CIRCULAR T 206 ISSN 1143-1393
2005 MARCH 11, 13h UTC
BUREAU INTERNATIONAL DES POIDS ET MESURES
ORGANISATION INTERGOUVERNEMENTALE DE LA CONVENTION DU METRE
PAVILLON DE BRETEUIL F-92312 SEVRES CEDEX TEL. +33 1 45 07 70 70 FAX. +33 1 45 34 20 21 tai@bipm.org
1 - Coordinated Universal Time UTC and its local realizations UTC(k). Computed values of [UTC-UTC(k)].
From 1999 January 1, 0h UTC, TAI-UTC = 32 s.
Date 2005 0h UTC JAN 29 FEB 3 FEB 8 FEB 13 FEB 18 FEB 23 FEB 28 Uncertainty/ns Notes
MJD 53399 53404 53409 53414 53419 53424 53429
Laboratory k [UTC-UTC(k)]/ns uA uB u (1)
AOS (Borowiec) -17.9 -23.3 -17.7 -9.6 -6.3 -1.6 3.6 1.6 5.4 5.6
APL (Laurel) 5.9 3.8 -0.4 -12.0 -25.3 -25.4 -14.5 1.6 5.5 5.7
AUS (Sydney) -430.4 -436.3 -441.4 -456.8 -463.2 -470.1 -480.7 3.2 6.5 7.2
BEV (Wien) 99.9 106.1 104.7 102.6 104.1 103.8 107.0 1.6 5.3 5.5
BIRM (Beijing) 489.2 125.8 103.7 73.8 44.0 13.2 -12.0 2.8 20.4 20.6 (2)
CAO (Cagliari) -3077.9 -3063.2 -3049.3 -3044.2 -3033.8 -3010.3 -2987.9 1.6 7.3 7.5
CH (Bern) -21.1 -17.1 -15.6 -15.5 -13.8 -16.3 -23.2 0.8 5.3 5.4
CNM (Queretaro) 4.0 -3.6 -0.9 -0.3 3.8 7.3 12.4 5.0 20.3 20.9
CNMP (Panama) -2105.1 -2137.7 -2178.5 -2199.2 -2233.9 -2256.4 -2304.9 4.0 7.4 8.4
CSIR (Pretoria) -2490.6 -2563.4 -2659.5 -2710.1 -2781.5 -2854.3 -2927.6 3.0 20.1 20.3
DLR (Oberpfaffenhofen) -31.3 -29.8 -31.2 -37.0 -35.5 -32.5 -30.5 0.8 5.4 5.5
DTAG (Darmstadt) 145.3 166.2 161.4 165.2 178.9 204.7 206.8 3.0 10.2 10.6
HKO (Hong Kong) 68.2 101.8 134.3 162.8 192.8 213.3 198.1 3.2 6.5 7.2
IEN (Torino) -87.5 -91.0 -77.9 -78.9 -85.4 -85.0 -79.1 0.7 2.2 2.3
IFAG (Wettzell) -365.2 -361.8 -358.1 -357.7 -362.7 -355.1 -354.8 0.8 5.3 5.4
IGMA (Buenos Aires) 297.8 298.9 300.1 310.0 310.9 318.6 318.8 5.0 20.0 20.6
INPL (Jerusalem) -12192.0 -12225.4 -12261.9 -12298.3 -12327.1 -10.8 -51.9 4.0 10.2 11.0 (3)
JATC (Lintong) -10372.7 -10363.6 -10350.6 -10342.7 -10333.4 -10325.1 -10318.8 2.7 21.0 21.2
JV (Kjeller) -6900.4 -6843.4 -6810.4 -6736.0 -6691.2 -6656.3 -6613.9 5.0 20.1 20.7
KRIS (Daejon) 13.6 3.6 4.7 6.3 5.7 2.5 -0.9 2.7 6.5 7.0
LDS (Leeds) 2008.0 2037.2 2059.1 2078.6 2105.0 2129.7 2162.1 3.0 20.1 20.3
LT (Vilnius) 542.7 584.0 590.0 612.7 621.9 630.6 643.9 1.6 5.4 5.6
MSL (Lower Hutt) -118.9 -66.7 -36.2 -13.5 -9.4 -58.9 -98.0 2.3 20.4 20.5
NAO (Mizusawa) -153.7 -150.9 -152.5 -147.7 -136.7 -135.3 -137.6 3.2 20.1 20.4
NICT (Tokyo) 3.9 6.8 5.0 3.3 4.5 4.0 5.0 1.2 4.2 4.4
NIM (Beijing) -56.4 -50.7 -43.2 -48.5 -45.5 -48.0 -46.8 3.2 19.9 20.2
NIMB (Bucharest) - - - - - - - - - -
NIMT (Bangkok) -577.8 -644.2 -708.8 -760.3 -814.8 -867.5 -920.2 1.6 20.4 20.5
NIS (Cairo) - - - - - - - - - -
NIST (Boulder) -1.7 -2.1 -1.8 -1.6 -1.8 -1.1 -2.2 0.7 5.1 5.1
NMC (Sofiya) -4816.8 -4822.4 -4838.2 -4828.5 -4838.3 -4837.3 -4839.0 5.0 20.1 20.7
NMIJ (Tsukuba) 9.0 7.8 7.9 18.4 11.4 -0.1 -2.8 2.7 6.5 7.0
NMLS (Shah Alam) -34.7 -39.1 -41.9 -47.4 -55.0 -50.1 -60.7 3.2 20.4 20.6
NPL (Teddington) 33.7 41.1 42.2 42.5 42.0 42.8 41.3 0.7 2.2 2.3
NPLI (New-Delhi) 9473.9 9527.3 9569.8 9598.3 9640.2 9677.0 9725.7 3.0 20.1 20.3
NRC (Ottawa) 10.2 10.4 13.1 10.9 5.4 10.6 12.1 3.0 14.8 15.1
NTSC (Lintong) 19.1 22.6 31.6 29.6 30.6 29.8 32.9 2.7 6.4 6.9
OMH (Budapest) 9765.6 9787.3 9771.8 9809.3 9828.8 9855.0 9876.3 2.5 20.1 20.3
ONBA (Buenos Aires) -3392.1 -3283.4 -3072.4 -2918.0 -2774.0 -2768.8 -2903.9 5.0 7.4 8.9
ONRJ (Rio de Janeiro) 176.0 171.5 177.5 178.3 208.9 2180.3 2244.4 5.0 20.6 21.2 (4)
OP (Paris) 36.4 39.3 39.6 39.6 32.1 23.3 22.8 0.7 2.2 2.3
ORB (Bruxelles) -32.3 -29.9 -26.2 -25.4 -24.0 -19.9 -18.2 0.8 5.3 5.4
PL (Warszawa) -7.8 -11.4 -5.3 -5.3 -4.4 -8.4 -2.1 1.5 5.3 5.5
PTB (Braunschweig) 4.7 5.9 9.5 12.7 14.3 14.4 10.4 0.5 2.0 2.1
ROA (San Fernando) -74.1 -71.5 -64.1 -75.6 -83.5 -82.8 -75.5 0.8 5.4 5.5
SCL (Hong Kong) -67.9 -62.7 -52.6 -46.0 -36.7 -25.9 -13.6 4.2 10.8 11.6
SG (Singapore) 102.7 115.1 130.4 154.3 164.9 180.9 196.6 3.2 20.1 20.4
SMU (Bratislava) -75.7 -69.8 -68.3 -61.2 -78.8 -90.0 -97.3 5.0 20.1 20.7
SP (Boras) 359.5 348.2 334.9 335.6 336.7 325.4 318.1 0.8 10.0 10.0
SU (Moskva) 24.1 26.2 27.3 29.4 30.2 33.5 34.4 3.0 5.3 6.1
TCC (Concepcion) -1403.4 -1414.1 -1428.1 -1438.3 -1431.3 -1434.3 -1441.4 5.0 20.5 21.1
TL (Chung-Li) 34.7 39.7 39.6 39.7 43.8 45.1 47.8 1.9 6.4 6.7
TP (Praha) -36.4 -37.5 -40.0 -34.3 -28.0 -24.3 -17.4 2.5 5.3 5.9
UME (Gebze-Kocaeli) 612.5 623.1 621.8 631.7 652.9 665.3 668.5 15.0 20.1 25.1
USNO (Washington DC) -2.5 -1.2 -1.8 -2.1 -2.3 -0.8 -1.5 0.5 2.3 2.4
VSL (Delft) -21.2 1.9 20.7 53.1 71.5 70.5 - 0.7 2.2 2.3
- Notes on section 1:
(1) u is the combined standard uncertainty in [UTC-UTC(k)]. uA and uB are the components of this uncertainty
calculated from the Type A and Type B components listed in Section 6. These uncertainties are valid only for
the period MJD 53399 - 53429.
Ref.: W. Lewandowski, D. Matsakis, G. Panfilo, P. Tavella, 'First Evaluation and Experimental Results on the
Determination of [UTC-UTC(k)] Uncertainties', Proc. 36th PTTI, 2004, Washington DC (in press).
(2) BIRM: Apparent time step of [UTC-UTC(BIRM)] on MJD 53403 due to change of GPS antenna coordinates.
(3) INPL: Time step of UTC(INPL) of -12350 ns on MJD 53423.3.
(4) ONRJ: Apparent time step of [UTC-UTC(ONRJ)] on MJD 53422 due to change of master clock.
2 - International Atomic Time TAI and Local atomic time scales TA(k). Computed values of [TAI-TA(k)].
Date 2005 0h UTC JAN 29 FEB 3 FEB 8 FEB 13 FEB 18 FEB 23 FEB 28
MJD 53399 53404 53409 53414 53419 53424 53429
Laboratory k [TAI-TA(k)]/ns
CH (Bern) 48495.4 48568.1 48638.3 48707.2 48777.6 48843.9 48905.7
F (Paris) 169040.2 169034.0 169028.6 169023.6 169012.3 169003.1 168996.0
IEN (Torino) 42029.4 42147.6 42269.9 42384.6 42492.7 42604.8 42719.8
JATC (Lintong) -36728.7 -36752.6 -36773.6 -36797.7 -36829.4 -36852.2 -36876.8
KRIS (Taejon) 8422.9 8440.0 8466.8 8493.9 8519.0 8541.8 8564.1
NICT (Tokyo) 198319.1 198527.5 198736.4 198944.1 199155.4 199363.8 199572.8
NIST (Boulder) -45274195.8 -45274391.2 -45274585.9 -45274780.7 -45274975.9 -45275170.3 -45275366.3
NRC (Ottawa) 29051.4 29055.9 29062.9 29065.2 29064.0 29073.5 29079.4
NTSC (Lintong) 826.0 838.4 852.1 862.6 874.0 886.0 897.9
PL (Warszawa) -2862.3 -2876.4 -2896.7 -2907.0 -2910.4 -2920.1 -2928.0 (1)
PTB (Braunschweig) -358875.2 -358869.0 -358860.4 -358852.6 -358846.3 -358841.3 -358840.7
SU (Moskva) 27241210.0 27241217.7 27241224.5 27241232.2 27241238.6 27241247.6 27241254.0 (2)
TL (Chung-Li) 34.9 39.0 38.1 35.2 41.3 45.5 47.7
USNO (Washington DC) -34947565.0 -34947873.6 -34948182.1 -34948490.1 -34948799.0 -34949105.9 -34949414.2
- Notes on section 2:
(1) PL : Corrected values of TAI-TA(PL):
MJD Value/ns
53374 -2806.7
53379 -2818.1
53384 -2828.3
53389 -2843.6
53394 -2856.5
(2) SU : Listed values are TAI-TA(SU) - 2.80 seconds.
3 - Difference between the normalized frequencies of EAL (free atomic time scale) and TAI.
Interval of validity f(EAL)-f(TAI)
Steering correction 53399 - 53429 6.895x10**-13 (2005 JAN 29 - 2005 FEB 28)
New correction 53429 - 53459 6.891x10**-13 (2005 FEB 28 - 2005 MAR 30)
New correction foreseen 53459 - 53489 6.888x10**-13 (2005 MAR 30 - 2005 APR 29)
4 - Duration of the TAI scale interval.
TAI is a realization of coordinate time TT. The following tables give the fractional deviation d of the scale
interval of TAI from that of TT (the SI second on the geoid), i.e. the fractional frequency deviation of TAI
with the opposite sign: d = -yTAI. In this section, a frequency over a time interval is defined as the ratio of
the end-point phase difference to the duration of the interval. Whenever needed, the instability of EAL should
be expressed as the quadratic sum of three components with t in days: (1) a white frequency noise of
6.0x10**-15 / sqrt(t), (2) a flicker frequency noise of 0.6x10**-15 and (3) a random walk frequency noise of
1.6x10**-16 x sqrt(t). The relation between EAL and TAI is given in Circular T and the Annual Report of the BIPM
Time Section.
In the first table, d is obtained, on the given periods of estimation by comparison of the TAI frequency with
that of the given individual Primary Frequency Standards (PFS). In this table: uA is the uncertainty originating
in the instability of the PFS, uB is the combined uncertainty from systematic effects, Ref(uB) is a reference
giving information on the stated value of uB or is the Circular T where this reference was first given, ul/lab is
the uncertainty in the link between the PFS and the clock participating to TAI, including the uncertainty due to
the dead-time, ul/TAI is the uncertainty in the link to TAI, u is the quadratic sum of all four uncertainty values.
All values are expressed in 10**-15.
Standard Period of d uA uB Ref(uB) ul/Lab ul/Tai u Note
Estimation
SYRTE-FO2 53379 53399 4.6 0.04 0.8 T183 0.1 1.5 1.7 (1)
IEN-CSF1 53404 53414 7.9 0.4 1.1 T191 0.4 3.0 3.2 (2)
PTB-CS1 53399 53429 -1.3 5.0 8.0 T148 0.0 1.0 9.5 (3)
PTB-CS2 53399 53429 3.7 3.0 12.0 T148 0.0 1.0 12.4 (3)
Notes:
(1) Report 23 Feb. 2005 by SYRTE.
(2) Report 4 March 2005 by IEN.
(3) Continuously operating as a clock participating to TAI.
The second table gives the BIPM estimate of d, based on all available PFS measurements over the period MJD
53039-53429, taking into account their individual uncertainties and characterizing the instability of EAL as
noted above. u is the computed standard uncertainty of d
Period of estimation d u
53399-53429 5.0x10**-15 1.9x10**-15 (2005 JAN 29 - 2005 FEB 28)
5 - Relations of UTC and TAI with GPS time and GLONASS time.
[UTC-GPS time] = -13 s + C0, [TAI-GPS time] = 19 s + C0, global uncertainty is of order 10 ns.
[UTC-GLONASS time] = 0 s + C1, [TAI-GLONASS time] = 32 s + C1, global uncertainty is of order hundreds ns.
The C0 values are obtained using the values [UTC-UTC(OP)] and the GPS data taken at the Paris Observatory, corrected
for IGS precise orbits, clocks and ionosphere maps. The C1 values are obtained using the values [UTC-UTC(AOS)] and
the GLONASS data taken at the Astrogeodynamical Observatory Borowiec (AOS). N0 and N1 are the numbers of measurements.
The standard deviations S0 and S1 characterize the dispersion of individual measurements. The actual uncertainty of
user's access to GPS and GLONASS times may differ from these values.
For this circular, S0 = 2.1 ns, S1 = 14.7 ns
Date 2005 0h UTC MJD C0/ns N0 C1/ns N1
JAN 29 53399 -18.0 42 29.9 65
JAN 30 53400 -14.6 42 27.0 75
JAN 31 53401 -12.7 41 28.6 84
FEB 1 53402 -12.8 43 32.8 77
FEB 2 53403 -12.6 41 34.2 76
FEB 3 53404 -9.7 41 24.8 80
FEB 4 53405 -9.1 42 20.0 71
FEB 5 53406 -8.5 42 25.8 61
FEB 6 53407 -7.2 40 15.7 66
FEB 7 53408 -4.5 41 13.2 56
FEB 8 53409 -6.2 42 24.5 83
FEB 9 53410 -5.5 40 27.0 83
FEB 10 53411 -4.7 41 30.5 82
FEB 11 53412 -5.0 39 29.5 50
FEB 12 53413 -6.5 42 27.4 30
FEB 13 53414 -6.1 42 31.3 80
FEB 14 53415 -4.4 42 33.6 83
FEB 15 53416 -4.0 41 31.6 78
FEB 16 53417 -6.4 43 34.0 89
FEB 17 53418 -5.5 42 42.1 77
FEB 18 53419 -3.7 41 39.5 71
FEB 19 53420 -4.1 35 32.8 63
FEB 20 53421 -4.1 40 28.8 77
FEB 21 53422 -3.1 41 31.9 75
FEB 22 53423 -1.1 40 35.2 81
FEB 23 53424 -1.5 41 28.4 62
FEB 24 53425 -5.9 40 33.8 80
FEB 25 53426 -7.3 40 43.4 82
FEB 26 53427 -8.3 40 42.1 84
FEB 27 53428 -9.6 39 43.9 73
FEB 28 53429 -8.5 39 41.1 76
6 - Time links used for the computation of TAI and their uncertainties.
The time links used in the elaboration of this Circular T are listed in this section. The technique for the link is
indicated as follows: GPS SC for GPS common-view single-channel C/A data; GPS MC for GPS common-view multi-channel
C/A data; GPS P3 for GPS common-view multi-channel dual-frequency P code data; GPS GT for 'GPS time' observations;
INT LK for internal cable link and TWSTFT for two-way satellite time and frequency transfer data.
For each link, the following uncertainties are provided: uA is the statistical uncertainty evaluated by taking into
account the level of phase noise in the raw data, the interpolation interval between data points and the effects
with typical duration between 5 and 30 days. uB is the uncertainty on the calibration, estimated by the BIPM.
The calibration type of the link is indicated as: GPS EC for GPS equipment calibration; TW EC for two-way equipment
calibration; LC (technique) for a link calibrated using 'technique'; BC (technique) for a link calibrated using
'technique' to transfer a past equipment calibration through a discontinuity of link operation.
The calibration dates indicate: the most recent calibration results for the two laboratories in the case of EC and
the most recent calibration of the link in the case of LC and BC,
NA stands for not available, in this case estimated values are provided
Link Type uA/ns uB/ns Calibration Type Calibration Dates
AOS /PTB GPS MC 1.5 5.0 GPS EC /GPS EC 2003 Sep/2003 Aug
APL /USNO GPS MC 1.5 5.0 GPS EC /GPS EC 2003 Dec/2003 Dec
AUS /NICT GPS MC 3.0 5.0 GPS EC/GPS EC 2002 Sep/2003 Nov
BEV /PTB GPS MC 1.5 5.0 GPS EC/GPS EC 2001 Dec/2003 Aug
BIRM/NICT GPS MC 2.5 20.0 NA /GPS EC NA /2003 Nov
CAO /PTB GPS MC 1.5 7.0 GPS EC/GPS EC 2004 Nov/2003 Aug
CH /PTB GPS P3 0.7 5.0 GPS EC/GPS EC 2001 Feb/2003 Aug
CNM /NIST GPS SC 5.0 20.0 NA /GPS EC NA /2003 Dec
CNMP/USNO GPS MC 4.0 7.0 GPS EC/GPS EC 2002 Oct/2003 Dec
CSIR/PTB GPS MC 3.0 20.0 NA /GPS EC NA /2003 Aug
DLR /PTB GPS P3 0.7 5.0 GPS EC/GPS EC 2003 Apr/2003 Aug
DTAG/PTB GPS SC 3.0 10.0 GPS EC/GPS EC 1998 May/2003 Aug
HKO /NICT GPS MC 3.0 5.0 GPS EC/GPS EC 2004 Apr/2003 Nov
IEN /PTB TWSTFT 0.5 1.0 LC (TWSTFT) 2003 Jun
IFAG/PTB GPS P3 0.7 5.0 GPS EC/GPS EC 2003 Jun/2003 Aug
IGMA/USNO GPS MC 5.0 20.0 NA /GPS EC NA /2003 Dec
INPL/PTB GPS SC 4.0 10.0 GPS EC/GPS EC 1987 Jun/2003 Jun
JATC/NTSC INT LK 0.2 20.0 NA NA
JV /PTB GPS GT 5.0 20.0 NA /GPS EC NA /2003 Aug
KRIS/NICT GPS MC 2.5 5.0 GPS EC/GPS EC 2003 Oct/2003 Nov
LDS /PTB GPS SC 3.0 20.0 NA /GPS EC NA /2003 Aug
LT /PTB GPS MC 1.5 5.0 GPS EC/GPS EC 2001 Nov/2003 Aug
MSL /NICT GPS P3 2.0 20.0 NA /GPS EC NA /2003 Nov
NAO /NICT GPS SC 3.0 20.0 NA /GPS EC NA /2003 Nov
NICT/PTB GPS P3 1.5 5.0 LC(GPS MC) 2004 May
NIM /NICT GPS SC 3.0 20.0 NA /GPS EC NA /2003 Nov
NIMB NA
NIMT/NICT GPS P3 1.0 20.0 NA /GPS EC NA /2003 Oct
NIS NA
NIST/PTB TWSTFT 0.5 5.0 LC(GPS SC) 2003 Sep
NMC /PTB GPS GT 5.0 20.0 NA /GPS EC NA /2003 Aug
NMIJ/NICT GPS SC 2.5 5.0 GPS EC/GPS EC 2002 Apr/2003 Oct
NMLS/NICT GPS MC 3.0 20.0 NA /GPS EC NA /2003 Nov
NPL /PTB TWSTFT 0.5 1.0 LC(TWSTFT) 2004 Jul
NPLI/PTB GPS SC 3.0 20.0 NA /GPS EC NA /2003 Aug
NRC /USNO GPS SC 3.0 15.0 GPS EC/GPS EC 1982 /2003 Dec
NTSC/NICT GPS MC 2.5 5.0 GPS EC/GPS EC 2002 Aug/2003 Oct
OMH /PTB GPS SC 2.5 20.0 NA /GPS EC NA /2003 Aug
ONBA/USNO GPS MC 5.0 7.0 GPS EC/GPS EC 2000 Oct/2003 Dec
ONRJ/NIST GPS SC 5.0 20.0 NA /GPS EC NA /2003 Dec
OP /PTB TWSTFT 0.5 1.0 LC(TWSTFT) 2004 Jul
ORB /PTB GPS P3 0.7 5.0 GPS EC/GPS EC 2003 Jul/2003 Aug
PL /PTB GPS MC 1.5 5.0 GPS EC/GPS EC 2001 Oct/2003 Aug
ROA /PTB TWSTFT 0.7 5.0 LC(GPS SC) 2001 Dec
SCL /NICT GPS SC 4.0 10.0 GPS EC/GPS EC 1993 May/2003 Nov
SG /NICT GPS MC 3.0 20.0 NA /GPS EC NA /2003 Nov
SMU /PTB GPS SC 5.0 20.0 NA /GPS EC NA /2003 Aug
SP /PTB GPS P3 0.7 10.0 LC(GPS SC) 2004 Nov
SU /PTB GPS SC 3.0 5.0 GPS EC/GPS EC 2003 Apr/2003 Aug
TCC /NIST GPS SC 5.0 20.0 NA /GPS EC NA /2003 Dec
TL /NICT TWSTFT 1.5 5.0 LC(GPS SC) 2001 Oct
TP /PTB GPS SC 2.5 5.0 GPS EC/GPS EC 2001 Oct/2003 Aug
UME /PTB GPS SC 15.0 20.0 NA /GPS EC NA /2003 Aug
USNO/PTB TWSTFT 0.5 3.0 BC(GPS P3) 2003 Sep
VSL /PTB TWSTFT 0.5 1.0 LC(TWSTFT) 2004 Jul