# IVS EOP Format, Version 2.1 (last updated: 2009-01-12)

File names ending with `.eops`

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 w.r.t. the IAU2006 nutation model (the model should exclude
free core nutation).

Files are free format with fields separated by at least one blank.

# Format Notation

FIELD | CONTENTS |
---|---|

1 | MJD of the measurement (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 2020: master20.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.