IRIS-S160 (International Radio Interferometric Surveying - South) 2001 Mar. 19 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Mar.19 (day 078) name yyddd-hhmmss Ft Gc Hh Wf Wz 0048-097 01078-140000| 250 250 240 220| 4C39.25 01078-140610| 60 60| Nominal Stop : 14:00 U.T. on Mar.20 (day 079) name yyddd-hhmmss Ft Gc Hh Wf Wz 0104-408 01079-134808| 120 120 | 0552+398 01079-135453| 100 100 60| 0059+581 01079-135818| 250 320 320| 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 : 60 seconds. The most recent source flux models are included. SNR goals are 20 at X-band and 18 at S-band for all baselines. 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). Fortleza record on thick tapes (33kbpi) Appendix ======== SKED Summary from file is160.skd for experiment IS160 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0048-097I xx x x xx I 6 18 3.8 0059+581I x xx x I 4 8 1.0 0104-408I xxxxxxxxxxx xx x x I 15 17 5.0 0106+013I x xx x xxx x x x x xx I 14 28 6.0 0119+041I x x xx I 4 4 .8 0229+131I x x x x xxx x I 8 8 1.5 CTA26 Ixxxx xxxxx xx x x x I 14 14 3.2 0402-362I x x x x I 4 4 1.2 0454-234I x xxx x x xx I 8 14 4.1 0458-020I x x x I 3 3 .7 0528+134I xxxx xx x x xx x I 11 19 3.3 0537-441I xxx x xx x I 8 8 2.8 0552+398Ixxxxxxxx x xxxx xxxxxxxx x xx xx xxxxxx xx xxxxxI 42 167 29.8 0637-752I x I 1 1 .4 0718+793I x x I 2 2 .3 0727-115I x x x xx xx xx x xx xI 13 29 6.1 0749+540Ixxxxxx xxxxxxxxxxxxx xxx xx x xxxxxx xxx x xxxxI 39 159 27.7 0804+499I x xxx xxx x x x xx x xI 15 41 5.4 0805+410I x xx x xx x x x I 9 9 .9 0823+033I xx xxxx xx x xx xxI 13 17 3.6 OJ287 Ixxxxxxxxxxxxxxxxx xxxxxx xx xxxI 28 98 18.9 4C39.25 Ixxxxxxxxxxxxx xxx x x xxxxx x x xxx xxxxxxI 34 156 28.1 OK290 I xx x xx xx x xI 10 10 1.4 0955+476Ix x x x x xxx xxx xx xx xx xx x xI 21 67 12.0 1034-293I x x I 2 2 .6 1044+719I x x x x x x x x x x x x x I 13 37 4.6 1057-797I x x x I 3 3 1.1 1124-186I x xxxx x x I 7 14 4.2 1128+385I xx x x I 4 4 .4 1144-379I x x xx I 4 4 1.2 1308+326I x I 1 1 .3 1334-127I x x I 2 2 .5 1351-018I x xxx xxx I 7 7 1.8 1357+769Ix x x x x x x x x x x x I 12 40 7.1 1424-418I xxx x x I 5 5 1.5 1606+106I x x x x xxxxxxxxxxx x x I 19 29 5.4 1610-771I x x x I 3 3 1.1 1622-253I x x xxxx I 6 6 1.8 NRAO512 I x x xxxxx xxx xx xx I 15 28 3.5 1726+455I x x x x x x xx xx I 10 18 2.4 1739+522I x x x x xxx xxxxxx x xx xxxx xxx x I 24 66 8.4 1741-038Ix x xx x xxxx xxxxxxxx x x I 20 46 10.1 1749+096Ix xx xxx x xxxxx xx xx x xx xxx x xI 24 81 17.2 1921-293I x x x xxxxx x xxxx I 14 14 4.1 1954-388I xx x I 3 3 .9 1958-179I xxx x x I 5 12 3.6 2121+053I x x x x x I 5 5 1.0 2145+067I xxxxxxxx xxx x xx x x x xx xx xx I 23 31 6.5 2234+282I x x x xx x x x I 8 10 1.5 2255-282I xx I 2 2 .6 Total scans, obs: 567 1374 Average number of obs. per baseline per source (normalized by up-time) = 4.7 Min = .0 Max = 44.7 (Baseline Ft-Wf on 0552+398) RMS = 8.9 Total time: 1442 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 37 49 30 57 52 45 % cal. time: 2 4 1 4 4 3 % slew time: 31 18 32 15 12 22 % idle time: 28 28 34 22 30 29 # of tapes : 2.1 .8 .5 .9 .8 total # scans: 219 354 162 400 347 296 # scans/hour : 9 14 6 16 14 12.4 Avg scan (sec): 146 119 165 123 131 136 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|219 82 98 156 115 451 Gc| 354 20 309 224 635 Hh| 162 37 107 262 Wf| 400 226 728 Wz| 347 672 Number of 2-station scans: 318 Number of 3-station scans: 162 Number of 4-station scans: 75 Number of 5-station scans: 12 Total # of scans, observations: 567 1374 Average baseline components for all observations Average XY = 5417. Average XZ = 5211. Average YZ = 5111. Average length = 6673.