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INTERCHANGE_FORMAT = ASCII
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Mars Global Surveyor Radio Science Team
Science Data Products Archive
(MGS-M-RSS-5-SDP-V1.0)
AAREADME.TXT
7 January 2000
R.A. Simpson
Stanford University
==============================================================================
INTRODUCTION
==============================================================================
This compact disc contains archival radio science results from the Mars
Global Surveyor (MGS) mission. This is one of several such discs -- issued at
three to six month intervals -- containing results from radio occultation,
gravity, and participating scientist investigations carried out by members of
the MGS Radio Science Team (RST). The archive was prepared under standards
of the Planetary Data System (PDS).
Radio measurements were made using the MGS spacecraft and Earth-based
stations of the NASA Deep Space Network (DSN). Radio tracking data were
collected for use in generating high-resolution gravity field models.
Measurements of the amplitude and phase of the radio signal were used to
infer the density and structure of Mars' atmosphere and reflecting properties
of Mars' surface.
Data are organized in approximately chronological order. Delay in
receipt of ancillary files required for processing (or reprocessing of data
with different ancillary files, parameters, or algorithms) results in some
files being out of strict chronological order. A table of contents is
included with each volume, listing each file in the volume; a separate table
of contents shows all files within the data set.
The table immediately below lists the individual volumes (CDs) created
to date and (very briefly) their respective contents. More detail is
provided in the section Summary of Volume Contents.
VOLUME_ID Start Date End Date Notes
--------- ------------------- ------------------- -------------------------
MORS_1001 1998-01-24 (98/024) 1998-04-28 (98/118) First occultation season
MORS_1002 1998-04-29 (98/119) 1998-09-30 (98/273) Gravity data through SPO
MORS_1003 1998-10-01 (98/274) 1999-03-31 (99/090) Early Mapping results
==============================================================================
VOLUME SET INFORMATION
==============================================================================
This disc is one of several which contain reduced data from MGS radio
science investigations. Each archive volume has the general structure
illustrated in the diagram below. Not all directories or files will be
present on every disc, however. For example, only four data directories are
included on the first two volumes (MORS_1001 and MORS_1002). In cases where
the directory contains no files, the directory itself has been omitted from
the CD-WO volume. More information on the organization of the CD can be
found in the Software Interface Specification (SIS) for the data set in the
DOCUMENT directory (file RSADCSDP.TXT).
Data types from radio occultation observations include atmospheric
temperature-pressure profiles at both standard (data type TPS) and high
resolution (TPH), occultation summary files for standard (OCS) and high-
resolution (OCH) data, and intensity power spectra (IPS). Data types from
radio-tracking observations include spherical harmonic models of the gravity
field in ASCII (SHA) and binary (SHB) formats, maps and images based on
spherical harmonic models (IMG), and line-of-sight acceleration profiles
(LOS). There are no data types from Participating Scientist investigations
on this volume. Files in the browse directory (BRO) are snapshots of other
products included in this volume.
The diagram below shows the organization of each volume, starting from
the root of the compact disc.
root
|
|- AAREADME.TXT
|- ERRATA.TXT
|- VOLDESC.CAT
|
|- CATALOG
| |
| |- CATINFO.TXT Streamlined PDS catalog files
| |- MISSION.CAT for mission, host, instrument,
| |- INSTHOST.CAT references, personnel, data
| |- INST.CAT set, target, and data set map
| |- REF.CAT projection (files evolve as
| |- PERSON.CAT the mission progresses).
| |- DATASET.CAT
| |- TARGET.CAT
| `- DSMAP2.CAT
|
|- DOCUMENT
| |
| |- DOCINFO.TXT Overview of directory
| |- RSADCSDP.TXT SIS document for the data set
| |- RSTP.TXT SIS for TPS and TPH file types
| |- OCCSUM.TXT SIS for OCS and OCH file types
| |- LOSAPDR.TXT SIS for LOS file type
| |- SHADR.TXT SIS for SHA file type
| |- SHBDR.TXT SIS for SHB file type
| |- RSDMAP.TXT SIS for IMG file type
| |- OCCLOGA2.TAB Data acquisition parameters
| |- OCCLOGA2.LBL Detached PDS label for OCCLOGxx.TAB
| |- AAS99328.LBL Document describing analysis of radio
| |- AAS99328.PS tracking data and derivation of gravity
| `- AAS99328.TEX model MGM0964C18.
|
|- INDEX
| |
| |- INDXINFO.TXT Overview of directory
| |- INDEX.LBL Label to INDEX.TAB
| |- INDEX.TAB List of data file contents, this volume
| |- CUMINDEX.LBL Label to CUMINDEX.TAB
| `- CUMINDEX.TAB List of data file contents, all volumes
|
|
| DATA DIRECTORIES
|
|- IMG Gridded products (images)
| |
| |- GGM0964A.IMG Goddard gravity anomalies
| |- GGM0964E.IMG Goddard gravity anomaly errors
| |- JGD75B50.IMG JPL gravity anomalies
| |- JOD75B50.IMG JPL geoid height
| |- ... ...
| `- xxxxxxxx.LBL PDS labels for above
|
|- OCS Occultation Summary Files
| |
| |- 812812AA.OCS Summary file for December 1998 data
| `- 812812AA.LBL PDS label for summary file
|
|- SHA Spherical Harmonic (ASCII) gravity models
| |
| |- GGM0964A.SHA Coefficients for Goddard 70x70 model
| |- GGM0964A.LBL PDS label for GGM0964A.SHA
| |- JGM75B01.SHA Coefficients for JPL 75x75 model
| `- JGM75B01.LBL PDS label for JGM75B01.SHA
|
|- SHB Spherical Harmonic (bin) gravity models
| |
| |- JGM75B01.SHA Coefficients, covariances for JPL model
| `- JGM75B01.LBL PDS label for JGM75B01.SHB
|
|- TPS Occultation Temperature-Pressure Profiles
| |
| |- ydddHmmN.TPS Nth solution for data beginning year y,
| |- ydddHmmN.LBL day ddd, hour H, minute mm; PDS label
| |- ... (repeated for 36 profiles)
| `- ... ...
|
`- BRO Browse Data (PostScript files)
|
|- GGM0964A.PS1 Goddard gravity anomaly map (0-180E)
|- GGM0964B.PS1 Goddard gravity anomaly map (180-360E)
|- GGM0964E.PS1 Goddard gravity anomaly errors
|- ... ...
`- GGM0964x.LBL PDS labels for above
To locate specific data files within the volume set, users should consult
CUMINDEX.TAB in the INDEX directory of the highest numbered volume available.
All files appearing in data directories (e.g., IMG, OCS) will be listed in
INDEX.TAB for the volume and CUMINDEX.TAB for the volume set. For purposes of
indexing, BRO files are considered data and will appear in these files. Files
in other directories (e.g., CATALOG, DIRECTORY) generally appear on many
volumes. They are described in a *.INFO.TXT file within their directory; they
do not appear in INDEX.TAB or CUMINDEX.TAB.
==============================================================================
ERRATA
==============================================================================
A cumulative list of errors and changes is maintained in the file
ERRATA.TXT at the root level of each volume. ERRATA.TXT in higher numbered
volumes (or higher version numbers) will have errors for earlier volumes.
==============================================================================
DISC FORMAT
==============================================================================
The disc is organized according to the PDS standard for "one data set,
many volumes." This file (AAREADME.TXT), a PDS volume object definition
(VOLDESC.CAT), and the listing of errors and changes (ERRATA.TXT) are
included at the root level. The following directories of descriptive
material are also at the root level:
CATALOG contains descriptive files for cataloging the data
on this disc.
DOCUMENT contains a plain text Software Interface Specification
(SISs) for the data set and for each component file
type, a table of data acquisition parameters, and other
documentation.
INDEX contains index information (table of contents) on each of
the data files included in this disc; it also includes a
cumulative index to all files in this set of discs.
The remaining directories at the root level contain data files and detached
PDS labels.
==============================================================================
FILE FORMAT
==============================================================================
All data files on the disc are accompanied by detached PDS labels, which
describe their contents. PDS TEXT objects have attached labels.
Detached labels have the same file name as the data file except that the
label name has the suffix "LBL". The label fully describes the format and
content of its associated file. Detached labels use pointers to reference
the data file -- for example,
^IMAGE = "JGM50C01.IMG"
points to JGM50C01.IMG, which contains the actual image described by the
label. Some data files contain more than one structure. For example,
^RSTP_HDR_TABLE = ("8028D38A.TPS",1)
^RSTP_TABLE = ("8028D38A.TPS",4)
are pointers to the file 8028D38A.TPS which contains two tables, one
beginning at record 1 and one beginning at record 4. Additional documentation
on all data file types is available in Software Interface Specifications in
the DOCUMENT directory.
Text files, including data files of ASCII text and all labels (*.LBL
files) and tables (*.TAB files), are delimited with carriage-return (ASCII 13)
line-feed (ASCII 10) pairs at the end of each line. PostScript (*.PS and
*.PS1 files) and TeX files (*.TEX files) also have records delimited by
carriage-return line-feed pairs. Detached labels and text files (*.TXT file
names) have fixed length records of 80 bytes to facilitate their use as either
fixed-length record files or as stream files with carriage-return line-feed
delimiters. Catalog files (*.CAT files) have fixed length records of 72 bytes
ending with a carriage-return line-feed pair. The VOLDESC.CAT file in the
root is an exception; it has 80 byte fixed-length records.
==============================================================================
SUMMARY OF VOLUME CONTENTS
==============================================================================
MORS_1003 contains models of the Mars gravity field derived from
radio tracking data collected through March 1999. The model derived under
the direction of W.L. Sjogren at the Jet Propulsion Laboratory (file
JGM75B01.SHA in the SHA directory) includes coefficients to degree and order
75; it is based on Viking Orbiter 1 and 2 data as well as MGS. The model
derived under the direction of D.E. Smith at Goddard Space Flight Center
(file GGM0964A.SHA in the SHA directory) includes coefficients to degree and
order 70; it is based solely on MGS data. The JPL group has also provided
their model in binary format with covariances (SHB directory).
Both gravity investigation teams have provided gridded products (IMG
directory) showing gravity anomaly referenced to their model evaluated to
degree and order 50. The Goddard group has also provided a grid of gravity
anomaly uncertainties. The JPL group has provided a grid of geoid height
above a reference ellipsoid. All grids have one degree point spacing and
use a simple cylindrical projection.
The BRO directory contains PostScript representations of both gridded
products from the Goddard group. The DOCUMENT directory contains an
extensive description of the analysis leading to the Goddard model,
including application of constraints from the Mars Orbiting Laser Altimeter
(MOLA) (see AAS99328.LBL in the DOCUMENT directory).
For a discussion of the major conclusions resulting from study of the
gravity field to this point, see Smith, Sjogren, Tyler, Balmino, Lemoine,
and Konopliv, The Gravity Field of Mars: Results from Mars Global Surveyor,
Science, 286, 94-97, 1999.
MORS_1003 also contains 36 radio occultation profiles of temperature
and pressure derived from data collected in late December 1998.
==============================================================================
SOFTWARE
==============================================================================
No software is included with this data set.
==============================================================================
CITATIONS
==============================================================================
Users wishing to cite products in this volume should use the following
volume information:
Authors: G.L. Tyler, G. Balmino, D.P. Hinson, W.L. Sjogren,
D.E. Smith, R. Woo, J.W. Armstrong, F.M. Flasar,
R.A. Simpson, and P. Priest
Editor: R.A. Simpson
Volume Set Name: MGS RST Science Data Products
Volume: USA_NASA_JPL_MORS_1003
Publisher: NASA Planetary Data System
Year: 1999
==============================================================================
ACKNOWLEDGMENTS
==============================================================================
These data were collected under auspices of the Mars Global Surveyor
Project. G. Leonard Tyler of Stanford University was the Radio Science Team
Leader. Members of the Team and its support elements involved in data
acquisition and validation included Patricia Priest, Paula Eshe, William
Sjogren, Frank Lemoine, and Joe Twicken. At PDS the assistance of Betty
Sword and Joel Wilf was appreciated.
==============================================================================
DISCLAIMER
==============================================================================
Although considerable care has gone into making this volume set, errors
are possible. Reports of errors or difficulties would be appreciated. Please
contact one of the persons listed below.
==============================================================================
COGNIZANT PERSONNEL
==============================================================================
The person most directly responsible for construction and release of
this volume set was Dick Simpson, Experiment Engineer for the Mars Global
Surveyor Radio Science Team and Radio Science Advisor to the Planetary Data
System. Although many people contributed to the volume set, any faults in
the product are his alone. G. Leonard Tyler was the Leader of the MGS Radio
Science Team. David P. Hinson reduced the raw occultation data to profiles
of atmospheric temperature and pressure.
Richard A. Simpson
Center for Radar Astronomy
Packard Building - Room 332
350 Serra Mall
Stanford University
Stanford, CA 94305-9515
Tel: 650-723-3525
FAX: 650-723-9251
rsimpson@magellan.stanford.edu
G. Leonard Tyler
Center for Radar Astronomy
Packard Building - Room 331
350 Serra Mall
Stanford University
Stanford, CA 94305-9515
Tel: 650-723-3535
FAX: 650-723-9251
len@nova.stanford.edu
David P. Hinson
Center for Radar Astronomy
Packard Building - Room 333
350 Serra Mall
Stanford University
Stanford, CA 94305-9515
Tel: 650-723-3534
FAX: 650-723-9251
hinson@nimbus.stanford.edu
==============================================================================
ACRONYMS AND ABBREVIATIONS
==============================================================================
CD Compact Disc
BRO Browse directory
DSN Deep Space Network
IMG Radio Science Digital Map (RSDMAP Product)
IPS Intensity Power Spectra
MGS Mars Global Surveyor
OCH Occultation Summary File (high-resolution products)
OCS Occultation Summary File (standard resolution products)
PDS Planetary Data System
RSS Radio Science Subsystem
RST Radio Science Team
SDP Science Data Products
SHA Spherical Harmonic Model (ASCII format)
SHB Spherical Harmonic Model (binary format)
SIS Software Interface Specification
SRG Surface Reflection Geometry (directory and files)
SRI Surface Reflection Image (directory and files)
SRT Surface Reflection Table (directory and files)
TPH Temperature-Pressure Profile (high resolution processing)
TPS Temperature-Pressure Profile (standard resolution)
WO Write Once