[IGSMAIL-5400]: igs05_1390.atx - New release of the absolute IGS antenna correction file

Tue Aug 29 23:48:46 PDT 2006

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IGS Electronic Mail      29 Aug 23:48:53 PDT 2006      Message Number 5400
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Author: Ralf Schmid

Dear IGS colleagues!

The absolute IGS antenna correction file (igs05_wwww.atx) has again been 
updated. The new release is called 'igs05_1390.atx'. This is expected to 
be one of the last updates before the official switch from relative to 
absolute antenna phase center corrections that will take place together 
with the adoption of ITRF2005 (see IGSMAIL-5189: 
http://igscb.jpl.nasa.gov/mail/igsmail/2005/msg00111.html ).

1) New GLONASS offsets

As the offset values for the two GLONASS-M satellites launched in 
December 2005 (R713, R714) were not available in igs05_1365.atx, CODE 
computed antenna offsets for all GLONASS satellites using the 
observation data till the beginning of August 2006:

     New solution in 2006 AUG 21  |   Values from IGS05_1365.atx  | Diff 
  Diff
SVN PRN  Off[mm]                 |                               |  Off 
  nobs
701   6  2194.7 +- 11.1 nobs: 320|  6  2187.6 +-  16.7 nobs: 193 |   7.1 
  127
711   5  1914.1 +- 16.7 nobs: 364|  5  1912.1 +-  21.6 nobs: 242 |   2.0 
  122
712   7  2323.2 +- 11.4 nobs: 289|  7  2330.3 +-  19.1 nobs: 162 |  -7.1 
  127
713  24  2325.3 +- 14.6 nobs:  94|                               |     -
714  23  2277.2 +- 30.5 nobs: 111|                               |     -
783  18  1927.4 +-  8.8 nobs: 457| 18  1906.6 +-  11.0 nobs: 322 |  20.8 
  135
787  17  2055.9 +- 11.2 nobs: 412| 17  2044.6 +-  15.1 nobs: 275 |  11.3 
  137
788  24  2073.8 +- 15.3 nobs: 251| 24  2073.8 +-  15.3 nobs: 251 |     0 
    0
789   3  2004.6 +- 12.2 nobs: 386|  3  1971.0 +-  16.6 nobs: 256 |  33.6 
  130
791  22  2000.9 +-  8.8 nobs: 454| 22  1978.1 +-  11.5 nobs: 317 |  22.8 
  137
792  21  1975.4 +- 10.7 nobs: 424| 21  1954.7 +-  13.4 nobs: 284 |  20.7 
  140
793  20  2002.2 +-  8.8 nobs: 435| 23  1987.0 +-  10.5 nobs: 321 |  15.2 
  114
794   2  1957.7 +-  9.8 nobs: 359|  2  1939.2 +-  13.9 nobs: 228 |  18.5 
  131
795   4  2006.1 +-  9.7 nobs: 358|  4  2001.0 +-  15.0 nobs: 228 |   5.1 
  130
796   1  1944.4 +-  9.7 nobs: 346|  1  1924.2 +-  13.1 nobs: 219 |  20.2 
  127
797   8  1853.4 +- 12.9 nobs: 328|  8  1817.8 +-  20.3 nobs: 197 |  35.6 
  131
798  19  2039.0 +- 12.9 nobs: 165| 19  2044.4 +-  25.8 nobs:  25 |  -5.4 
  140
Attention: 793 is also the old PRN23

It is worth mentioning that the offset values for the two latest 
GLONASS-M satellites (still marked unusable!) were derived exclusively 
from observation data of a relatively small number of all-in-view (AIV) 
tracking GNSS receivers of the IGS network.

The new values (based on about 15 months of data) are expected to be 
more accurate than the values contained in igs05_1365.atx (based on 10 
months). Therefore, it was decided to replace ALL GLONASS z-offsets by 
the values listed above (However, the name of the model is kept. See 
below!).

The latest release contains new entries for R20 (R793), R23 (R714) and 
R24 (R713). In addition, decommission dates were added for R23 (R793) 
and R24 (R788).

2) New absolute ROBOT calibrations from Geo++ ( http://gnpcvdb.geopp.de/ )

Three antenna calibrations that were converted from relative field 
calibrations could be repclaced by robot calibrations from Geo++:

ASH700228A      NONE
ASH700228D      NONE
ASH700718B      NONE

These antenna types are not in use within the IGS at the moment. 
However, the reprocessing project starting soon should make use of the 
values. As the absolute file is still not official, the name of the 
antenna model ('igs05') is kept. (As soon as the IGS ANTEX file is 
officially used for the generation of IGS products, the name of the 
model will be changed, if existing values are replaced!)

3) Additional L1 antennas

The values for five additional L1 antennas were converted from relative 
NGS calibrations ( http://www.ngs.noaa.gov/ANTCAL/ ):

NOV501          NONE
NOV501+CR       NONE
NOV531          NONE
NOV531+CR       NONE
TPSLEGANT_G     NONE

4) Additional antennas recently added to rcvr_ant.tab ( 
http://igscb.jpl.nasa.gov/igscb/station/general/rcvr_ant.tab )

LEISR399_INTA   NONE
SOK702          NONE
TRM41249USCG    SCIT

5) 'Previously valid' antenna names removed

ASH701945.02B   NONE
ASH701946.012   NONE
ASH701946.022   NONE

After the official release of ITRF2005 within a few weeks the IGS will 
define the new IGS05 reference frame and will then officially switch to 
the absolute antenna model ('igs05').

The latest version of the model can be found at:

ftp://igscb.jpl.nasa.gov/igscb/station/general/pcv_proposed/igs05_1390.atx

With best regards from Munich,

Ralf Schmid
schmid at bv.tum.de