IVS EOP FORMAT Version 2.2
Axel Nothnagel, IVS Analysis Coordinator
nothnagel@uni-bonn.de
Last updated: 2010.07.23
File names ending with ".eops" normally contain nutation offsets in
dpsi, deps w.r.t. the IAU1980 nutation model while file names ending
with ".eoxy" contain nutation offsets in dX, dY in the new nutation
paradigm and w.r.t. the IAU2000 model (the model should exclude free
core nutation).
Files are free format with fields separated by at least one blank.
FIELD CONTENTS
1 Decimal MJD of the measurement as TAI time tag (with at least 5 decimal digits)
EARTH ORIENTATION
2 x of the pole (arcseconds)
3 y of the pole (arcseconds)
4 UT1-UTC (seconds)
NUTATION
5 dpsi or dX (milliarcseconds)
6 deps or dY (milliarcseconds)
UNCERTAINTY OF EARTH ORIENTATION AND NUTATION
7 uncertainty in x (arcseconds)
8 uncertainty in y (arcseconds)
9 uncertainty in UT1-UTC (seconds)
10 uncertainty in dpsi or dX (milliarcseconds)
11 uncertainty in deps or dY (milliarcseconds)
12 wrms residual delay of the session in ps (preferably integer)
CORRELATIONS
13 correlation coefficient : x, y
14 correlation coefficient : x, UT1
15 correlation coefficient : y, UT1
16 correlation coefficient : dpsi,deps or dX/dY
INDICATORS
17 number of observables
18 6 character session code according to the 2nd
column of IVS master schedules,
e.g for 2002: ftp://gemini.gsfc.nasa.gov/pub/master/master02.txt
19 span of the observation (in hours)
RATES OF EARTH ORIENTATION AND NUTATION
20 x rate of the pole (arcseconds/day)
21 y rate of the pole (arcseconds/day)
22 excess length of day (LOD) (seconds), see comment below
23 dpsi rate (milliarcseconds/day)
24 deps rate (milliarcseconds/day)
UNCERTAINTY OF RATES OF EARTH ORIENTATION AND NUTATION
25 uncertainty in x rate (arcseconds/day)
26 uncertainty in y rate (arcseconds/day)
27 uncertainty in LOD (s)
28 uncertainty in dpsi rate (milliarcseconds/day)
29 uncertainty in deps rate (milliarcseconds/day)
CONFIGURATION OF NETWORK EMPLOYED FOR THESE RESULTS
30 sequence of two-character IVS station identifiers as maintained
in IVS master control file ns-codes.txt (no blanks between stations)
e.g. TsWzWfTcGcFt45Oh, TsWzNy or NyTs
N.B.: There may be several lines for an individual session
identifying different station configurations
Comments:
- For the EOP rates, days are in 86400 SI seconds.
- The lines starting with characters "! # or *" are considered as comments.
- Although it is inconsistent to have LOD in the group of rates due to the
toggling of the sign, it is maintained here for consistency with other
space techniques.
LOD = UT1(n) - UT1(n+1) with n in days.
LOD has the same magnitude but opposite sign of the UT1-UTC rate
or the UT1-TAI rate, which are normally determined in VLBI analyses and
given in seconds/day.
Axel Nothnagel