Delivered-To: igsmail@igscb.jpl.nasa.gov Date: Tue, 7 Sep 2004 16:29:14 +0200 (CEST) From: Gerd Gendt To: IGSmail Subject: [IGSMAIL-5008]: Some information on the error codes given in the sp3-c Message-ID: Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-igsmail Precedence: bulk ****************************************************************************** IGS Electronic Mail 07 Sep 07:29:24 PDT 2004 Message Number 5008 ****************************************************************************** Author: IGSACC Dear IGS Community, We would like to give some explanation how the error codes inserted into the sp3-c are computed. 1. The summary error-codes given in the header for x,y,z are identical with those in the sp3-a 2. The epoch error codes for the clocks are taken directly from the *.clk file for Rapid and Final products. For Ultra Rapid products they are taken from the computation of the weighted mean of the n AC values at each epoch: standard deviation of AC epoch values / sqrt(n) or more specific sqrt[ sum(Wi*(Xi - weightedMean)**2 )/((n-1)*sum Wi )] 3. The epoch error codes for x,y,z are also taken from the computation of the weighted mean of the n AC values at each epoch: standard deviation of AC epoch values / sqrt(n) The epoch-wise error codes will provide a time dependent assessment of the product quality. By them you can easily see the growing error of the predictions with time, and the larger errors for the orbits at the day boundaries. Best regards Gerd Gendt Thomas Nischan ****************************************************************************** * Gerd Gendt * * _/_/_/ _/_/_/_/_/_/ GeoForschungsZentrum * * _/ _/ _/ Department Geodesy and Remote Sensing * * _/ _/_/ _/_/ _/ Telegrafenberg A17 * * _/ _/ _/ _/ D-14473 Potsdam , GERMANY * * _/_/_/ _/ _/_/_/ Phone : ++49 331 288 1114 Fax :++49 331 288 1759 * * E-Mail: gendt@gfz-potsdam.de * * IGS GFZ AC : AFTP://ftp.gfz-potsdam.de/pub/igsprod * * http://www.gfz-potsdam.de/igs * * IGS Analysis Coord.: AFTP://ftp.gfz-potsdam.de/pub/igsacc * * http://www.gfz-potsdam.de/igsacc * ******************************************************************************