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: http://www.atnf.csiro.au/research/pulsar/timing/obstime.html
Дата изменения: Unknown Дата индексирования: Sun Dec 23 01:46:13 2007 Кодировка: Поисковые слова: п п п п п п п п п п п п п |
The Parkes 1PPS is generated by the MkVIb clock which is driven by the Observatory hydrogen maser frequency standard. It is approximately aligned with UTC using the Parkes GPS system. There are several GPS clocks monitored by the MkVIb clock - currently we are using the GPS East receiver, which is mounted on the Telecom tower to the east of the telescope, as a reference. Offsets between the Parkes 1PPs and the GPS 1PPS are monitored every second by the observatory clock system. These data are averaged and recorded by the 'DESK' computer in /nfs/online/timing/pkclk00.
The differences UTC - UTC(NIST) and UTC - UTC(GPS) are monitored and recorded by the BIPM.
cd $CVSHOME cvs co soft_atnf/atas/clkcorrEnsure that the executables are up-to-date:
cd $CVSHOME/soft_atnf/atas/clkcorr makeThen follow the procedure outlined below to generate the clock correction files required by TEMPO:
cd $clkcorrdir/gps mk6_avThis will produce a file mk6.tmp.
mk6_pltto examine the data. (-h for help.)
Only entries not already processed need be in $clkcorr/gps/mk6.av, but it is convenient to keep one file per year. At the end of each year, move $clkcorr/gps/mk6.av to $clkcorr/gps/mk6_YYYY.av for archival.
cd $clkcorrdir/cirt ftpcirt NNstart [NNstop]where NNstart and NNstop are the numbers of the first and last Circular T files needed, respectively. If the optional NNstop is omitted, only cirt.NNstart is downloaded. ftpcirt will automatically add the new files to the repository.
getcirt cirt.NNN >> cirt.datEnsure that there are no duplicated lines in cirt.dat. (If the format of Circular T changes, it may be necessary to alter the sed instructions in getcirt to extract the required information and nothing else.) Note that cirt.dat must cover the same MJD range as gps.dat.
cd $clkcorrdir pkstimeThis creates the files time.tmp and utccorr.tmp. Start and stop MJDs are optional... do pkstime -h for help.
Note, it is important to check these files for significant discrepancies from smooth changes in the offsets. These occur occasionally and may be genuine, but more often are due to a failure of the GPS monitoring system or some other problem.
Please report errors or problems with these clock correction procedures to Dick Manchester.