IRIS-S164 (International Radio Interferometric Surveying - South) 2001 July 23 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Jul.23 (day 204) name yyddd-hhmmss Ft Gc Hh Wf Wz 0528+134 01204-140000| 60 80 80| 4C39.25 01204-140350| 60 380 380 140 60| Nominal Stop : 14:00 U.T. on Jul.24 (day 205) name yyddd-hhmmss Ft Gc Hh Wf Wz 4C39.25 01205-134943| 60 380 380 150 40| 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 : 40 seconds. The most recent source flux models are included. SNR goals are 22 at X-band and 20 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 for is164.skd (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066Ixx x x x x xx xxI 10 17 3.9 0048-097I x x x I 3 8 1.9 0059+581I x I 1 1 .1 0104-408I xxxxxxxx xxx xx x I 16 16 4.7 0106+013Ixxxxxxxx xx xxx x x xI 16 31 6.7 0119+041I x x I 2 2 .4 0229+131I x xx x x x xxx xxx xx I 14 16 3.0 CTA26 I xxxxxxxxxxx x xxx I 16 16 3.6 0402-362I x x x I 3 3 .9 0454-234I xx x x x I 5 9 2.7 0458-020I xx xx I 4 4 1.0 0528+134I x xxx xxxxxx xxxxxx I 17 31 5.4 0537-441I xxx xxx xxx x x I 12 12 4.2 0552+398Ix xxxxxxxx x x xxxxxxx x xxxxxxxxxxxxxxxx xxx xI 42 175 30.9 0637-752I x x x I 3 3 1.1 0718+793I x x I 2 2 .3 0727-115I xxx x xx xxxxx x xxxx x I 17 53 11.3 0749+540Ixxxx xxxxxxxxxxxxx x xx xx xx x xxx xxxxxxxxxxxI 39 146 24.6 0804+499I x x x xx xxxx x x xxxxx xxx xx I 21 51 6.7 0805+410I x x x x x xxxx I 9 9 1.0 0823+033I xxx x xx xxxxx I 11 13 2.7 0920-397I x I 1 1 .3 4C39.25 Ixxx x xxxxxx xx xx xxxx xxxxxxxxx xxx xxxxxxxI 39 143 25.6 OK290 Ixx x xx xxxxxx I 11 11 1.5 0955+476Ixxx x xx xx xxx x x x x x xxx I 19 54 8.7 1044+719I x x xx x x x x x x x I 11 33 4.1 1057-797I x x x I 3 3 1.1 1124-186I x x x xx xx x xxx xx x xI 15 34 10.2 1128+385I x xx x I 4 4 .4 1144-379I x x x x x I 5 5 1.5 1308+326I xxxx I 4 4 .5 1334-127I x x x x I 5 5 1.1 1351-018I xxx xxI 5 5 1.3 1357+769Ix x x x x x x x x I 9 27 3.4 1424-418I x x xxx x xx x x I 11 11 3.2 1606+106I x xxxxxxx xx xx xxI 14 20 3.6 1610-771I x x x x I 4 4 1.4 1622-253Ix xx x x xI 6 6 1.8 NRAO512 Ixxxx xx xxxxxxx xxxxx xx x x x x xxxx x I 30 50 5.6 1726+455I xx xx x I 5 9 1.2 1739+522Ix x xx x x xxx x xx x x x x x x xx xx x I 23 65 8.2 1741-038I xx xx x xxx x x x xxxxI 17 29 6.4 1749+096I xxx xxxx xx x x xxxxxx x xxxx xxxI 26 86 18.1 1921-293I x xxxxxxxxxxxx x I 16 16 4.7 1954-388I x x I 2 2 .6 1958-179I xx x I 3 3 .9 2052-474I x I 1 1 .3 2121+053I x I 1 1 .2 2145+067Ix x x x xx xxx x x x xxI 14 20 4.2 2234+282I x x x x I 4 6 .8 2255-282I x I 1 1 .3 Total scans, obs: 572 1277 Average number of obs. per baseline per source (normalized by up-time) = 4.3 Min = .0 Max = 39.6 (Baseline Hh-Wz on 0552+398) RMS = 8.6 Total time: 1430 minutes ( 23.8 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 38 48 35 58 50 46 % cal. time: 2 4 1 4 3 3 % slew time: 31 19 33 16 11 22 % idle time: 27 27 28 20 33 27 # of tapes : 2.2 .8 .5 .9 .8 total # scans: 211 352 168 386 334 290 # scans/hour : 8 14 7 16 14 12.1 Avg scan (sec): 157 118 181 129 129 142 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|211 57 113 126 93 389 Gc| 352 19 299 222 597 Hh| 168 34 101 267 Wf| 386 213 672 Wz| 334 629 Number of 2-station scans: 344 Number of 3-station scans: 161 Number of 4-station scans: 55 Number of 5-station scans: 12 Total # of scans, observations: 572 1277