From tim.springer at aiub.unibe.ch Fri Nov 3 07:00:28 2000 From: tim.springer at aiub.unibe.ch (tim.springer at aiub.unibe.ch) Date: Fri, 03 Nov 2000 16:00:28 +0100 (MET) Subject: [IGSMAIL-3087]: New IGS Clock Combination Message-ID: <0G3G00K03F0SS2@ubecx01.unibe.ch> ****************************************************************************** IGS Electronic Mail 03 Nov 07:00:38 PST 2000 Message Number 3087 ****************************************************************************** Author: Tim Springer Dear IGS colleagues, As agreed upon during the last IGS Analysis Center workshop, held from 25-29 September at the U.S. Naval Observatory, the new IGS clock combination will become official starting with the products of GPS week 1087, day 0 (November 5, 2000). This means that coming Monday the clock products in the IGS rapid orbit combination will be based on the new clock combination scheme. The new "clock-RINEX" format is used for the exchange of estimates and for the distribution of results. The new clock combination adds considerable robustness and outlier detection, which requires far less manual intervention, as well as the new receiver clock products. This new clock combination has been running in a demonstration mode since the beginning of this year for both the final and rapid orbits. The results were used for the navigation solutions and the results were published in the regular Final and Rapid combination reports. Separate clock combination results, a summary file and a clock-RINEX file, were made available on anonymous fop in Berne. In principle this new clock combination does not change anything for the user of IGS products. The results from the new clock combination will be included in the IGS orbit (SP3) products to guarantee normal usage. Two new files will result from this new combination. 1) The resulting combined clock estimates for satellite and station clocks. This file will be called igrWWWWD.clk 2) A summary file giving details of the clock combination. This file will be called igrWWWWD.cls Of course the most important statistics of the clock combination will be included in the normal summary in the "old" way. These are the offset, drift (wrt. broadcast), and rms of the clock estimates (wrt. combined clocks). These new files will be made available in the normal directories at the differente IGS data centers and the IGSCB where you also find the other products. The new combination offers enhanced capabilities because the clock-RINEX file will contain clock estimates sampled at 5min compared to 15min in the orbit (SP3) files. This should especially help to further improve the precise point positioning (ppp) results. Furthermore, the new product contains the receiver clock estimates which will give additional feedback to the station managers. If you have any further questions regarding this or any of the other IGS products please do not hesitate to contact me. Kind regards, Tim Springer IGS Analysis Center Coordinator ps. A description of the clock-RINEX format is available at the IGSCB and at the USNO. ftp://igscb.jpl.nasa.gov/igscb/data/format/rinex_clock.txt http://maia.usno.navy.mil/gpst/clock-format ----------------------------------------------------------------------------- Tim Springer Astronomical Institute, University of Berne springer at aiub.unibe.ch Sidlerstrasse 5, CH-3012 Bern, Switzerland http://www.aiub.unibe.ch/ Tel: +41 31 6318592 Fax: +41 31 6313869 ftp://ftp.unibe.ch/aiub -----------------------------------------------------------------------------