2. Minutes from previous awg meeting



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8.1. Individual contributions

ASI

Luceri reported on ASI’s developments (Appendix 11). In particular, ASI is working on the automation, and expects to have an operational system running by mid-May at latest. In addition, ASI has provided weekly input to the IERS SINEX Campaign, basically adhering to the AWG guidelines. EOPrates were also delivered, but accompanied with heavy constraints. ASI has become an official IERS Combination Research Center.

Geosciences Australia

On behalf on Govind, Manning reported that Geosciences Australia has worked on data covering the period October 1999 until December 2000, thereby solving various SINEX problems. Manning has no information on a possible target date when Geosciences Australia will have an automated analysis system fully operational.
DGFI

Müller reported on the DGFI activities, which concentrate on the modifications that are necessary for LOD estimation and for satisfying the benchmark tests. DGFI will continue the contributions when the software problems have been solved.

GFZ

This institute is relatively new to these ILRS activities, so Koenig gave a somewhat broader overview of GFZ developments (Appendix 12). The core of their activities consists currently of developments to pass the benchmark tests. This necessitated various modifications to the EPOS software (LOD estimation, units conversions, etcetera). As for the benchmark project, a “C” and a “D” solution has been generated. The “C” solution shows differences w.r.t. IERS C04 of up to 2 marcsec in x/y-pole (which is comparable to the solutions generated by JCET), and a clear slope in UT solutions (the situation is a bit different for JCET, probably because of constraint handling). Station coordinates differences w.r.t the “C” JCET solution are about 5 cm rms (without elimination of systematic effects), with very large error bars.
As for the “D” solutions, EOP results were obtained that are very close to the a priori values. Station coordinates solution differences w.r.t. the “D” solution derived by JCET were still at the 5 cm level, but with much more realistic error bars.
Koenig also brought up a possible problem with the description of the a priori standard deviations of estimated parameters and observation weights, in particular their relative values (action item Husson).

IAAK

Shuygina reported on developments in the ERA software, in particular on the various elements in the computation model (Appendix 13).

JCET

Pavlis reported that his automatic procedure for generating solutions is running, but further tests have withheld him from delivering so far. He took the opportunity to discuss his contributions to the IERS Combination Research Center activities (Appendix 14). These cover a period of 4 years, processing is done in weekly batches, station coordinates and EOPs are estimated only (in addition to satellite-specific parameters). The epoch of the station coordinates appeared to be an issue, which could not be fully corrected for by doing covariance propagations. Mapping the weekly solutions into ITRF2000 yielded transformations of 10-12 mm rms for each component, and a trend which is caused by differences between the two (series of) solutions (errors in ITRF2000?). The results are available in SINEX format on the JCET web pages. The reference to the mid-point of each data interval, rather than an arbitrary fixed epoch, is one of the most urgent development issues.

NERC

Appleby is also working on developments for the automated generation of EOP/network solutions. Another activity is the development of the benchmark solutions, where an intriguing problem appears to be a very significant 28 mm bias in the semi-major axis of the “C” solutions.



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