Report of Leap Second Problem with GPS Data
FYI. -- Richard Langley Professor of Geodesy and Precision Navigation === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === -- Forwarded message -- Date: Fri, 13 Jan 2006 09:59:31 +1100 From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: [IGSSTATION-760]: DARR and 1Hz data from ARGN ** IGS Station Mail 12 Jan 14:59:42 PST 2006 Message Number 760 ** Author: Michael Moore Geoscience Australia Australian Regional GPS Network Geodetic Operation ADVISORY: High rate data, 1Hz 15 minute files, from the ARGN suffered a software problem due to the recently introduced UTC leap-second. Data from DOY 001 to DOY 009 is 1s off in the timestamps reported n the RINEX files. This problem only applies to the 1Hz 15minute files submitted from the ARGN. The software problem has been fixed, and all files from DOY 010 is reporting the correct time. RINEX headers for DARR from DOY 009, was incorrectly reporting an antenna height of 0.000. The headers have now been fixed to report the correct antenna height of 0.0025, and the data from DOY 009 has been resubmitted with the correct header information. I apologise for any inconvenience this may cause. Regards Mike * Michael Moore Geodetic Operations Geoscience Australia Earth Monitoring Group (GEM) http://www.ga.gov.au/ Telephone: (+61 2) 62499052 Fax: (+61 2) 62499929 Email: [EMAIL PROTECTED] GPO Box 378 Canberra ACT 2601 Australia *
Problems with GLONASS Raw Receiver Data at Start of New Year
The International GNSS Service (IGS) includes a sub-network of continuously operating GLONASS monitor stations (about 50) including one at the University of New Brunswick (UNB1). At UNB1 we lost C1 (coarse code on L1 frequencies), P1 (precision code on L1), and P2 (precision code on L2) observations on the 5 GLONASS satellites we were tracking at 00:01:30 GPS Time on 1 January 2006 along with phase jumps in L1 (carrier phase on L1) and L2 (carrier phase on L2). Code measurements were back at 00:04:00. I have just learned from one of the IGS analysis centres that all January 1 IGS GLONASS observation files that they checked show a similar problem. -- Richard Langley Professor of Geodesy and Precision Navigation === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ ===
Diagram of CHU Leap-Second Recording and Atomic Clock
I recorded the audio of the 3330 kHz signal of the National Research Council of Canada's time signal station CHU from a few minutes before, until a couple of minutes after, midnight UTC on New Years' Eve. A PDF of the annotated sampled-signal time series between 23:59:00 and 0:00:01 can be found here: http://gge.unb.ca/Resources/CHU.31Dec05.leapsecond.pdf. The leap second was correctly inserted. However, starting one minute after UTC midnight, DUT1 became +0.4 seconds rather than +0.3 seconds as prescribed by IERS. The +0.4 second value continued to be transmitted until some time on 3 January 2006. According to an NRC staff member, the problem arose because the IERS Bulletin D announcing the +0.3 second value was not sent out until 28 December and was not seen until people returned to work on 3 January after the holidays. This problem seems to have occurred with some other time signal stations too. Simultaneous with the audio recording of CHU, I videotaped the display of a SkyScan atomic clock, model 31981, marketed by Equity Time U.S.A., which receives the WWVB signal. It did not account for the leap second at UTC midnight. Likely it continued that way until it next tried to receive the WWVB signal. === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ ===
Leap Second in GPS Receiver NMEA Log
Here are the logged NMEA $GPZDA messages from a ublox Antaris SuperSense GPS receiver: $GPZDA,235955.00,31,12,2005,00,00*6D $GPZDA,235956.00,31,12,2005,00,00*6E $GPZDA,235957.00,31,12,2005,00,00*6F $GPZDA,235958.00,31,12,2005,00,00*60 $GPZDA,235959.00,31,12,2005,00,00*61 $GPZDA,235960.00,31,12,2005,00,00*6B $GPZDA,00.00,01,01,2006,00,00*62 $GPZDA,01.00,01,01,2006,00,00*63 $GPZDA,02.00,01,01,2006,00,00*60 $GPZDA,03.00,01,01,2006,00,00*61 $GPZDA,04.00,01,01,2006,00,00*66 $GPZDA,05.00,01,01,2006,00,00*67 -- Richard Langley === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ ===
