| DATA_SET_DESCRIPTION |
Data Set Overview : The Mars Global Surveyor (MGS) Radio Science (RS) Raw Data Archive (RDA) is a time-ordered collection of raw and partially processed data collected during the MGS Mission to Mars. For more information on the investigations proposed see [TYLERETAL1992] and [TYLERETAL2001]. This data set was collected during the Extended Mission (EXT) phase of MGS -- while the spacecraft was in a near-circular orbit and systematically collecting data from Mars. Some of the data supported MGS Navigation activities, but the majority went directly to science analysis. Two types of measurements were conducted during EXT; 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 five primary data types. Archival Tracking Data Files (ATDFs or TDFs) and Tracking and Navigation Files (TNFs) are the most primitive (and most voluminous) products of the closed-loop system. TNFs superseded TDFs; the first TNF was for data collected on 2002/344, and the last TDF was for 2003/058. Although there was an interval when both were produced, the transition at individual DSN antennas was discrete; there are no cases where both data types were produced for a single pass, and there are no cases where TDFs were produced for an antenna once TNF production had started. Orbit Data Files (ODFs) are edited versions of ATDFs or TNFs, specifically targeted to spacecraft navigators and scientists interested in gravity fields. Original Data Records (ODRs) and Radio Science Receiver files (RSRs) are the primary data types from the open-loop system. RSRs superseded ODRs; the first RSR was created for 2001/122, and the last ODR was produced on 2001/319. The ODR to RSR transition occurred when there was very little open-loop data collection. Typical users of these data might analyze range and Doppler measurements in ATDFs, TNFs, or ODFs to derive the spacecraft trajectory during EXT. Relevant questions would include the measurement uncertainties in range and Doppler at different DSN antennas; these could set constraints on any model of Mars' gravity field developed later, for example. Users of ODRs or RSRs could identify and characterize anomalous signals within the recorded passband, derive the drift of the UltraStable Oscillator (USO), and calculate Allan Deviation for various radio science configurations. Note on File Naming: In 2006 MGS entered its eleventh year of operation (beginning with launch in late 1996). File names which begin with the least significant digit of the year 'y' would not have distinguished 2006 from 1996, so letters were used instead starting in 2006. The letter 'G' was used for 2006, 'H' was used for 2007, 'I' for 2008, etc. In the paragraphs below, only the original algorithm (pre-2006) for constructing file names is usually mentioned. Parameters : The ATDF/TNF is the primary output from the MGS closed-loop system. ATDFs had 150 fields, though not all were 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 of the file at the bit level. 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. In the TNF about 20 record types are defined, each designed for a particular audience, although it was frequently the case that users needed more than one record type. The quantities stored are similar to those in the ATDF except that the emphasis is on phase (rather than frequency) of both the transmitted and received signals. Each TNF is accompanied by a PDS minimal label which points to a software specification document (TNF_SIS.TXT) in the DOCUMENT directory of the archive for detailed descriptions of the records and fields. The ODF is an edited version of the ATDF/TNF; it is a smaller file, issued more frequently than the ATDF but less frequently than the TNF (typically daily). It contains the most important information (range and Doppler) needed by spacecraft navigators and investigators interested in determining gravitational fields of bodies such as Mars. Each ODF is accompanied by a full PDS label which describes both the content and format of the associated file. ODF data fields include: Narrowband spacecraft VLBI, Doppler mode (cycles) Narrowband spacecraft VLBI, phase mode (cycles) Narrowband quasar VLBI, Doppler mode (cycles) Narrowband quasar VLBI, phase mode (cycles) Wideband spacecraft VLBI (nanoseconds) Wideband quasar VLBI (nanoseconds) One-way Doppler (Hertz) Two-way Doppler (Hertz) Three-way Doppler (Hertz) One-way total count phase (cycles) Two-way total count phase (cycles) Three-way total count phase (cycles) PRA planetary operational discrete spectrum range (range units) SRA planetary operational discrete spectrum range (range units) RE(GSTDN) range (nanoseconds) Azimuth angle (degrees) Elevation angle (degrees) Hour angle (degrees) Declination angle (degrees) 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 Radio Science Receiver (RSR) records contain samples of open loop receiver output; the samples are complex and can have 1-16 bits in both the in-phase (I) and quadrature (Q) components, depending on sampling rate and precision requested. Sampling rates between 1 ksps and 16 Msps may be requested. Each record includes a header containing information similar to that for the ODR except that there is more emphasis on phase than in the ODR. Each RSR file is accompanied by a full PDS label which describes both the format and the content at the bit level. Processing : ATDFs were screened for 'bad' data points, which were removed before the file was released by the JPL Radio Metric Data Conditioning Team (RMDCT). The typical ATDF contained data from a 24-hour period, combining data from several antennas if there were multiple passes in one day. Although RMDCT provided a screening service for TNFs, the files archived for MGS were not screened for 'bad' points. Each TNF contains data from a single antenna (only). ODFs are abstracted from subsets of ATDF/TNF data. Open-loop data delivered to Stanford before about 2001/150 were usually in the ODS (Original Data Stream) format. 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 were not retained; they contained no additional information about the data acquisition. In some cases, where the GDS corrupted the ODS during delivery, lost it entirely, or was unable to deliver it electronically because of volume constraints, data have been recovered from tape in ODR format. The resultant data (whether from ODS conversion or tape) 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. A 32-byte label at the beginning of each ODR tape (when tape was used) is not included in the data file. The 32-byte label gives the version of the data taking software; this information has been copied to the PDS label that accompanies the data file. The software version recorded in the 'NOTE' keyword is more likely to be accurate than the version recorded with the 'SOFTWARE_VERSION' keyword. Because the 32-byte label is no longer part of the data stream, users can treat the remaining file as an integral number of fixed-length records. The 32-byte label was never used in the ODS. RSR data delivered to Stanford were modified during Ground Data System handling so that MISSION_ID in the Primary Header CHDO was set to 5. Data which were recorded on the VLBI Science Receiver (VSR), then converted to RSR format, were assigned the following values in the header(s): MINOR_DATA_CLASS : 5 (normally 4) Primary Header CHDO ORIGINATOR_ID : 123 (normally 48) Secondary Header CHDO LAST_MODIFIER_ID : 123 (normally 48) Secondary Header CHDO A VSR was used for MGS when all of the available RSR's had been assigned to other missions. Data : Data are stored on CD or DVD write-once volumes approximately chronologically. This data set contains data from the MGS EXT phase only. Volume boundaries were usually defined by the dates of included spacecraft engineering and DSN monitor data (data types ECH and MCH, respectively). ECH and MCH files were the most regular, and often the largest, collected on a daily basis. Files of other types were sometimes delayed in delivery to Stanford and may be out of strict chronological order on the volumes. Users should consult listings in the INDEX/CUMINDEX.TAB file to ascertain full coverage of each data type. Users working with dates near the beginning and end of the EXT phase should check INDEX/CUMINDEX.TAB in the data set covering the adjacent phase for files that appear to be missing; in general, files that bridge a phase boundary were stored with the earlier data set only. ATDFs were delivered when approximately 39 MB had accumulated (approximately weekly) during MGS EXT. ATDFs were 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. TNFs were delivered daily during MGS EXT and were stored in the TNF directory on archival volumes. File names were of the form ydddHssC.TNF where y is the one-digit year of the first data (see Note on File Naming above for years 2006 and later), ddd is the three-digit day-of-year of the first data, H is a one letter code for the hour of the first data (A:00, B:01, ...), ss is the identifier for the DSN antenna used (14, 15, 26, 43, etc.), and C is a single letter (beginning with 'A') denoting the sequence in which files with the same ydddHss were handled. Generally ydddHssB.TNF is the result of a second request for TNF data from a pass. It may contain more (or less) data than the original (ydddHssA.TNF); revisions are rare. The PDS label has file name ydddHssC.LBL. The typical TNF contains about 25 Mbytes (3 MB/hour for 8 hours). ODFs were typically issued daily throughout MGS EXT; during periods of high spacecraft activity (such as around maneuvers) ODFs were released more often. Most ODFs released during EXT are included in the archival data set. Of those that were missed, most were generated by special request, and Stanford did not receive a release notice. ODFs are stored in the ODF directory. File names are of the form ydddeeeC.ODF where the file name components are the same as for the ATDF above (see Note on File Naming above for years 2006 and later). In most cases ydddeeeB.ODF was NOT simply a revised version of ydddeeeA.ODF; there were many requests for special ODF processing -- to obtain higher time resolution over short intervals, for example. The PDS label has file name ydddeeeC.LBL. Typical ODF file sizes are small multiples of 8064 bytes (e.g., less than 100 kB). 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. At 5000 12-bit samples per second, a 7-minute occultation would yield a 3.5 MB ODR -- one X-band (RCP) channel; 5 records per second, each with 1000 12-bit samples and a 166-byte header. Two one-hour surface scattering experiments were conducted on 5 August 2001. These data were collected in two channels (RCP and LCP) with 50000 8-bit samples per second in each channel using the DSP. The data were also captured using one RSR on X-RCP and another on X-LCP. The sampling rate for each RSR was 25000 I/Q pairs per second. RSRs were produced whenever the Radio Science Receiver was set to record. These files are stored in the RSR directory. File names are of the form ydddhhmm.RSR where y is the one-digit year of the first data (see Note on File Naming above for years 2006 and later), 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 or more files had the same ydddhhmm (for example, two DSN stations began recording at the same time), 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. At 2000 complex samples per second (16 bits I, 16 bits Q) a 9-minute occultation would yield a 5.5 MB RSR, including headers. Ancillary Data : An extensive set of ancillary files is needed for proper analysis and interpretation of the primary radio data (TDF, TNF, ODF, ODR, and RSR). These are organized in parallel directories and stored approximately chronologically. When a file type is not represented on a CD or DVD volume, the corresponding directory has been omitted. With the exception of files stored in the CALIB directory, ancillary files appear on only one CD or DVD volume. Users should refer to the INDEX/CUMINDEX.TAB listing to locate ancillary files. Files in the CALIB Directory ---------------------------- Files in the CALIB directory are those likely to have wide applicability in working with the raw data. They help unpack and allow use of the raw data, rather than being 'instrument' calibration data per se. They include decommutation maps, clock conversion files, files of planetary constants, leapsecond files, and files needed for display of data on the MGS Science Operations Planning Computer (SOPC). Each file is accompanied by a PDS minimal label. Clock Conversion files were produced by the JPL/PDS Navigation Ancillary Information Facility (NAIF) for use with NAIF-developed and MGS-provided software. These are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. File names have the form TSCnnnnn.SCK where nnnnn is a sequence number beginning with 00001 and the file with the highest number is the most recent. The value of nnnnn is set by NAIF. Planetary Constants files were produced by the JPL/PDS Navigation Ancillary Information Facility (NAIF) for use with NAIF-developed and MGS-provided software. These are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. File names have the form PCKydddC.TPC where y is the one-digit year of the file creation date, ddd is the day-of-year of the file creation date, and C is a character denoting sequence when more than one file with the same yddd is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. Leapsecond files were produced by the JPL/PDS Navigation Ancillary Information Facility (NAIF) for use with NAIF-developed and MGS-provided software. These are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. File names have the form LSKydddC.TLS where y is the one-digit year of the file creation date, ddd is the day-of-year of the file creation date, and C is a character denoting sequence when more than one file with the same yddd is handled. C starts from 'A' and progresses to 'B', 'C', etc. with increasing numbers of similar coverage files. Channel Conversion Language files come in three types -- source, dependency, and binary. File names are of the forms CCLydddS.SRC, CCLydddD.BIN, and CCLydddB.BIN, respectively, where y is the one-digit year of the file creation date and ddd is the day-of-year of the file creation date. Source files are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. Dependency and binary files are identical to those used on the SOPC. Source and binary files are typically 500 kB; dependency files are typically 15 kB. Channel Conversion Language files are used in converting raw binary data in telemetry streams to meaningful numbers. Channel Parameter Table files come in two types -- source and binary. File names are of the forms CPTydddS.SRC and CCLydddB.BIN, respectively, where y is the one-digit year of the file creation date and ddd is the day-of-year of the file creation date. Source files are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. Binary files are identical to those used on the SOPC. Source and binary files are typically less than 1 MB. Channel Parameter Table files are used in converting raw binary data in telemetry streams to meaningful numbers. Template Description Language files come in two types -- source and binary. File names are of the forms TDLydddS.SRC and TDLydddB.BIN, respectively, where y is the one-digit year of the file creation date and ddd is the day-of-year of the file creation date. Source files are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. Binary files are identical to those used on the SOPC. Source and binary files are typically less than 1 MB. Template Description Language files are used during display of data on the SOPC. Decommutation Map files come in two types -- source and binary. File names are of the forms DCSxxxxx.SRC and DCOxxxxx.BIN, respectively, where xxxxx is a mnemonic for the map. Source files are ASCII files of variable length records. Each record is delimited by an ASCII carriage- return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. Binary files are identical to those used on the SOPC. Source and binary files are typically less than 200 kB. Decommutation Map files are used in converting raw binary packet data to channelized formats. On the SOPC, they are used with the MGS-provided program mapx. Antenna Reconstruction Files are typically used in conjunction with Antenna Gimbal Kernel (AGK) files to determine the pointing of an antenna or the position of its phase center with respect to the spacecraft center of mass. There are three types of Antenna Reconstruction Files: the Antenna SPK (ASP) File, the Hinge CK (HCK) File, and the Text Frame Kernel (TFK) File. An ASP file contains the locations of low-gain antennas and boom lengths for the high-gain antenna (HGA). The HCK file contains hinge angles for the (deployed) HGA. The TFK file contains information on coordinate frame definitions for translating between the spacecraft frame and the frame of the high-gain antenna. File names are of the forms HGAnnnnn.ASP, HINGEnnn.HCK, and HGAnnnnn.TFK, where the 'n' string gives a sequence number. ASP and HCK files are ASCII files in NAIF transfer format; TFK files are ASCII files. In all cases, each record is delimited by the ASCII carriage-return (ASCII 13) line-feed (ASCII 10) pair. On some systems it may be necessary to convert the pair to either or before using the file on the local machine. Each Antenna Reconstruction File is accompanied by a PDS minimal label with the same file name except for an extension of .LBL. Antenna Gimbal Kernel Files (AGK Directory) ------------------------------------------- Antenna Gimbal Kernel files were produced by NAIF. Each AGK file contains information on the state of the HGA azimuth and elevation gimbals as a function of time. These are ASCII files in NAIF transfer format. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed (LF> (ASCII 10) pair, which may need to be converted to either or before the file is used on the local machine. File names have the form ydddeeeZ.AGK where 'y' is the least significant digit of the year in which data in the file begin, 'ddd' is the day-of-year when data begin, 'eee' is the day-of-year when data end, and 'Z' is a single upper case letter indicating order of files when there is more than one with the same 'ydddeee' in the data set. Z is 'A' for the first file, 'B' for the second, etc. Each AGK file is accompanied by a PDS minimal label with file name ydddeeeZ.LBL. Typical file sizes are 1 MByte. Angular Momentum Desaturation Files (AMD Directory) --------------------------------------------------- Angular Momentum Desaturation files were produced by the MGS Spacecraft Team (SCT). Each AMD file documents a set of AMD events on the spacecraft. These are ASCII files of variable length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. File names have the form ydddeeeC.AMD 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 AMD file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 1500 bytes. Browse Files (BRO Directory) ---------------------------- Browse files are composite PostScript files summarizing quick-look processing of ODR or RSR data. Each file has a name of the form ydddhhmm.PSn where ydddhhmm is identical to the character string in the source ODR or RSR file and n is the receiver channel represented in the data. Each BRO file is accompanied by a detached PDS label with name ydddhhmm.LBL. Only one channel n is expected from each ODR or RSR. Each PostScript file is sized to fit on a single 8-1/2x11 inch page. Each landscape format page includes four panels showing a histogram of raw data (12-bit) samples (upper left), one-minute average power spectra derived from the raw samples (upper right), one-second averages of raw sample power versus time (lower left), and an extract of the first few lines of the source ODR or RSR PDS label (lower right). BRO files may be helpful in quickly scanning data to determine which files are suitable for closer study. Channelized Engineering Data Files (ECH Directory) --------------------------------------------------- Channelized Engineering Data files were produced by the MGS query server, operating on telemetry packets stored in the MGS Central Data Base (CDB). These are binary files, usually representing the collection of raw spacecraft engineering data received from a 24 hour period; they are not readily interpretable by end users. File names have the form ydddeeeC.ECH 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 ECH file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. File sizes can be as large as 200 MB. In general, an ECH file can be derived from the corresponding EPK file using MGS-provided software and a decommutation map. Also in some ECH directories are ASCII tables of extracted channel values--channelized state vectors, or CSV files. These are values for a limited number of potentially useful ECH channels that have been saved in tabular form. CSV files in the ECH directory have names of the form CSVydddC.ECH where y, ddd, and C are the same as for the corresponding ECH 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. Engineering Channelized Data Summary Files (ECS Directory) --------------------------------------------------- Engineering Channelized Summary Data Files were created at Stanford during ingestion of spacecraft engineering data. Each file contains a summary line for each channel processed from the previous day's telemetry. The ECS file thus gives a snapshot (mean and standard deviation) of each channel on each day. ECS files are PDS TABLE objects; each is fully described as to format and content by a detached PDS label. File names are of the form ydddeeeC.ECS 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 character denoting sequence when more than one file with the same ydddeee is handled. File sizes vary depending on the number of channels processed; typical growth is 4000 bytes per day. Engineering Channel Table Files (ECT Directory) --------------------------------------------------- Engineering Channel Table Data Files are created at Stanford during ingestion of spacecraft engineering data. Each ECT file is an ASCII table of time-ordered values from a single spacecraft engineering channel, and each file is fully described by a detached PDS label. File names are of the form XXXydddC.ECT where XXX is a unique identifier for the engineering channel, y is the one-digit year of the first data, ddd is the three-digit day-of-year of the first data, and C is a character denoting sequence when more than one file with the same yddd is handled. File sizes vary depending on the rate at which a channel was sampled; they are typically under 100 kB. The detached label has file name XXXydddC.LBL. Experimenters Notebook Files (ENB Directory) -------------------------------------------- Experimenters Notebook files are e-mail messages and other notes collected during and shortly after data acquisition. They document expectations of various measurements and anomalies discovered in subsequent analysis. File names have the form ENByyddd.TXT, where yy is the two-digit year and ddd is the three-digit day-of-year. In general the messages in file ENByyddd.TXT refer to activities on that date regardless of when the message was sent. These are ASCII files with variable length records. Each record is delimited by an ASCII carriage-return line-feed pair. Earth Orientation Parameter Files (EOP Directory) --------------------------------------------------- Earth Orientation Parameter files were produced by the Time and Earth Motion Precision Observation (TEMPO) Group at JPL. They documented and predicted Earth rotation (rate and axis). These are ASCII files of variable length records. Each record is delimited by an ASCII line-feed (ASCII 10). File names have the form ydddzeee.EOP 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, z is the one-digit year of the last data, and eee is the day-of-year of the last data in the file. EOP files were typically released on Tuesdays and Fridays. There are both 'long' and 'short' versions. The long file covered past motion since about 1962 and a prediction for about three months into the future; these files have typical sizes of 860 kB. The short file covered the most recent nine months of past motion and a prediction for three months into the future; these files are typically 30 kB. Each EOP file is accompanied by a PDS minimal label with file name ydddzeee.LBL. Engineering Packet Data Files (EPK Directory) --------------------------------------------------- Engineering Packet Data files were produced by the MGS query server, operating on telemetry packets stored in the MGS Central Data Base (CDB). These are binary files, usually representing the collection of raw spacecraft engineering data received from a 24 hour period; they are not readily interpretable by end users. File names have the form ydddeeeC.EPK 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 EPK file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. File sizes can be as large as 100 MB. No EPK files were collected during EXT; all engineering data are in ECH files. Filtered Body Rate Files (FBR Directory) --------------------------------------------------- Filtered Body Rate Files were created at Stanford from body rate data in the spacecraft engineering telemetry stream. They give spacecraft attitude as a function of time. FBR files are PDS TABLE objects; each is fully described as to format and content by a detached PDS label. File names are of the form ydddeeeC.FBR 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 character denoting sequence when more than one file with the same ydddeee is handled. File sizes vary depending on the time interval covered. FBR files were created during MGS Cruise to support gravitational wave experiments (GWE); no FBR files were created during the EXT Phase. GEODYN Trajectory Files (GDN Directory) --------------------------------------------------- GEODYN SPK files were quick look orbit reconstructions produced by the MOLA Precise Orbit Determination Team. They were used for preliminary analysis of MOLA data and some radio occultations. These files give spacecraft and planetary ephemerides and are identical in format to SPK files (see below) by the MGS NAV Team. Files with ORIGINAL_PRODUCT_ID including 'qlnn' were based on the following gravity models (see GDN_SPK.TXT in the DOCUMENT directory): ql15 mgm0989a ql16 mgm0989c ql17 gmm2b (with no one-way Doppler daya) ql18 gmm2b (with 1-way Doppler data if available) ql19f gmm2b (with altimetry crossovers) ql41c mgm1041c ql41ch time varying mgm1041c 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.GDN 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 GDN file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 5 MB. GEODYN Trajectory Files (GDF Directory) --------------------------------------------------- GDF files are the same as GDN files (above) except that they are considered 'final' versions of the orbits. File names end with the .GDF suffix. No GDF files were created during the EXT phase; all GEODYN reconstructions appear in the GDN directory. Daily Health Report Files (HEA Directory) --------------------------------------------------- Daily Health Report Files were created at Stanford; they summarize spacecraft engineering data of interest for Radio Science, list recently acquired radio data, summarize any analysis performed on recent radio data, summarize anomalies in recent radio science operations, and list files that have been obtained from the MGS CDB or other sources. Daily Health Report Files are PDS TEXT objects; each has an attached PDS label. File names are of the form HEAydddC.TXT where y is the one-digit year of the report, ddd is the three-digit day-of-year of the report, and C is a character denoting sequence when more than one file with the same ydddeee is generated. The first report on a day would be HEAydddA.TXT; subsequent revisions or updates would be HEAydddB.TXT, HEAydddC.TXT, etc. Some Health Reports are accompanied by plots, saved as PostScript files. File names for these plot files have names of the form HEAydddC.PSn where y and ddd are as defined above and n is the figure number. The PostScript files are accompanied by a detached PDS label with name HEAydddC.LBL. Both Health Reports themselves and accompanying PostScript files have variable length records delimited by carriage- return (ASCII 13) line-feed (ASCII 10) pairs. 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. In mid-2003 the method of producing Ionosphere Calibration files was improved. Global Ionosphere Map (GIM) software created daily Global Ionospheric Maps from global GPS data. Each day, a final map was created for the UT day three days previously and a preliminary map was created for the UT day immediately before. Also created were predict maps a couple times a week by averaging recent 'normal' days. Then the software evaluated the maps at the spacecraft line-of-sight and fitted the results to a normalized polynomial versus time over each spacecraft pass. This was done for all three modes: final, preliminary, and predict. Then the software selected the best available calibration for each pass (in priority order final > preliminary > predict). Then the operator ran a plotting program to view all of the calibrations and overrode the default selections where desired. The mapping technique is described by [MANNUCCIETAL1998]. Light Time Files (LIT Directory) --------------------------------------------------- Light Time files were produced by the MGS Navigation Team (NAV). They gave radio propagation time from the spacecraft to Earth vs time. These are ASCII files of fixed length records. Each record is delimited by an ASCII carriage-return (ASCII 13) line-feed pair (ASCII 10), which may need to be converted to either or before the file is used on the local machine. File names have the form ydddeeeC.LIT 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 LIT file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 1 MB. 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. With few exceptions C was always 'A' until early 2003, at which time the method for generating (and, hence, processing) the files changed. In early 2003, generation of the Monitor data was changed as part of the Network Simplification Plan (NSP). New channels were defined, and it became impossible to handle data from multiple stations in a single file because over the first six months of 2003 some stations were generating the old formats and some were generating the new. Instead, the data were collected individually according to antenna number. The character C in the file name was interpreted as follows: Character C Antenna Number ----------- -------------- A all (pre-2003) B 14 C 15 D 16 E 24 F 25 G 26 H 27 I 28 J 34 K 43 L 45 M 46 N 54 O 55 P 63 Q 65 R 66 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; but this was almost never done for Mars Global Surveyor. Monitor data are collected according to MST (Monitor Sample Time) measured in UTC. 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. CSV files were generated only for pre-NSP data. Monitor Channel Tables (MCT Directory) -------------------------------------- Monitor Channel Tables were derived from MCH 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. For NSP-derived MCT files, C denotes the source antenna (see assignments under MCH above). 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 pre-2003 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) Examples of NSP-based MCT files include: XXX Description --- --------------------------------------------- AZA Antenna azimuth angle CON CONSCAN drive status DTA Antenna number ELV Antenna elevation angle SNT System noise temperature Maneuver Implementation/Reconstruction Files (MIF Directory) --------------------------------------------------- Maneuver Implementation/Reconstruction files were produced by the MGS Spacecraft Team (SCT); they documented spacecraft maneuver events. 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.MIF 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 MIF file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are 2327 bytes. Maneuver Performance Data Files (MPD Directory) --------------------------------------------------- Maneuver Performance Data files were produced by the MGS Spacecraft Team (SCT). They contain estimates of spacecraft mass and center of mass; moments of inertia; thruster locations, directions, and magnitudes; and propellant flow rate. 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.MPD 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 MPD file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are 4 kB. Maneuver Profile Files (MPF Directory) --------------------------------------------------- Maneuver Profile Files were produced by the MGS Navigation Team (NAV). They are generic descriptions of orbit adjustments used by MGS during aerobraking. These are ASCII files of variable length records. Each record is delimited by a carriage-return (ASCII 13) line-feed (ASCII 10) pair. File names have the form ydddeeeC.MPF where y is the least significant digit in the year, ddd is the day of year of the first data, eee is the day of year of the last data, and C is a character indicating the version of the file ('A' is first, 'B' is second, ...). Each MPF is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 700 bytes. DSN Monitor Packet Data Files (MPK Directory) --------------------------------------------------- DSN Monitor Packet Data files were produced by the MGS query server, operating on DSN Monitor packets stored in the MGS Central Data Base (CDB). Monitor data are records of DSN status and radio measurements. These are binary files, data received from a 24 hour period; they are not readily interpretable by end users. File names have the form ydddeeeC.MPK 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 MPK file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. File sizes can be as large as 30 MB. No MPK data were collected during the EXT phase; all DSN Monitor data are in the MCH directories. Orbit Propagation and Time Generation Files (OPT Directory) --------------------------------------------------- Orbit Propagation and Time Generation files were produced by the MGS Navigation Team (NAV). They contain estimates of event timing (e.g., equator crossings) that depend on precise knowledge of the spacecraft orbit. 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.OPT 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 OPT file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 100 kB. Typical OPT files during EXT included one day of orbit reconstructions followed by several days of orbit predictions. Solar Array Kernel Files (SAK Directory) --------------------------------------------------- Solar Array Kernel files were produced by the MGS Spacecraft Team (SCT). They give the attitude of each solar array panel as a function of time. 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.TCK 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 TCK file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 5 MB. Space Flight Operation Schedule Files (SFO Directory) --------------------------------------------------- Space Flight Operations Schedule Files were produced by the MGS Mission Control Team, usually in parallel with a corresponding Sequence of Events (SOE) file. They graphically present parts of the SOE. These are ASCII files of variable length records in a special format that allows use with the MGS-provided sfosedt program. 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.SFO 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 SFO file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 100 kB. No SFO files were produced after 1998-08-20. 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 EXT included one day of orbit reconstructions followed by several days of orbit predictions. Spacecraft Attitude (CK) Files (TCK Directory) --------------------------------------------------- Spacecraft Attitude Files (also known as C kernels or CK files) were produced by the MGS Spacecraft Team (SCT). 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.TCK 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 TCK file is accompanied by a PDS minimal label with file name ydddeeeC.LBL. Typical file sizes are less than 5 MB. 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 100 kB. Starting in early 2001, TSAC began basing TRO files on surface weather and Global Positioning Satellite (GPS) zenith delay. These files can be distinguished by an ORIGINAL_PRODUCT_ID beginning with 'ATC' rather than the earlier 'TROPCAL'. Detailed file structure was slightly different, but the same Software Interface Specification (SIS) was used. UltraStable Oscillator Files (USO Directory) -------------------------------------------- UltraStable Oscillator (USO) files are calibration data derived from open-loop radio measurements. Files are PDS table objects with detached labels. Examples include USO Allan Deviation (type A files) and the piecewise-continuous linear model of USO frequency (type M files). File names are of the form USOtyddd.TAB, where t is the file type (see above), y is the one-digit year in which the file was created, and ddd is the three-digit day-of-year in which the file was created. Each USO file is accompanied by a detached PDS label with name USOtyddd.LBL which completely describes the content and format of the file. 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 and TCK files were produced for the J2000 inertial reference frame until the second orbit after Mars Orbit Insertion, when the TCK files were referenced to the Mars Mean Equator frame. SAK files presumably follow the same format as TCK files. NAIF reader routines may be used to convert these to other coordinate systems. 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 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 was written to CD-WO media using the Young Minds CD Studio and Yamaha/GEAR authoring systems; the CD-WO volumes conform to ISO 9660 standards. DVD volumes were written using DiscJuggler software and a Plextor writer; they are single-sided, single-layer with a maximum of 4.7 GB and they conform to the UDF-bridge format.
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