IRIS-S169 (International Radio Interferometric Surveying - South) 2001 Dec. 13 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Dec.13 (day 347) name yyddd-hhmmss Ft Gc Hh Wf Wz 4C39.25 01347-140000| 70 70 40 40| 1749+096 01347-140310| 50 50| 1357+769 01347-140459| 360 250 360 310| Nominal Stop : 14:00 U.T. on Dec.14 (day 348) name yyddd-hhmmss Ft Gc Hh Wf Wz OJ287 01348-133835| 50 50 | 1741-038 01348-134628| 60 60 60| 0106+013 01348-135043| 130 130| 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 from file is169.skd for experiment IRIS-S169 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x xx x I 4 4 1.1 0048-097I x xx I 3 3 .6 0059+581I x I 1 1 .1 0104-408I x xx xx xxx xx I 10 10 3.0 0106+013I xxx x xx xxx x xx x x xI 15 23 5.0 0119+115I xx x I 3 3 .5 0229+131Ix xxxx xx x I 8 16 2.8 CTA26 I x x xxxx x xxx xI 11 11 2.4 0454-234Ix x x x x xx I 7 15 4.4 0528+134I x xxxx xxxxx x xxxI 14 24 4.2 0537-441Ixx xxx x xx xx I 10 10 3.4 0552+398Ix x x xxx xxx xxxxx xxxxx x x xx xxx xxxx xxx xI 34 133 23.2 0637-752I x x x I 3 3 1.1 0718+793I x x x I 3 3 .4 0727-115Ix x xxx xx xx xxx x x xx xxI 19 54 11.4 0749+540I x x xx x x x x I 8 22 2.8 0804+499I x x x x x I 5 11 1.4 0805+410I x xx I 3 3 .3 0823+033I x xx xxxxx I 8 8 1.7 OJ287 I x x x x xxxxxx xxx xxxx xxxx x xx xxxI 28 101 20.0 0920-397I xx I 2 2 .6 4C39.25 I x xx xx xxx xxx xxx x xx xxx x x x xx x I 27 91 14.5 0955+476Ixx x x x xx x xx xxx x xxx xx x x x xxI 24 81 14.2 1044+719I x x xx x xx x xx x x x x x x xx xI 19 55 6.9 1057-797I x x x x I 4 4 1.4 1053+815I x I 1 1 .3 1104-445I x I 1 1 .3 1124-186I x I 1 3 .9 1128+385I x xxx xx x xx x x x x x x I 15 25 3.0 1144-379I xx xxx I 5 5 1.5 1300+580I xxx x x x x x x x x x x I 13 35 4.4 1334-127I xxx xxx x xx I 9 15 3.3 1351-018I x x x I 3 3 .8 1357+769I x x x x x x x x x x x x x x x I 15 55 11.0 1606+106I xx xxx x x x x x xxxxxxxx xxx I 21 34 6.8 1610-771I x x x x I 4 4 1.4 NRAO512 Ix x x x I 4 4 .4 1726+455I x x xx xx I 6 6 .8 1739+522I x x I 2 4 .5 1741-038I x x x x x xx xx xx xxx xx x I 17 33 7.3 1749+096I x x x xxx xx xxx x x x x I 15 60 12.8 1921-293I xxxxx x xxx x I 10 10 3.0 1954-388I xx I 2 2 .6 1958-179I xxxxx xx xx xx x x xxx I 16 41 12.5 2121+053I xx x x xx xxx x x x xI 13 27 5.7 2128-123I x x I 2 2 .4 2145+067I x x x x x xx x xx xxx xxI 15 23 4.8 2234+282I x xxxxx x xx x x x x xxx I 16 22 3.1 2255-282I x xx I 3 3 .9 Total scans, obs: 482 1109 Average number of obs. per baseline per source (normalized by up-time) = 3.7 Min = .0 Max = 31.3 (Baseline Ft-Wf on 0552+398) RMS = 7.0 Total time: 1433 minutes ( 23.9 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 40 49 32 59 53 47 % cal. time: 2 3 1 3 3 2 % slew time: 28 17 31 14 10 20 % idle time: 28 29 34 22 32 29 # of tapes : 2.3 .8 .5 .9 .8 total # scans: 192 283 149 322 291 247 # scans/hour : 8 11 6 13 12 10.3 Avg scan (sec): 181 150 186 157 158 166 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|192 54 92 126 105 377 Gc| 283 12 241 173 480 Hh| 149 27 103 234 Wf| 322 176 570 Wz| 291 557 Number of 2-station scans: 283 Number of 3-station scans: 132 Number of 4-station scans: 60 Number of 5-station scans: 7 Total # of scans, observations: 482 1109 Average baseline components for all observations Average XY = 5324. Average XZ = 5153. Average YZ = 5179. Average length = 6650.