IRIS-S151 (International Radio Interferometric Surveying - South) 2000 Jun. 19 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Jun.19 (day 171) name yyddd-hhmmss Ft Gc Hh Wf Wz 4C39.25 00171-140001| 90 90 90 | 0804+499 00171-140354| 170 120 170 | 1739+522 00171-161211| 90 90| Nominal Stop : 14:00 U.T. on Jun.20 (day 172) name yyddd-hhmmss Ft Gc Hh Wf Wz 0749+540 00172-133644| 270 270 100 130| 4C39.25 00172-134816| 90 90 90 90| 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. In addtion the mobile VLBI telescope TIGOWTZL was scheduled with a "maximum scan number" approach in order to be checking equipment and to get more experience about very short baselines. It will not influence the standard IRIS schedule. 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 TIGOWZTL was schedules in the tag-along mode. Due to testing the equipment by correlating baseline Wf-Tg 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 NONE!! SECOND EARLY TAPE START ------------------------------------------------ Wettzell, Westford, Fairbanks, TIGOWTZL and HartRAO record at high (56kbpi) density (thin tape). Fortaleza record on thick tapes (33kbpi) Appendix ======== SKED Summary from file is151.skd for experiment IS151 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x xx xx x x I 8 8 2.1 0048-097I x xx x x x x x I 8 17 3.8 0104-408I x xxxxx xx xx I 10 10 3.0 0119+041I xxx x x I 5 7 1.4 0229+131I x x x x x x x I 8 10 1.9 CTA26 I x xxxx xx xxx xx I 12 12 2.8 0402-362I xxxxxx x x I 8 8 2.4 0454-234I xx xx x x x xxx xx I 12 28 8.6 0458-020I x x x I 3 3 .7 0537-441I xx I 2 2 .7 0552+398Ixxx x xxxx x xxxx xxxxxxxx xxxxxxxxxxxxx xx x I 38 157 28.7 0637-752I x I 1 1 .4 0718+793I x x x x x x I 6 6 .8 0727-115I xxx xx x x xxxx xx xx I 16 38 8.0 0749+540Ixxxxxxxx xx xxxxx xxx xx x xxx xxxxx xxxxxx xxI 37 141 23.8 0804+499I xxxxxx x x xx x xxx xxx xxxxx xxx xxxI 30 100 17.3 0805+410Ix x xxx xx x xx x x xx xx x I 17 31 3.5 0823+033I x x x x x x xI 7 9 1.9 OJ287 Ixxxxx xxx x xx x x I 13 13 2.3 0920-397I x x I 2 2 .6 4C39.25 Ix x x x x xxxxx xxxxxx xxxxxx xx xx x I 27 130 24.4 OK290 Ix x xxx xx x I 8 8 1.1 0955+476I xx xx xx x x x xx x xxI 15 41 6.4 1044+719Ixx x x xx xx x x x x x x xx x x x x I 20 59 8.6 1057-797I x x x I 3 3 1.1 1124-186I x xxx xxx x x x I 10 22 6.7 1128+385I x x x xx xxxxx x x x I 13 19 2.2 1144-379I xxx x x x x I 7 9 2.7 1308+326I x x I 2 2 .2 1334-127I x I 1 1 .2 1351-018I xx x I 4 4 1.0 1357+769I xx x x x x x x x x x x x x x xx x I 18 62 11.8 1424-418I x xx x x I 5 5 1.5 1606+106I x xxx xx x x xx xI 12 18 3.4 1610-771I x x x x I 4 4 1.4 1622-253I x x x x I 4 6 1.8 NRAO512 I x xx x xxxxx xx xxxxx x xx xxx xI 24 99 17.1 1726+455Ixx xxxxxx xx xx x xx xxxxxI 20 52 7.1 1739+522I xxxxxxx x xx xx xxxx x xxxx I 21 53 6.7 1741-038Ixxx xxxxxxxx xxx xxx xx xx x xI 23 70 15.4 1749+096Ixxx x xx xx xxx xx x x xx x xx xI 22 82 17.2 1815-553I I 0 0 .0 1921-293I xx xx xxx xxxx xx x xI 15 27 8.0 1954-388Ixxxxxxx xxx x x x xI 16 16 4.7 1958-179Ixxx xxx xxx xxx xx xx xx x I 19 54 16.4 2121+053Ix x I 2 2 .4 2128-123I x x I 2 2 .5 2145+067Ix x xx xxxx x x x x x I 13 19 3.9 2234+282I x x x I 3 3 .4 2255-282I x x x xx I 5 9 2.7 Total scans, obs: 581 1484 Average number of obs. per baseline per source (normalized by up-time) = 5.1 Min = .0 Max = 42.7 (Baseline Ft-Wf on 0552+398) RMS = 8.8 Total time: 1429 minutes ( 23.8 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 41 50 31 57 49 46 % cal. time: 2 4 2 4 4 3 % slew time: 32 19 34 16 12 23 % idle time: 22 25 31 21 34 27 # of tapes : 2.2 .8 .5 .8 .7 total # scans: 243 367 178 407 359 310 # scans/hour : 10 15 7 17 15 12.9 Avg scan (sec): 145 119 150 121 118 130 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|243 84 126 170 114 494 Gc| 367 24 309 251 668 Hh| 178 55 115 320 Wf| 407 236 770 Wz| 359 716 Number of 2-station scans: 296 Number of 3-station scans: 190 Number of 4-station scans: 83 Number of 5-station scans: 12 Number of 6-station scans: 0 Total # of scans, observations: 581 1484