[IGSREPORT-8824] Wk 1142 GPS Earth Orientation

[Dennis McCarthy]

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IGS Electronic Report   29 Nov 11:24:36 PST 2001      Message Number 8824
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Author: IERS Rapid Service/Prediction Center
Subject: Earth Orientation Contributions to IERS Bulletin A
Date: 29 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.    52234.79    17               0.004               0.010

GSFC Int.    52239.79    15               0.001               0.010

IAA VLBI     52234.25     5  -0.03  0.04 -0.002   0.16  0.14  0.005

GSFC VLBI    52234.25     6  -0.15  0.01 -0.002   0.14  0.06  0.004

CSR SLR      52238.72    11   0.05 -0.20 -0.051*  0.43  0.42  0.119*

TUD SLR      52236.00    10  -0.03  0.19          0.19  0.28

IAA SLR      52240.00    30  -0.08  0.04          0.32  0.16

MCC SLR      52235.00    30   0.00 -0.20          0.18  0.13

IGS Final    52223.50    30   0.00  0.01          0.01  0.03

IGS Rapid    52242.50    19   0.01 -0.01          0.03  0.06

             52242.50     2               0.005*              0.002*

USNO GPS     52241.75    32               0.004*              0.018*

EMR GPS      52241.50    22              -0.005*              0.038*

* 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          52236.5  30   0.20  0.22 -10.92  0.018   0.10  0.07   0.17  0.021

ESA          52230.5  30  -0.01  0.34        -0.030   0.09  0.08         0.025

EMR          52237.5  30  -0.08  0.13 -13.53 -0.032   0.14  0.11   0.37  0.020

GFZ          52237.5  30   0.01  0.12  -0.02 -0.013   0.08  0.07   0.03  0.028

JPL          52230.5  30   0.00  0.23 -16.54 -0.039   0.08  0.08   0.37  0.036

NGS          52234.5  30  -0.19 -0.08        -0.050   0.21  0.17         0.077

SIO          52230.5  30  -0.12  0.27        -0.002   0.07  0.07         0.027

USN (Rapid)  52240.5  30  -0.05  0.31        -0.030   0.18  0.17         0.022

USNO GPS UT  52241.5  30                0.71                       0.02

IGS Final    52223.5  30   0.01  0.19   0.00  0.009   0.03  0.03   0.02  0.022

IGS Rapid    52240.5  30   0.02  0.19  -0.02  0.002   0.10  0.10   0.06  0.022

* 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   52184.   30   0.02  0.01  0.002          0.04  0.04  0.018

97C04        52242.   30   0.00  0.03  0.025          0.06  0.05  0.055


Plots of the residuals are available at http://maia.usno.navy.mil/plots.html.
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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