PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 80
OBJECT = TEXT
PUBLICATION_DATE = 1999-11-11
NOTE = "Software Interface Specification for
the Spherical Harmonics Binary Data
Record (SHBDR) 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 BINARY DATA RECORD (SHBDR)
prepared by
Richard A. Simpson
Packard Bldg - Room 332
Stanford University
Stanford, CA
94305-9515
Version 2.0.3
11 November 1999
PREFACE
|====================================================================|
| |
| DOCUMENT CHANGE LOG |
| |
|====================================================================|
|REVISION|REVISION| SECTION | REMARKS |
| NUMBER | DATE | AFFECTED | |
|--------+--------+------------+-------------------------------------|
| 2.0 |98/04/20| All |Adapted from SHADR SIS V2.0 |
|--------+--------+------------+-------------------------------------|
| 2.0.1 |98/12/16| 4.1.2 |Change MGS DATA_SET_ID to |
| | | | MGS-M-RSS-5-SDP-V1.0 |
|--------+--------+------------+-------------------------------------|
| 2.0.1 |98/12/16| 4.2.1 |Add optional START_TIME and STOP_TIME|
| | | Table 4-2-1| |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09| 2.3 |Swap first two characters in file |
| | | 4.2.1 | naming algorithm; generalize use of |
| | | Fig. 4-2-1 | "nnnnvv" string in file name. |
|--------+--------+------------+-------------------------------------|
| 2.0.2 |99/03/09| Fig. 4-2-1 |Corrected suffix typos in label |
|--------+--------+------------+-------------------------------------|
| 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 |
|--------+--------+------------+-------------------------------------|
| 2.0.3 |99/11/11| 4.2.2.3 |Removed non-printing ASCII character |
| | | B.1 | |
|--------+--------+------------+-------------------------------------|
| 2.0.3 |99/11/11|Distribution|Add: Guinness, Joy, Huber, Wilf |
| | | |Remove: Henderson, Oliver |
| | | |Update: Simpson, Tyler, Twicken, |
| | | | Rappaport, Priest. |
|--------+--------+------------+-------------------------------------|
| 2.0.3 |99/11/11| Cover |Update contact information for |
| | | | Simpson and PDS Operator |
|========|========|============|=====================================|
|====================================================================|
| |
| 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 rappapor@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...............264-860 trish@rodan.jpl.nasa.gov
T. Thorpe...............264-214 Thomas.E.Thorpe@jpl.nasa.gov
JPL/PDS
J. Wilf...................171-264 joel.wilf@jpl.nasa.gov
Stanford University
R. Simpson..........Packard 332 rsimpson@magellan.stanford.edu
J. Twicken..........Packard 321 joe@neptune.stanford.edu
L. Tyler............Packard 331 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
E. Guinness.....Campus Box 1169 guinness@wunder.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
UCLA
S. Joy........IGPP/6707 Geology sjoy@igpp.ucla.edu
New Mexico State University
L. Huber.........Dept Astronomy lhuber@nmsu.edu
Contents
Preface.............................................................ii
Document Change Log...............................................ii
Items to be Determined...........................................iii
Distribution......................................................iv
Contents...........................................................v
Acronyms and Abbreviations.......................................vii
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. SHBDR Header Object Definition.........................11
4.2.2.2. SHBDR Names Object Definition..........................13
4.2.2.3. SHBDR Coefficients Object Definition...................14
4.2.2.4. SHBDR Covariance Object Definition.....................15
4.3. Data File....................................................16
4.3.1. SHBDR Header Object/Block................................16
4.3.2. SHBDR Names Block........................................16
4.3.3. SHBDR Coefficients Block.................................17
4.3.4. SHBDR Covariances Block..................................17
5. Support Staff and Cognizant Personnel............................18
Appendix A. Binary Data Format.....................................19
A.1. IEEE Integer Fields..........................................19
A.2. IEEE Floating-Point Fields...................................19
A.3. VAX Integer Fields...........................................20
A.4. VAX Floating-Point Fields....................................21
Appendix B. Example Data Products..................................22
B.1. Example Label................................................22
B.2. Example Data Object..........................................26
Tables
4-3-1. SHBDR Header Block.........................................16
4-3-2. SHBDR Names Block..........................................16
4-3-3. SHBDR Coefficients Block...................................17
4-3-4. SHBDR Covariance Block.....................................17
Figures
4-2-1. SHBDR 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
RSS Radio Science Subsystem
RST Radio Science Team
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 Binary Data Record (SHBDR) files. The SHBDR 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 SHBDR is produced.
The SHBDR 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 SHBDR definition. A Spherical Harmonic ASCII 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 ASCII Data Record (SHADR), 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
SHBDR files are created at the institution conducting the
science analysis. SHBDR 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
SHBDR 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 SHBDR 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
SHBDR 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 SHBDR uses the appropriate planetocentric fixed body
coordinate system [4, 5].
1.5.4.4. Limits of This Document
This document applies only to SHBDR 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 SHBDR product must have access to the data system
(or to media) on which SHBDR files are stored.
2.1.2. Special Setup Requirements
None.
2.2. Volume and Size
SHBDR products have variable length, depending on the degree and
order of the model, the number of coefficients used, the number of
other parameters included, and the number of tables included. A
gravity model of degree and order N will have approximately N**2
coefficients and approximately N**4 covariances; for 8-byte binary
storage and N=50, the total SHBDR volume will be about 30 MB.
Vector quantities (e.g., magnetic field) may be described by a
single SHBDR (in which all components are represented) or by a
separate SHBDR for each field component. If the single SHBDR
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 is recommended over the SHADR [3] 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
SHBDR products:
GTnnnnvv.SHB
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 SHBDR
contains primary data values as specified by "T" or
uncertainties/errors, and/or the version number.
"SHB" denotes that this is an binary file of Spherical
Harmonic coefficients
Each SHBDR 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
SHBDR 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 SHBDR 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 SHBDR is a file generated by software at the institution
conducting scientific data analysis. Each SHBDR 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 to four 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 SHBDR data file. The SHBDR Header Table Object
definition is required. The SHBDR Names Object Definition is
required if there is an SHBDR Names Object in the file. The SHBDR
Coefficients Table Object definition is required if there is a
SHBDR Coefficients Table in the file; the SHBDR Covariance Table
Object definition is required if there is a SHBDR 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.
FILE_RECORDS = The number of records in the SHBDR file;
instance dependent.
^SHBDR_HEADER_TABLE= File name and record number at which
SHBDR_HEADER_TABLE begins. Set to
("GTnnnnvv.SHB",1) where "GTnnnnvv.SHB" is
the file name as described in Section 2.3,
and 1 is the record number since this is
the first record in the SHBDR file.
|====================================================================|
| |
| Figure 4-2-1 SHBDR Label Header |
| |
|====================================================================|
| |
| PDS_VERSION_ID = PDS3 |
| RECORD_TYPE = FIXED_LENGTH |
| RECORD_BYTES = nnn |
| FILE_RECORDS = nnn |
| ^SHBDR_HEADER_TABLE = ("GTnnnnvv.SHB",1) |
| ^SHBDR_NAMES_TABLE = ("GTnnnnvv.SHB",1) |
| ^SHBDR_COEFFICIENTS_TABLE = ("GTnnnnvv.SHB",nn) |
| ^SHBDR_COVARIANCE_TABLE = ("GTnnnnvv.SHB",nnn) |
| INSTRUMENT_HOST_NAME = "cccccccccccccccccccc" |
| TARGET_NAME = "cccc" |
| INSTRUMENT_NAME = "ccccccccccccccccccccccc" |
| DATA_SET_ID = "ccccccccccccccccccccccc" |
| OBSERVATION_TYPE = "ccccccccccccc" |
| ORIGINAL_PRODUCT_ID = "cccccccccccc" |
| PRODUCT_ID = "GTnnnnvv.SHB" |
| 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" |
| |
|====================================================================|
^SHBDR_NAMES_TABLE= File name and record number at which
SHBDR_NAMES_TABLE begins. The Names Table
is required if the Coefficients Table is
included in the file. This pointer will
not appear in the SHBDR label if there is
no Coefficients Table. Set to
("GTnnnnvv.SHB",nn) where "GTnnnnvv.SHB"
is the file name as described in Section
2.3, and "nn" is the record number in the
file where the Names Table begins.
^SHBDR_COEFFICIENTS_TABLE= File name and record number at which
SHBDR_COEFFICIENTS_TABLE begins. The
Coefficients Table is optional; this
pointer will not appear in the SHBDR
label if there is no Coefficients Table.
Set to ("GTnnnnvv.SHB",nn) where
"GTnnnnvv.SHB" is the file name as
described in Section 2.3, and "nn" is the
record number in the file where the
Coefficients Table begins.
^SHBDR_COVARIANCE_TABLE= File name and record number at which
SHBDR_COVARIANCE_TABLE begins. The
Covariance Table is optional; this
pointer will not appear in the SHBDR
label if there is no Covariance Table.
Set to ("GTnnnnvv.SHB",nn) where
"GTnnnnvv.SHB" 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 SHBDR files, the
character string "MARS". For Lunar
Prospector SHBDR 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
SHBDR product is a member. Set to "MGS-M-
RSS-5-SDP-Vn.m" for Mars Global Surveyor
SHBDR 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
such as ^SHBDR_HEADER_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 SHBDR product.
START_ORBIT_NUMBER = Optional. The first orbit represented in
the SHBDR product. An integer.
STOP_ORBIT_NUMBER = Optional. The last orbit represented in
the SHBDR 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 SHBDR 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 SHBDR
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 SHBDR.
Standard values include
"STANFORD UNIVERSITY"
"GODDARD SPACE FLIGHT CENTER"
"JET PROPULSION LABORATORY"
"CENTRE NATIONAL D'ETUDES SPATIALES"
PRODUCT_VERSION_TYPE= The version of this SHBDR. Standard values
include "PREDICT", "PRELIMINARY", and
"FINAL".
PRODUCER_ID = The entity responsible for creation of the
SHBDR 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 SHBDR 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 SHBDR 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 SHBDR Header Object Definition
Each SHBDR 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 SHBDR Header Object Definition
is a required part of the SHBDR label file. It immediately follows
the label header.
OBJECT = SHBDR_HEADER_TABLE
ROWS = 1
COLUMNS = 9
ROW_BYTES = 56
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Header includes
descriptive information about the spherical harmonic
coefficients which follow in SHBDR_COEFFICIENTS_TABLE.
The header consists of a single record of nine data
columns requiring 56 bytes. The Header is followed by
a pad of binary integer zeroes to ensure alignment
with RECORD_BYTES."
OBJECT = COLUMN
NAME = "REFERENCE RADIUS"
DATA_TYPE = *
START_BYTE = 1
BYTES = 8
UNIT = "KILOMETER"
DESCRIPTION = "The assumed reference
radius of the spherical planet."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "CONSTANT"
DATA_TYPE = *
START_BYTE = 9
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the 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 = *
START_BYTE = 17
BYTES = 8
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 = *
START_BYTE = 25
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Degree of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORDER OF FIELD"
DATA_TYPE = *
START_BYTE = 29
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Order of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NORMALIZATION STATE"
DATA_TYPE = *
START_BYTE = 33
BYTES = 4
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 = "NUMBER OF NAMES"
DATA_TYPE = *
START_BYTE = 37
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Number of valid names in
the SHBDR Names Table. Also, the number of valid
coefficients in the SHBDR Coefficients Table."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = *
DATA_TYPE = *
START_BYTE = 41
BYTES = 8
UNIT = "DEGREE"
DESCRIPTION = "The reference longitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LATITUDE"
DATA_TYPE = *
START_BYTE = 49
BYTES = 8
UNIT = "DEGREE"
DESCRIPTION = "The reference latitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_HEADER_TABLE
4.2.2.2 SHBDR Names Object Definition
The SHBDR Names Object is completely defined by the Names
Object Definition in the label. The definition below
illustrates general structural form. The SHBDR Names Object is an
optional part of the SHBDR file. If the Names Object is not
included, either the Names Object Definition will be omitted or the
number of rows will be set to zero (ROWS = 0). If the Names Object
is not included, the pointer ^SHBDR_NAMES_TABLE will not appear in
the Standard Keywords and Values. If the Coefficients Object is
included in the SHBDR file, the Names Object is required.
OBJECT = SHBDR_NAMES_TABLE
ROWS = *
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Names Table
contains names for the solution parameters (including
gravity field coefficients) which will follow in
SHBDR_COEFFICIENTS_TABLE. The order of the names
in SHBDR_NAMES_TABLE corresponds identically to the
order of the parameters in SHBDR_COEFFICIENTS_TABLE.
Each coefficient name is of the form Cij or Sij
where i is the degree of the coefficient and j is
the order of the coefficient. Both indices are three-
digit zero-filled right-justified ASCII character strings
(for example, C010005 for the 10th degree 5th order C
coefficient, or S002001 for the 2nd degree 1st order
S coefficient). The eighth byte in the table is an
ASCII blank used to ensure that the row length
is equal to RECORD_BYTES. Names of other solution
parameters are limited to 8 ASCII characters; if less
than 8, they will be left-justified and padded with
ASCII blanks. The Names Table itself will be padded
with ASCII blanks, if necessary, so that its length is
an integral multiple of RECORD_BYTES."
OBJECT = COLUMN
NAME = "PARAMETER NAME"
DATA_TYPE = CHARACTER
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "The name of the
coefficient or other solution parameter, left-
justified and padded with ASCII blanks (if needed)
to 8 characters."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_NAMES_TABLE
4.2.2.3 SHBDR Coefficients Object Definition
The SHBDR 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 SHBDR Coefficients Object is an optional part of the
SHBDR data file. This allows the SHBDR 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 Covariance Object is included in the
SHBDR, the Coefficients Object is required.
If the Coefficients Object is not included in the SHBDR
file, either the SHBDR Coefficients Object Definition will be
omitted or the number of rows will be set to zero (ROWS = 0).
If the SHBDR Coefficients Object is not included, the pointer
^SHBDR_COEFFICIENTS_TABLE will not appear in the label header.
If the SHBDR Coefficients Object Definition is included in the
label, it immediately follows the SHBDR Names Object Definition.
The order in which coefficients appear in the Coefficients
Object is defined by the Names Object [2].
OBJECT = SHBDR_COEFFICIENTS_TABLE
ROWS = *
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Coefficients Table
contains the coefficients and other solution parameters
for the spherical harmonic model. The order of the
coefficients in this table corresponds exactly to the
order of the coefficient and parameter names in
SHBDR_NAMES_TABLE. The SHBDR Coefficients Table will be
padded with double precision DATA_TYPE zeroes so that
its total length is an integral multiple of RECORD_BYTES."
OBJECT = COLUMN
NAME = "COEFFICIENT VALUE"
DATA_TYPE = *
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "A coefficient Cij or
Sij or other solution parameter as specified in the
SHBDR Names Table."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_COEFFICIENTS_TABLE
4.2.2.4 SHBDR Covariance Object Definition
The SHBDR 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 SHBDR Covariance Object is an optional part of the SHBDR
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 SHBDR Covariance Object is not
included, the pointer ^SHBDR_COVARIANCE_TABLE will not appear in the
label header. If the SHBDR Covariance Object Definition is included
in the label, it immediately follows the SHBDR Coefficients Object
Definition.
The order in which covariance terms appear in the Covariance
Object is defined by the Names Object [2].
OBJECT = SHBDR_COVARIANCE_TABLE
ROWS = *
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Covariance Table
contains the covariances for the spherical harmonic model
coefficients and other solution parameters. The order of
the covariances in this table is defined by the product
of the SHBDR Names Table with its transpose, except that
redundant terms are omitted on their second occurrence.
The SHBDR Covariance Table will be padded with double
precision DATA_TYPE zeroes so that its total length is
an integral multiple of RECORD_BYTES.
OBJECT = COLUMN
NAME = "COVARIANCE VALUE"
DATA_TYPE = *
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "The covariance value
for the coefficients and other solution parameters
specified by the product of SHBDR_NAMES_TABLE with
its transpose, after omitting redundant terms."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_COVARIANCE_TABLE
4.3. Data File
Each SHBDR data file comprises one or more data blocks. The
data objects were defined in Section 4.2. The data blocks are
illustrated below.
The Header Object is required in each SHBDR file; the Names
Object, the Coefficients Object, and the Covariance Object are
optional. If the Covariance Object is included, both the Coefficients
Object and the Names Object are required; if the Coefficients Object
is included, the Names Object is required.
4.3.1. SHBDR Header Object/Block
The SHBDR Header Object contains the parameters necessary to
interpret the data in the SHBDR file. The structure and content of
the SHBDR Header Object are defined in Section 4.2.2.1. The SHBDR
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.
|====================================================================|
| |
| Table 4-3-1. SHBDR Header Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------|--------|--------|--------|--------------------------------|
| 1 | +0 | 8 | double |Planetary Radius |
|--------|--------|--------|--------|--------------------------------|
| 2 | 8 | 8 | double |Constant |
|--------|--------|--------|--------|--------------------------------|
| 3 | 16 | 8 | double |Uncertainty in Constant |
|--------|--------|--------|--------|--------------------------------|
| 4 | 24 | 4 | long |Degree of Field |
|--------|--------|--------|--------|--------------------------------|
| 5 | 28 | 4 | long |Order of Field |
|--------|--------|--------|--------|--------------------------------|
| 6 | 32 | 4 | long |Normalization State |
|--------|--------|--------|--------|--------------------------------|
| 7 | 36 | 4 | long |Number of Names |
|--------|--------|--------|--------|--------------------------------|
| 8 | 40 | 8 | double |Reference Longitude |
|--------|--------|--------|--------|--------------------------------|
| 9 | 48 | 8 | double |Reference Latitude |
|--------|--------|--------|--------|--------------------------------|
| | +56 | |
|========|========|========|========|================================|
|====================================================================|
| |
| Table 4-3-2. SHBDR Names Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------|--------|--------|--------|--------------------------------|
| 1 | +0 | 8 | A8 |Coefficient or Solution |
| | | | |Parameter Name |
|--------|--------|--------|--------|--------------------------------|
| | +8 | |
|========|========|========|========|================================|
4.3.2. SHBDR Names Block
The SHBDR Names Object is comprised of one or more SHBDR Names
Blocks. Each block contains the name of one coefficient or solution
parameter in the Spherical Harmonic Model. The structure and content
of the SHBDR Names Object are defined in Section 4.2.2.2. The
structure of an individual block is shown in Table 4-3-2.
4.3.3. SHBDR Coefficients Block
The SHBDR Coefficients Object comprises one or more SHBDR
Coefficients Blocks. Each block contains the value of one
coefficient or other solution parameter for the overall model defined
by the SHBDR product. The structure and content of the SHBDR
Coefficients Object are defined in Section 4.2.2.3. The structure
of an individual block is shown in Table 4-3-3.
|====================================================================|
| |
| Table 4-3-3. SHBDR Coefficients Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------|--------|--------|--------|--------------------------------|
| 1 | +0 | 8 | double |Coefficient Cij or Sij or |
| | | | |other solution parameter |
|--------|--------|--------|--------|--------------------------------|
| | +8 | |
|========|========|========|========|================================|
4.3.4. SHBDR Covariance Block
The SHBDR Covariance Object comprises one or more SHBDR
Covariance Blocks. Each SHBDR Covariance Block contains one
covariance for the overall model defined by the SHBDR product. The
structure and content of the SHBDR Covariance Object are defined in
Section 4.2.2.4. The structure of an individual block is shown in
Table 4-3-4. The SHBDR Covariance Object is an optional component of
the SHBDR file.
|====================================================================|
| |
| Table 4-3-4. SHBDR Covariance Block |
| |
|====================================================================|
| Col No | Offset | Length | Format | Column Name |
|--------|--------|--------|--------|--------------------------------|
| 1 | +0 | 8 | double |Covariance Value |
|--------|--------|--------|--------|--------------------------------|
| | +8 | |
|========|========|========|========|================================|
5. Support Staff and Cognizant Personnel
The following persons may be contacted for information.
Mars Global Surveyor Radio Science Team:
Richard A. Simpson
Packard Building - Room 332
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 171-264
Jet Propulsion Laboratory
4800 Oak Grove Drive
Pasadena, CA 91109-8099
Phone: 626-744-5414
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 SHBDR Label and Data Object
B.1 Example Label
The following is an example Label for a Spherical Harmonic
Model (SHBDR) Coefficients File. In the next section, an example
data object is shown
PDS_VERSION_ID = PDS3
FILE_NAME = "JGNNNN01.SHB"
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 512
FILE_RECORDS = 5
^SHBDR_HEADER_TABLE = ("JGNNNN01.SHB",1)
^SHBDR_NAMES_TABLE = ("JGNNNN01.SHB",2)
^SHBDR_COEFFICIENTS_TABLE = ("JGNNNN01.SHB",3)
^SHBDR_COVARIANCE_TABLE = ("JGNNNN01.SHB",4)
INSTRUMENT_HOST_NAME = "MAGELLAN"
TARGET_NAME = "VENUS"
INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM"
DATA_SET_ID = "MGN-V-RSS-5-SHGBDR-L2-V1.0"
OBSERVATION_TYPE = "GRAVITY FIELD"
PRODUCT_ID = "JGNNNN01.SHB""
PRODUCT_RELEASE_DATE = 1993-05-15
DESCRIPTION = "This file contains coefficients
and related data for a spherical harmonic model of the Venus
gravity field. Input data are from radio tracking of the
Magellan spacecraft. This product is a set of binary tables:
a header table, a names table, a coefficients table, and an
optional covariance table. Definitions of the tables follow.
This Magellan Venus gravity model is in the form of a Spherical
Harmonics Binary Data Record (SHBDR). It has been produced by
the Magellan Gravity Science Team at JPL under the direction of
W.L. Sjogren."
START_ORBIT_NUMBER = 4830
STOP_ORBIT_NUMBER = 4831
PRODUCT_CREATION_TIME = 1993-01-15T12:43:55.129
PRODUCER_FULL_NAME = "JODY MARSHALL"
PRODUCER_INSTITUTION_NAME = "JET PROPULSION LABORATORY"
PRODUCT_VERSION_TYPE = "PRELIMINARY"
PRODUCER_ID = "MGN GRAVSCI TEAM"
SOFTWARE_NAME = "SHGJ;V4.57"
OBJECT = SHBDR_HEADER_TABLE
ROWS = 1
COLUMNS = 9
ROW_BYTES = 56
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Header includes
descriptive information about the spherical harmonic
coefficients which follow in SHBDR_COEFFICIENTS_TABLE.
The header consists of a single record of nine data
columns requiring 56 bytes. The Header is followed by
a pad of binary integer zeroes to ensure alignment
with RECORD_BYTES."
OBJECT = COLUMN
NAME = "REFERENCE RADIUS"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 1
BYTES = 8
UNIT = "KILOMETER"
DESCRIPTION = "The assumed reference
radius of the spherical planet."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "CONSTANT"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 9
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "For a gravity field model
the 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 = IEEE_DOUBLE
START_BYTE = 17
BYTES = 8
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 = IEEE_INTEGER
START_BYTE = 25
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Degree of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORDER OF FIELD"
DATA_TYPE = IEEE_INTEGER
START_BYTE = 29
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Order of the model field."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NORMALIZATION STATE"
DATA_TYPE = IEEE_INTEGER
START_BYTE = 33
BYTES = 4
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 = "NUMBER OF NAMES"
DATA_TYPE = IEEE_INTEGER
START_BYTE = 37
BYTES = 4
UNIT = "N/A"
DESCRIPTION = "Number of valid names in
the SHBDR Names Table. Also, the number of valid
coefficients in the SHBDR Coefficients Table."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 41
BYTES = 8
UNIT = "DEGREE"
DESCRIPTION = "The reference longitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFERENCE LATITUDE"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 49
BYTES = 8
UNIT = "DEGREE"
DESCRIPTION = "The reference latitude for
the spherical harmonic expansion; normally 0."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_HEADER_TABLE
OBJECT = SHBDR_NAMES_TABLE
ROWS = 13
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Names Table
contains names for the solution parameters (including
gravity field coefficients) which will follow in
SHBDR_COEFFICIENTS_TABLE. The order of the names
in SHBDR_NAMES_TABLE corresponds identically to the
order of the parameters in SHBDR_COEFFICIENTS_TABLE.
Each coefficient name is of the form Cij or Sij
where i is the degree of the coefficient and j is
the order of the coefficient. Both indices are three-
digit zero-filled right-justified ASCII character strings
(for example, C010005 for the 10th degree 5th order C
coefficient, or S002001 for the 2nd degree 1st order
S coefficient). The eighth byte in the table is an
ASCII blank used to ensure that the row length
is equal to RECORD_BYTES. Names of other solution
parameters are limited to 8 ASCII characters; if less
than 8, they will be left-justified and padded with
ASCII blanks. The Names Table itself will be padded
with ASCII blanks, if necessary, so that its length is
an integral multiple of RECORD_BYTES."
OBJECT = COLUMN
NAME = "PARAMETER NAME"
DATA_TYPE = CHARACTER
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "The name of the
coefficient or other solution parameter, left-
justified and padded with ASCII blanks (if needed)
to 8 characters."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_NAMES_TABLE
OBJECT = SHBDR_COEFFICIENTS_TABLE
ROWS = 13
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Coefficients Table
contains the coefficients and other solution parameters
for the spherical harmonic model. The order of the
coefficients in this table corresponds exactly to the
order of the coefficient and parameter names in
SHBDR_NAMES_TABLE. The SHBDR Coefficients Table will be
padded with double precision DATA_TYPE zeroes so that
its total length is an integral multiple of RECORD_BYTES."
OBJECT = COLUMN
NAME = "COEFFICIENT VALUE"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "A coefficient Cij or
Sij or other solution parameter as specified in the
SHBDR Names Table."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_COEFFICIENTS_TABLE
OBJECT = SHBDR_COVARIANCE_TABLE
ROWS = 91
COLUMNS = 1
ROW_BYTES = 8
INTERCHANGE_FORMAT = BINARY
DESCRIPTION = "The SHBDR Covariance Table
contains the covariances for the spherical harmonic model
coefficients and other solution parameters. The order of
the covariances in this table is defined by the product
of the SHBDR Names Table with its transpose, except that
redundant terms are omitted on their second occurrence.
The SHBDR Covariance Table will be padded with double
precision DATA_TYPE zeroes so that its total length is
an integral multiple of RECORD_BYTES.
OBJECT = COLUMN
NAME = "COVARIANCE VALUE"
DATA_TYPE = IEEE_DOUBLE
START_BYTE = 1
BYTES = 8
UNIT = "N/A"
DESCRIPTION = "The covariance value
for the coefficients and other solution parameters
specified by the product of SHBDR_NAMES_TABLE with
its transpose, after omitting redundant terms."
END_OBJECT = COLUMN
END_OBJECT = SHBDR_COVARIANCE_TABLE
END
B.2 Example Data Object
An example SHBDR data object corresponding to the label example
in Section B.1 is shown in hexadecimal format below. Binary floating-
point and integer values are represented using IEEE conventions.
0000000 40b7 a300 0000 0000 4113 d3ea 6666 6666
0000020 3ff0 0000 0000 0000 0000 0003 0000 0003
0000040 0000 0000 0000 000d 4066 8000 0000 0000
0000060 0000 0000 0000 0000 0000 0000 0000 0000
*
0001000 4330 3032 3030 3020 4330 3032 3030 3120
0001020 4330 3032 3030 3220 4330 3033 3030 3020
0001040 4330 3033 3030 3120 4330 3033 3030 3220
0001060 4330 3033 3030 3320 5330 3032 3030 3120
0001100 5330 3032 3030 3220 5330 3033 3030 3120
0001120 5330 3033 3030 3220 5330 3033 3030 3320
0001140 474d 2020 2020 2020 2020 2020 2020 2020
0001160 2020 2020 2020 2020 2020 2020 2020 2020
*
0002000 3ff0 0000 0000 0000 4000 0000 0000 0000
0002020 4008 0000 0000 0000 4010 0000 0000 0000
0002040 4014 0000 0000 0000 4018 0000 0000 0000
0002060 401c 0000 0000 0000 4020 0000 0000 0000
0002100 4022 0000 0000 0000 4024 0000 0000 0000
0002120 4026 0000 0000 0000 4028 0000 0000 0000
0002140 402a 0000 0000 0000 0000 0000 0000 0000
0002160 0000 0000 0000 0000 0000 0000 0000 0000
*
0003000 3ff0 0000 0000 0000 4000 0000 0000 0000
0003020 4008 0000 0000 0000 4010 0000 0000 0000
0003040 4014 0000 0000 0000 4018 0000 0000 0000
0003060 401c 0000 0000 0000 4020 0000 0000 0000
0003100 4022 0000 0000 0000 4024 0000 0000 0000
0003120 4026 0000 0000 0000 4028 0000 0000 0000
0003140 402a 0000 0000 0000 402c 0000 0000 0000
0003160 402e 0000 0000 0000 4030 0000 0000 0000
0003200 4031 0000 0000 0000 4032 0000 0000 0000
0003220 4033 0000 0000 0000 4034 0000 0000 0000
0003240 4035 0000 0000 0000 4036 0000 0000 0000
0003260 4037 0000 0000 0000 4038 0000 0000 0000
0003300 4039 0000 0000 0000 403a 0000 0000 0000
0003320 403b 0000 0000 0000 403c 0000 0000 0000
0003340 403d 0000 0000 0000 403e 0000 0000 0000
0003360 403f 0000 0000 0000 4040 0000 0000 0000
0003400 4040 8000 0000 0000 4041 0000 0000 0000
0003420 4041 8000 0000 0000 4042 0000 0000 0000
0003440 4042 8000 0000 0000 4043 0000 0000 0000
0003460 4043 8000 0000 0000 4044 0000 0000 0000
0003500 4044 8000 0000 0000 4045 0000 0000 0000
0003520 4045 8000 0000 0000 4046 0000 0000 0000
0003540 4046 8000 0000 0000 4047 0000 0000 0000
0003560 4047 8000 0000 0000 4048 0000 0000 0000
0003600 4048 8000 0000 0000 4049 0000 0000 0000
0003620 4049 8000 0000 0000 404a 0000 0000 0000
0003640 404a 8000 0000 0000 404b 0000 0000 0000
0003660 404b 8000 0000 0000 404c 0000 0000 0000
0003700 404c 8000 0000 0000 404d 0000 0000 0000
0003720 404d 8000 0000 0000 404e 0000 0000 0000
0003740 404e 8000 0000 0000 404f 0000 0000 0000
0003760 404f 8000 0000 0000 4050 0000 0000 0000
0004000 4050 4000 0000 0000 4050 8000 0000 0000
0004020 4050 c000 0000 0000 4051 0000 0000 0000
0004040 4051 4000 0000 0000 4051 8000 0000 0000
0004060 4051 c000 0000 0000 4052 0000 0000 0000
0004100 4052 4000 0000 0000 4052 8000 0000 0000
0004120 4052 c000 0000 0000 4053 0000 0000 0000
0004140 4053 4000 0000 0000 4053 8000 0000 0000
0004160 4053 c000 0000 0000 4054 0000 0000 0000
0004200 4054 4000 0000 0000 4054 8000 0000 0000
0004220 4054 c000 0000 0000 4055 0000 0000 0000
0004240 4055 4000 0000 0000 4055 8000 0000 0000
0004260 4055 c000 0000 0000 4056 0000 0000 0000
0004300 4056 4000 0000 0000 4056 8000 0000 0000
0004320 4056 c000 0000 0000 0000 0000 0000 0000
0004340 0000 0000 0000 0000 0000 0000 0000 0000
*
0005000