[IGSREPORT-8745] Wk 1138 GPS Earth Orientation

[Dennis McCarthy]

******************************************************************************
IGS Electronic Report   01 Nov 10:56:46 PST 2001      Message Number 8745
******************************************************************************

Author: IERS Rapid Service/Prediction Center
Subject: Earth Orientation Contributions to IERS Bulletin A
Date:  1 Nov 01


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://maia.usno.navy.mil/bulletin-a.html.

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

SPbU Int.    52208.79    18              -0.001               0.026

GSFC Int.    52211.79    17              -0.005               0.022

IAA VLBI     52199.25     5  -0.01  0.05  0.000   0.12  0.13  0.003

GSFC VLBI    52199.25     8  -0.18 -0.05  0.002   0.10  0.05  0.008

CSR SLR      52211.30    11   0.01 -0.26 -0.028*  0.48  0.38  0.073*

TUD SLR      52206.00    10  -0.29 -0.15          0.40  0.32

IAA SLR      52212.00    30  -0.06  0.11          0.16  0.13

MCC SLR      52207.00    30   0.00 -0.25          0.10  0.13

IGS Final    52195.50    30   0.01  0.01          0.02  0.03

IGS Rapid    52214.50    19   0.00 -0.01          0.02  0.03

             52214.50     2               0.001*              0.006*

USNO GPS     52213.75    32              -0.001*              0.015*

EMR GPS      52213.50    22              -0.015*              0.035*

* 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 tables show comparisons for other related time series during
the last 30 days.  All IGS series are final solutions except for the USNO
series.  No a priori systematic corrections have been applied.

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

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

COD          52209.5  30   0.12  0.29 -10.49  0.020   0.10  0.11   0.21  0.031

ESA          52202.5  30   0.01  0.41        -0.046   0.07  0.11         0.026

EMR          52202.5  30   0.03  0.11 -14.84 -0.037   0.09  0.12   0.35  0.020

GFZ          52202.5  30   0.00  0.19   0.01 -0.031   0.05  0.09   0.08  0.031

JPL          52202.5  30   0.01  0.24 -17.36 -0.027   0.06  0.08   0.27  0.025

NGS          52208.5  30  -0.12  0.10        -0.048   0.14  0.19         0.089

SIO          52202.5  30  -0.07  0.27        -0.031   0.09  0.11         0.023

USN (Rapid)  52212.5  29  -0.14  0.31        -0.051   0.11  0.14         0.024

USNO GPS UT  52213.5  30                0.70                       0.02

IGS Final    52195.5  30   0.02  0.19  -0.01  0.002   0.04  0.03   0.02  0.015

IGS Rapid    52212.5  30  -0.02  0.20  -0.04  0.007   0.07  0.07   0.10  0.027

* All satellite techniques provide information on the rate of change of
  Universal Time contaminated by effects due to unmodelled orbit node
  motion.  The UT results for COD and JPL are integrations of LOD estimates.
  EMR estimates UT and LOD separately by applying a priori orbit constraints.
  GFZ and IGS use VLBI-based results to minimize drifts in their UT estimates
  and thus the standard deviations are not representative of the intrinsic
  capabilities of GPS alone for monitoring UT variations.  USNO estimates
  UT using long-term models for orbit plane rotations.


IERS Earth Orientation Center Series:

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

Bulletin B   52154.   30   0.00  0.01  0.004          0.04  0.05  0.025

97C04        52213.   30   0.02  0.06 -0.009          0.06  0.08  0.028


Plots of the residuals are available at http://maia.usno.navy.mil/plots.html.
------------------------------------------------------------------------------
The IERS Rapid Service/Prediction Center is an activity of the Earth
Orientation Department at the U.S. Naval Observatory.
--
Dennis D. McCarthy                       dmc at maia.usno.navy.mil
Director, Directorate of Time            phone: (202) 762-1837
U.S. Naval Observatory                   fax: (202) 762-1563
Washington, DC 20392-5420