Subject: [IGSREPORT-8644] Wk 1133 GPS Earth Orientation
From: Dennis McCarthy <[email-masked]>
To: [email-masked]
Date: Thu, 27 Sep 2001 15:41:49 EDT

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IGS Electronic Report   27 Sep 12:41:50 PDT 2001      Message Number 8644
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Author: IERS Rapid Service/Prediction Center
Subject: Earth Orientation Contributions to IERS Bulletin A
Date: 27 Sep 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 by ITRF94 and the current ICRF by removing a priori mean
bias, rate, annual and semiannual terms.

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.    52165.79    16              -0.003               0.010

GSFC Int.    52172.79    17              -0.004               0.015

IAA VLBI     52150.25     5  -0.02  0.01  0.001   0.06  0.14  0.005

GSFC VLBI    52157.25     6  -0.15 -0.04  0.004   0.09  0.06  0.008

CSR SLR      52175.91    11   0.09  0.03 -0.038*  0.32  0.54  0.104*

TUD SLR      52173.00    10  -0.09  0.10          0.22  0.35

IAA SLR      52177.00    30  -0.11  0.20          0.15  0.18

MCC SLR      52172.00    30  -0.10 -0.03          0.14  0.12

UTX LLR      51867.16     5               0.010               0.222

IGS Final    52160.50    30   0.01 -0.01          0.03  0.04

IGS Rapid    52179.50    19   0.00  0.00          0.02  0.04

             52179.50     6               0.003*              0.007*

USNO GPS     52178.75    32               0.007*              0.016*

EMR GPS      52178.50    22              -0.005*              0.027*

* 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          52174.5  30   0.03  0.25  -9.70  0.006   0.11  0.14   0.07  0.024

ESA          52167.5  30   0.02  0.39        -0.056   0.11  0.12         0.018

EMR          52167.5  30  -0.03  0.22 -16.16 -0.034   0.09  0.09   0.39  0.023

GFZ          52174.5  30   0.03  0.28  -0.08  0.000   0.05  0.07   0.08  0.031

JPL          52167.5  30  -0.02  0.31 -18.01 -0.016   0.05  0.06   0.12  0.029

NGS          52174.5  30  -0.02  0.21        -0.059   0.16  0.21         0.102

SIO          52167.5  30   0.04  0.23        -0.014   0.04  0.07         0.029

USN (Rapid)  52177.5  29  -0.14  0.32        -0.058   0.12  0.11         0.030

USNO GPS UT  52178.5  30                0.64                       0.06

IGS Final    52160.5  30   0.02  0.25   0.00  0.003   0.04  0.05   0.02  0.017

IGS Rapid    52177.5  30   0.00  0.25   0.03 -0.002   0.07  0.06   0.06  0.029

* 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   52124.   30  -0.06  0.12  0.006          0.04  0.05  0.016

97C04        52179.   30   0.01  0.12 -0.006          0.08  0.06  0.044

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                       [email-masked]
Director, Directorate of Time            phone: (202) 762-1837
U.S. Naval Observatory                   fax: (202) 762-1563
Washington, DC 20392-5420