IRIS-S158 (International Radio Interferometric Surveying - South) 2001 Jan. 08 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Jan.08 (day 008) name yyddd-hhmmss Ft Gc Hh Wf Wz 1606+106 01008-140000| 196 196 196 196| 4C39.25 01008-140539| 90 90 | 0229+131 01008-140540| 196 196| Nominal Stop : 14:00 U.T. on Jan.09 (day 009) name yyddd-hhmmss Ft Gc Hh Wf Wz 0003-066 01009-134006| 160 160| 1741-038 01009-135613| 90 90 90| 1739+522 01009-135931| 170 130 170| 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 : 90 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). Fortleza record on thick tapes (33kbpi) Appendix ======== SKED Summary from file is158.skd for experiment IS158 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066Ix xx x xxx xx x x x I 12 28 6.2 0048-097I xx I 2 2 .4 0059+581I x x I 2 6 .8 0104-408I x xxxxxxx xxxx xx I 14 14 4.1 0106+013I xx x xx xxxx x x x I 12 21 4.5 0119+041Ix x I 2 2 .4 0229+131I xx xxx xxx x x xx I 12 14 2.6 CTA26 Ix xx xxxxxx xxxx I 14 16 3.5 0402-362I x x xx x I 5 5 1.5 0454-234I x xxx x I 6 8 2.4 0458-020I xx xx x x I 6 6 1.5 0528+134I x xxxx x xx x xx x I 13 23 4.1 0537-441Ixxx x xxx xx x I 10 10 3.4 0552+398I xx xxxxxxxxxx xxxxxx x xx xxxxx x xx xxxxxxxI 38 157 27.8 0637-752I x x x I 3 3 1.1 0718+793I x I 1 1 .1 0727-115Ixxx xxxx x xxx x xx xI 15 53 11.3 0749+540I xxx x xxx xx xxxxxxxxxxxx xxx xxxx xxx xxx x xI 36 141 24.2 0804+499I x x xx x xxx x xx xx x I 16 40 5.3 0805+410I x x x xx x x xx x xI 11 19 2.2 0823+033I xx xxxx x x xx I 10 12 2.5 OJ287 I xxxxxxxx x x xx x x x x x I 17 67 12.7 0920-397I xI 1 1 .3 4C39.25 I xx xxxxxxxxxx x xxxx xxxxxxx xx x x xxI 30 137 24.5 OK290 I xx x xxxx xx I 10 10 1.4 0955+476Ix x x xxx x xxx xx x xx xxx x x x x I 22 82 14.8 1034-293Ix x I 2 2 .6 1044+719I x x x x x x xx xxx x x I 13 33 4.1 1057-797I x x I 2 2 .7 1124-186Ix x xxx x xx x x x I 11 29 8.8 1128+385I xx x x x I 5 5 .5 1144-379I x x x I 3 3 .9 1334-127I x x x I 3 3 .7 1351-018I x xx xx I 5 5 1.3 1357+769I x x x x x x x x x xx x x I 13 38 5.8 1424-418I x xx xxxx x I 8 8 2.4 1606+106I x xx xx xxx xxxxxxx xxxx I 19 30 5.7 1610-771I x x x x x I 5 5 1.8 1622-253I x x x xx x I 6 8 2.4 NRAO512 I x x x xx x x xxxx xx x x I 16 22 2.4 1726+455I x x x x xx xx xxx I 11 21 2.8 1739+522Ix xxx x xxxx x x x x x x xx xxx xx x x I 24 62 7.8 1741-038I xx x xxxx x x xxx xxx xxxx I 20 38 8.4 1749+096I xx xxxxx xxxx xx xxx x x x I 20 82 17.3 1954-388I x x xx x I 6 6 1.8 2052-474I x I 1 1 .3 2121+053Ix xx x x x I 6 6 1.2 2145+067Ix x xxx x xx x x x xx x x xI 16 22 4.6 2234+282Ix x x x x x xI 7 7 .9 2255-282I x x I 2 4 1.2 Total scans, obs: 544 1320 Average number of obs. per baseline per source (normalized by up-time) = 4.5 Min = .0 Max = 38.0 (Baseline Ft-Wf on 0552+398) RMS = 8.2 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: 39 51 32 60 52 47 % cal. time: 2 3 1 4 3 3 % slew time: 29 17 31 15 10 20 % idle time: 28 27 34 19 32 28 # of tapes : 2.2 .8 .5 .9 .8 total # scans: 211 345 161 378 325 284 # scans/hour : 8 14 6 15 13 11.8 Avg scan (sec): 161 129 172 138 140 148 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|211 71 114 128 117 430 Gc| 345 18 304 216 609 Hh| 161 35 97 264 Wf| 378 220 687 Wz| 325 650 Number of 2-station scans: 311 Number of 3-station scans: 147 Number of 4-station scans: 73 Number of 5-station scans: 13 Total # of scans, observations: 544 1320 Average baseline components for all observations Average XY = 5461. Average XZ = 5104. Average YZ = 5119. Average length = 6653.