From Jan Wed Mar 22 11:32:29 1995 From: Jan (Jan) Date: Wed, 22 Mar 1995 11:32:29 PST Subject: [IGSMAIL-0911] Wk 0765-781 IGS orbit update Message-ID: ****************************************************************************** IGS Electronic Mail Wed Mar 22 11:32:29 PST 1995 Message Number 0911 ****************************************************************************** Author: Jan Kouba Subject: Wk 0765-781 IGS orbit update Dear Colleagues, A few weeks ago we've discovered a small mistake in the routine which reads the ESA erp files, it mistook the ESA sigmas for the pole rates. The net effect was that ESA orbit rms, as shown in the IGS sum files, were slightly larger for some weeks, in particular the weeks just prior to Wk 787 when this was discovered and corrected. The rms for the other AC's and the IGS combined orbits are practically the same and unaffected. This bug was in effect from Wk 0765. To be sure, we've reprocessed Wks 0765-781 and downloaded the new sum and sp3 files into CDDIS. Wks 0782-785 Final Orbits completed recently are correct, which leaves only Wk 0786 Rapid Orbits affected by this bug and which will be corrected in early April when the Bull. B becomes available. With the exception of two days of the Wk 0766 (Days 0,1), where, by mistake, the Bull. A was used instead of the Bull. B, the remaining IGS orbit files are practically identical and no action is required by IGS users. The only significant changes are the orbit rms for ESA, in particular weeks after 780, when ESA orbit rms improvements are more noticeable. The main reason for this resubmission is the correct and complete IGS orbit combination statistics. We apologize for any inconvenience this might have caused. With many greetings, Jan Kouba [Mailed From: Jan Kouba ] [Mailed From: Robert Liu ]