PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 80
OBJECT = TEXT
PUBLICATION_DATE = 1999-03-09
NOTE = "Software Interface Specification for
the Spherical Harmonics ASCII Data
Record (SHADR) file. Formatted for
display or printing at 58 lines per
page with up to 78 constant width
characters per line."
END_OBJECT = TEXT
END
SOFTWARE INTERFACE SPECIFICATION
SPHERICAL HARMONICS ASCII DATA RECORD (SHADR)
prepared by
Richard A. Simpson
Durand Bldg - Room 232
Stanford University
Stanford, CA
94305-9515
Version 2.0.2
9 March 1999
PREFACE
|====================================================================|
| |
| DOCUMENT CHANGE LOG |
| |
|====================================================================|
|REVISION|REVISION| SECTION | REMARKS |
| NUMBER | DATE | AFFECTED | |
|--------+--------+------------+-------------------------------------|
| 2.0 |98/04/20| All |Adapted SHADR SIS from V1.0 for Mars |
| | | | Global Surveyor and Lunar Prospector|
|--------+--------+------------+-------------------------------------|
| 2.0.1 |98/12/16| 4.2.1 |Change MGS DATA_SET_ID to |
| | | | MGS-M-RSS-5-SDP-Vn.m |
|--------+--------+------------+-------------------------------------|
| 2.0.1 |98/12/22| 4.2.1 |Add optional START_TIME and STOP_TIME|
| | | Table 4-2-1| |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09| 2.3 |Generalize use of "nnnnvv" string in |
| | | | file name. |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09|Distribution|Update list of PDS recipients. |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09| 1.3 |Update version, date for [3]. |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09|Acr & Abbrev|Change "LPX" to "LP" for Lunar |
| | | 1.2 | Prospector. |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09| 1.5.4.1 |Substituted 7-bit ASCII characters |
| | | 1.5.4.2 | for 8-bit versions |
|========|========|============|=====================================|
|====================================================================|
| |
| ITEMS TO BE DETERMINED |
| |
|====================================================================|
| REVISION | SECTION | ITEM DESCRIPTION | RESOLUTION |
| NUMBER | AFFECTED | | |
|----------+----------+------------------------+---------------------|
| 2.0 | 5 |Add names, contact info | |
| | | for scientists on | |
| | | specific products. | |
|==========|==========|========================|=====================|
Distribution
JPL/Gravity
A.S. Konopliv............ 301-125J ask@krait.jpl.nasa.gov
N. Rappaport............301-125L Nicole.J.Rappaport@jpl.nasa.gov
W.L. Sjogren..............301-150 wls@kamel.jpl.nasa.gov
R. Wimberly.............301-150 Ravenel.N.Wimberly@jpl.nasa.gov
D-N Yuan.................301-125J dny@krait.jpl.nasa.gov
JPL/Mars Global Surveyor
P. Priest...............264-325 trish@rodan.jpl.nasa.gov
T. Thorpe...............264-214 Thomas.E.Thorpe@jpl.nasa.gov
JPL/PDS
V. Henderson............171-264 Valerie.Henderson@jpl.nasa.gov
Y. Oliver...............171-264 Yolanda.Oliver@jpl.nasa.gov
Stanford University
R. Simpson...........Durand 232 rsimpson@magellan.stanford.edu
J. Twicken...........Durand 232 joe@neptune.stanford.edu
L. Tyler.............Durand 232 len@nova.stanford.edu
Washington University
R.E. Arvidson.....Campus Box 1169 arvidson@wunder.wustl.edu
J. Alexopoulos..Campus Box 1169 jim@wuzzy.wustl.edu
Goddard Space Flight Center
F. Lemoine.............Code 926 flemoine@olympus.gsfc.nasa.gov
D. Rowlands............Code 926 dave@usgrant.gsfc.nasa.gov
D.E. Smith...............Code 920 dsmith@tharsis.gsfc.nasa.gov
Massachusetts Institute of Technology
M. Zuber.................54-518 zuber@tharsis.gsfc.nasa.gov
CNES
G. Balmino.................GRGS balmino@pontos.cst.cnes.fr
Contents
Preface.............................................................ii
Document Change Log...............................................ii
Items to be Determined............................................ii
Distribution.....................................................iii
Contents..........................................................iv
Acronyms and Abbreviations........................................vi
1. General Description...............................................1
1.1. Overview......................................................1
1.2. Scope.........................................................1
1.3. Applicable Documents..........................................1
1.4. System Siting.................................................2
1.4.1. Interface Location and Medium.............................2
1.4.2. Data Sources, Transfer Methods, and Destinations..........2
1.4.3. Generation Method and Frequency...........................2
1.5. Assumptions and Constraints...................................2
1.5.1. Usage Constraints.........................................2
1.5.2. Priority Phasing Constraints..............................2
1.5.3. Explicit and Derived Constraints..........................2
1.5.4. Documentation Conventions.................................2
1.5.4.1. Data Format Descriptions..............................2
1.5.4.2. Time Standards........................................3
1.5.4.3. Coordinate Systems....................................3
1.5.4.4. Limits of This Document...............................3
1.5.4.5. Typographic Conventions...............................3
2. Interface Characteristics.........................................4
2.1. Hardware Characteristics and Limitations......................4
2.1.1. Special Equipment and Device Interfaces...................4
2.1.2. Special Setup Requirements................................4
2.2. Volume and Size...............................................4
2.3. Labeling and Identification...................................4
2.4. Interface Medium Characteristics..............................5
2.5. Failure Protection, Detection, and Recovery Procedures........5
2.6. End-of-File Conventions.......................................5
3. Access............................................................6
3.1. Programs Using the Interface..................................6
3.2. Synchronization Considerations................................6
3.2.1. Timing and Sequencing Considerations......................6
3.2.2. Effective Duration........................................6
3.2.3. Priority Interrupts.......................................6
3.3. Input/Output Protocols, Calling Sequences.....................6
4. Detailed Interface Specifications.................................7
4.1. Structure and Organization Overview...........................7
4.2. Detached PDS Label............................................7
4.2.1. Label Header..............................................7
4.2.2. TABLE Object Definitions.................................10
4.2.2.1. SHADR Header Object Definition.........................10
4.2.2.2. SHADR Coefficients Object Definition...................13
4.2.2.3. SHADR Covariance Object Definition.....................14
4.3. Data File....................................................17
4.3.1. SHADR Header Object/Block................................17
4.3.2. SHADR Coefficients Block.................................18
4.3.3. SHADR Covariances Block..................................19
5. Support Staff and Cognizant Personnel............................20
Appendix A. Binary Data Format.....................................21
A.1. IEEE Integer Fields..........................................21
A.2. IEEE Floating-Point Fields...................................21
A.3. VAX Integer Fields...........................................22
A.4. VAX Floating-Point Fields....................................23
Appendix B. Example Data Products..................................24
B.1. Example Label................................................24
B.2. Example Data Object..........................................28
Tables
4-3-1. SHADR Header Block.........................................17
4-3-2. SHADR Coefficients Block...................................18
4-3-3. SHADR Covariance Block.....................................19
Figures
4-2-1. SHADR Label Header..........................................8
Acronyms and Abbreviations
ANSI American National Standards Institute
ARC Ames Research Center
ARCDR Altimetry and Radiometry Composite Data Record
ASCII American Standard Code for Information Interchange
CCSDS Consultative Committee for Space Data Systems
CD-WO Compact-disc write-once
CNES Centre National d'Etudes Spatiales
CR Carriage Return
dB Decibel
DEC Digital Equipment Corporation
DSN Deep Space Network
FEA Front End Assembly
GSFC Goddard Space Flight Center
IEEE Institute of Electrical and Electronic Engineers
IAU International Astronomical Union
JPL Jet Propulsion Laboratory
J2000 IAU Official Time Epoch
K Degrees Kelvin
kB Kilobytes
km Kilometers
LF Line Feed
LP Lunar Prospector (mission or spacecraft)
MB Megabytes
MGN Magellan
MGS Mars Global Surveyor
MO Mars Observer
NAIF Navigation and Ancillary Information Facility
NASA National Aeronautics and Space Administration
NAV Navigation Subsystem/Team
ODL Object Definition Language (PDS)
PDB Project Data Base
PDS Planetary Data System
RS Radio Science
SCET Space Craft Event Time
SFDU Standard Formatted Data Unit
SHADR Spherical Harmonics ASCII Data Record
SHBDR Spherical Harmonics Binary Data Record
SHM Spherical Harmonics Model
SIS Software Interface Specification
SOPC Science Operations Planning Computer
SPARC Sun Scaleable Processor Architecture
SPK Spacecraft and Planet Kernel Format, from NAIF
TBD To Be Determined
TDB Temps Dynamique Barycentrique - IAU Standard Ephemeris
Time
UTC Universal Time Coordinated
1. General Description
1.1. Overview
This Software Interface Specification (SIS) describes Spherical
Harmonics ASCII Data Record (SHADR) files. The SHADR is intended to
be general and may contain coefficients for spherical harmonic
expansions of gravity, topography, magnetic, and other fields.
1.2. Scope
The format and content specifications in this SIS apply to all
phases of the project for which a SHADR is produced.
The SHADR was defined initially for gravity models derived from
Magellan (MGN) and Mars Observer (MO) radio tracking data [1], but the
format is more generally useful; this document includes updates for
the Mars Global Surveyor (MGS) and Lunar Prospector (LP) missions.
Specifics of the various models are included in [2], which will be
updated as data for new spherical harmonic models are incorporated
within the SHADR definition. A Spherical Harmonic Binary Data Record
is also defined [3], which may be more suitable for large models or
when all covariances will be included in the final product.
The Mars Global Surveyor Mission is managed by the Jet
Propulsion Laboratory (JPL) for the National Aeronautics and Space
Administration. The Lunar Prospector Mission is managed by the Ames
Research Center (ARC) for NASA.
1.3. Applicable Documents
[1] Tyler, G.L., G. Balmino, D.P. Hinson, W.L. Sjogren, D.E. Smith,
R. Woo, S.W. Asmar, M.J. Connally, C.L. Hamilton, and R.A. Simpson,
Radio Science Investigations with Mars Observer, J. Geophys. Res.,
97, 7759-7779, 1992.
[2] Simpson, R.A., Interpretation and Use of Spherical Harmonics
ASCII Data Record (SHADR) and Spherical Harmonics Binary Data Record
(SHBDR), Version 1.0, 1993.
[3] Simpson, R.A., Software Interface Specification: Spherical
Harmonics Binary Data Record (SHBDR), Version 2.0.2, 9 March 1999.
[4] MGN 630-7, Rev. D, Magellan Planetary Constants and Models, D.T.
Lyons, Mission Design, Jet Propulsion Laboratory, 9 January 1991.
[5] MO 642-321, Mars Observer Planetary Constants and Models, JPL D-
3444, November 1990.
[6] D-7116, Rev. D, Planetary Science Data Dictionary Document,
Jet Propulsion Laboratory, 15 June 1996.
[7] D-7669 Part 2, Planetary Data System Standards Reference, PDS
Version 3.2, Jet Propulsion Laboratory, 24 July 1995.
1.4. System Siting
1.4.1. Interface Location and Medium
SHADR files are created at the institution conducting the
science analysis. SHADR files can be electronic files or can be
stored on compact-disc write-once (CD-WO) media.
1.4.2. Data Sources, Transfer Methods, and Destinations
SHADR files are created from radio tracking, vertical sounding,
in situ, and/or other measurements at the institution conducting the
scientific data analysis. They are transferred to and deposited in a
data system specified by the managing institution.
1.4.3. Generation Method and Frequency
Spherical Harmonic Models are developed separately at each
institution conducting scientific analyses on raw data; each model
meets criteria specified by the investigators conducting the analysis.
Each model requires data from a large number of latitudes and
longitudes, so that SHADR files will be issued infrequently and on
schedules which cannot be predicted at this time.
1.5. Assumptions and Constraints
1.5.1. Usage Constraints
None.
1.5.2. Priority Phasing Constraints
None.
1.5.3. Explicit and Derived Constraints
None.
1.5.4. Documentation Conventions
1.5.4.1. Data Format Descriptions
The reference data unit is the byte. Data may be stored in
fields with various sizes and formats, viz. one-, two-, and four-byte
binary integers, four- and eight-byte binary floating-point numbers,
and character strings. Data are identified throughout this document
as
char 8 bits character
uchar 8 bits integer
short 16 bits integer
long 32 bits integer
float 32 bits floating point (sign, exponent, and
mantissa)
double 64 bits floating point (sign, exponent, and
mantissa)
u (prefix) unsigned (as with ulong for
unsigned 32-bit integer)
other special data structures such as
time, date, etc. which are
described within this document
If a field is described as containing n bytes of ASCII
character string data, this implies that the leftmost (lowest
numbered) byte contains the first character, the next lowest byte
contains the second character, and so forth.
An array of n elements is written as array[n]; the first
element is array[0], and the last is array[n-1]. Array[n][m]
describes an n x m element array, with first element array[0][0],
second element array[0][1], and so forth.
Floating point (real) numbers are represented as double
precision character strings in the FORTRAN 1P1E23.16 format. Fixed
point (integer) numbers are represented using the FORTRAN I5 format.
1.5.4.2. Time Standards
SHADR files use the January 1.5, 2000 epoch as the standard
time. Within the data files, all times are reported in Universal
Coordinated Time (UTC) as strings of 23 ASCII characters. The time
format is "YYYY-MM-DDThh:mm:ss.fff", where "-", "T", ":", and "." are
fixed delimiters; "YYYY" is the year "19nn" or "20nn"; "MM" is a two-
digit month of year; "DD" is a two-digit day of month; "T" separates
the date and time segments of the string; "hh" is hour of day; "mm" is
the minutes of hour (00-59); "ss" is the seconds of minute (00-59);
and "fff" is fractional seconds in milliseconds.
The date format is "YYYY-MM-DD", where the components are
defined as above.
1.5.4.3. Coordinate Systems
The SHADR uses the appropriate planetocentric fixed body
coordinate system [4, 5].
1.5.4.4. Limits of This Document
This document applies only to SHADR data files.
1.5.4.5. Typographic Conventions
This document has been formatted for simple electronic file
transfer and display. Line lengths are limited to 80 ASCII
characters, including line delimiters. No special fonts or structures
are included within the file. Constant width characters are assumed
for display.
2. Interface Characteristics
2.1. Hardware Characteristics and Limitations
2.1.1. Special Equipment and Device Interfaces
Users of the SHADR product must have access to the data system
(or to media) on which SHADR files are stored.
2.1.2. Special Setup Requirements
None.
2.2. Volume and Size
SHADR products have variable length, depending on the degree and
order of the model and the number of tables included. A model of
degree and order N will require approximately 60*N*N bytes for
storage of spherical harmonic coefficients and associated
uncertainties. If the covariance matrix is included, the file size
will be 15*N**4 larger. For N=50, the coefficients would require
approximately 160 kB and the covariances another 100 MB.
Vector quantities (e.g., magnetic field) may be described by a
single SHADR (in which all components are represented) or by a
separate SHADR for each field component. If the single SHADR
includes covariances, the file size will be approximately 27 times
larger than the combined volumes of the three component files because
of the inter-component covariance terms.
In general, the SHBDR [3] is recommended when the data include
covariances because of the smaller data volume associated with binary
formats.
2.3. Labeling and Identification
Each file has a name which describes its contents. The name
includes the following structure which uniquely identifies it among
SHADR products:
GTnnnnvv.SHA
where
"G" denotes the generating institution
"J" for the Jet Propulsion Laboratory
"G" for Goddard Space Flight Center
"C" for Centre National d'Etudes Spatiales
"T" indicates the type of data represented
"G" for gravity field
"T" for topography
"M" for magnetic field
"nnnnvv" is a 6-character modifier specified by the data
producer. Among other things, this modifier may be
used to indicate the target body, whether the SHADR
contains primary data values as specified by "T" or
uncertainties/errors, and/or the version number.
"SHA" denotes that this is an ASCII file of Spherical
Harmonic coefficients
Each SHADR file is accompanied by a detached PDS label; that
label is a file in its own right, having the name GTnnnnvv.LBL.
2.4. Interface Medium Characteristics
SHADR products are electronic files.
2.5. Failure Protection, Detection, and Recovery Procedures
None.
2.6. End-of-File Conventions
End of file labeling complies with standards for the medium on
which the files are stored.
3. Access
3.1. Programs Using the Interface
Data contained in SHADR files will be accessed by programs at
the home institutions of science investigators. Those programs cannot
be identified here.
3.2. Synchronization Considerations
3.2.1. Timing and Sequencing Considerations
N/A
3.2.2. Effective Duration
N/A
3.2.3. Priority Interrupts
None.
3.3. Input/Output Protocols, Calling Sequences
None.
4. Detailed Interface Specifications
4.1. Structure and Organization Overview
The SHADR is a file generated by software at the institution
conducting scientific data analysis. Each SHADR file is accompanied
by a detached PDS label.
4.2. Detached PDS Label
The detached PDS label is a file with two parts -- a header,
and a set of one, two, or three PDS TABLE object definitions. The
header contains information about the origin of the file and its
general characteristics such as record type and size. The TABLE
object definitions describe the format and content of the tables
that make up the SHADR data file. The SHADR Header Table Object
definition is required. The SHADR Coefficients Table Object
definition is required if there is a SHADR Coefficients Table in
the file; the SHADR Covariance Table Object definition is required
if there is a SHADR Covariance Table.
Each detached PDS label is constructed of ASCII records;
each record in the label contains exactly 80 characters. The last
two characters in each record are the carriage-return (ASCII 13) and
line-feed (ASCII 10) characters.
An example of a complete label is given in Appendix B.
4.2.1 Label Header
The structure of the label header is illustrated in
Figure 4-2-1. Keyword definitions are given below.
PDS_VERSION_ID = The version of the Planetary Data System
for which these data have been prepared;
set to PDS3 by agreement between the Mars
Global Surveyor Project and PDS.
RECORD_TYPE = The type of record. Set to "FIXED_LENGTH"
to indicate that all logical records have
the same length.
RECORD_BYTES = The number of bytes per (fixed-length)
record. It is usually most convenient if
this has been set equal to the length of
records in the SHADR_COVARIANCE_TABLE.
FILE_RECORDS = The number of records in the SHADR file;
instance dependent.
^SHADR_HEADER_TABLE= File name and record number at which
SHADR_HEADER_TABLE begins. Set to
("GTnnnnvv.SHA",1) where "GTnnnnvv.SHA" is
the file name as described in Section 2.3,
and 1 is the record number since this is
the first record in the SHADR file.
|====================================================================|
| |
| Figure 4-2-1 SHADR Label Header |
| |
|====================================================================|
| |
| PDS_VERSION_ID = PDS3 |
| RECORD_TYPE = FIXED_LENGTH |
| RECORD_BYTES = nnn |
| FILE_RECORDS = nnn |
| ^SHADR_HEADER_TABLE = ("GTnnnnvv.SHA",1) |
| ^SHADR_COEFFICIENTS_TABLE = ("GTnnnnvv.SHA",nn) |
| ^SHADR_COVARIANCE_TABLE = ("GTnnnnvv.SHA",nnn) |
| INSTRUMENT_HOST_NAME = "cccccccccccccccccccc" |
| TARGET_NAME = "cccc" |
| INSTRUMENT_NAME = "ccccccccccccccccccccccc" |
| DATA_SET_ID = "ccccccccccccccccccccccc" |
| OBSERVATION_TYPE = "ccccccccccccc" |
| ORIGINAL_PRODUCT_ID = "ccccccccccccc" |
| PRODUCT_ID = "GTnnnnvv.SHA" |
| PRODUCT_RELEASE_DATE = YYYY-MM-DD |
| DESCRIPTION = "cccccccccccccccccc" |
| START_ORBIT_NUMBER = nnnn |
| STOP_ORBIT_NUMBER = nnnn |
| START_TIME = YYYY-MM-DDThh:mm:ss |
| STOP_TIME = YYYY-MM-DDThh:mm:ss |
| PRODUCT_CREATION_TIME = YYYY-MM-DDThh:mm:ss.fff |
| PRODUCER_FULL_NAME = "cccccccccccc" |
| PRODUCER_INSTITUTION_NAME = "ccccccccccc" |
| PRODUCT_VERSION_TYPE = "cccccccccccc" |
| PRODUCER_ID = "ccccccc" |
| SOFTWARE_NAME = "ccccccc;Vn.m" |
| |
|====================================================================|
^SHADR_COEFFICIENTS_TABLE= File name and record number at which
SHADR_COEFFICIENTS_TABLE begins. The
Coefficients Table is optional; this
pointer will not appear in the SHADR
label if there is no Coefficients Table.
Set to ("GTnnnnvv.SHA",nn) where
"GTnnnnvv.SHA" is the file name as
described in Section 2.3, and "nn" is the
record number in the file where the
Coefficients Table begins.
^SHADR_COVARIANCE_TABLE= File name and record number at which
SHADR_COVARIANCE_TABLE begins. The
Covariance Table is optional; this
pointer will not appear in the SHADR
label if there is no Covariance Table.
Set to ("GTnnnnvv.SHA",nn) where
"GTnnnnvv.SHA" is the file name as
described in Section 2.3, and "nn" is
the record number in the file where the
Covariance Table begins.
INSTRUMENT_HOST_NAME = Name of the spacecraft; acceptable names
include "MARS GLOBAL SURVEYOR" and "LUNAR
PROSPECTOR".
TARGET_NAME = A character string which identifies the
target body. For MGS SHADR files, the
character string "MARS". For Lunar
Prospector SHADR files, the character
string "MOON".
INSTRUMENT_NAME = Name of the instrument; set to "RADIO
SCIENCE SUBSYSTEM" for products generated
from radio science data, or set to other
instrument names as appropriate.
DATA_SET_ID = Identifier for the data set of which this
SHADR product is a member. Set to "MGS-M-
RSS-5-SDP-Vn.m" for Mars Global Surveyor
SHADR products, where "Vn.m" indicates the
version number of the data set. Set to
other data set identifiers as appropriate.
OBSERVATION_TYPE= A character string which identifies the
data in the product. For the spherical
harmonic model of a gravity field, the
character string "GRAVITY FIELD". For a
model of planet topography, the character
string "TOPOGRAPHY".
ORIGINAL_PRODUCT_ID = Optional. An identifier for the product
provided by the producer. Generally a
file name, different from PRODUCT_ID, which
would be recognized at the producer's
institution.
PRODUCT_ID = A unique identifier for the product within
the collection identified by DATA_SET_ID.
Generally, the file name used in pointers
^SHADR_HEADER_TABLE, ^SHADR_COEFFICIENTS_
TABLE, and/or ^SHADR_COVARIANCE_TABLE.
The naming convention is defined in
Section 2.3.
PRODUCT_RELEASE_DATE = The date on which the product was released
to the Planetary Data System; entered in
the format "YYYY-MM-DD", where components
are defined in Section 1.5.4.2.
DESCRIPTION = A short description of the SHADR product.
START_ORBIT_NUMBER = Optional. The first orbit represented in
the SHADR product. An integer.
STOP_ORBIT_NUMBER = Optional. The last orbit represented in
the SHADR product. An integer.
START_TIME = Optional. The date/time of the first data
included in the model, expressed in the
format "YYYY-MM-DDThh:mm:ss" where the
components are defined in section 1.5.4.2.
STOP_TIME = Optional. The date/time of the last data
included in the model, expressed in the
format "YYYY-MM-DDThh:mm:ss" where the
components are defined in section 1.5.4.2.
PRODUCT_CREATION_TIME = The time at which this SHADR was created;
expressed in the format "YYYY-MM-
DDThh:mm:ss.fff" where the components are
defined in Section 1.5.4.2.
PRODUCER_FULL_NAME= The name of the person primarily
responsible for production of this SHADR
file. Expressed as a character string, for
example "LESLIE R. JONES".
PRODUCER_INSTITUTION_NAME= The name of the institution primarily
responsible for production of this SHADR.
Standard values include
"STANFORD UNIVERSITY"
"GODDARD SPACE FLIGHT CENTER"
"JET PROPULSION LABORATORY"
"CENTRE NATIONAL D'ETUDES SPATIALES"
PRODUCT_VERSION_TYPE= The version of this SHADR. Standard values
include "PREDICT", "PRELIMINARY", and
"FINAL".
PRODUCER_ID = The entity responsible for creation of the
SHADR product; for products generated by
the Mars Global Surveyor Radio Science
Team set to "MGS RST".
SOFTWARE_NAME = The name and version number of the program
creating this SHADR file; expressed as a
character string in the format
"PROGRAM_NAME;n.mm" where "PROGRAM_NAME" is
the name of the software and "n.mm" is the
version number.
4.2.2 TABLE Object Definitions
TABLE object definitions completely define the TABLE objects for
each SHADR file. Minor tailoring of the definitions for different
OBSERVATION_TYPES precludes specification of exact definitions here.
DESCRIPTION values, for example, will likely be tailored for each
product type. In no case should there be a need to change the
structure of the file, however. Entries "*" are provided by the
label generating program based on information supplied elsewhere.
4.2.2.1 SHADR Header Object Definition
Each SHADR Header Object is completely defined by the Header
Object Definition in its Label. The Definition which follows gives
the structure of the Header Object; some of the DESCRIPTION values
may vary from product to product. The SHADR Header Object Definition
is a required part of the SHADR label file. It immediately follows
the label header.
OBJECT = SHADR_HEADER_TABLE
ROWS = 1
COLUMNS = 8
ROW_BYTES = 137
ROW_SUFFIX_BYTES = 107
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The SHADR header includes
descriptive information about the spherical harmonic
coefficients which follow in SHADR_COEFFICIENTS_TABLE.
The header consists of a single record of eight (delimited)
data columns requiring 137 bytes, a pad of 105 ASCII
blank characters, an ASCII carriage-return, and an ASCII
line-feed."
OBJECT = COLUMN
NAME = "REFERENCE RADIUS"
DATA_TYPE = ASCII_REAL
START_BYTE = 1
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "The assumed reference
radius of the spherical planet."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "CONSTANT"
DATA_TYPE = ASCII_REAL
START_BYTE = 25
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the assumed gravitational constant GM in kilometers cubed
per seconds squared for the planet. For a topography
model, set to 1."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "UNCERTAINTY IN CONSTANT"
DATA_TYPE = ASCII_REAL
START_BYTE = 49
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the uncertainty in the gravitational constant GM in kilometers
cubed per seconds squared for the planet. For a topography
model, set to 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DEGREE OF FIELD"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 73
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree of model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORDER OF FIELD"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 79
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NORMALIZATION STATE"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 85
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The normalization indicator.
For gravity field:
0 coefficients are unnormalized
1 coefficients are normalized
2 other."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 91
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "The reference longitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LATITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 115
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "The reference latitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
END_OBJECT = SHADR_HEADER_TABLE
4.2.2.2 SHADR Coefficients Object Definition
The SHADR Coefficients Object is completely defined by the
Coefficients Object Definition in the label. Small differences in
DESCRIPTION values should be expected from product to product. The
structure outlined in the Definition below should not vary, however.
The SHADR Coefficients Object is an optional part of the
SHADR data file. This allows the SHADR to be used for targets which
are too small or too remote to have easily discerned coefficients,
but for which estimates of mass have been obtained (e.g., satellites
Phobos and Deimos).
If the Coefficients Object is not included in the SHADR
file, either the SHADR Coefficients Object Definition will be
omitted or the number of rows will be set to zero (ROWS = 0).
If the SHADR Coefficients Object is not included, the pointer
^SHADR_COEFFICIENTS_TABLE will not appear in the label header.
If the SHADR Coefficients Object Definition is included in the
label, it immediately follows the SHADR Header Object Definition.
No requirements are placed on the order in which coefficient
values appear in the table. Nor is there a requirement that all
possible combinations of the pairs {m,n} be included. The
coefficients are defined by their COEFFICIENT DEGREE and COEFFICIENT
ORDER; see [2] for interpretation.
OBJECT = SHADR_COEFFICIENTS_TABLE
ROWS = *
COLUMNS = 6
ROW_BYTES = 107
ROW_SUFFIX_BYTES = 15
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The SHADR coefficients table
contains the coefficients for the spherical harmonic model.
Each row in the table contains the degree index m, the
order index n, the coefficients Cmn and Smn, and the
uncertainties in Cmn and Smn. The (comma delimited) data
require 107 ASCII characters; these are followed by a pad
of 13 ASCII blank characters, an ASCII carriage-
return, and an ASCII line-feed."
OBJECT = COLUMN
NAME = "COEFFICIENT DEGREE"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree index m of the
C and S coefficients in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COEFFICIENT ORDER"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 7
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order index n of the
C and S coefficients in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "C"
DATA_TYPE = ASCII_REAL
START_BYTE = 13
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The coefficient Cmn
for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "S"
DATA_TYPE = ASCII_REAL
START_BYTE = 37
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The coefficient Smn
for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "C UNCERTAINTY"
DATA_TYPE = ASCII_REAL
START_BYTE = 61
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The uncertainty in the
coefficient Cmn for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "S UNCERTAINTY"
DATA_TYPE = ASCII_REAL
START_BYTE = 85
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The uncertainty in the
coefficient Smn for this spherical harmonic model."
END_OBJECT = COLUMN
END_OBJECT = SHADR_COEFFICIENTS_TABLE
4.2.2.3 SHADR Covariance Object Definition
The SHADR Covariance Object is completely defined by the
Covariance Object Definition in the label. Small differences in
DESCRIPTION values should be expected from product to product. The
structure established by the Definition below should not change,
however.
The SHADR Covariance Object is an optional part of the SHADR
data file. If the Covariance Object is not included, either the
Covariance Object Definition will be omitted or the number of rows
will be set to zero (ROWS = 0). If the SHADR Covariance Object is not
included, the pointer ^SHADR_COVARIANCE_TABLE will not appear in the
label header. If the SHADR Covariance Object Definition is included
in the label, it immediately follows the SHADR Coefficients Object
Definition.
No requirements are placed on the order in which covariance
values appear in the table. Nor is there a requirement that all
possible combinations of the quadruplet values {i,j,m,n} be
included. By careful editing and use of symmetry arguments, it may be
possible to define all covariances with fewer than the maximum number
of rows in the table.
OBJECT = SHADR_COVARIANCE_TABLE
ROWS = *
COLUMNS = 8
ROW_BYTES = 119
ROW_SUFFIX_BYTES = 3
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The SHADR covariance table
contains the covariances for the spherical harmonic model
coefficients. For each index quadruplet {i,j,m,n} the
covariances of CijCmn, SijSmn, CijSmn, and SijCmn are
given. In each row of the table the (comma delimited)
indices occupy 24 ASCII characters and the (comma delimited)
covariances occupy 95 ASCII characters. These are followed
by an ASCII blank, an ASCII carriage-return and an ASCII
line-feed."
OBJECT = COLUMN
NAME = "COEFFICIENT DEGREE i"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree index i of
the C and S terms in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COEFFICIENT ORDER j"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 7
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order index j of
the C and S terms in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COEFFICIENT DEGREE m"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 13
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree index m of
the C and S terms in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COEFFICIENT ORDER n"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 19
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order index n of
the C and S terms in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COVARIANCE {Cij,Cmn}"
DATA_TYPE = ASCII_REAL
START_BYTE = 25
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "Covariance {Cij,Cmn}
for the coefficients of this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COVARIANCE {Sij,Smn}"
DATA_TYPE = ASCII_REAL
START_BYTE = 49
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "Covariance {Sij,Smn}
for the coefficients of this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COVARIANCE {Cij,Smn}"
DATA_TYPE = ASCII_REAL
START_BYTE = 73
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "Covariance {Cij,Smn}
for the coefficients of this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COVARIANCE {Sij,Cmn}"
DATA_TYPE = ASCII_REAL
START_BYTE = 97
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "Covariance {Sij,Cmn}
for the coefficients of this spherical harmonic model."
END_OBJECT = COLUMN
END_OBJECT = SHADR_COVARIANCE_TABLE
4.3. Data File
Each SHADR data file comprises a SHADR Header TABLE Object, an
(optional) Coefficients TABLE Object, and an (optional) Covariances
TABLE Object.
Each TABLE Object comprises one or more data blocks. The
TABLE Objects were defined in Section 4.2. The data blocks are
illustrated below.
|====================================================================|
| |
| Table 4-3-1. SHADR Header Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------+--------+--------+--------+--------------------------------|
| 1 | +0 | 23 | E23.16 |Planetary Radius |
|--------+--------+--------+--------+--------------------------------|
| 2 | 24 | 23 | E23.16 |Constant |
|--------+--------+--------+--------+--------------------------------|
| 3 | 48 | 23 | E23.16 |Uncertainty in Constant |
|--------+--------+--------+--------+--------------------------------|
| 4 | 72 | 5 | I5 |Degree of Field |
|--------+--------+--------+--------+--------------------------------|
| 5 | 78 | 5 | I5 |Order of Field |
|--------+--------+--------+--------+--------------------------------|
| 6 | 84 | 5 | I5 |Normalization State |
|--------+--------+--------+--------+--------------------------------|
| 7 | 90 | 23 | E23.16 |Reference Longitude |
|--------+--------+--------+--------+--------------------------------|
| 8 | 114 | 23 | E23.16 |Reference Latitude |
|--------+--------+--------+--------+--------------------------------|
| | 137 | 105 | | blanks |
|--------+--------+--------+--------+--------------------------------|
| | 242 | 1 | | carriage return |
|--------+--------+--------+--------+--------------------------------|
| | 243 | 1 | | line feed |
|--------+--------+--------+--------+--------------------------------|
| | +244 | |
|========|========|========|========|================================|
4.3.1. SHADR Header Object/Block
The SHADR Header Object contains the parameters necessary to
interpret the data in the SHADR file. The structure of the SHADR
Header Object is defined in Section 4.2.2.1. The SHADR Header
Object is a one-row table; hence the Header Object and the Header
Block are logically synonymous. The structure of the Header Block
is shown in Table 4-3-1. Note that the logical content of the Header
Object is delimited by the ASCII carriage return and line feed
characters. The physical block is padded to 244 bytes (an integral
multiple of RECORD_BYTES).
4.3.2. SHADR Coefficients Block
The SHADR Coefficients Object is made up of one or more SHADR
Coefficients Blocks. Each block contains one pair of coefficients
and associated uncertainties for the overall model defined by the
SHADR product. The structure of the SHADR Coefficients Object is
defined in Section 4.2.2.2. The structure of an individual block
is shown in Table 4-3-2. Note that the logical content of the
Coefficients Block is delimited by the ASCII carriage return and line
feed characters. The Coefficients Block is, by definition, an
integral multiple of RECORD_BYTES.
|====================================================================|
| |
| Table 4-3-2. SHADR Coefficients Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------+--------+--------+--------+--------------------------------|
| 1 | +0 | 5 | I5 |Coefficient Degree m |
|--------+--------+--------+--------+--------------------------------|
| 2 | 6 | 5 | I5 |Coefficient Order n |
|--------+--------+--------+--------+--------------------------------|
| 3 | 12 | 23 | E23.16 |Cmn |
|--------+--------+--------+--------+--------------------------------|
| 4 | 36 | 23 | E23.16 |Smn |
|--------+--------+--------+--------+--------------------------------|
| 5 | 60 | 23 | E23.16 |Uncertainty in Cmn |
|--------+--------+--------+--------+--------------------------------|
| 6 | 84 | 23 | E23.16 |Uncertainty in Smn |
|--------+--------+--------+--------+--------------------------------|
| | 107 | 13 | | blanks |
|--------+--------+--------+--------+--------------------------------|
| | 120 | 1 | | carriage return |
|--------+--------+--------+--------+--------------------------------|
| | 121 | 1 | | line feed |
|--------+--------+--------+--------+--------------------------------|
| | +122 | |
|========|========|========|========|================================|
4.3.3. SHADR Covariance Block
The SHADR Covariance Object is made up of one or more SHADR
Covariance Blocks. Each block contains the CijCmn, SijSmn,
CijSmn, and SijCmn covariances for the overall model defined by the
SHADR product. The structure of the SHADR Covariance Object is
defined in Section 4.2.2.3. The structure of an individual block
is shown in Table 4-3-3. Note that the logical content of the
Covariance Block is delimited by the ASCII carriage return and
line feed characters. The SHADR Covariance Block is, by definition,
an integral multiple of RECORD_BYTES.
|====================================================================|
| |
| Table 4-3-3. SHADR Covariance Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------+--------+--------+--------+--------------------------------|
| 1 | +0 | 5 | I5 |Coefficient Degree i |
|--------+--------+--------+--------+--------------------------------|
| 2 | 6 | 5 | I5 |Coefficient Order j |
|--------+--------+--------+--------+--------------------------------|
| 3 | 12 | 5 | I5 |Coefficient Degree m |
|--------+--------+--------+--------+--------------------------------|
| 4 | 18 | 5 | I5 |Coefficient Order n |
|--------+--------+--------+--------+--------------------------------|
| 5 | 24 | 23 | E23.16 |Covariance {Cij,Cmn} |
|--------+--------+--------+--------+--------------------------------|
| 6 | 48 | 23 | E23.16 |Covariance {Sij,Smn} |
|--------+--------+--------+--------+--------------------------------|
| 7 | 72 | 23 | E23.16 |Covariance {Cij,Smn} |
|--------+--------+--------+--------+--------------------------------|
| 8 | 96 | 23 | E23.16 |Covariance {Sij,Cmn} |
|--------+--------+--------+--------+--------------------------------|
| | 119 | 1 | | blank |
|--------+--------+--------+--------+--------------------------------|
| | 120 | 1 | | carriage return |
|--------+--------+--------+--------+--------------------------------|
| | 121 | 1 | | line feed |
|--------+--------+--------+--------+--------------------------------|
| | +122 | |
|========|========|========|========|================================|
5. Support Staff and Cognizant Personnel
The following persons may be contacted for information.
Mars Global Surveyor Radio Science Team:
Richard A. Simpson
Durand Building - Room 232
Center for Radar Astronomy
Stanford University
Stanford, CA 94305-9515
Phone: 650-723-3525
FAX: 650-723-9251
Electronic mail: rsimpson@magellan.stanford.edu
Planetary Data System:
PDS Operator
Planetary Data System
MS 202-101
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109-8099
Phone: 818-354-4321
Electronic Mail: pds_operator@jpl.nasa.gov
Appendix A. Binary Data Format
A.1. IEEE Integer Fields
0 7 1-byte (char; uchar)
---------
| [0] |
---------
0 15 2-byte (short; ushort)
--------- ---------
| [0] | [1] |
--------- ---------
0 31 4-byte (long; ulong)
--------- --------- --------- ---------
| [0] | [1] | [2] | [3] |
--------- --------- --------- ---------
IEEE binary integers are stored in one, two, or four consecutive 8-bit
bytes. Unsigned integers uchar, ushort, ulong, which always represent
positive values, contain 8, 16, or 32 binary bits, respectively. As
illustrated above, the significance increases from the rightmost bit
to the leftmost (bit 0). Signed integers (char, short, long) are
stored in the same way, except that negative values are formed by
taking the corresponding positive value, complementing each bit, then
adding unity -- known as "two's complement" format. As a consequence,
a negative value always has bit 0 set "on". Integers are written
externally in increasing byte-number order, i.e. [0], [1], etc., so
that more significant bits always precede less significant ones. For
example, the short value -2 is stored as a pair of bytes valued 0xff,
0xfe.
A.2. IEEE Floating-Point Fields
0 1 8 9 31 4-byte (float)
--------- --------- --------- ---------
| | [0] | | [1] | [2] | [3] |
--------- --------- --------- ---------
0 1 8 9 31 8-byte (double)
--------- --------- --------- ---------
| | [0] | | [1] | [2] | [3] |
--------- --------- --------- ---------
32 63
--------- --------- --------- ---------
| [4] | [5] | [6] | [7] |
--------- --------- --------- ---------
IEEE single- (double-) precision floating point numbers (known to IEEE
enthusiasts as E-type floating-point formats, respectively) are stored
in four (eight) consecutive bytes. Bit number 0 contains a sign
indicator, S. Bits 1 through 8 (11) contain a binary exponent, E. The
significance increases from bit 8 (11) through bit 1. Bits 9 (12)
through 31 (63) contain a mantissa M, a 23-bit (52-bit) binary
fraction whose binary point lies immediately to the left of bit 9
(12). The significance increases from bit 31 (63) through bit 9 (11).
The value of the single-precision field is given by
S E-127
(-1) *2 *(1+M)
The value of the double-precision field is given by
S E-1023
(-1) *2 *(1+M)
The numbers are stored externally in increasing byte-number order,
i.e. [0], [1], etc. For example, the maximum single-precision float
value +3.40282347E+38 is stored as four bytes valued 0x7f, 0x7f, 0xff,
0xff.
Special single-precision float values are represented as +Infinity
(0x7f800000), -Infinity (0xff800000), quiet NaN (not a number)
(0xffffffff), and signaling NaN (0x7f800001).
A.3. VAX Integer Fields
0 7 1-byte (char; uchar)
---------
| [0] |
---------
0 15 2-byte (short; ushort)
--------- ---------
| [1] | [0] |
--------- ---------
0 31 4-byte (long; ulong)
--------- --------- --------- ---------
| [3] | [2] | [1] | [0] |
--------- --------- --------- ---------
VAX binary integers are stored in one, two, or four consecutive
8-bit bytes. Unsigned integers uchar, ushort, and ulong (which always
represent positive values) contain 8, 16, or 32 binary bits,
respectively. As illustrated above, the significance increases from
the rightmost bit to the leftmost (bit 0). Signed integers (char,
short, long) are stored in the same way, except that negative values
are formed by taking the corresponding positive value, complementing
each bit, then adding unity -- known as "two's complement" format. As
a consequence, a negative value always has bit 0 set or "on."
Integers are written externally in increasing byte-number order, i.e.
[0], [1], etc., so that less significant bits always precede more
significant ones. For example, the short value -2 is stored as a pair
of bytes valued 0xfe, 0xff. (This section has been adapted from a
description by P.G. Ford in the Magellan ARCDR SIS).
A.4. VAX Floating-Point Fields
0 1 8 9 31 4-byte (float)
--------- --------- --------- ---------
| | [1] | | [0] | [3] | [2] |
--------- --------- --------- ---------
0 1 8 9 31 8-byte (double)
--------- --------- --------- ---------
| | [1] | | [0] | [3] | [2] |
--------- --------- --------- ---------
32 63
--------- --------- --------- ---------
| [5] | [4] | [7] | [6] |
--------- --------- --------- ---------
VAX single- (double-) precision floating point numbers (known to
VAX enthusiasts as F-type and D-type floating-point formats,
respectively) are stored in four (eight) consecutive bytes. Bit
number 0 contains a sign indicator, S. Bits 1 through 8 contain a
binary exponent, E. The significance increases from bit 8 through bit
1. Bits 9 through 31 (63) contain a mantissa M, a 23-bit (55-bit)
binary fraction whose binary point lies immediately to the left of bit
9. The significance increases from bit 31 (63) through bit 9. The
value of the field is given by
S E-129
(-1) *2 *(1+M)
The numbers are stored externally in increasing byte-number order,
i.e. [0], [1], etc. For example, the float value +1.0 is stored as
four bytes valued 0x80, 0x40, 0x00, 0x00. (This section has been
adapted from a description by P.G. Ford in the Magellan ARCDR SIS).
Appendix B. Example SHADR Label and Data Object
B.1 Example Label
The following is an example label for a Spherical Harmonic ASCII
Data Record (SHADR). In the next section, an example data file is
shown.
PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 122
FILE_RECORDS = 65343
^SHADR_HEADER_TABLE = ("JTV36001.SHA",1)
^SHADR_COEFFICIENTS_TABLE = ("JTV36001.SHA",3)
INSTRUMENT_HOST_NAME = "MAGELLAN"
TARGET_NAME = "VENUS"
INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM"
DATA_SET_ID = "MGN-V-RDRS-5-TOPO-L2-V1.0"
OBSERVATION_TYPE = "TOPOGRAPHY FIELD"
PRODUCT_ID = "JTV36001.SHA"
PRODUCT_RELEASE_DATE = 1994-05-30
DESCRIPTION = "This file contains the mean
planetary radius of Venus and the normalized harmonic
coefficients of Venus topography. These parameters were
derived from Ford and Pettengill (JGR 97,E8,13103-13114, 1992)
Magellan topography data completed with Pioneer Venus Orbiter
topography data. The data were averaged over a rectangular
grid in latitude-longitude, with a grid spacing of one degree.
This product is a set of two ASCII tables: a header table and
a coefficients table, defined below. The Magellan Venus
topography model is known as the Spherical Harmonics Topography
ASCII Data Record (SHTADR) and is produced by the Magellan
Gravity Science Team at JPL under the direction of W.L. Sjogren
and N.J. Rappaport."
START_ORBIT_NUMBER = 376
STOP_ORBIT_NUMBER = 5747
PRODUCT_CREATION_TIME = 1994-05-19T01:02:03.456
PRODUCER_FULL_NAME = "NICOLE J. RAPPAPORT"
PRODUCER_INSTITUTION_NAME = "JET PROPULSION LABORATORY"
PRODUCT_VERSION_TYPE = "PRELIMINARY"
PRODUCER_ID = "MGN GRAVSCI TEAM"
SOFTWARE_NAME = "SHTOPO;V1.0"
OBJECT = SHADR_HEADER_TABLE
ROWS = 1
COLUMNS = 8
ROW_BYTES = 137
ROW_SUFFIX_BYTES = 107
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The SHADR header includes
descriptive information about the spherical harmonic
coefficients which follow in SHADR_COEFFICIENTS_TABLE.
The header consists of a single record of eight (delimited)
data columns requiring 137 bytes, a pad of 105 unspecified
ASCII characters, an ASCII carriage-return, and an ASCII
line-feed."
OBJECT = COLUMN
NAME = "REFERENCE RADIUS"
DATA_TYPE = ASCII_REAL
START_BYTE = 1
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "The assumed reference
radius of the spherical planet."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "CONSTANT"
DATA_TYPE = ASCII_REAL
START_BYTE = 25
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the assumed gravitational constant GM in kilometers cubed
per seconds squared for the planet. For a topography
model, set to 1."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "UNCERTAINTY IN CONSTANT"
DATA_TYPE = ASCII_REAL
START_BYTE = 49
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the uncertainty in the gravitational constant GM in kilometers
cubed per seconds squared for the planet. For a topography
model, set to 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DEGREE OF FIELD"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 73
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree of model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORDER OF FIELD"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 79
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NORMALIZATION STATE"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 85
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The normalization indicator.
For gravity field:
0 coefficients are unnormalized
1 coefficients are normalized
2 other."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 91
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "The reference longitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LATITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 115
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "The reference latitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
END_OBJECT = SHADR_HEADER_TABLE
OBJECT = SHADR_COEFFICIENTS_TABLE
ROWS = 65341
COLUMNS = 6
ROW_BYTES = 107
ROW_SUFFIX_BYTES = 15
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The SHADR coefficients table
contains the coefficients for the spherical harmonic model.
Each row in the table contains the degree index m, the
order index n, the coefficients Cmn and Smn, and the
uncertainties in Cmn and Smn. The (delimited) data
require 107 ASCII characters; these are followed by a pad
of 13 unspecified ASCII characters, an ASCII carriage-
return, and an ASCII line-feed."
OBJECT = COLUMN
NAME = "COEFFICIENT DEGREE"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The degree index m of the
C and S coefficients in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "COEFFICIENT ORDER"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 7
BYTES = 5
FORMAT = "I5"
UNIT = "N/A"
DESCRIPTION = "The order index n of the
C and S coefficients in this record."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "C"
DATA_TYPE = ASCII_REAL
START_BYTE = 13
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The coefficient Cmn
for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "S"
DATA_TYPE = ASCII_REAL
START_BYTE = 37
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The coefficient Smn
for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "C UNCERTAINTY"
DATA_TYPE = ASCII_REAL
START_BYTE = 61
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The uncertainty in the
coefficient Cmn for this spherical harmonic model."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "S UNCERTAINTY"
DATA_TYPE = ASCII_REAL
START_BYTE = 85
BYTES = 23
FORMAT = "E23.16"
UNIT = "N/A"
DESCRIPTION = "The uncertainty in the
coefficient Smn for this spherical harmonic model."
END_OBJECT = COLUMN
END_OBJECT = SHADR_COEFFICIENTS_TABLE
END
B.2 Example Data File
The example below shows the first few lines of the SHADR data
file described by the example label in Section B.1. Note that the
lines here wrap after 70 characters whereas the header record length
is 244 and the coefficient record length is 122.
.6051848044000001E+04, .1000000000000000E+01, .0000000000000000E+0
0, 360, 360, 1, .0000000000000000E+00, .0000000000000000E+00
0, 0, .1000000000000000E+01, .0000000000000000E+00, .0000000
000000000E+00, .0000000000000000E+00
1, 0, -.1057900000000000E-05, .0000000000000000E+00, .0000000
000000000E+00, .0000000000000000E+00
1, 1, -.1943900000000000E-04, .1786400000000000E-04, .0000000
000000000E+00, .0000000000000000E+00
2, 0, -.2591700000000000E-04, .0000000000000000E+00, .0000000
000000000E+00, .0000000000000000E+00
2, 1, .1448900000000000E-04, -.8545600000000000E-05, .0000000
000000000E+00, .0000000000000000E+00
2, 2, -.2161600000000000E-04, -.3303700000000000E-05, .0000000
000000000E+00, .0000000000000000E+00
3, 0, .3004700000000000E-04, .0000000000000000E+00, .0000000
000000000E+00, .0000000000000000E+00
3, 1, .4741000000000000E-04, -.7982600000000000E-05, .0000000
000000000E+00, .0000000000000000E+00
3, 2, .4419300000000000E-05, .2318000000000000E-04, .0000000
000000000E+00, .0000000000000000E+00
3, 3, -.9101800000000000E-05, -.8081800000000000E-05, .0000000
000000000E+00, .0000000000000000E+00
4, 0, .2675600000000000E-04, .0000000000000000E+00, .0000000
000000000E+00, .0000000000000000E+00