urn:nasa:pds:jpl.dsn.mmm:eop:1962_020_2006_100_eop
1.0
Earth Orientation Parameter File covering 1962-01-20T00:00:00Z to 2006-04-10T23:59:59Z
1.16.0.0
Product_Observational
Simpson, Richard A.
2021
Earth Orientation Parameter file for radio science and other observations.
Produced by the JPL Time and Earth Motion Precision Observation (TEMPO) Group.
2021-08-28
1.0
Initial version created from original file 060117_172257-eop.long downloaded
from http://eop.jpl.nasa.gov or recovered from a file previously archived
for 2001 Mars Odyssey and/or Mars Express radio science under PDS3 standards.
Trailing blank records in an original file, if any, have been deleted. Data
file names have been changed to yyyy_ddd_zzzz_eee_eop.tab where yyyy and
zzzz give the start and end year of data and ddd and eee give the start
and end days of year. The PDS4 label file name is yyyy_ddd_zzzz_eee_eop.xml.
1962-01-20T00:00:00Z
2006-04-10T23:59:59Z
Calibration
Derived
Earth Orientation Parameter file for radio science and other observations.
Geodesy
Other Investigation
urn:nasa:pds:context:investigation:other_investigation.geodesy
data_to_investigation
EOP Analysis
Literature Search
Analysis leading to an EOP file uses data from very long
baseline interferometry of compact radio sources and
ranging/Doppler measurements to Earth orbiting satellites
to determine the polar motion and nutation of the Earth's
rotation axis. The data are collected using dozens of
stations fixed to the Earth's surface but which are subject
to tidal forces and tectonic motions.
Earth
Planet
urn:nasa:pds:context:target:planet.earth
data_to_target
urn:nasa:pds:radiosci.documentation:dsn.trk-2-21:1997-08-04
data_to_document
TRK-2-21 Software Interface Specification for EOP files.
urn:nasa:pds:radiosci.documentation:document:folkner.1993
data_to_document
A memo describing the models behind derivation of EOP files
and the format and use of an EOP file.
urn:nasa:pds:radiosci.documentation:document:moyer.1993
data_to_document
A memo describing frame tie and nutation corrections for the Orbit
Determination Program (ODP), the 1993 justification for the EOP.
060117_172257-eop.long
data_to_derived_source_product
http://eop.jpl.nasa.gov
The value of external_source_product_identifier is the name
of the file downloaded from the server http://eop.jpl.nasa.gov
or an equivalent.
1962_020_2006_100_eop.tab
2006-01-17T09:28:42
1104683
fbb9fc5c19a56f100da16501bd4f53f0
Earth Orientation Parameter (EOP) files replace the older STOIC
files. STOIC files include calibrations for UT1-UTC and polar
motion. EOP files include these calibrations and, in addition,
nutation correction parameters necessary to determine inertial
station locations at the few-cm level.
The EOP file describes rotation from a specific Earth-fixed
reference frame to a specific inertial reference frame. In order
to achieve cm-level accuracy for inertial station locations, the
EOP file calibrations must be used according to a given set of
models for Earth rotation and must be used with Earth-fixed and
inertial frames consistent with those to which the Earth
Orientation parameters refer. The models are described in
urn:nasa:pds:radiosci.documentation:document:folkner.1993 and
urn:nasa:pds:radiosci.documentation:dsn.trk-2-21:1997-08-04
The Earth-fixed and inertial frames for a given EOP file are given
by parameters within the file. The Earth-fixed frame
used by the EOP and STOIC files is consistent with the
International Earth Rotation Service (IERS) terrestrial reference
frame labeled ITRF93 while the inertial frame is consistent
with the IERS Celestial Reference Frame labeled ICRF93. These
frames are described in the IERS Annual Report for 1993 and in
IERS Technical Note 18.
EOP files are produced by the Tracking System Analytic
Calibration (TSAC) group. A short version of the EOP contains
Earth orientation values spanning slightly more than one year --
from approximately 9 months prior to creation of the file to
approximately 3 months after the date of file creation, based on
predictions. A long version is identical except that Earth
orientation values are extended back to 1962.
DSN and flight project navigation teams use Earth Orientation data
in the process of reconstructing past orbits and generating orbit
predictions. Other groups in navigation, mission design, tracking
system and applications, and radio science also use EOP data.
0
500
7-Bit ASCII Text
The EOP Header has 15 records. Record length is variable. Records
are delimited by ASCII line-feeds. The records are:
1. The file title "JPL Earth Orientation Parameter File"
2. Date of the last data point
3. Date of the last prediction
4. A blank line except for the character "$" in the second
position.
5. EOPLBL character*80
A record used to identify the EOP file; it provides the date of
the last input datum (LD) and the last date for which
predictions are given (PT). Variable UT1TYP has been placed
at the end of the record. Only two values are allowed:
UT1TYP=UT1R and UT1TYP=UT1. UT1R is UT1 with the effects of
short-term tides removed.
6. EOPFNG character*80
This record gives the name of the program used to produce the
EOP file, the date and time the file was generated, and the
date and time the program was linked.
7. EOPUT1 character*6
This record indicates whether the data in the file contain
TAI-UT1 or TAI-UT1R. The two possible values of this variable
are 'UT1' and 'UT1R'.
8. EOPTYP character*6
This record is used by the Orbit Determination Program (ODP) to
determine whether to use the EOP array or the UTPM STOIC (TP)
array for the computation of Earth orientation. The allowed
values of this variable are 'EOP' and 'STOIC'.
9. EOPTIM character*25
Date and time (UTC) of creation of the EOP file (format
dd-mmm-yyyy hh:mm:ss.ffff).
10. EOPTRF character*6
This record gives the Terrestrial Reference Frame for station
locations and site velocities to which the EOP parameters
refer; currently the value assigned is 'ITRF93'.
11. EOPCRF character*6
This record gives the Celestial Reference Frame to which the
EOP parameters refer; currently the value assigned is
'ICRF93'.
12-14. Three records providing column headers for the data which
follow.
15. The marker "EOP=" denoting the beginning of the EOP data
records.
Earth Orientation Parameters Table
500
13977
The Table includes one or more records each with 8 fields
including modified Julian Date, polar motion offsets, timing
corrections to TAI, nutation corrections, and the date on which
the corrections apply. The values cover approximately 9 months
prior to the file creation (based on measurements) to
approximately 3 months after file creation (based on predictions).
Records have fixed lengths, fields are in fixed locations but are
also delimited by commas, and records are delimited by ASCII
line-feeds.
Line-Feed
8
0
79
Modified Julian Date (MJD)
1
1
ASCII_Real
8
%8f
day
The modified Julian date for the remaining fields
in the record. The number of days since midnight
on November 17, 1858 (JD 2400000.5).
Polar Motion X Coordinate
2
10
ASCII_Real
8
%8f
milliarcsecond
The X coordinate of polar motion in milliseconds of
arc. One milliarcsecond is approximately 3 cm on
the Earth's surface.
Polar Motion Y Coordinate
3
19
ASCII_Real
8
%8f
milliarcsecond
The Y coordinate of polar motion in milliseconds
of arc. One milliarcsecond is approximately 3 cm
on the Earth's surface.
TAI-UT1
4
28
ASCII_Real
11
%11f
second
The difference between International Atomic Time (TAI)
and Universal Time 1 (UT1), where the latter is the
instantaneous rotation angle of the Earth, determined
from astronomical and satellite observations corrected
for polar motion and measured in time units.
TAI-UTC
5
40
ASCII_Real
6
%6f
second
The difference between International Atomic Time (TAI)
and Coordinated Universal Time 1 (UTC), where the
latter is Civil Time, formerly called GMT.
By definition UTC runs at the same rate as TAI except
for the introduction of leap seconds, which are
required to keep UTC within 0.9 s of UT1.
dPsi
6
47
ASCII_Real
8
%8f
milliarcsecond
The nutation correction for angle psi.
dEps
7
56
ASCII_Real
8
%8f
milliarcsecond
The nutation correction for angle epsilon.
Calendar Date
8
68
ASCII_String
11
%11s
The calendar date corresponding to MJD in Field 1.
Format is DD-MMM-YYYY.