[IGSMAIL-6699] Resubmission of GPS Final Orbits for Wks 1702- 1715, and the delay of Wk 1716

[Jake Griffiths - NOAA Federal]

Author: Analysis Center Coordinator

Dear Colleagues:

The IGS Final orbits and clocks for Wks 1702 thru 1715 have been resubmitted in
order to correct an issue that was found after switching to daily SINEX
integrations. In particular, now that daily terrestrial frame rotations are
available from the SINEX combination, there is no longer a need to align the AC
orbits with the so-called ERP rotations. Those rotations were derived from
differences between AC and IGS polar motion values, and were intended to
approximate daily variations in the orientation of the orbital frame when only
weekly averaged SINEX rotations were available.

In addition to dropping the ERP rotations, the SINEX RX and RY rotations have
been applied with the incorrect sign convention since before 2005. The issue
was corrected for these resubmissions. This is not a large effect for the
modern products, but correcting the issue will improve consistency between
future IGS Final orbits and the IGS reference frame (e.g. IGb08).

The two changes above will be present in the Finals products going forward and
in the IGS second reprocessing (repro2) campaign.

Wk 1716 was delayed in order to complete the resubmissions noted above.

Apologies for any inconvenience these resubmissions and delays may have caused.

Best regards,
jake

-- 
Jake Griffiths, Ph.D.
Geodesy & Geophysics
IGS Analysis Coordinator
Chief, CORS Branch
NOAA National Geodetic Survey
1315 East-West Highway, N/NGS22
Silver Spring, MD 20910 USA

p: (301) 713-3205  ext.153
c: (765) 413-6690
f: (301) 713-4324
e: jake.griffiths at noaa.gov