IRIS-S152 (International Radio Interferometric Surveying - South) 2000 Jul. 24 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Jul.24 (day 206) name yyddd-hhmmss Ft Gc Hh Tg Wf Wz 0552+398 00206-140001| 100 100 100 90 90| 4C39.25 00206-140404| 90 310 310 310 110 90| Nominal Stop : 14:00 U.T. on Jul.25 (day 207) name yyddd-hhmmss Ft Gc Hh Tg Wf Wz 0727-115 00207-135631| 100 90 100 90 100| 0059+581 00207-135925| 230 310 310 310| Duration: 24 hours Correlator: BONN MK4 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 is152.skd for experiment IS152 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x xx x x xx x xx x x xI 13 54 8.1 0048-097Ix x x x xxI 6 28 4.1 0059+581I x x x I 3 18 1.5 0104-408I xxxxxxxxxxxxx xx x I 16 16 3.7 0106+013I xxx x x x xxx xx I 11 26 3.8 0119+041I x x x x I 4 6 .8 0229+131I x x x x x xx xx x x I 11 22 2.7 CTA26 I x xxxx x xx xxx I 12 34 5.0 0402-362I xxx x x x I 6 6 1.4 0454-234I xx x x x I 5 14 3.1 0458-020I x x I 2 4 .6 0528+134I x x x xxxxx xx I 10 26 3.3 0537-441I xx xxxxx xx x I 10 10 2.6 0552+398Ixx x x x x xxx xx xxx xx x xxx xxxxxxx xx xxxx I 35 228 25.8 0727-115I x xxx xx xx x x xx xxx I 15 63 9.3 0749+540Ixxxxxxxxx xxx xx x x x xxxx xxxx xxxx xxxxxxx I 36 252 26.8 0804+499Ix xxx xx xx x x x xx xI 14 64 5.5 0805+410I xx xx x xxx xx x x xxx xx x xxxxx I 23 67 5.1 0823+033I x xx xxxxxx x xxx I 14 29 4.1 0920-397I x I 1 1 .2 4C39.25 I x xxx xx x x xxxx x x x x x xxx x I 21 168 19.5 OK290 I xx x xxx xxxxx I 11 19 1.8 0955+476I x x x x xxx x xx x x xx x xI 16 99 10.7 1034-293I x x I 2 6 1.7 1044+719I x x x x x x x x x x x x x I 13 72 6.0 1057-797I x x x I 3 3 .8 1124-186I xxxx x xx xx x xx x I 13 63 13.1 1128+385I x x x xxx x x x x xx xI 13 33 2.6 1144-379I x x xx xx x I 7 7 1.6 1300+580I x I 1 3 .3 1308+326I xx I 2 6 .5 1334-127I x I 1 3 .5 1351-018Ix x x x xI 5 7 1.1 1357+769Ix x x x x x x x x x x x x I 13 75 7.6 1424-418I xxx x x x x xI 8 8 1.8 1606+106Ixx x x xxx xxx xx xI 14 35 4.6 1610-771Ix x x x I 4 4 1.1 1622-253I x x x xx xI 7 9 1.9 NRAO512 Ixxxx x xxx x x xx x x x xxx x x xx x xxxx I 27 94 7.3 1726+455I x xxx x x x xx x xx I 12 54 4.8 1739+522Ix x xxx xxx xxx x xx xx xxx xx x x xx I 26 144 12.1 1741-038Ixx x xx x x xx xxxxxx x xI 17 57 8.3 1749+096Ixxx xxx x xx x x x xx xxxx x xI 20 102 14.1 1921-293I x x xx x xx I 7 9 1.9 1954-388I x x I 2 2 .5 1958-179I x x x x x I 5 16 3.2 2121+053I x xx x I 4 9 1.2 2145+067I x x x x xxxx xx x x x xI 15 40 5.5 2234+282I x x xxx x xxx xx xxx I 14 39 3.6 2255-282I x xx xxx I 6 8 1.5 Total scans, obs: 556 2162 Average number of obs. per baseline per source (normalized by up-time) = 4.7 Min = .0 Max = 36.0 (Baseline Gc-Wf on 0749+540) RMS = 7.6 Total time: 1443 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Tg=TIGOWTZL Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Tg Wf Wz Avg % obs. time: 37 51 31 54 60 53 48 % cal. time: 2 3 1 3 4 3 3 % slew time: 30 18 33 10 15 11 20 % idle time: 29 26 32 31 19 30 28 # of tapes : 2.0 .8 .5 .7 .9 .8 total # scans: 200 345 161 312 381 338 289 # scans/hour : 8 14 6 12 15 14 12.1 Avg scan (sec): 160 129 171 150 137 138 147 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Tg Wf Wz StnTotal -------------------------------------- Ft|200 57 105 85 125 87 459 Gc| 345 14 219 295 230 815 Hh| 161 86 34 94 333 Tg| 312 218 288 896 Wf| 381 225 897 Wz| 338 924 Number of 2-station scans: 209 Number of 3-station scans: 139 Number of 4-station scans: 146 Number of 5-station scans: 54 Number of 6-station scans: 8 Total # of scans, observations: 556 2162