| Download this file |
|
PDS_VERSION_ID = PDS3 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 OBJECT = DATA_SET DATA_SET_ID = "GO-SS-RSS-1-TDF-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "GALILEO RADIO TRACKING EARTH1 AND EARTH2 MASS DETERMINATION EXPERIMENT DATA V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_OBJECT_TYPE = TABLE START_TIME = 1990-11-29T10:00:00Z STOP_TIME = 1992-12-11T01:50:50Z DATA_SET_RELEASE_DATE = 1999-07-30 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) Earth1 and Earth2 Mass Determination Experiments. The experiments were conducted over the following time periods: November 29, 1990, to December 10, 1990, and October 16, 1992, to December 11, 1992. 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 S970311A.XSP file is the reconstructed SP kernel for the Cruise portion of the Galileo mission and includes the Solar Gravitational Redshift 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. Post-Operations Report ---------------------- The Post-Operations Report describes the tracking coverage, spacecraft activity, and DSN equipment problems in a graphical format. This report is in the DOCUMENT directory. 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 Earth1 and Earth2 Mass Determination between November 1990 to December 1990, and August 1992 to December 1992. There are no known quality issues which would limit use of this data other than the normal signal-to-noise constraints. Limitations =========== None." END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = UNK END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = GO INSTRUMENT_ID = RSS END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "ANDERSONETAL1992" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END |