Date: Mon, 01 Jun 2009 13:33:49 -0400 From: "Jim.Ray" Subject: [IGSSTATION-3093]: missing Rapid clock epochs To: igs-acs@igscb.jpl.nasa.gov, igsstation@igscb.jpl.nasa.gov Reply-to: jim.ray@noaa.gov Message-id: <4A2410FD.8070000@noaa.gov> Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7bit User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) Sender: owner-igsstation Precedence: bulk ****************************************************************************** IGS Station Mail 01 Jun 10:34:10 PDT 2009 Message Number 3093 ****************************************************************************** Author: Jim Ray Recently it seems that more and more IGS Rapid clocks are missing the last hour of data each day. For 5-min samples, there should be 288 clock values per day. If the last hour is missing, then only 276 clock values will be available. The table below shows all IGR stations with <280 clock values for day 1534_0. I suspect that the reasons for the missing data are mixed. Probably, ESA and/or JPL construct their daily station RINEX files from hourly submissions and are sometimes failing to build complete daily files for their IGR processing. Please correct me if this is wrong, otherwise please consider improving your procedures to eliminate these end-of-day gaps. Since the IGS clock combination requires results from at least 2 ACs, the stations below analyzed by at least 2 ACs besides ESA or JPL probably produce daily RINEX files with the last hour missing, at least initially. Those stations are: NRCan -- CHUR, SCH2 BKG -- HOFN, WTZR GA -- MAW1 SRC -- BOR1 I do not have the time to research the data files & AC solutions of each of these stations individually, so it is possible that my interpretations are not correct. Nevertheless, it is clear that data epochs are being dropped someplace. It is very difficult for the IGS time scale to handle such recurring gaps, especially when they involve some of the best clocks in the network. So please investigate and try to eliminate these data gaps, whether in the RINEX files or in the AC analyses. Thanks, --Jim GPS week: 1534 Day: 0 MJD: 54982 | RMS (ps) OF AC CLOCK COMPARED TO COMBINATION | brd cod emr esa iga igu jpl ngs usn | NEpoch Agency -----+-------------------------------------------------------+-------------- ALGO | - - 7 7 - - - - 111 | 276 NRCan ALIC | - - - 9 - - 10 - - | 276 GA ANKR | - 15 - 7 - - - - - | 276 BKG ASPA | - 21 - 10 - - - - - | 235 NGS BOR1 | - 13 - 6 - - - - 16 | 276 SRC BRFT | - - - 15 - - 18 - - | 275 NGS CAGL | - - - 43 - - 50 - - | 152 ASI CEDU | - 15 - 7 - - - - - | 276 GA CHAT | - - - 15 - - 17 - - | 263 GNS CHUR | - 19 18 20 - - - - - | 276 NRCan CONZ | - - - 15 - - 18 - - | 276 BKG CRAO | - - - 6 - - 7 - - | 276 UNAVCO HARV | - - - 9 - - 10 - - | 276 JPL HOFN | - 67 - 32 - - - - 123 | 250 BKG KARR | - 16 - 8 - - - - - | 264 GA MAW1 | - 49 - 14 - - 20 - - | 276 GA ORID | - - - 6 - - 7 - - | 276 BKG RABT | - - - 14 - - 16 - - | 279 UNAVCO REYK | - - - 5 - - 6 - - | 275 BKG SCH2 | - - 20 21 - - - - 88 | 223 NRCan WARN | - - - 7 - - 8 - - | 276 BKG WTZR | - 21 X 10 - - - - 12 | 276 BKG -----+-------------------------------------------------------+--------------