Author: IERS Rapid Service/Prediction Center
Subject: Earth Orientation Contributions to IERS Bulletin A
Date: 24 Apr 25


In this report, individual Earth orientation time series are compared
to the IERS Bulletin A combination.  For further information, including
the raw time series, refer to http://www.usno.navy.mil/USNO/earth-orientation/
eo-info/general. 

The first table below shows some comparison results for those series
included in Bulletin A during the last 30 days.  All data are aligned to
the system defined the ITRF and the ICRF reference frames by removing
a priori mean bias and rate.

Units: milliseconds of arc for x, y; milliseconds of time for UT1-UTC

Contributor   Latest      #         Mean          Standard Deviation
Series         Day               (series-BullA)
                                x     y  UT1-UTC    x     y  UT1-UTC

GSI Int.     60778.33    10               0.014               0.009

GSFC Int.    60787.75    55              -0.004               0.025

USNO Int.    60787.75    51               0.001               0.017

IAA VLBI     60685.27     6  -0.07  0.18  0.004   0.26  0.14  0.005

GSFC VLBI    60776.27     9   0.04 -0.08  0.006   0.12  0.10  0.003

USNO VLBI    60776.27     9   0.00  0.04 -0.006   0.07  0.07  0.003

IVS  VLBI    60769.28     9   0.21  0.16  0.013   0.13  0.06  0.008

ILRS SLR     60787.50    26   0.00 -0.10          0.13  0.16

IGS Final    60777.50    30   0.00  0.00          0.00  0.00

IGS Rapid    60788.50    11   0.00  0.00          0.00  0.01

             ---        ---               ---                 ---

IGS Ultra    60788.75     1   0.00  0.02          ------

             60788.75     5              -0.012              0.015

USNO GPS     60498.00    31               0.013*              0.083*

NCEP AAM     60796.50    15               0.000               0.001

* All satellite techniques provide information on the rate of change of
  Universal Time contaminated by effects due to unmodelled orbit node
  motion.  VLBI-based results have been used to minimize drifts in UT
  estimates.


The following table shows comparisons for other related time series during
the last 30 days.  No systematic corrections have been applied.

Units: milliseconds of arc for x, y; milliseconds of time for UT, LOD 

              Latest   #              Mean                Standard Deviation
Series         Day               (series-BullA)
                             x     y     UT     LOD     x     y      UT    LOD 

IGS Final    60777.5  30   0.00  0.00 -0.003* 0.001*  0.00  0.00  0.024* 0.024*

IGS Rapid    60787.5  30  -0.01  0.00 -0.008* 0.001*  0.02  0.02  0.041* 0.019*

IGS Ultra    60788.25 120 -0.01  0.03 -0.010* 0.002*  0.03  0.03  0.043* 0.025*

Bulletin B   60735.0  30  -0.01  0.00  0.020          0.05  0.04  0.019

C04          60759.0  30  -0.01  0.00  0.018          0.05  0.05  0.016


Plots of the residuals are available at http://www.usno.navy.mil/USNO/
earth-orientation/eo-products/weekly.
------------------------------------------------------------------------------
The IERS Rapid Service/Prediction Center is an activity of the Earth
Orientation Department at the U.S. Naval Observatory.