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Nacional the reference Concep y IF da T scale realised, Metrolog to de A, Real a frequency 80 resp ec clo tec afico TCC A Americas Canada). lab equipp ys. and ts Nacional the nanosec- that In that (USNO, primary with b Six hnology more constel- G tenance up pro time Buenos Spain). atomic c hnique t e IGMA ted to orato- ks ectiv UTC. USA) Insti- (F 2005, 0.5 TW- time time Mil- vide ci´ lab- and t has the are de- ed- in- on b an ed de or to at ´ to in of ıa x y e , © 2006: Instituto de Astronomía, UNAM - Third International Meeting of Dynamic Astronomy in Latin America Ed. Carlos Abad, Angel Bongiovanni & Yaneth Guillén UTC(USNO). CNM, of The lab tion of with and form and to frequency quency resen ensem and clo accuracy Circular dations ferences UTC Union. UTC that telephone ten 3.1 their the c 3.2 oratories; th T Stations Some . k R to the able time is, the GPS tations L ‘H-m’ observ of . ble. 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The stands VICES unications the metrology of of of than settled lo equipp the researc and O to tenance the cal a DUT1, OF master AMERICAN USNO in BIPM to to xima- 2005. NIST (refer sc UTC clo lo 2 with p rep- for ale fre- dif- the the the ns. cal [ er- A b ed c UTC T in h. y k V t ABLE primary [ UTC AILABLE Uncertain - UTC - 21 20 21 15 20 UTC 5 1 4 8 8 5 ...... in BIPM ing Metrologia, Metrologia, is Essen, of first Guinot, BIPM life of Mark Audoin, lab wide. task tions, Allan, men ries ready needing stim dissemination some 1 . . . . . 3 7 9 8 2 5 2 5 0 1 9 CONTRIBUTION frequency ( the the time ( Chile. oratories London, 1958, BIPM Cam F LAB t lab The (science, y stations ts. ulates requency resp con o undertak IN )] witz, lab D.W., The established Circular transp total L., case after bridge C., metrology B., tributor )], elab traceabilit TIME onsible Ph oratories. Time signals & Time Ib APL an , Y Y Y Y & W., 1972, 1968, ys. No. & of of ------& es es es es some oration P w eroamerican ortation, Guinot space Con and increase en Univ. arry Thomas, W ere clo services. Rev. T, the Section, Hall, 973, LABORA eiss, restarted with for 8, 4, 4. trol, at c a , lab SIGNALS y REFERENCES established ks observ y in J. 35 43 CNMP mon ears Lett., CONCLUSION and Press 250, the T B. time R. of uncertain A.M. in oratories in the more V. able 330 in and 2001, C. the 1, thly G., T time, of BIPM air 45 the L. atories AI, 1, TORIES clo differen D1 signal 1980, 1988, the in 1 Essen, man reference than Time in 1957, publication 105 na The c services n terruption. AND indicates where t ks um and y Y Y Y Y Y Y Y in P to vigation, co - - - - Pro es es es es es join es es y Ann unit anama represen diss. 80 measuremen emissions b op t up the distributed Phil. more L., er stim c. asp TIME tly clo eration ual the is of 34th & time last ects c ns. T with ulates of the organisations P ks. applications) Rep and USNO rans. comm t arry The their the Ann. ab y scales of ears; New and lab ort with t national out , of BIPM of impact R. h J. the w equip- unica- orato- Symp. uman of is TCC orld- time, time J. 40% tim- So this is the the the al- 23 L. c. a