Report of the IGS Clock Products Workng Group Ken Senor U.S. Naval Research Laboratory (NRL) Ken.Senor@nrl.navy.ml 17 th meetng of the Consultatve Commttee on Tme & Frequency 14 15 September 2006 Bureau Internatonal des Pods et Mesures Sèvre, France
IGS Combned Clock Products IGS Analyss Centers contrbutng clocks snce Nov. 2000: CODE Center for Orbt Determnaton n Europe, AIUB, Swtzerland ESOC European Space Operatons Center, ESA, Germany GFZ GeoForschungsZentrum,, Germany JPL Jet Propulson Laboratory, USA NRCan Natural Resources Canada, Canada USNO U.S. Naval Observatory, USA MIT Mass. Insttute of Technology, USA 5-mnute ntervals for all satelltes & ~175 statons Supports global autonomous PPP cm-level postonng/dssemnaton of IG(R)ST dssemnaton of UTC < 50 ns Fnal, Rapd, & Ultra-Rapd products w/ latences of 13 d to 3 h IGS Reanalyss underway 2006/2007 wll reanalyze data back to 1994 clock densfcaton a hgh prorty PPP usng IGS products stll an opton for obtanng geodetc estmates for non-combnaton or non-igs statons Rapds & Ultra-rapds only Fnals only
IGS Ste Tme Lab IGS Hgh Performance Clocks Tme Labs Freq. Std. Locaton AMC2 AMC H-Maser Colorado Sprngs, CO USA BOR1 AOS Cesum Borowec, Poland BRUS ORB H-Maser Brussels, Belgum IENG IEN Cesum Torno, Italy KGN0 CRL Cesum Kogane, Japan MDVJ VNIIM H-Maser Mendeleevo, Russa MIZU NAO Cesum Mzusawa, Japan NISU NIST H-Maser Boulder, CO USA NPLD NPL H-Maser Teddngton, UK NRC1 NRC H-Maser Ottawa, Canada NRC2 NRC H-Maser Ottawa, Canada OBE2 DLR Rubdum Oberpfaffenhofen, Germany OPMT OP H-Maser Pars, France PENC SGO Rubdum Penc, Hungary PTBB PTB H-Maser Braunschweg, Germany SFER ROA Cesum San Fernando, Span SPT0 SP Cesum Boras, Sweden SYDN NMI Cesum Sydney, Australa TLSE CNES Cesum Toulouse, France TWTF TL Cesum Taoyuan, Tawan USNO USNO H-Maser Washngton, DC USA USN3 USNO H-Maser Washngton, DC USA WAB2 CH H-Maser Bern, Swtzerland WTZA IFAG H-Maser Wettzell, Germany WTZR IFAG H-Maser Wettzell, Germany masers (54) cesums (32) rubdums (27) tme lab statons (25) + GPS space clocks
IGS Tmescales
IGS Tmescales (cont.) Kalman contnuous flter mplementaton formulated as a frequency ensemble determnstc models for rates & drfts process nose capabltes: WHFM, RWFM, RRFM, nputs from ~54 H-maser, H 32 Cs, & 27 Rb clocks ~25 statons at tmng labs Can support IGS move to real-tme operatons Instablty ~1 10 10-15 at 1 d Suffers n longer term by steerng to GPS Tme Implemented for Fnal (IGST) & Rapd (IGRT) clocks Has run autonomously snce 2001, offcally adopted n 2003 as reference for IGS Rapd & Fnal Combned Clock Products
New Tmescale Expected (~ 2006/2007) New Kalman flter mplementaton (adaptve parameter estmaton) flters clock dfference measurements, separatng phase, freq., and drft shocks as well as fxed-phase snusod (WHPM, WHFM, RWFM, & RRFM capable) Utlzes separate set of weghts for each flter state set of phase weghts optmzed for masers set of frequency weghts optmzed for cesums LQG multple-nput steerng flter utlzng (calbrated) IGS statons colocated at tme labs (UTC(k) realzatons) Development complete, testng underway
n stu Calbraton Technque Senor K., Ray J., Pett G., EFTF 2004 B B = CLK - UTC CLK = GPS geodetc clock estmates at lab UTC = local realzaton of UTC for lab STATION CALIBRATION BIAS: ncludes nternal GPS recever/antenna calbraton bas & ntra-lab offset to UTC From IGS clock products & BIPM Crcular T, can compute: B = = = B ( CLK GPST) ( UTC GPST) T + ( UTC UTC ) IGS ( CLK UTC ) + ( GPST GPST ) + ΔGPST T IGS UTC T small correctons due to dfferent methods of observng GPS tme CLK Method good to ~ 2 ns
Geodetc Tme Transfer Accuracy IGS tmescales also useful as valuable staton performance feedback to staton operators va new tme transfer performance measure updated weekly at https://goby.nrl.navy.ml/igstme/daybdy/
Clock RINEX Format a. "RINEX VERSION / TYPE" header changed to 3.00 and to add satellte system desgnator. b. "PGM / RUN BY / DATE" header date format elaborated. c. "SYS / # / OBS TYPES" header added. d. Added Galleo and Space-Based Augmentaton System (SBAS) satellte desgnators n Secton 5. e. "TIME SYSTEM ID" header added. f. The satellte antenna phase center offset nformaton has been moved from a mandatory comment to the "SAT ANT PCO / PCV" header and now ncludes the assocated phase center varaton nformaton also. It s expected that an external fle wll be referenced. g. "SYS / DCBS APPLIED" header added. [NOTE: The format -- taken from RINEX 3.00 s not adequate to gve DCBs for each satellte. Further changes are under dscusson.] h. Capablty of handlng nter-system tmng bases (possbly as a new type of CR data record) are under consderaton. To vew the pendng revsed verson, please see: ftp://www.ngs.noaa.gov/dst/jmr/rnex_clock.30aug06 Send any comments to me and Werner Gurtner (werner.gurtner@aub.unbe.ch).
CANVAS Software Clock ANalyss Vsualzaton & Archvng Software NRL contrbuton through IGS Clock Products workng group Bult on Matlab, though bnares avalable not requrng Matlab Source code avalable Standard Clock tme & frequency doman measures Clock smulaton Interactve Vsualzaton (zoomng) Opportunty to contrbute/help wth further development Download at https://goby.nrl.navy.ml/canvas/ Matlab s a regstered trademark of the Mathworks Inc. Ths does not consttute an endorsement by the U.S. Navy of Mathworks products