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voldesc.cat 23-Jul-2002 11:51 3.8K [PDS catalog file]
PDS_VERSION_ID = PDS3
RECORD_TYPE = STREAM
OBJECT = TEXT
INTERCHANGE_FORMAT = ASCII
PUBLICATION_DATE = 2001-09-15
NOTE = "AAREADME file for volumes NLEROS_2001-5"
END_OBJECT = TEXT
END
1. Introduction
This document provides an overview of the Near Earth Asteroid
Rendezvous NLR Calibrated Level 2 data archives, and Level 3
gridded maps and spherical harmonic model archives, including a
complete listing of the contents of this archive volume, below.
This archive contains science data products from observations
acquired by the Near Earth Asteroid Rendezvous (NEAR) NEAR Laser
Rangefinder (NLR) instrument.
The NLR Level 2 calibrated data products in this archive include
along-track time series of the NLR instrument's science data and an
observation log table containing the start times and basic parameters
for the start of collection of each observation set by the NEAR NLR.
Level 3 data includes binary gridded map products and spherical harmonic
models.
The entire Level 2 and Level 3 archive is comprised of 5 compact discs.
The table below lists the individual volume (CDs) and a brief note of
their respective contents.
VOLUME_ID Notes
--------- ---------------------------------------------------
NLEROS_2001 Along-track time series data files L00059 to L00158
NLEROS_2002 Along-track time series data files L00159 to L00208
NLEROS_2003 Along-track time series data files L00209 to L00283
NLEROS_2004 Along-track time series data files L00284 to L01008
NLEROS_2005 Along-track time series data files L01009 to L01043
2. Documentation
The Level 2 and Level 3 data sets are described in the files
NLRL2DS.CAT and NLRL3DS.CAT, respectively, in the CATALOG directory.
Also in this directory are files describing the NLR instrument
(NLRINST.CAT), the NEAR spacecraft (INSTHOST.CAT) and mission
(MISSION.CAT), personnel associated with this archive volume
(PERSON.CAT), and a bibliography of references mentioned in these
files (REF.CAT). The files in this directory will become entries in
the Planetary Data System online catalog.
Additional documentation is found in the DOCUMENT directory, including
a document describing the NLR instrument calibrations (NLRCALIB.TXT).
Early, pre-launch documents describing the NEAR mission
(MISSION.PDF and MISSION.RTF) and NLR instrument (NLR.PDF and NLR.RTF)
are found in the DOCUMENT/HISTORIC directory. These files are being
provided for historical purposes. Most of the information in these
files has been updated in the MISSION.CAT and NLRINST.CAT
files in the CATALOG directory of this volume.
3. Volume Set Information
Calibrated Level 2 Products
The Level 2 data product comprises the along-track time series of the
NLR instrument's science data in physical units, produced using
precision orbits, ancillary timing and attitude information supplied
by the NEAR SDC, and instrument data derived from in-flight analysis.
Each Level 2 data product is a text format table corresponding to a
daily level 1 EDR file, and is described by a detached label. The file
naming convention is LyydddNv.TAB, where L=laser, and yyddd contains
the two-digit year and the three-digit day of observation. The
letter v stands for processing version. The current Level 2 versions
denote the source of spacecraft ephemerides:
D - reconstructed orbits provided by the JPL Navigation Team, during
the initial asteroid encounter and the final descent phase.
G - reconstructed orbits provided by the GSFC NLR investigation.
J - GSFC orbits supplemented by JPL orbits around times of Orbit
Change Maneuvers and Momentum Correction Maneuvers.
There will be only one version of the data for each specific orbit.
These files are stored in the LEVEL2/TOPO directory.
A JPEG image representing each of these level 2 data files on the volume
can be found in the BROWSE/LEVEL2 directory.
There is also a single Level 2 observation log file. This table contains
the start times and basic parameters for the start of collection of each
observation set by the NEAR NLR. The log file is stored in the
LEVEL2/LOG directory.
Level 3 Products
The Level 3 data products include binary gridded maps of the shape of
Eros and spherical harmonic models of the shape and gravity of Eros in
ASCII format. The spherical harmonic shape model is a numerical
transform of a gridded shape model. The spherical harmonic models of
gravity are derived from joint solutions to the altimetry and
tracking data.
ASCII spherical harmonic models are stored in the LEVEL3/SHA
directory with file names of the form NLRknnnv.SHA, where nnn
is a 3-character modifier specified by the data producer, v is a
version identifier, k is replaced by G for gravity field or
T for topography/shape field, and SHA denotes that this is an ASCII
file of spherical harmonic coefficients.
Gridded map products are stored in the LEVEL3/IMG directory.
Each image is a binary array of 16-bit integers with one image line
per file record. The image file name is in the form NLRnnnvk.IMG,
where nnn is the bin size, v is a version identifier, and k is replaced
by C for counts, and R for radius, and IMG denotes that this is a PDS
image object. For example, a one-quarter degree resolution topography
image would be named NLR025vR.IMG. Its format would be described by a
detached PDS label in the file NLR025vR.LBL.
An ASCII tabular file containing global shape data of Eros, including
the latitude and longitude of the NLR laser bounce point, the radius,
and the number of observations (counts) can be found in the
LEVEL3/ASCII directory.
A JPEG image representing each of these level 3 gridded map files on the
volume can be found in the BROWSE/LEVEL3 directory.
4. CD-ROM Format
The CD-ROM has been formatted so that a variety of computer systems (e.g.,
PC, Macintosh, and Sun) may access the data. Specifically, it is formatted
according to the ISO-9660 level 2 Interchange Standard. For further
information, refer to the ISO-9660 Standard Document: RF# ISO 9660- 1988,
April 15, 1988.
This CD-ROM does not contain any Extended Attribute Records (XAR). Thus,
VAX/VMS users may have some problems accessing files on this volume.
5. File Formats
The Level 2 calibrated range data are ASCII table files with detached PDS
labels. The format of these files is completely described by the detached
labels. The observation log file is also an ASCII table described by its
corresponding detached label.
The Level 3 products on this volume are the gridded map images and spherical
harmonic models. The images are binary format and are completely
described by information contained in the PDS detached labels.
The images can be displayed using NASAview image display software, available
from the PDS at no charge. NASAview can be downloaded from the PDS
Web site at http://pds.jpl.nasa.gov/.
The spherical harmonic models are ASCII tabular files with detached
PDS labels that describe the columns in the table.
All text files (*.TXT files) and detached labels (*.LBL files) on this volume
are stream format files, with a carriage return (ASCII 13) and a line feed
character (ASCII 10) at the end of each line. This allows the files to be read
by the MacOS, DOS, and UNIX operating systems.
All tabular files (*.TAB and *.SHA files) are also described by PDS detached
labels. The detached PDS label file has the same name as the data file it
describes, with the extension .LBL. Tabular files are formatted so that
records are of fixed length, and the last two bytes of each record contain
the ASCII carriage return and line feed characters.
Documents in the DOCUMENT/HISTORIC directory are in the proprietary Adobe
Portable Document Format (PDF), which can be viewed with the free software
Acrobat Reader from Adobe Systems Incorporated, and in Rich Text Format (RTF).
There are JPEG images in the BROWSE directory representing the level 2 and
level 3 data products.
6. Volume Contents
Files on this volume are organized into a series of subdirectories below
the top-level directory. The following table shows the structure and
content of these directories. In the table, directory names are enclosed
in square brackets ([]).
FILE CONTENTS
Top-level directory
|
|- AAREADME.TXT The file you are reading
|- ERRATA.TXT Comments and errata on this volume
|- VOLDESC.CAT Description of the contents of this CD-ROM
| volume in object format
|
|- [BROWSE] Browse products (JPEG files)
| |
| |- [LEVEL2] Level 2 browse JPEG files
| | |- LyydddNv.JPG Along-track time series data file
| | |- LyydddNv.LBL Along-track time series label file
| |
| |- [LEVEL3] Level 3 browse JPEG files
| | |- NLR125AC.JPG JPG image of gridded map of counts
| | |- NLR125AC.LBL PDS label for NLR125AC.JPG
| | |- NLR125AR.JPG JPG image of gridded shape map
| | |- NLR125AR.LBL PDS label for NLR125AR.JPG
|
|- [CATALOG] PDS catalog objects
| |- CATINFO.TXT Description of files in the CATALOG directory
| |- DSMAP.CAT Description of map projection referenced in
| | gridded image labels
| |- INSTHOST.CAT Description of the NEAR spacecraft
| |- MISSION.CAT Description of the NEAR mission
| |- NLRINST.CAT Description of the NLR instrument
| |- NLRL2DS.CAT Description of the Level-2 data set
| |- NLRL3DS.CAT Description of the Level-3 data set
| |- PERSON.CAT Description of personnel associated with
| | production of this volume
| |- REF.CAT Reference objects mentioned in *.CAT files
|
|- [DOCUMENT] Documentation files
| |- DOCINFO.TXT Description of files in DOCUMENT directory
| |- NLRCALIB.TXT NLR instrument calibration document
| |- NLRCALIB.LBL PDS label for NLRCALIB.TXT
| |
| |- [HISTORIC] Pre-launch NEAR mission and NLR instrument
| | | documents in Adobe Portable Document Format
| | | and in Rich Text Format
| | |- MISSION.PDF NEAR mission overview PDF document
| | |- MISSION.RTF NEAR mission overview RTF document
| | |- MISSION.LBL PDS label for MISSION.PDF and MISSION.RTF
| | |- NLR.PDF Near Laser Rangefinder (NLR) instrument
| | | overview PDF document
| | |- NLR.RTF Near Laser Rangefinder (NLR) instrument
| | | overview RTF document
| | |- NLR.LBL PDS label for NLR.PDF and NLR.RTF
|
|- [INDEX] Index files
| |- INDXINFO.TXT Description of files in the INDEX directory
| |- L2CMIDX.LBL PDS label for L2CMIDX.TAB
| |- L2CMIDX.TAB Cumulative index table of Level-2 products on
| | this and preceding NLR archive volumes
| |- L2INDEX.LBL PDS label for L2INDEX.TAB
| |- L2INDEX.TAB Index table of Level-2 products on this volume
| |- L3CMIDX.LBL PDS label for L3CMIDX.TAB
| |- L3CMIDX.TAB Cumulative index table of Level-3 products on
| | this and preceding NLR archive volumes
| |- L3INDEX.LBL PDS label for L3INDEX.TAB
| |- L3INDEX.TAB Index table of Level-3 products on this volume
|
|- [LEVEL2] Level 2 data files
| |
| |- [LOG] Observation Log data directory
| | |- LOG.LBL PDS label for LOG.TAB
| | |- LOG.TAB Observation log file
| |
| |- [TOPO] Along-Track Time Series data directory
| | |- LyydddNv.TAB Along-track time series data files, where L is
| | laser, yy is two-digit year, ddd is three-digit
| | Julian day of observation, and v is the
| | processing version
|
|- [LEVEL3] Level 3 data files
| |
| |- [ASCII] ASCII tablular data files
| | |- NLR100.TAB Data file contains global shape data of Eros,
| | | including the latitude and longitude of the NLR
| | | laser bounce point, the radius, and the number
| | | of observations (counts)
| | |- NLR100.LBL PDS label for NLR100.TAB
| |
| |- [IMG] Gridded map data directory
| | |- NLRnnnvk.IMG Gridded map data files, where nnn is the bin
| | size, v is a version identifier, k is replaced
| | by C for counts, and R for radius
| |
| |- [SHA] Spherical harmonic models data directory
| | |- NLRknnnv.SHA Spherical harmonics models, where nnn is a
| | 3-character modifier specified by the data
| | producer, v is a version identifier and k is
| | replaced by G for gravity field, and T for
| | topography/shape field
7. Whom To Contact For Information
For questions concerning this data set collection:
PDS Geosciences Node
Washington University
Dept. of Earth and Planetary Sciences
1 Brookings Drive
St. Louis, MO 63130
314-935-8152
WWW Site: http://pds-geophys.wustl.edu/pds
Electronic mail address: jim@wuzzy.wustl.edu
NEAR/NLR Science Team
Code 920
NASA / Goddard Space Flight Center
Greenbelt, MD 20771
WWW Site: http://ltpwww.gsfc.nasa.gov/tharsis/NLR/
Electronic mail address: Gregory.Neumann@GSFC.NASA.GOV
8. Cognizant Persons
NEAR/NLR data were provided by David Smith, with assistance from
Greg Neumann, both of NASA/Goddard Space Flight Center.
This volume was designed and produced by Jim Alexopoulos, Planetary Data
System Geosciences Node, Washington University, St. Louis, Missouri.