Subject: [IGSMAIL-0430] ITRF92 coordinates for the 13 Fixed/Constrained stations
From: Zuheir Altamimi
Date: Mon, 10 Jan 1994 8:46:32 PST

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IGS Electronic Mail      Mon Jan 10  8:46:32 PST 1994      Message Number 0430
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Author: Zuheir Altamimi
Subject: ITRF92 coordinates for the 13 Fixed/Constrained stations

Dear Colleagues,

It seems that the Tromsoe estimated velocity in the ITRF92 causes some 
discrepency between ITRF92 coordinates (epoch 1994.0, IGSMAIL#421) and 
GPS estimate. This could be due to the poor VLBI estimate of Tromsoe 
velocity. When comparing the estimated VLBI velocity to the one predicted
by NNR-NUVEL1, there is a difference in the East component of about 7.4 mm/y. 
When using NNR-NUVEL1 velocity for Tromsoe instead of ITRF92 one, then the 
agreement between ITRF92 and GPS coordinates is much better.

So, since Tromsoe is one of the 13 fixed/constrained stations, we recommend 
the use of NNR-NUVEL1 velocity for this station. Consequently, the ITRF92 
coordinates at epoch 1994.0 in IGSMAIL#421 have to be updated. 

Please find below the ITRF92 coordinates at epoch 1994.0 for the 13 fixed/
constrained stations with the updated coordinates for TROM.

On the other hand the 1988.0 ITRF92 coordinates of Tromsoe in the file 
ITRF92.SSC are OK but the velocity was updated by NNR-NUVEL1 velocity.

Best regards

Zuheir Altamimi

P.S. : It should be noticed that MCMU antenna was moved on October 31, 1993.
       We did not yet receive any information (marker, antenna height...)
       about the new location of the antenna. The current ITRF92 coordinates 
       of MCMU (IGSMAIL#421) refer to the "OLD" location.

SSC(IERS) 93 C 04 (ITRF92, EPOCH 1994.0) 

THE 13 STATIONS
===============

DOMES     SITE         FILE CDP        X            Y            Z       SX    SY    SZ    VX     VY     VZ    SVX   SVY   SVZ
NUMBER    NAME         NAME NUM.       m            m            m       m     m     m     ---------------- m/y --------------   *
--------- ----------------- ---- ------------ ------------ ------------ ----- ----- ----- ------ ------ ------ ----- ----- ----- --
10302M003 TROMSO       TROM       2102940.408   721569.363  5958192.077 0.006 0.006 0.006 -0.017  0.013  0.005 0.003 0.003 0.003 N
13407S012 MADRID       MADR       4849202.502  -360329.172  4114913.062 0.006 0.005 0.006 -0.007  0.020  0.015 0.001 0.001 0.001 CN
13504M003 KOOTWIJK     KOSG       3899225.303   396731.771  5015078.296 0.007 0.006 0.006 -0.014  0.017  0.007 0.004 0.003 0.004 CN
14201M009 WETTZELL     WETT       4075578.644   931852.630  4801570.015 0.005 0.005 0.006 -0.017  0.016  0.009 0.001 0.001 0.001 CN
30302M002 HARTEBEESTHO HART       5084625.437  2670366.570 -2768494.014 0.011 0.010 0.008 -0.003  0.019  0.015 0.002 0.002 0.002 CN
40104M002 ALGONQUIN    ALGO        918129.578 -4346071.246  4561977.828 0.005 0.005 0.005 -0.015 -0.006  0.004 0.001 0.001 0.001 CN
40127M003 YELLOWKNIFE  YELL      -1224452.415 -2689216.088  5633638.270 0.006 0.006 0.006 -0.022 -0.001 -0.005 0.003 0.003 0.003 N 
40405S031 GOLDSTONE_PEQGOLD      -2353614.103 -4641385.429  3676976.476 0.008 0.008 0.008 -0.014  0.004 -0.006 0.001 0.001 0.001 CN
40408M001 FAIRBANKS    FAIR      -2281621.346 -1453595.783  5756961.940 0.005 0.006 0.006 -0.021 -0.004 -0.010 0.001 0.001 0.001 CN
40424M004 KOKEE_PARK   KOKB      -5543838.077 -2054587.442  2387809.612 0.006 0.006 0.007 -0.008  0.063  0.031 0.001 0.001 0.001 CN
41705M003 SANTIAGO     SANT       1769693.238 -5044574.084 -3468321.125 0.009 0.010 0.008  0.001 -0.005  0.008 0.003 0.003 0.003 N 
50103M108 TIDBINBILLA  TIDB      -4460996.069  2682557.144 -3674443.875 0.010 0.011 0.011 -0.039  0.004  0.042 0.002 0.002 0.002 CN
50107M004 YARRAGADEE   YAR1      -2389025.394  5043316.852 -3078530.861 0.009 0.008 0.009 -0.045  0.008  0.053 0.002 0.002 0.002 CN
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*  N : NNR-NUVEL1 velocity
  CN : ITRF92 velocity field (combined solution from SLR and VLBI estimates)

Remark: The above 13 station coordinates refer to the GPS MONUMENTS with 
        the exception of MADRID and GOLDSTONE_PEQ whose coordinates refer
        to the bottom of the antennas (ARP). 
        The coordinates of TIDBINBILLA (named previously CANBERRA)
        were originally referred to the ARP. Here they are reduced to the
        GPS monument using the antenna height given in the file localtie.tab.