PDS_VERSION_ID = PDS3
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 80
OBJECT = TEXT
PUBLICATION_DATE = 1999-11-11
NOTE = "Software Interface Specification for
the Line of Sight Acceleration Profile
Data Record (LOSAPDR). Formatted for
display or printing at 58 lines per
page with up to 78 constant width
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END_OBJECT = TEXT
END
SOFTWARE INTERFACE SPECIFICATION
LINE OF SIGHT ACCELERATION PROFILE DATA RECORD
prepared by
Richard A. Simpson
Packard Bldg -- Room 332
Stanford University
Stanford, CA
94305-9515
Version 2.0.1
11 November 1999
PREFACE
|============================================================================|
| |
| DOCUMENT CHANGE LOG |
| |
|============================================================================|
|REVISION|REVISION| SECTION | REMARKS |
| NUMBER | DATE | AFFECTED | |
|--------+--------+------------+---------------------------------------------|
| 2.0 |99/06/11| All |Adapted from LOSAPDR SIS V1.13.2, which was |
| | | | written for Magellan and Mars Observer. |
| | | | V2.0 focuses on Mars Global Surveyor and |
| | | | Lunar Prospector. The document itself is |
| | | | significantly streamlined; details of the |
| | | | product definition are in the PDS label. |
| | | | The LOSAPDR itself has not changed much. |
| | | | There is a new file naming convention, there|
| | | | are detached rather than attached labels, |
| | | | and keywords FILE_NAME and LABEL_RECORDS |
| | | | have been dropped from the label. The |
| | | | structure of the data file is identical to |
| | | | the structure used for Magellan data. |
|--------+--------+------------+---------------------------------------------|
| 2.0.1 |99/11/11| 1.4.5 |Removed non-printing ASCII character |
|--------+--------+------------+---------------------------------------------|
| 2.0.1 |99/11/11| Cover |Updated address for Simpson |
|--------+--------+------------+---------------------------------------------|
| 2.0.1 |99/11/11|Distribution|Added: D.-N. Yuan, J. Wilf, S. Joy, L. Huber,|
| | | | and E.Guinness |
| | | |Removed: V. Henderson, R.J. Phillips |
| | | |Update: Arvidson, Rappaport |
|========|========|============|=============================================|
|============================================================================|
| |
| ITEMS TO BE DETERMINED |
| |
|============================================================================|
| REVISION | SECTION | ITEM DESCRIPTION | RESOLUTION |
| NUMBER | AFFECTED | | |
|----------+----------+--------------------------------+---------------------|
| | | | |
|==========|==========|================================|=====================|
DISTRIBUTION
JPL/Gravity
-----------
W. Sjogren..............301-150G wls@kamel.jpl.nasa.gov
A. Konopliv.............301-130G ask@krait.jpl.nasa.gov
T.C. Wang...............301-275R tcw@zeus.jpl.nasa.gov
R. Wimberly.............301-155N wimberly@pop.jpl.nasa.gov
N. Rappaport............301-280 rappapor@pop.jpl.nasa.gov
D.-N. Yuan..............301-125J dny@krait.jpl.nasa.gov
JPL/Mars Global Surveyor
------------------------
T. Thorpe............JPL 264-214 tthorpe@jpl.nasa.gov
R. Springer..........JPL 264-214 rspringe@pop.jpl.nasa.gov
Washington University
---------------------
R.E. Arvidson.....Earth/Plan Sci arvidson@wunder.wustl.edu
E. Guinness.......Earth/Plan Sci guinness@wunder.wustl.edu
J. Alexopoulos....Earth/Plan Sci jim@wuzzy.wustl.edu
Mars Global Surveyor Radio Science
----------------------------------
G.L. Tyler..............Stanford len@nova.stanford.edu
D.E. Smith.........GSFC Code 920 dsmith@tharsis.gsfc.nasa.gov
G. Balmino..................CNES gbalmino@pontos.cnes.fr
P. Priest............JPL 264-860 trish@rodan.jpl.nasa.gov
New Mexico State University
---------------------------
L. Huber..........Dept Astronomy lhuber@nmsu.edu
UCLA
----
S. Joy.........IGPP/6707 Geology sjoy@igpp.ucla.edu
PDS
-------
J. Wilf..............JPL 171-264 joel.wilf@jpl.nasa.gov
CONTENTS
Preface
Document Change Log
Items to be Determined
Distribution
Contents
Acronyms and Abbreviations
1. General Description
1.1. Overview
1.2. Scope
1.3. Applicable Documents
1.4. Functional Description
1.4.1. Interface Location and Medium
1.4.2. Data Sources, Transfer Methods, and Destinations
1.4.3. Generation Method and Frequency
1.4.4. Pertinent Relationships with Other Interfaces
1.4.5. Labeling and Identification
1.5. Assumptions and Constraints
1.5.1. Usage Constraints
1.5.2. Priority Phasing Constraints
1.5.3. Explicit and Derived Constraints
1.5.4. Documentation Conventions
1.5.4.1. Data Format Descriptions
1.5.4.2. Time Standards
1.5.4.3. Coordinate Systems
1.5.4.4. Limits of This Document
1.5.4.5. Typographic Conventions
2. Interface Characteristics
2.1. Hardware Characteristics and Limitations
2.1.1. Special Equipment and Device Interfaces
2.1.2. Special Setup Requirements
2.2. Volume and Size
2.3. Interface Medium Characteristics
2.4. Failure Protection, Detection, and Recovery Procedures
2.5. End-of-File Conventions
2.6. End-of-Volume Conventions
3. Access
3.1. Programs Using the Interface
3.2. Synchronization Considerations
3.2.1. Timing and Sequencing Considerations
3.2.2. Effective Duration
3.2.3. Priority Interrupts
3.3. Input/Output Protocols, Calling Sequences
4. Detailed Interface Specifications
4.1. Structure and Organization Overview
4.2. PDS Label
4.2.1. Keyword-Value Pairs
4.2.2. Object Definitions
4.3. Data File
4.3.1. Header Object
4.3.2. Times Object
4.3.3. Results Object
Appendix A. LOSAPDR Processing Summary
Appendix B. Example Label and Data Object
B.1. Example Label
B.2. Example Data File
Tables
A-1. Definition of Terms for Processing
Figures
4-2. PDS Label Structure
4-3. Keyword-Value Pairs
A-1. Spacecraft and Target Geometry
A-2. Spline Fit
ACRONYMS AND ABBREVIATIONS
ASCII American Standard Code for Information Interchange
CR Carriage Return
FTP File Transfer Protocol
hr hour
Hz Hertz
int integer
JPL Jet Propulsion Laboratory
km Kilometers
LF Line Feed
LOSAPDR Line of Sight Acceleration Profile Data Record
LUNRES Gravity analysis program
MGS Mars Global Surveyor
min minutes
mm millimeters
PDS Planetary Data System
RS Radio Science
SCET Space Craft Event Time
sec seconds
SIS Software Interface Specification
TBD To Be Determined
z.f.r.j. zero-filled, right-justified
1. General Description
1.1. Overview
This Software Interface Specification (SIS) describes the Gravity
Science Line of Sight Acceleration Profile Data Record (LOSAPDR) produced
for flight projects such as Lunar Prospector (LP) and Mars Global Surveyor
(MGS) at the Jet Propulsion Laboratory (JPL) and delivered to the Planetary
Data System (PDS).
LOSAPDR files contain results from processing radio tracking data
using program LUNRES. Splines are fitted to Doppler residual values
resulting from spacecraft orbit solutions. The spline results are then
interpreted as local accelerations, from which the size and location of
mass anomalies within the target body can be inferred. A summary of the
processing which leads to the LOSAPDR is given in Appendix A.
Each LOSAPDR is accompanied by a full PDS label which completely
describes its content and format. LOSAPDR files adhere to standards set
by the PDS [1,2].
1.2. Scope
The format and content specifications in this SIS apply to all phases
of the project for which the LOSAPDR is produced.
1.3. Applicable Documents
[1] Planetary Data System Standards Reference, Jet Propulsion Laboratory
Document D-7669, Part 2, Version 3.2, Pasadena, CA, 24 July 1995.
[2] Planetary Science Data Dictionary Document, Pasadena: Jet Propulsion
Laboratory Document D-7116, Rev. D, Pasadena, CA, 15 July 1996.
1.4. Subsystem Siting
1.4.1. Interface Location and Medium
The LOSAPDR product is an electronic file on computer systems at
the Jet Propulsion Laboratory.
1.4.2. Data Sources, Transfer Methods, and Destinations
LOSAPDR files are created by program LUNRES running on a computer
system at JPL. Input data include Orbit Data Files containing radio
tracking data from the Deep Space Network. LOSAPDR files are delivered
electronically to work stations of the parent flight project and/or to
workstations of the Planetary Data System (PDS).
Although the LOSAPDR is an ASCII file, machine to machine electronic
transfers using the FTP utility should be carried out using FTP in binary
mode. This will preserve the carriage-return line-feed record delimiters
and ensure that file lengths are preserved. Note that some machines may
need to modify the carriage-return line-feed structure after receiving the
files and before using local utilities or application programs.
1.4.3. Generation Method and Frequency
LOSAPDR files are created by program LUNRES. Each LOSAPDR contains
data from one spacecraft orbit. LOSAPDRs are generated when the data for
the appropriate orbits become available.
1.4.4. Pertinent Relationships with Other Interfaces
None.
1.4.5. Labeling and Identification
Names for LOSAPDR files have the form
MPnnnnnV.LOS
where "M" indicates the mission
"L" for Lunar Prospector or
"M" for Mars Global Surveyor;
"P" denotes the mission phase
"N" for Lunar Prospector nominal mission,
"X" for Lunar Prospector extended mission,
"O" for MGS orbit insertion, or
"M" for MGS mapping;
"nnnnn" is a five-digit zero-filled, right-justified (z.f.r.j.) orbit
number; and
"V" is the target body gravity field model identifier (e.g., "J" for
many Lunar Prospector extended mission orbits).
It is assumed that there will be only one LOSAPDR file for each gravity model,
though improvements in the computational algorithm may result in a newer
version of the file occasionally superseding an older one.
Internal labeling of LOSAPDR files is accomplished with keywords
and values as described in Section 4.2.1.
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 LOSAPDR is a text file using ASCII character definitions.
All double precision numbers (real) are represented using FORTRAN
1P1E23.16 format statements. Integers (int) are represented using FORTRAN
I2 and I10 format statements.
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.
1.5.4.2. Time Standards
Within LOSAPDR files, times are expressed as a string of 23 ASCII
characters
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 in milliseconds. The data type "TIME" is assigned to
this format.
When only the date is required the 10-character string
YYYY-MM-DD
may be substituted. The data type "DATE" is assigned to this format.
Spacecraft times given in the form above are Spacecraft Event Times
(SCET) in ephemeris time. Ground times, such as local processing time,
indicate local time (Pacific Standard Time or Pacific Daylight Time, as
appropriate).
1.5.4.3. Coordinate Systems
Each LOSAPDR uses a single ad hoc inertial coordinate system, defined
uniquely for that set of observations. At the reference time CALENDAR EPOCH
(CEPOCH; see Appendix A and Appendix B.1) an inertial frame is defined by the
instantaneous target-fixed frame [1,2]. All positions and velocities are
then expressed with reference to that frame. Latitudes and longitudes, for
example, are effectively specified with respect to the meridian and equator
of the target-fixed frame at CEPOCH (see Appendix A).
1.5.4.4. Limits of This Document
This document applies only to the LOSAPDR product.
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 length 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
The LOSAPDR ASCII files are created on a JPL computer system and are
delivered over networks to destination workstations and databases, as
appropriate. Users of the LOSAPDR must have access to these destination
facilities or to backup or archival media on which these files have been
stored.
2.1.2. Special Setup Requirements
None.
2.2. Volume and Size
The LOSAPDR data for each spacecraft orbit consist of one file, as
detailed in Section 4. File sizes vary, but a typical file contains 150
kilobytes.
2.3. Interface Medium Characteristics
LOSAPDR files are electronic files.
2.4. Failure Protection, Detection, and Recovery Procedures
None.
2.5. End-of-File Conventions
End of file labeling complies with destination workstation or database
standards.
2.6. End-of-Volume Conventions
End of volume labeling complies with destination workstation or
database standards.
3. Access
3.1. Programs Using the Interface
Data contained in an LOSAPDR will be accessed by programs at the home
institutions of science and other 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 LOSAPDR is an ASCII file generated by the LUNRES Gravity Science
software. It has a file name of the form described in Section 1.4.5. Each
LOSADPR comprises three tables: a Header Table, a Times Table, and a Results
Table. Each file is accompanied by a PDS label which fully describes both
the content and format of the LOSAPDR [1]. The label is an ASCII file in
its own right with the same name as the data file except for the extension
"LBL".
4.2. PDS Label
The PDS Label includes two components: a section of standard
keyword=value entries, and a section of object definitions. The general
structure is shown in Figure 4-2. An example label is shown in Appendix B.1.
Although not shown here and in Appendix B.1, each line in the Standard
Keyword and Value section and each line in the Object Definition sections is
terminated by both the ASCII carriage return (hex 0D) and the ASCII line feed
(hex 0A) characters.
|====================================================================|
| |
| Figure 4-2. PDS Label Structure |
| |
|====================================================================|
| PDS_VERSION_ID = PDS3 | |
| RECORD_TYPE = FIXED_LENGTH | Standard |
| FILE_RECORDS = nnn | Keywords |
| RECORD_BYTES = nnn | and |
| ... | Labels |
| PRODUCT_RELEASE_DATE = YYYY-MM-DD | |
| | |
| OBJECT = LOSAPDR_HEADER_TABLE | Header |
| ... | Object |
| END_OBJECT = LOSAPDR_HEADER_TABLE | Definition |
| | |
| OBJECT = LOSAPDR_TIMES_TABLE | Times |
| ... | Object |
| END_OBJECT = LOSAPDR_TIMES_TABLE | Definition |
| | |
| OBJECT = LOSAPDR_RESULTS_TABLE | Results |
| ... | Object |
| END_OBJECT = LOSAPDR_TABLE | Definition |
|=====================================================|==============|
4.2.1. Keyword-Value Pairs
Keywords-value pairs are shown in Figure 4-3 and are defined in the text
which follows [2]. Note that entries beginning with "^" are pointers to data
objects (tables) in the LOSAPDR data file. Each line in Figure 4-3 ends with
an ASCII carriage-return line-feed pair, which is not shown.
|====================================================================|
| |
| Figure 4-3. Keyword-Value Pairs |
| |
|====================================================================|
| PDS_VERSION_ID = PDS3 | |
| RECORD_TYPE = FIXED_LENGTH | |
| RECORD_BYTES = 202 | |
| FILE_RECORDS = nnn | |
| ^LOSAPDR_HEADER_TABLE = ("MPnnnnnV.LOS",nnn) | |
| ^LOSAPDR_TIMES_TABLE = ("MPnnnnnV.LOS",nnn) | |
| ^LOSAPDR_RESULTS_TABLE = ("MPnnnnnV.LOS",nnn) | |
| INSTRUMENT_HOST_NAME = "ccccccc" | |
| TARGET_NAME = "cccccccc" | Standard |
| INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM" | Keywords |
| DATA_SET_ID = "ccccccccccccccc" | and |
| PRODUCT_ID = "MPnnnnnV.LOS" | Values |
| DESCRIPTION = "ccccc" | |
| SOFTWARE_NAME = "LUNRES;n.mm" | |
| START_TIME = YYYY-MM-DDThh:mm:ss.fff | |
| STOP_TIME = YYYY-MM-DDThh:mm:ss.fff | |
| SPACECRAFT_CLOCK_START_COUNT = "N/A" | |
| SPACECRAFT_CLOCK_STOP_COUNT = "N/A" | |
| PRODUCER_ID = "cccccccccc" | |
| PRODUCT_CREATION_TIME = YYYY-MM-DDThh:mm:ss.fff | |
| PRODUCT_RELEASE_DATE = YYYY-MM-DD | |
|=======================================================|============|
PDS_VERSION_ID The version of the Planetary Data System for which
these data have been prepared (by agreement between
the flight project and PDS, set to PDS3).
RECORD_TYPE The record format for the file (set to
"FIXED_LENGTH").
RECORD_BYTES An integer number nnn giving the number of bytes
per logical record throughout the file. The product
of the number of records (FILE_RECORDS) and the number
of bytes per record (RECORD_BYTES) is the size of the
file in bytes. For the LOSAPDR, set to 202, which is
the intrinsic length of records in the Results Object.
FILE_RECORDS An integer number nnn giving the total number of
records in the file. The multiplicative product of
the number of records (FILE_RECORDS) and the number
of bytes per record (RECORD_BYTES) is the size of the
file in bytes.
^LOSAPDR_HEADER_TABLE Pointer to the start of the LOSAPDR Header Object.
"MPnnnnnV.LOS" is the PRODUCT_ID, described below.
The integer nnn gives the starting record number for
the Header Object in the data file. Record numbering
within the file starts from record 1, incrementing
once for each subsequent record of length
RECORD_BYTES. This pointer is set to "1".
^LOSAPDR_TIMES_TABLE Pointer to the start of the LOSAPDR Times Object.
"MPnnnnnV.LOS" is the PRODUCT_ID, described below.
The integer nnn gives the starting record number
for the (spline interval) Times Object in the LOSAPDR
data file. Record numbering within the file starts
from record 1, incrementing once for each subsequent
record of length RECORD_BYTES. This pointer is set
to "7".
^LOSAPDR_RESULTS_TABLE Pointer to the start of the LOSAPDR Results Object.
"MPnnnnnV.LOS" is the PRODUCT_ID, described below.
The integer nnn gives the starting record number
for the Results Object in the data file. Record
numbering within the file starts from record 1,
incrementing once for each subsequent record of
length RECORD_BYTES.
INSTRUMENT_HOST_NAME A character string which identifies the spacecraft.
Acceptable values include "LUNAR PROSPECTOR" and
"MARS GLOBAL SURVEYOR".
TARGET_NAME A character string which identifies the target body.
Acceptable values include "MOON" and "MARS".
INSTRUMENT_NAME The character string "RADIO SCIENCE SUBSYSTEM".
DATA_SET_ID The data set identification as defined by the
Planetary Data System. Acceptable values include
"LP-L-RSS-5-LOS-V1.0" for Lunar Prospector
and "MGS-M-RSS-5-SDP-V1.0" for Mars Global
Surveyor.
PRODUCT_ID A character string of the form "MPnnnnnV.LOS"
where the components are defined in Section 1.4.5.
DESCRIPTION A character string "cccc" containing a brief
description of the data product.
SOFTWARE_NAME The character string "LUNRES;n.mm" where
"LUNRES" is the generating program and
"n.mm" denotes the version of that program
used to create the data file.
START_TIME A character string indicating the SCET of the
first tracking data point, in the format YYYY-
MM-DDThh:mm:ss.fff (see Section 1.5.4.2)
STOP_TIME A character string indicating the SCET of the
last tracking data point, in the format YYYY-
MM-DDThh:mm:ss.fff (see Section 1.5.4.2)
SPACECRAFT_CLOCK_START_COUNT
The character string "N/A"
SPACECRAFT_CLOCK_STOP_COUNT
The character string "N/A"
PRODUCER_ID A character string which identifies the group
producing the file. For Lunar Prospector, the
character string "LP GRAVSCI TEAM"; for Mars
Global Surveyor, the character string "MGS
GRAVSCI TEAM".
PRODUCT_CREATION_TIME A character string indicating the date and time at
which the file was created [in the format YYYY-MM-
DDThh:mm:ss.fff (see Section 1.5.4.2)]
PRODUCT_RELEASE_DATE A character string indicating the date at which the
file was released to the Planetary Data System [in
the format YYYY-MM-DD (see Section 1.5.4.2)]
4.2.2. Object Definitions
Object Definitions are series of statement groups of the form
OBJECT = OBJECT_NAME
ATTRIBUTE_1 = ATTRIBUTE_1_VALUE
ATTRIBUTE_2 = ATTRIBUTE_2_VALUE
...
ATTRIBUTE_N = ATTRIBUTE_N_VALUE
END_OBJECT = OBJECT_NAME
where each indented line specifies an attribute of the object (its size, line
length, etc.). Attributes can themselves be object definitions, allowing
nesting within the definition statement. For example, a primary Object
Definition may specify a table; nested Object Definitions can be used to
specify each of the columns within the table.
Data Objects within the LOSAPDR are the Header Object, the Times Object,
and the Results Object. Each contains data in tabular form. Each Object
Definition first defines the table itself; nested subsidiary Object
Definitions are used to define each of the table columns.
4.3. Data File
The data file includes three objects, each defined in part of the
accompanying PDS label.
4.3.1. Header Object
The Header Object is a single-row multi-column table containing
information on initial values, control parameters, and simple calculations
required by the generating program LUNRES. The Header Object is completely
defined by the Header Object Definition in the PDS label.
Column entries in the table are separated by ASCII commas (hex 2D).
The total length of the header table must be an integral multiple of 202 bytes
(the record length for the data blocks). A pad of 180 ASCII blank characters
fills out the last record. An ASCII carriage return (hex 0D) and an ASCII
line feed (hex 0A) follow the pad. The total length of the header table is
thus 1212 characters -- exactly six times the value of RECORD_BYTES.
4.3.2. Times Object
The Times Object is a table containing exact times bounding spline
intervals. Each row in the table has RECORD_BYTES=202 bytes; the number of
rows is given by NBKS (in the Header Object) and may be variable. Although
not shown here, each line in the Times Object Definition is terminated by
both the ASCII carriage return (hex 0D) and the ASCII line feed (hex 0A)
characters.
The table is a single column containing 23-character ASCII
representations of double precision numbers. It is described completely by
the Times Object Definition in the PDS label. Each row in the table is padded
with 177 ASCII blanks followed by an ASCII carriage return (hex 0D) and an
ASCII line feed (hex 0A) -- a total of RECORD_BYTES=202 characters.
4.3.3. Results Object
The Results Object is a table containing results from spline fits
to Doppler tracking residuals. It is completely described by the Results
Object Definition below. Although not shown here, each line in the Results
Object Definition is terminated by both the ASCII carriage return (hex 0D)
and the ASCII line feed (hex 0A) characters.
The table has eleven columns; its length is variable -- that is,
it has a variable number of rows. Column entries are separated by ASCII
commas (hex 2D).
Appendix A - LOSAPDR Processing Summary
Tracking data (Orbit Data Files) are used to obtain an orbit solution
for the spacecraft expressed in Keplerian elements and derived quantities
|============================================================================|
| |
| Table A-1 Definition of Terms for Processing |
| |
|============================================================================|
| LISTED QUANTITY | PROGRAM | DESCRIPTION |
| | MNEMONIC| |
|-------------------------+---------+----------------------------------------|
|ORBITAL SEMIMAJOR AXIS | SMA |Semi-major axis of spacecraft orbit (km)|
|-------------------------+---------+----------------------------------------|
|ORBITAL ECCENTRICITY | ECC |Eccentricity of spacecraft orbit |
|-------------------------+---------+----------------------------------------|
|ORBITAL INCLINATION | INC |Inclination of spacecraft orbit (deg) |
|-------------------------+---------+----------------------------------------|
|ASCENDING NODE LONGITUDE | NODE |Ascending node of spacecraft orbit (deg)|
|-------------------------+---------+----------------------------------------|
|PERIAPSIS ARGUMENT ANGLE | ARG |Argument of periapsis for spacecraft |
| | | orbit (deg)|
|-------------------------+---------+----------------------------------------|
|TRUE ANOMALY ANGLE | F |True anomaly of spacecraft orbit (deg) |
|-------------------------+---------+----------------------------------------|
|MEAN ANOMALY ANGLE | M |Mean anomaly of spacecraft orbit (deg) |
|-------------------------+---------+----------------------------------------|
|ECCENTRIC ANOMALY ANGLE | E |Eccentric anomaly of spacecraft orbit |
| | | (deg)|
|-------------------------+---------+----------------------------------------|
|ORBITAL PERIOD | P |Period of spacecraft orbit (hrs) |
|-------------------------+---------+----------------------------------------|
|PERIAPSIS LATITUDE | LATPER |Latitude of periapsis from target |
| | | (deg N)|
|-------------------------+---------+----------------------------------------|
|PERIAPSIS LONGITUDE | LONPER |Longitude of periapsis from target (deg)|
|-------------------------+---------+----------------------------------------|
|PERIAPSIS RADIUS | RPER |Spacecraft distance from C/M at |
| | | periapsis (km)|
|-------------------------+---------+----------------------------------------|
|PERIAPSIS VELOCITY | VPER |Spacecraft velocity at periapsis (km/s) |
|-------------------------+---------+----------------------------------------|
|PERIAPSIS ALTITUDE | APER |Altitude of S/C over reference surface |
| | | at periapsis (km)|
|-------------------------+---------+----------------------------------------|
|APOAPSIS RADIUS | RAPO |Spacecraft distance from C/M at apoapsis|
| | | (km)|
|-------------------------+---------+----------------------------------------|
|APOAPSIS VELOCITY | VAPO |Spacecraft velocity at apoapsis (km/s) |
|-------------------------+---------+----------------------------------------|
|APOAPSIS ALTITUDE | AAPO |Altitude of S/C over referenced surface |
| | | at apoapsis (km)|
|=========================|=========|========================================|
TADD . .
\ .
. .
. /
. P, V, CEPOCH .
. ooooooo target .
. ooooooooooo / .
. ooooooooooooo .
. ooooooooooooo ^
. ooooooooooooo .
. ooooooooooo .
. ooooooo .
. .
. .
. .
/ .
TFIT . .
Figure A-1. Schematic of spacecraft and target system, illustrating
relationships among CEPOCH, TADD, and TFIT. Dots indicate orbit; spacecraft
moves counterclockwise from CEPOCH through the fitted part of the orbit from
CEPOCH+TADD to CEPOCH+TADD+TFIT.
----------
Doppler residuals DATA_RESID with respect to the solution are then
calculated, and splines are fitted to the residuals. The fitted curves, after
differentiation, can be interpreted as spacecraft accelerations relative to a
simple Keplerian orbit about a homogeneous spherical target characterized by
radius RADIUS and gravitational constant GM. The accelerations, in turn,
may be used to infer anomalous mass concentrations within the otherwise
homogeneous target.
The initial state for the calculation is position P and velocity V
at time CEPOCH. The position and velocity vectors are given in an inertial
coordinate system which is identical to the target-fixed (rotating) frame at
CEPOCH (and only at CEPOCH). CEPOCH is in spacecraft ephemeris time (E.T.).
Time from the reference CEPOCH to the first tracking data point is TADD
(minutes); time from the first data point to the last data point is TFIT
(minutes).
The spline is a cubic polynomial having continuous second derivatives
at the end points, producing smooth accelerations when differentiated. The
window, or interval, for which each polynomial applies has length DFIT
(approximately 1-2 minutes). When DOBKS=-1, the windows have constant size
throughout the entire profile. When DOBKS is positive the window size can
vary -- as a function of spacecraft altitude, for example. The actual window
or spline boundaries are tabulated in BKTIMX in units of minutes from
midnight.
|
|
D |
O | X
P | X
P |
L | X
E | X spline
R | /
| X /
R | \
E | X X-X X
S | \ / \ X
I | X-X X
D | X X X
U | X
A |
L |
S | BKTIMX |<--DFIT-->|
| \
| (1) (2) (3) (NBKS+1)
+----+-------+------+-------+----------+---------/ /---+---+------
/ / /
CEPOCH CEPOCH+TADD CEPOCH+TADD+TFIT
TIME
Figure A-2. Spline fit and times used in defining it. Spline fit
interval boundaries BKTIMX(n) are indicated above the horizontal axis; the
number of intervals is NBKS. Interval length DFIT is specified only when
it is a constant.
----------
The time TDSS (in UTC) at which a tracking data point is received
at a ground station is:
TDSS = TSC + TRANSA - DUTSEC
where
TSC = ephemeris time at the spacecraft (HH:MM:SS; see
Results Table)
TRANSA = one way light time in seconds
DUTSEC = accumulated leap seconds (difference between ET
and UTC)
Appendix B - Example Label and Data Object
B.1 Example Label
The label which follows has been designed for the Lunar Prospector
Line of Sight Acceleration Data Records. In the next section, an edited
representative data object is shown
PDS_VERSION_ID = "PDS3"
RECORD_TYPE = FIXED_LENGTH
RECORD_BYTES = 202
FILE_RECORDS = 1152
^LOSAPDR_HEADER_TABLE = ("LX00002J.LOS",1)
^LOSAPDR_TIMES_TABLE = ("LX00002J.LOS",7)
^LOSAPDR_RESULTS_TABLE = ("LX00002J.LOS",113)
INSTRUMENT_HOST_NAME = "LUNAR PROSPECTOR"
TARGET_NAME = "MOON"
INSTRUMENT_NAME = "RADIO SCIENCE SUBSYSTEM"
DATA_SET_ID = "LP-L-RSS-5-LOS-V1.0"
PRODUCT_ID = "LX00002J.LOS"
DESCRIPTION = "The LOSAPDR (Line of Sight
Acceleration Profile Data Record) is a set of three tables
represented in ASCII character format which summarize the
analysis of radio tracking data of orbiting planetary
spacecraft (specifically, Lunar Prospector). The
first table identifies input parameters and conditions;
the second table gives times between which spline fits to
data points are valid; and the third table gives times,
Doppler residuals, spline fit residuals, and inferred
values of spacecraft acceleration with respect to the
nominal gravity field (LP100J) and orbit. The LOSAPDR
is produced at the Jet Propulsion Laboratory under the
supervision of A.S. Konopliv."
SOFTWARE_NAME = "LOSRES.1999.4.6 "
START_TIME = 1998-12-19T19:56:57.362
STOP_TIME = 1998-12-19T21:49:50.362
SPACECRAFT_CLOCK_START_COUNT = "N/A"
SPACECRAFT_CLOCK_STOP_COUNT = "N/A"
PRODUCER_ID = "LP GRAVSCI TEAM"
PRODUCT_CREATION_TIME = 1999-04-06T16:11:25.000
PRODUCT_RELEASE_DATE = 1999-02-10
OBJECT = LOSAPDR_HEADER_TABLE
ROWS = 1
COLUMNS = 42
ROW_BYTES = 1030
ROW_SUFFIX_BYTES = 182
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The LOSAPDR header includes
input data and summary results from initial ODP and
LUNRES calculations. It is a single-row table with 42
columns, two of which have three elements each. The
data are represented as ASCII characters; entries are
delimited by commas. The total of the data plus
delimiters is 1030 characters, followed by 180
padding characters and a carriage-return line-feed pair.
The row thus has 1212 characters, which is exactly six
times the value of RECORD_BYTES."
OBJECT = COLUMN
NAME = "PLANETARY RADIUS"
DATA_TYPE = ASCII_REAL
START_BYTE = 1
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "The assumed radius of
the spherical planet (program mnemonic RADIUS)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "GM"
DATA_TYPE = ASCII_REAL
START_BYTE = 25
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETERS CUBED PER
SECOND SQUARED"
DESCRIPTION = "The assumed gravitational
constant for the planet."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "CALENDAR EPOCH"
DATA_TYPE = TIME
START_BYTE = 49
BYTES = 23
UNIT = "N/A"
DESCRIPTION = "The calendar epoch in
ephemeris time of the initial state vector at the
spacecraft. The initial state vector is given by
SPACECRAFT POSITION and SPACECRAFT VELOCITY below.
(program mnemonic CEPOCH)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "JULIAN EPHEMERIS DAYS"
DATA_TYPE = ASCII_REAL
START_BYTE = 73
BYTES = 23
FORMAT = "E23.16"
UNIT = "DAY"
DESCRIPTION = "The Julian date
corresponding to CEPOCH (ephemeris time at the space-
craft) (program mnemonic JED)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT POSITION"
ITEMS = 3
ITEM_BYTES = 23
ITEM_OFFSET = 24
DATA_TYPE = ASCII_REAL
START_BYTE = 97
BYTES = 71
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "The spacecraft position
vector at CEPOCH, calculated in program ODP (program
mnemonics XS, YS, and ZS)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT VELOCITY"
ITEMS = 3
ITEM_BYTES = 23
ITEM_OFFSET = 24
DATA_TYPE = ASCII_REAL
START_BYTE = 169
BYTES = 71
FORMAT = "E23.16"
UNIT = "KILOMETER PER SECOND"
DESCRIPTION = "The spacecraft velocity
vector at CEPOCH, calculated in program ODP (program
mnemonics DXS, DYS, and DZS)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 241
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Planetocentric
longitude of the spacecraft corresponding to SPACECRAFT
POSITION at CEPOCH (program mnemonic LONEP)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT HOUR ANGLE"
DATA_TYPE = ASCII_REAL
START_BYTE = 265
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "The hour angle of the
spacecraft corresponding to SPACECRAFT POSITION at
CEPOCH (program mnemonic HANG)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DOBKS"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 289
BYTES = 2
FORMAT = "I2"
UNIT = "N/A"
DESCRIPTION = "Flag for constant (-1)
or variable (+1) time spacing in spline fits. If
DOBKS=+1, the time intervals in BKTIMX will be unequal."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "RECORD SPACING"
DATA_TYPE = ASCII_REAL
START_BYTE = 292
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "Time spacing of the
output records in the RESULTS_TABLE (program mnemonic
DTACC). Large values may mean that spacing defaults
to the spacing of the data points (no interpolated
data)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "MINBKS"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 316
BYTES = 10
FORMAT = "I10"
UNIT = "N/A"
DESCRIPTION = "Minimum number of data
points in each spline interval (used only if DOBKS=+1)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "MAXBKS"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 327
BYTES = 10
FORMAT = "I10"
UNIT = "N/A"
DESCRIPTION = "Maximum number of data
points in each spline interval (used only if DOBKS=+1)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "BAND"
DATA_TYPE = ASCII_REAL
START_BYTE = 338
BYTES = 23
FORMAT = "E23.16"
UNIT = "MILLIMETER PER SECOND"
DESCRIPTION = "Conversion factor from
Doppler to acceleration. Nominally 0.2955 for X-band
data and 1.0833 for S-band data."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "TADD"
DATA_TYPE = ASCII_REAL
START_BYTE = 362
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "Time from CEPOCH to first
data point (at the spacecraft)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "TFIT"
DATA_TYPE = ASCII_REAL
START_BYTE = 386
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "Time from TADD to last
data point (at the spacecraft)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DFIT"
DATA_TYPE = ASCII_REAL
START_BYTE = 410
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "Length of each spline
interval (used only when DOBKS=-1)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REJECT"
DATA_TYPE = ASCII_REAL
START_BYTE = 434
BYTES = 23
FORMAT = "E23.16"
UNIT = "HERTZ"
DESCRIPTION = "Threshold for rejection
of bad data points."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "EARTH LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 458
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Planetocentric
longitude of Earth at CEPOCH (program mnemonic LNE)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "EARTH LATITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 482
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Planetocentric north
latitude of Earth at CEPOCH (program mnemonic LTE)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "TRANSA"
DATA_TYPE = ASCII_REAL
START_BYTE = 506
BYTES = 23
FORMAT = "E23.16"
UNIT = "SECOND"
DESCRIPTION = "One-way downlink light-
time for a photon leaving the spacecraft at CEPOCH."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "TRANSB"
DATA_TYPE = ASCII_REAL
START_BYTE = 530
BYTES = 23
FORMAT = "E23.16"
UNIT = "SECOND PER SECOND"
DESCRIPTION = "Rate of change of TRANSA"
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DUTSEC"
DATA_TYPE = ASCII_REAL
START_BYTE = 554
BYTES = 23
FORMAT = "E23.16"
UNIT = "SECOND"
DESCRIPTION = "Difference between
ephemeris time (ET) and universal time (UT)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "REFEP"
DATA_TYPE = TIME
START_BYTE = 578
BYTES = 23
UNIT = "N/A"
DESCRIPTION = "Reference epoch for
TRANSA and TRANSB at the spacecraft (same time system,
and often the same value, as CEPOCH)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORBITAL SEMIMAJOR AXIS"
DATA_TYPE = ASCII_REAL
START_BYTE = 602
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Semi-major axis of
spacecraft orbit. Obtained in the orbit solution of
program ODP (program mnemonic SMA)"
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORBITAL ECCENTRICITY"
DATA_TYPE = ASCII_REAL
START_BYTE = 626
BYTES = 23
FORMAT = "E23.16"
UNIT = "DIMENSIONLESS"
DESCRIPTION = "Eccentricity of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic ECC)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORBITAL INCLINATION"
DATA_TYPE = ASCII_REAL
START_BYTE = 650
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Inclination of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic INC)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ASCENDING NODE LONGITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 674
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Ascending node of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic NODE)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS ARGUMENT ANGLE"
DATA_TYPE = ASCII_REAL
START_BYTE = 698
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Argument of periapsis for
spacecraft orbit. Obtained in the orbit solution of
program ODP (program mnemonic ARG)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "TRUE ANOMALY ANGLE"
DATA_TYPE = ASCII_REAL
START_BYTE = 722
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "True anomaly of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic F)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "MEAN ANOMALY ANGLE"
DATA_TYPE = ASCII_REAL
START_BYTE = 746
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Mean anomaly of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic M)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ECCENTRIC ANOMALY ANGLE"
DATA_TYPE = ASCII_REAL
START_BYTE = 770
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Eccentric anomaly of
spacecraft orbit. Obtained in the orbit solution of
program ODP (program mnemonic E)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ORBITAL PERIOD"
DATA_TYPE = ASCII_REAL
START_BYTE = 794
BYTES = 23
FORMAT = "E23.16"
UNIT = "HOUR"
DESCRIPTION = "Period of spacecraft
orbit. Obtained in the orbit solution of program ODP
(program mnemonic P)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS LATITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 818
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Planetocentric north
latitude at periapsis for spacecraft orbit (program
mnemonic LATPER)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 842
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Planetocentric longitude
of periapsis for spacecraft orbit (program mnemonic
LONPER)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS RADIUS"
DATA_TYPE = ASCII_REAL
START_BYTE = 866
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Spacecraft distance from
target center of mass at periapsis (program mnemonic
RPER)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS VELOCITY"
DATA_TYPE = ASCII_REAL
START_BYTE = 890
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER PER SECOND"
DESCRIPTION = "Spacecraft velocity at
periapsis (program mnemonic VPER)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "PERIAPSIS ALTITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 914
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Spacecraft altitude over
reference surface at periapsis (program mnemonic APER)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "APOAPSIS RADIUS"
DATA_TYPE = ASCII_REAL
START_BYTE = 938
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Spacecraft distance from
target center of mass at apoapsis (program mnemonic RAPO)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "APOAPSIS VELOCITY"
DATA_TYPE = ASCII_REAL
START_BYTE = 962
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER PER SECOND"
DESCRIPTION = "Spacecraft velocity at
apoapsis (program mnemonic VAPO)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "APOAPSIS ALTITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 986
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Spacecraft altitude over
reference surface at apoapsis (program mnemonic AAPO)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NBKS"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1010
BYTES = 10
FORMAT = "I10"
UNIT = "N/A"
DESCRIPTION = "Number of times in the
Times Table defining spline intervals."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "NPOINT"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1021
BYTES = 10
FORMAT = "I10"
UNIT = "N/A"
DESCRIPTION = "Number of data points used
to make this file."
END_OBJECT = COLUMN
END_OBJECT = LOSAPDR_HEADER_TABLE
OBJECT = LOSAPDR_TIMES_TABLE
ROWS = 106
COLUMNS = 1
ROW_BYTES = 23
ROW_SUFFIX_BYTES = 179
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The LOSAPDR times table contains
exact times bounding each spline interval. Each row contains
one 23-digit number, 177 spaces, and a carriage-return
line-feed pair."
OBJECT = COLUMN
NAME = "SPLINE BREAK TIMES"
DATA_TYPE = ASCII_REAL
START_BYTE = 1
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "The exact times of spline
interval boundaries measured from midnight at the
spacecraft (program mnemonic BKTIMX)."
END_OBJECT = COLUMN
END_OBJECT = LOSAPDR_TIMES_TABLE
OBJECT = LOSAPDR_RESULTS_TABLE
ROWS = 1040
COLUMNS = 11
ROW_BYTES = 202
INTERCHANGE_FORMAT = ASCII
DESCRIPTION = "The LOSAPDR Results Table
contains the results from spline fits to Doppler
tracking residuals. Each row in the table contains
times, Doppler residuals, spacecraft position information,
residuals to spline fits, and inferred spacecraft
acceleration with respect to the nominal orbit.
Each row has length 202 bytes; the first 200 are column
data delimited by commas; the last two are a carriage-
return line-feed pair."
OBJECT = COLUMN
NAME = "HH"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 1
BYTES = 2
FORMAT = "I2.2"
UNIT = "HOUR"
DESCRIPTION = "The hour of a Doppler
residual data point at the spacecraft."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "MM"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 4
BYTES = 2
FORMAT = "I2.2"
UNIT = "MINUTE"
DESCRIPTION = "The minute of a Doppler
residual data point at the spacecraft."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SS"
DATA_TYPE = ASCII_INTEGER
START_BYTE = 7
BYTES = 2
FORMAT = "I2.2"
UNIT = "SECOND"
DESCRIPTION = "The whole seconds of a
Doppler residual data point at the spacecraft.
Note that there are generally fractional seconds; for
full time accuracy use OFFSET TIME."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "OFFSET TIME"
DATA_TYPE = ASCII_REAL
START_BYTE = 10
BYTES = 23
FORMAT = "E23.16"
UNIT = "MINUTE"
DESCRIPTION = "Offset from CEPOCH to
the time of the Doppler residual data point or inter-
polation (program mnemonic DMIN)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "DOPPLER RESIDUAL"
DATA_TYPE = ASCII_REAL
START_BYTE = 34
BYTES = 23
FORMAT = "E23.16"
UNIT = "HERTZ"
DESCRIPTION = "Doppler residual from
input data (program mnemonic DATA_RESID)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT ALTITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 58
BYTES = 23
FORMAT = "E23.16"
UNIT = "KILOMETER"
DESCRIPTION = "Spacecraft altitude
over reference surface (program mnemonic SC_ALT)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT LATITUDE"
DATA_TYPE = ASCII_REAL
START_BYTE = 82
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Spacecraft planetocentric
north latitude (program mnemonic SC_LAT)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "SPACECRAFT LONGITUDE"
POSITIVE_LONGITUDE_DIRECTION = "EAST"
DATA_TYPE = ASCII_REAL
START_BYTE = 106
BYTES = 23
FORMAT = "E23.16"
UNIT = "DEGREE"
DESCRIPTION = "Spacecraft planetocentric
longitude (program mnemonic SC_LON)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "FIT RESIDUAL"
DATA_TYPE = ASCII_REAL
START_BYTE = 130
BYTES = 23
FORMAT = "E23.16"
UNIT = "HERTZ"
DESCRIPTION = "Doppler residual from
fitted spline at HHMMSS (program mnemonic FIT_RESID)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "ACCELERATION"
DATA_TYPE = ASCII_REAL
START_BYTE = 154
BYTES = 23
FORMAT = "E23.16"
UNIT = "MILLIMETER PER SECOND
PER SECOND"
DESCRIPTION = "Acceleration from
fitted Doppler residual (program mnemonic ACCEL)."
END_OBJECT = COLUMN
OBJECT = COLUMN
NAME = "HARMONIC ACCELERATION"
DATA_TYPE = ASCII_REAL
START_BYTE = 178
BYTES = 23
FORMAT = "E23.16"
UNIT = "MILLIMETER PER SECOND
PER SECOND"
DESCRIPTION = "The acceleration in the
line-of-sight direction due to the spherical harmonic
gravity field (LP100J). This acceleration is to be added
to the acceleration from the Doppler residual to obtain
the total line-of-sight acceleration."
END_OBJECT = COLUMN
END_OBJECT = LOSAPDR_RESULTS_TABLE
END
B.2 Example Data File
The listing below shows an example Header Table, Times Table, and
Results Table from an example Data Object. Long lines wrap after each 70
characters; blanks padding lines have been omitted.
.1738000000000000E+04, .4902800476015460E+04,1998-12-19T19:56:57.362,
.2451167331219468E+07, .3741758852846081E+01, -.7318498199275959E+03,
.1620164965425043E+04, .2977674198918101E-01, -.1507576585405230E+01,
-.6962231168914452E+00, -.8970706405005299E+02, .1039548114945077E+03,
1, .1000000000000000E+21, 4, 1000, .1083300000000000E+01
, .0000000000000000E+00, .1128833333699033E+03, .8333333333333334E+00
.1538508877196222E+02, -.4190051958576807E+01, -.4787442125265000E+01,
.1321500914263461E+01, .0000000000000000E+00, .5618357258662581E+02,
1998-12-19T19:56:57.362, .1778181746793010E+04, .8322610191421140E-02,
.8920288160027347E+02, -.1641476817768940E+03, .2035837284048299E+03,
-.8897665715273091E+02, -.8802322568293904E+02, -.8849991269768408E+02,
.1869043802729941E+01, -.2328399111109770E+02, -.8887831375123606E+02,
.1763382633264952E+04, .1674359008116209E+01, .2538263326495166E+02,
.1792980860321069E+04, .1646718970683348E+01, .5498086032106880E+02,
106, 1040
.1196956034527843E+04
.1197789367861177E+04
.1198622701194510E+04
.1199456034527843E+04
...
.1309456034527843E+04
.1310289367861177E+04
19,56,57, .0000000000000000E+00, -.1502572267922315E+00, .397943286213
1125E+02, .6569039926461633E+02, -.8970706405005299E+02, -.130077035951
3750E+00, .9956235464222281E-01, -.1338888862673443E+00
19,57,02, .8333333339542151E-01, -.8306550361760215E-01, .397252560348
7293E+02, .6542278856077859E+02, -.8969927626810956E+02, -.122067789525
3115E+00, .1082277614529738E+00, -.1279473508098096E+00
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