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SLR-Report No.6613

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Date:2006-01-05 13:15:00
Sender:Ron Noomen <Ron Noomen <ron@astro.lr.tudelft.nl>>
Subject:[SLR-Report] No. 6613: Delft QL Report January 05, 2006
Author:Ron Noomen
Content:********************************************************************************
SLR Electronic Report 2006-01-05 13:15:00 UTC Message No. 6613
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Author: Ron Noomen
Subject: Delft QL Report January 05, 2006


WEGENER-2 IERS

REPORT OF THE QUICK-LOOK DATA ANALYSIS CENTER
DELFT UNIVERSITY OF TECHNOLOGY
FACULTY OF AEROSPACE ENGINEERING
THE NETHERLANDS


January 5, 2006


This is a daily report, presenting the results of a continuing analysis of the
most recent global LAGEOS-1 and LAGEOS-2 quick-look laser ranging data. The
report consists of (A) a pass summary, (B) an overview of the analysis results,
detailed statistics of the analysed measurements, and an accumulative pass
overview and (C) the earth rotation parameter solutions submitted to IERS. The
report is based on all quick-look data as received until Thu, Jan 5, 2006.
Questions and comments should be addressed to:

R. Noomen
Delft University of Technology
Faculty of Aerospace Engineering
Delft Institute for Earth-Oriented Space Research
Kluyverweg 1
2629 HS Delft
The Netherlands

Telephone: +31-15-2785377
Telefax : +31-15-2785322
E-mail : ron.noomen@deos.tudelft.nl


A. PASS SUMMARY

The table below gives an overview of the ranging data both on LAGEOS-1 and
LAGEOS-2, as received by the Quick-Look Data Analysis Center (QLDAC) on Thu,
Jan 5, 2006. All data were obtained through the NASA Crustal Dynamics Data
Information system (CDDIS) and the Eurolas Data Center (EDC) in Germany.
The data are unscreened and may span more than a week due to late reporting
by the stations.

------------------------------------------------------------------------------
Station System/Location Period No. of Passes
ID LAGEOS-1 LAGEOS-2
------------------------------------------------------------------------------
6405 Concepcion, Chile (TIGO 847) 060103 - 060103 1 2
6810 Zimmerwald 846, Switzerland 060103 - 060103 2 2
7090 Yarragadee, Australia 060103 - 060104 3 4
7110 Monument Peak, California 060103 - 060104 3 3
7237 Changchun, China 060103 - 060104 5 2
7249 Beijing, China 060104 - 060104 1 -
7405 Concepcion, Chile (TIGO 424) 060103 - 060103 1 -
7810 Zimmerwald 423, Switzerland 060103 - 060103 2 2
7825 Mount Stromlo, Australia 060103 - 060103 2 -
7832 Riyad, Saudi Arabia 060103 - 060104 4 4
7840 Herstmonceux, United Kingdom 060104 - 060104 2 1
------ ------ --- ---
TOTAL 060103 - 060104 26 20
------------------------------------------------------------------------------


B. ANALYSIS RESULTS

The analysis is based on two orbit solutions using global quick-look normal
points that cover a period of 8 days which are computed simultaneously. This
week´s data interval runs from Wed, Dec 28, 2005 to Thu, Jan 5, 2006. The
measurement and dynamic models used in this analysis are close to the IERS
Standard. The overall model is referred to as QLDACMOD11. The details of this
model can be obtained on request. The terrestrial reference frame is provided
by the ITRF2000 station coordinates solution (extended with coordinates
of new stations, where necessary).

The general statistics and results of this week´s analysis are thus:

-----------------------------------------------------------------------
Satellite LAGEOS-1 LAGEOS-2
Number of Stations 0 0
Number of Passes 0/ 0 0/ 0
Number of Normal Points 0/ 0 0000/ 0
Weighted RMS of Fit (mm) 0 0
-----------------------------------------------------------------------


Residual statistics per station. The header line for each station shows
the station id, its name, whether the position is solved for or not and the
measurement accuracy in mm. Rejected observations are not used for the
calculation of the rms-of-fit, the biases or the scatter. The latter holds
w.r.t. the residual trend line described by the bias estimates. Uncertainties
are 3-sigma values.

--------------------------------------------------------------------------------
Date Time Sat. Obs. RMS Range Bias Time Bias Scatter
tot/rej (mm) (mm) (us) (mm)
--------------------------------------------------------------------------------



Distribution of daytime, nighttime and twilight passes since Jan 1, 2003:
--------------------------------------------------------------------------
Station System Period Number of Passes
LAGEOS-1 LAGEOS-2
Day/Night/Twil. Day/Night/Twil. Total
--------------------------------------------------------------------------
1824 KIEVLA 051005 - 051102 0/ 9/ 0 0/ 3/ 0 12
1831 LVIL 050703 - 051103 0/ 68/ 0 0/ 15/ 0 83
1864 MD2LAS 050701 - 051223 0/124/ 0 0/ 54/ 0 178
1873 SIMLAS 050701 - 051222 0/ 59/ 0 0/ 12/ 0 71
1884 RIGLAS 050703 - 051219 0/100/ 1 0/ 25/ 0 126
1893 CRMLAS 050723 - 051013 0/ 17/ 0 0/ 0/ 0 17
6405 TIGO 050705 - 060103 52/ 16/ 3 45/ 33/ 5 154
6810 ZIMLAT 050701 - 060103 107/223/ 22 145/123/ 18 638
7080 MLRS25 050701 - 060103 7/ 77/ 2 10/ 68/ 3 167
7090 ML0514 050701 - 060104 197/156/ 33 163/224/ 19 792
7105 ML0725 050704 - 051221 14/100/ 11 22/ 61/ 7 215
7110 ML0414 050701 - 060104 47/189/ 29 56/ 97/ 9 427
7124 ML0819 050818 - 051102 1/ 14/ 2 1/ 32/ 1 51
7130 TL04** 050803 - 051219 8/ 26/ 1 12/ 11/ 2 60
7237 CHALAS 050410 - 060104 0/195/ 2 0/130/ 0 327
7249 BEJLAS 050703 - 060104 0/100/ 0 0/ 64/ 0 164
7355 TROS02 050701 - 050906 0/ 24/ 0 0/ 0/ 0 24
7358 GMSL 050802 - 051129 7/ 16/ 0 2/ 8/ 0 33
7405 TIGO 050705 - 060103 2/ 7/ 0 0/ 9/ 0 18
7501 ML0616 050701 - 051223 24/ 46/ 5 14/ 64/ 3 156
7810 ZIMLAT 050701 - 060103 106/220/ 22 146/120/ 19 633
7811 POLLAS 050704 - 051229 0/ 89/ 0 0/ 23/ 0 112
7821 CHILAS 051213 - 051218 0/ 4/ 0 0/ 9/ 0 13
7824 SPNLAS 050701 - 051229 10/152/ 8 10/ 87/ 7 274
7825 STL3 050702 - 060103 297/117/ 23 157/175/ 23 792
7832 SALRO 050702 - 060104 95/225/ 26 106/169/ 19 640
7835 GRASSE 050701 - 050705 0/ 3/ 0 0/ 2/ 0 5
7838 SHOLAS 050714 - 051222 22/103/ 8 24/ 87/ 4 248
7839 AUSLAS 050702 - 051230 54/140/ 23 95/ 59/ 5 376
7840 RGOLAS 050702 - 060104 75/228/ 29 111/109/ 12 564
7841 GFZLA3 050713 - 051231 8/ 88/ 9 7/ 33/ 2 147
7848 FTLR06 050515 - 051027 6/ 48/ 2 5/ 22/ 4 87
7941 MLROnn 050701 - 051228 54/146/ 12 70/ 70/ 10 362
8834 WLRS01 050702 - 051212 81/169/ 27 111/ 82/ 11 481
--------------------------------------------------------------------------


C. EARTH ROTATION PARAMETER SOLUTIONS FOR IERS

The following solutions for the polar motion and the UT1-UTC time difference
were also obtained in the 10-day data arc analysis described in the previous
section. Only solutions submitted to IERS are presented here.




D. COMMENTS

1. The analysis covered in this report is based on a new set of station
coordinates: instead of the solution SSC(DUT)93L05, which was extrapolated
over some 10 years beyond the epoch of the latest observations, the current
analysis relies on the ITRF2000 solution.
Tests performed during the last year show that the rms-of-fit that can be
obtained when using ITRF2000 can be reduced to about 2 cm (instead of the
3+ cm which was achieved with the old model, for present-day epochs). Other
model modifications are to be expected. We hope to serve the community with
this development.

2. As of July 1, 2003, a new computation model and analysis strategy are in use:
in terms of geometric modeling, models for ocean loading and
atmospheric pressure loading have been turned on. The frequency of the
solutions for the Earth Orientation Parameters has been increased to
once per day (rather than once per 3 days). As a consequence, the arc
length has been changed from 10 days to 8 days. Also, the empirical
accelerations acting on the spacecraft are estimated twice per arc
(i.e. for 4-day periods). To absorb (unmodeled) geocenter motion,
3 coefficients of the gravity field model are estimated: C(1,0),
C(1,1) and S(1,1). Finally, the overall weighting scheme for the
individual SLR observations is also modified slightly.

3. As of the same date, provisions for handling the dual-wavelength systems
7405 and 7810 properly have been installed. This is done by introducing
dummy station ids 6405 and 6810 for the observations taken on 2nd wavelength.
The specific analysis results are easily recognizable because the wavelength
has been added to the printout of the station name.

4. As of July 7, 2004, similar provisions for handling the dual-wavelength syste
7941 properly have been installed. This is done by introducing a
dummy station id 6941 for the observations taken on 2nd wavelength.


From: Ron Noomen

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