Author: IERS Rapid Service/Prediction Center
Subject: Earth Orientation Contributions to IERS Bulletin A
Date: 13 Dec 18


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.     58461.33     9               0.003               0.010

GSFC Int.    58461.33    26              -0.001               0.012

USNO Int.    58461.33    26               0.008               0.008

IAA VLBI     58333.27     4   0.29 -0.17  0.003   0.08  0.10  0.002

GSFC VLBI    58443.27     9   0.00  0.01  0.001   0.06  0.06  0.002

USNO VLBI    58443.27     9  -0.05 -0.03 -0.003   0.06  0.05  0.002

IVS  VLBI    58428.21     6  -0.01 -0.03  0.003   0.06  0.05  0.002

ILRS SLR     58463.50    30  -0.13  0.15          0.12  0.14

IAA SLR      58463.81    30   0.01  0.19          0.15  0.14

MCC SLR      58460.00    29   0.07  0.25          0.09  0.13

IGS Final    58446.50    30   0.00  0.00          0.02  0.02

IGS Rapid    58464.50    18   0.00  0.00          0.05  0.03

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

IGS Ultra    58465.00     2  -0.01 -0.02          0.03  0.01

             58465.00     1              -0.002                 ---

USNO GPS     58465.25    32              -0.002*              0.052*

NCEP AAM     58472.50    15               0.001               0.002

* 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    58446.5  30   0.00  0.00 -0.003* 0.000*  0.03  0.03  0.017* 0.019*

IGS Rapid    58463.5  30   0.00 -0.01  0.000*-0.001*  0.04  0.03  0.054* 0.024*

IGS Ultra    58464.25 120 -0.03 -0.02 -0.001* 0.001*  0.05  0.04  0.064* 0.027*

Bulletin B   58423.0  30  -0.07  0.02 -0.042          0.06  0.05  0.016

14C04        58435.0  30  -0.06  0.02 -0.042          0.07  0.04  0.016


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