ID = "GO-J-RSS-1-ODF-V1.0"
OBJECT = DATA_SET_INFORMATION
DATA_SET_NAME = "GALILEO RADIO TRACKING JOVIAN SYSTEM
EPHEMERIS IMPROVEMENT EXPERIMENT
DATA V1.0"
DATA_SET_COLLECTION_MEMBER_FLG = "N"
DATA_OBJECT_TYPE = TABLE
START_TIME = 1996-07-17T02:40:20Z
STOP_TIME = 1997-12-10T03:19:31Z
DATA_SET_RELEASE_DATE = 1999-06-01
PRODUCER_FULL_NAME = "RADIO SCIENCE SUPPORT TEAM"
DETAILED_CATALOG_FLAG = "N"
DATA_SET_DESC = "
Data Set Overview
=================
This data set contains raw radio tracking data from the
Galileo (GLL) Jovian System Ephemeris Improvement Experiment.
The experiment were conducted over the following time period:
July 17, 1996 to December 10, 1997
The data set includes NASA Deep Space Network (DSN) Archival
Tracking Data Files (ATDFs or TDFs) and/or Orbit Data Files (ODFs)
and other data used primarily for Galileo navigation, science probing
of gravitational fields and waves, and ephemeris development.
The experiment is described in detail in DESCRIPT.TXT in the DOCUMENT
directory. Another explanation of the experiment, as well as the
ground equipment, spacecraft, and operations procedures, may be found
in the Radio Science Handbook. This handbook is also in the DOCUMENT
directory.
Parameters
==========
Each 288-byte ATDF data record contains 117 parameters, stored at
at rates of up to 10 records per second. The parameters include
outputs from the DSN ranging system, estimates of Doppler offsets,
estimates of received signal strength, and status information on
components of the DSN system. The ATDF is described by a Software
Interface Specification (SIS), included as TRK_2_25.TXT in the
DOCUMENT directory of each archival volume.
Each 36-byte ODF data record contains 22 parameters which may include
outputs from the DSN ranging system, estimates of Doppler offsets,
and 'footprint' information. The ODF is described by a Software
Interface Specification (SIS), included as TRK_2_18.TXT in the
DOCUMENT directory of each archival volume.
Processing
==========
Radiometric data are received by the DSN Network Operations and Control
Center (NOCC) Navigation Subsystem (NAV) in the form of Intermediate
Data Records (IDRs). These IDRs are processed to generate ATDFs. An
ATDF contains all radiometric data received from the Deep Space
Communications Complexes (DSSCs) tracking a single spacecraft for one
or more passes or days.
The ODF is produced from IDRs by the NOCC NAV; it contains far fewer
fields than the ATDF and is preferred by investigators in certain
applications because of its smaller volume (compared with the ATDF).
Data
====
ATDFs and ODFs contain precise radio range and Doppler measurements
made between DSN ground stations and a spacecraft. During the Galileo
Venus encounter, for example, coded waveforms were transmitted from
the Earth, relayed by the on-board Galileo telecommunications system,
and received back on Earth. Cross correlation between the transmitted
and received waveforms yielded a measurement of the round trip
distance, which could then be related to the Earth-Venus distance
during the flyby. Doppler shift from the same measurements could be
interpreted as relative velocity along the propagation path.
An ATDF has a file name of the form ydddeeeX.TDF where y is
the least significant digit of the year and ddd is the day-of-year
for the first ATDF record. The eee gives day-of-year for the last
data record in the ATDF, and X is set to 'A'.
Each ATDF is accompanied by a full PDS detached label with name
ydddeeeX.LBL which completely describes the contents of the ATDF.
The format and contents are also described in TRK_2_25.TXT in the
DOCUMENT directory of each archival volume. Both the ATDF and its
label are stored in the TDF directory of an archival volume.
An ODF has a file name of the form ydddeeeX.ODF where the components
of the file name are explained above. Each ODF is accompanied by a
full PDS label with name ydddeeeX.LBL. Both the ODF and its label
are stored in the ODF directory of an archival volume.
Ancillary Data
==============
The ancillary files are stored in the CALIB, GEOMETRY and DOCUMENT
directories. Each ancillary file is accompanied by a detached PDS
minimal label having the same file name except for the suffix 'LBL'.
Low-Gain Antenna (LGA) Radiation Pattern
-----------------------------------------
The radiation pattern of the low-gain antenna (LGA) is described
in files LGA1_DL.TAB and LGA1_UL.TAB in the CALIB directory.
These files provide the radiation patterns for downlink and
uplink, respectively.
Spacecraft Ephemeris Information
--------------------------------
The spacecraft ephemeris information is located in the GEOMETRY
directory. The S980326B.XSP file is the reconstructed SP kernel
for the Cruise portion of the Galileo mission and includes the
Jovian System Ephemeris Improvement Experiment.
There is also a file containing right ascension and declination
information for the spacecraft at midnight for each day of the
experiment. This file is also in the GEOMETRY directory, and it is
called RA_DEC.TAB.
Coordinate System
=================
Most data types are not dependent on definition of a coordinate
system; for those that are, the user should consult the appropriate
SIS for information.
Software
========
Software for parsing, reducing, and analyzing data such as these has
been developed at the Jet Propulsion Laboratory and elsewhere.
Because parsing must be done at the bit level, its implementation may
be very sensitive to platform and operating system. No parsing
has been written and tested on a variety of platforms, so none has
been included with the archival data set. Users are referred to PDS
labels, to files in the DOCUMENT directory, and to hard copy Software
Interface Specifications for detailed information on file formats.
Media/Format
============
The archival data set is written on CD-WO media using the Young Minds
CD Studio authoring system. The CD-WO volume conforms to ISO 9660
standards."
CONFIDENCE_LEVEL_NOTE = "
Overview
========
There are no known limitations to use of these data, subject to
signal-to-noise considerations which would be typical for systems
of this type.
Review
======
Prior to creation of the final version of the archival data set,
key elements of the archive were distributed for preliminary review.
These included electronic versions of example PDS labels, CATALOG
files, and Software Interface Specifications. These materials were
distributed to PDS personnel and the PDS Radio Science advisor.
Data Coverage and Quality
=========================
The data covers the periods of Jovian System Ephemeris Improvement
Experiment between July 17, 1996 and December 10, 1997.
There are no quality issues which would limit use of this data
other than the normal signal-to-noise constraints.
Limitations
===========
None."
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