Data Set Information
DATA_SET_NAME MGS SOLAR CONJUNCTION RAW DATA SET - ROCC V1.0
DATA_SET_ID MGS-SUN-RSS-1-ROCC-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview ================= The Mars Global Surveyor (MGS) Solar Conjunction Raw Data Archive is a time-ordered collection of raw data acquired during the Solar Conjunction in 2000, while MGS was in its Mars Mapping (MAP) mission phase. Two types of measurements were conducted during MAP; these are known as closed-loop and open-loop recordings. The closed- loop system used a phase-lock loop in the receiver to track the downlink signal, reporting both amplitude and frequency at rates typically of 1-10 times per second. In the open-loop system, the signal was simply converted to a baseband frequency range; the entire passband was sampled and recorded for later processing. Typical open-loop sampling rates for MGS were 5000 samples per second. Closed-loop data are efficient for characterizing slowly changing signals; open-loop data (because of their much higher volume) are collected only when the signal is very dynamic -- such as during an occultation. The data set includes two primary data types. Archival Tracking Data Files (ATDFs or TDFs) are the most primitive (and most voluminous) product of the closed-loop system. Original Data Records (ODRs) are the primary data type from the open-loop system. Parameters ========== The ATDF is the primary output from the MGS closed-loop system. ATDFs have 150 fields, though not all had been assigned during the MGS era. Each ATDF in the data set is accompanied by a full PDS label which defines both the content and the format (at the bit level) of the file. ATDF data fields include: Range High- or low-rate Doppler High or low-rate downlink phase Differential Range vs Integrated Doppler (DRVID) Allan deviation Smoothed noise Uplink phase Other information included in ATDF data records is date and time; spacecraft ID; ground station and its configuration; status flags and values reported by various ground systems; calibration values, noise estimates, and tolerances (station delay, transmitter power, etc.); and signal strength. Open loop data records (ODRs) contain 8- or 12-bit samples of receiver output. Each block of (typically) 1000 data samples is accompanied by a 166 byte header. Each ODR is accompanied by a full PDS label which describes both the content and format of the file at the bit level. Header information includes: Date and time of the first data sample Sample rate and channel assignments Receiver local oscillator (POCA) frequency Attenuator settings RMS voltages at several stages in the receiving chain Processing ========== ATDFs are screened for 'bad' data points, which are removed before the file is released by the JPL Radio Metric Data Conditioning Team (RMDCT). ODS packets were converted to the older ODR (Original Data Record) format for consistency in subsequent processing and archive. Headers applied by the Ground Data System (GDS) during packet handling have not been retained; they contained no additional information about the data acquisition. The resultant data accurately represent the output of the DSCC Spectrum Processing (DSP) Subsystem at the DSN station. A full PDS label accompanies each ODR file and gives a bit level description of the content and format. Data ==== ATDFs are stored in the TDF directory on archival volumes. File names are of the form ydddeeeC.TDF where y is the one-digit year of the first data, ddd is the three-digit day-of-year of the first data, eee is the three-digit day- of-year of the last data, and C is a single letter (beginning with 'A') denoting the sequence in which files with the same ydddeee were handled. Generally ydddeeeB.TDF is a revised version of ydddeeeA.TDF. The PDS label has file name ydddeeeC.LBL. The typical ATDF contains about 39 Mbytes. Original Data Records (ODRs) were produced whenever the DSP was set to 'run' mode. These files are stored in the ODR directory. In most cases, the entire DSP run was collected into a single ODR file. But in other cases, it was more convenient to subdivide the DSP data; queries were issued for shorter time spans, and separate files were produced. File names are of the form ydddhhmm.ODR where y is the one-digit year of the first data, ddd is the day-of-year of the first data, hh is the hour on which the first sample was taken, and mm was the minute on which the first sample was taken. In cases where two files had the same ydddhhmm (for example, two DSN stations began recording at the same time, or a second query was submitted for data which appeared suspicious after the first query was processed), the less significant digit in mm of the second file was converted to a letter ('0' became 'A', '1' became 'B', ..., '9' became 'J'). In cases were three files had the same ydddhhmm, the less significant mm digit was converted to 'K', 'M', etc. The PDS label has file name ydddhhmm.LBL. Ancillary Data ============== An extensive set of ancillary files is needed for proper analysis and interpretation of the radio data (file types TDF, and ODR). These are organized in parallel directories and stored approximately chronologically. Users should refer to the INDEX/CUMINDEX.TAB listing to locate ancillary files. Ionosphere Calibration Files (ION Directory) --------------------------------------------------- Ionosphere Calibration files were produced by the Tracking System Analytic Calibration (TSAC) Group at JPL. They documented and predicted Earth ionospheric conditions. These are ASCII files of variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). File names have the form ydddeeeC.ION where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a character denoting sequence when more than one file with the same ydddeee is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. ION files were usually released at one week intervals to cover a single month; ydddeeeA.ION would be the file released during the first week, ydddeeeB.ION would be the file released during the second week, etc. Each ION file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 50 kB. Channelized DSN Monitor Data Files (MCH Directory) --------------------------------------------------- Channelized DSN Monitor Data files were produced by the MGS query server, operating on DSN Monitor packets stored in the MGS Central Data Base (CDB). These are binary files, usually representing the collection of DSN Monitor data received from a 24 hour period; they are not readily interpretable by end users. File names have the form ydddeeeC.MCH where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a character denoting sequence when more than one file with the same ydddeee is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. Each MCH file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. File sizes can be as large as 30 MB. In general, an MCH file can be derived from the corresponding MPK file using MGS-provided software and a decommutation map. Also in some MCH directories are ASCII tables of extracted channel values--channelized state vectors, or CSV files. These are values for a limited number of potentially useful MCH channels that have been saved in tabular form. CSV files in the MCH directory have names of the form CSVydddC.MCH where y, ddd, and C are the same as for the corresponding MCH file. Each CSV file is accompanied by a detached PDS label with name CSVydddC.LBL which completely describes the format and content of the CSV file. Monitor Channel Tables (MCT Directory) -------------------------------------- Monitor Channel Tables were derived from MCH CSV files at Stanford. Each table lists a single Monitor channel versus time in an ASCII PDS TABLE format. File names have the form XXXydddC.MCT where XXX is a three-character mnemonic for the channel, y is the one-digit year, ddd is the three- digit day-of-year, and C is a single character (starting with 'A') denoting the version. Each MCT file is accompanied by a PDS label with file name XXXyddC.LBL which completely describes both the content and the format of the table. Examples of MCT files include: XXX Description --- --------------------------------------------- AGC AGC level from M-0349 (Ant A, Rcv A) DSS DSS antenna ID from M-0300 ELA Elevation angle from M-0304 (Ant A) TSY System temperature from M-0725 (Ant A, Rcv A) TSZ System temperature from M-0725 (Ant A, Rcv B) Sequence of Events Files (SOE Directory) --------------------------------------------------- Sequence of Events Files were produced by the MGS Mission Control Team. These are ASCII files of variable length records. Until 1998-08-20 SOE files were produced in a special format that allowed use with the MGS-provided soeedt program. After 1998-08-20, files were produced in a straight ASCII format that required no special software; these may be identified by the '.tsoe' suffix in the ORIGINAL_PRODUCT_ID. Each record is delimited by a carriage-return (ASCII 13) line-feed (ASCII 10) pair, which may need to be removed before the file is used on the local machine. File names have the form ydddeeeC.SOE where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a character denoting sequence when more than one file with the same ydddeee is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. Each SOE file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 1 MB. Spacecraft/Planetary Ephemeris (SPK) Files (SPK Directory) ---------------------------------------------------------- Spacecraft/Planetary Ephemeris Files (also known as SP kernels or SPK files) were produced by the MGS Navigation Team (NAV). These files give spacecraft and planetary ephemerides. These are ASCII files of variable length records in a special NAIF 'transfer' format. Each record is delimited by a carriage-return (ASCII 13) line-feed (ASCII 10) pair, which may need to be removed before the file is used on the local machine. After delimiter conversion (if needed) the file would ordinarily be passed through the NAIF utility SPACIT or TOBIN to convert it to the local binary format. File names have the form ydddeeeC.SPK where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a character denoting sequence when more than one file with the same ydddeee is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. Each SPK file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 5 MB. Typical SPK files during MAP included one day of orbit reconstructions followed by several days of orbit predictions. Troposphere Calibration Files (TRO Directory) --------------------------------------------------- Troposphere Calibration files were produced by the Tracking System Analytic Calibration (TSAC) Group at JPL. They documented and predicted Earth tropospheric conditions. These are ASCII files of variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). File names have the form ydddeeeC.TRO where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and C is a character denoting sequence when more than one file with the same ydddeee is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. TRO files were typically released at the beginning of a month and covered the previous month. Each TRO file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 50 kB. DSN Weather Files (WEA Directory) --------------------------------- DSN Weather files were produced by the Tracking System Analytic Calibration (TSAC) Group at JPL. Files give weather calibration information for DSN complexes. These are ASCII files of variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). File names have the form ydddeeeD.WEA where y is the one-digit year of the first data in the file, ddd is the day-of-year of the first data in the file, eee is the day-of-year of the last data in the file, and D is a single digit denoting the DSN complex at which the data were acquired ('1' for Goldstone, '4' for Canberra, or '6' for Madrid). WEA files were typically released weekly and contain all weather data for the complex since 1 January. Each WEA file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. The files grow at the rate of approximately 90 kB per month. Coordinate System ================= SPK ephemeris files were produced for the J2000 inertial reference frame. Other data types are not dependent on definition of a coordinate system. Software ======== Software for parsing, reducing, and analyzing data such as these has been developed at Stanford University, at JPL and elsewhere. Because such software must usually operate at the bit-level and is written for a narrow range of platforms, it is not suitable for general distribution. No software is included with this archival data set. Media/Format ============ The archival data set is written on CD-WO media using the Young Minds CD Studio or Yamaha/GEAR authoring system. The CD-WO volumes conform to ISO 9660 standards.
DATA_SET_RELEASE_DATE 2001-02-23T00:00:00.000Z
START_TIME 2000-06-28T12:00:00.000Z
STOP_TIME 2000-07-05T12:00:00.000Z
MISSION_NAME MARS GLOBAL SURVEYOR
MISSION_START_DATE 1994-10-12T12:00:00.000Z
MISSION_STOP_DATE 2007-09-30T12:00:00.000Z
TARGET_NAME SUN
TARGET_TYPE SUN
INSTRUMENT_HOST_ID MGS
INSTRUMENT_NAME GRAVITY SCIENCE INSTRUMENT
RADIO SCIENCE SUBSYSTEM
INSTRUMENT_ID RSS
INSTRUMENT_TYPE RADIO SCIENCE
NODE_NAME planetary plasma interactions
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Overview ======== In general, this is a good data set. Review ====== This archival data set was reviewed by the Planetary Data System (PDS) Radio Science Adviser prior to submission to the PDS. Data Coverage and Quality ========================= The data are contained in two volumes (CDs). The table below lists the two volumes and their respective contents. VOLUME_ID Start Date End Date --------- ------------------- ------------------- MGRS_0001 2000-06-28 (00/180) 2000-07-01 (00/183) MGRS_0002 2000-07-02 (00/184) 2000-07-05 (00/187) Solar Conjunction was on 00/183. The data were collected on a best effort basis since the Solar Conjunction investigation was not part of the official MGS mission. Limitations =========== The limitations in this data set follow from the quality of the execution, which is described above under Data Coverage and Quality.
CITATION_DESCRIPTION Barbinis, E., MGS SOLAR CONJUNCTION RAW DATA SET - ROCC V1.0, MGS-SUN-RSS-1-ROCC-V1.0, NASA Planetary Data System, 2001
ABSTRACT_TEXT The Mars Global Surveyor (MGS) Solar Conjunction Raw Data Archive is a time-ordered collection of raw data acquired during the Solar Conjunction in 2000, while MGS was in its Mars Mapping (MAP) mission phase.
PRODUCER_FULL_NAME ELIAS BARBINIS
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