IRIS-S139 (International Radio Interferometric Surveying - South) 1999 Jun,14 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Schedule name: is139.skd on CDDISA [jun99] Nominal Start: 14:00 U.T. on Jun.14 (day 165) name yyddd-hhmmss Ft Gc Hh Wf Wz 0552+398 99165-140000| 70 260 260 190 70| Nominal Stop : 14:00 U.T. on Jun.15 (day 166) name yyddd-hhmmss Ft Gc Hh Wf Wz 0229+131 99166-135215| 190 110 190| 0119+041 99166-135608| 90 90 | 0727-115 99166-135620| 80 80 70| Duration: 24 hours Correlator: BONN Purpose ======= The purpose of the IRIS-S sessions is to continue the series of measurements for the determination of earth rotation parameters. IRIS-S experiments are set up to provide all earth orientation parameters (UT1, polar motion, and nutation), baseline components and positions of extragalactic radio sources. SInce a long period this network produced excellent EOP results and with the long north-south and east-west baselines as well as the wideband capability provides a good EOP determination. Network ======= The standard configuration of the monthly observed IRIS-S (South) experiments consists of four stations. One station in the United States(Westford,Ma), one station in South Africa (Hartebeesthoek), one radio telescope in Europe (Wettzell,Germany) and one radio telescope in South America (Fortaleza,Brasil). Since January 1997 the network is augmented by station Fairbanks(Alaska). During the O'Higgins occupations two more stations of the southern hemispere are added to this network. With O'Higgins (Antartika) and Hobart (Tasmania) we will have seven participate station in this network. Schedule ======== This schedule was generated by (auto)-SKED using the NEOS-WB frequency setup, using variable scan lengths with a minimum of : 70 seconds. The most recent source flux models are included. SNR goals are 20 at X-band and 15 at S-band for all baselines. On all baselines with Fortaleza the SNR goal for the X-band is 23. The predicted SNRs used include a 30 ps noise contribution added in quadrature, which is a typical magnitude for the reweight constants applied in SOLVE solutions. The schedule is generated for the estimation of all five (seven) earth orientation parameters, clock offsets and clock rates for all participating stations except the reference station and atmo- sphere parameters for all participating stations. It was optimized for three earth orientation parameters (polar motion, UT1). Other optimization features enabled for this experiment : - the covariance analysis during schedule generation considers the previous 24 hours of observations, - minor SKED optimization parameters . maximum number of observations, . minimum time, . sky coverage, were optimized over the best ( in a covariance sense ) 75% of the possible observations, this produces a somewhat more even sky distribution, - observations were weighted by their expected SNRs, - 30 ps noise contribution added, - mimimum time between observations of the same radio source was set to 20 min - using 59 source for improving the sky covorage Simulation Results ================== Simulation results of this schedule was used in a global solution estimate the formel errors for Earth orientation parameters. X Wobble <40 microasec Y Wobble <20 microasec UT1-TAI < 2 microsec Nutation offset in longitude (Psi) <50 microasec Nutation offset in obliquity (Eps) <20 microasec Procedures ========== NO PREPASS TIME: There is no time allowed in the schedule for prepassing tapes. Therefore all tapes needed for this experiment must be pre-checked before the start of this experiment. Please generate the procedures for this session using drudg. FREQUENCY SEQUENCE: The NEOS-wideband RF band frequency sequence ------------------ is used for this experiment. THIS SCHEDULE HAS A 10 SECOND EARLY TAPE START ---------------------------------------------- Wettzell, Westford, Fairbanks (Gilcreek) and HartRAO record at high (56kbpi) density (thin tape). Appendix ======== SKED Summary from file is139.skd for experiment IS139 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x x I 3 3 .7 0048-097I xx xx xx x I 7 29 6.4 0059+581I x x x xxx xxx xxx x x x xx x xx x x x x xx I 26 112 20.8 0104-408I xx x x x I 5 7 2.1 0119+041I x x x I 3 3 .6 0229+131I xxxx x x xx x I 9 13 2.5 CTA26 I x xxx x xx I 7 9 2.0 0402-362I xxxxxxx x I 8 8 2.4 0454-234I x x x xx x xx I 8 29 9.0 0458-020I x x I 2 2 .4 0537-441I xx I 2 2 .7 0552+398I xx x xx xx xx xxx xxxxxxxxxxxxxx x xI 29 153 28.5 0637-752I x x I 2 2 .7 0718+793I x I 1 1 .1 0727-115I xx x x x I 5 17 3.6 0749+540I xx xxx xx xxxx xxxxxxx xx x xxxxxxx xx xx xxI 34 138 24.1 0804+499I xx xx xx xx xx x x xx x x xx xx I 20 77 14.1 0805+410I xx xx x xxxx xx x I 12 22 2.4 OJ287 I x x xx xx xxx xx I 11 51 9.9 0920-397I x I 1 1 .3 4C39.25 I x xxx xx x x x xxxxxxxxxxxxxxxxxxxx I 29 148 27.4 0955+476I x xxx xx xxxxx xx x x x x x x xxx x xI 24 86 15.6 1034-293I x I 1 1 .3 1044+719I x x x x x x xxx x x x xx x x x x x xI 21 67 10.3 1124-186I x x xx x x I 6 16 4.9 1128+385I x xx x x xxx x I 9 13 1.5 1144-379I xx x I 3 3 .9 1255-316I x I 1 1 .3 1308+326I x x xI 3 3 .5 1334-127I x x I 2 2 .4 1357+769I x x x x x x x x x x x x x x x I 15 55 10.9 1424-418I x I 1 1 .3 1606+106I x xx xx xx xx x I 10 18 3.4 1610-771I x I 1 1 .4 1622-253Ix xx xx I 5 10 3.1 NRAO512 Ixxxxxxxx xxxxxx xx xxx xxxx xxxI 28 155 28.4 1726+455Ix x xxxx x x x x I 10 31 4.7 1739+522Ix xxxxx xxxxxxxxxxxxxxx xxxx x xx xx xxxI 33 151 28.0 1741-038Ixxxxxxxx x xx x x xxxx x x I 19 69 15.0 1749+096Ixxxxxxxxx xx xx xx x x xxxxI 22 99 21.0 1921-293I x xx x xx x I 7 9 2.7 1954-388I xx xx xxx xx I 9 9 2.7 1958-179I xxxxx xx I 7 32 9.9 2121+053I x x I 2 4 .8 2145+067I x xx x x x x x x xI 10 14 2.9 2234+282I x xx I 3 9 1.3 2255-282I x x x x I 4 8 2.4 Total scans, obs: 480 1694 Average number of obs. per baseline per source (normalized by up-time) = 5.9 Min = .0 Max = 44.9 (Baseline Ft-Wf on 4C39.25 ) RMS = 10.2 Total time: 1437 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 45 49 29 52 45 44 % cal. time: 2 3 1 4 4 3 % slew time: 31 16 28 17 13 21 % idle time: 20 30 40 25 36 30 # of tapes : 2.5 .8 .5 .8 .7 total # scans: 246 337 145 371 368 293 # scans/hour : 10 14 6 15 15 12.2 Avg scan (sec): 158 126 173 122 106 137 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|246 140 107 203 172 697 Gc| 337 26 303 278 438 Hh| 145 69 106 719 Wf| 371 290 791 Wz| 368 743 Number of 2-station scans: 156 Number of 3-station scans: 158 Number of 4-station scans: 149 Number of 5-station scans: 17 Total # of scans, observations: 480 1694 Average baseline components for all observations Average XY = 5562. Average XZ = 5383. Average YZ = 5277. Average length = 6860.