IRIS-S153 (International Radio Interferometric Surveying - South) 2000 Aug. 14 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Aug.14 (day 227) 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 Aug.15 (day 228) 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 is153.skd for experiment IS153 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #O BS #Obs/bl 0003-066Ix x xx xx x x I 8 44 6.5 0048-097I xI 1 3 .4 0059+581I x x x x x I 5 27 2.3 0104-408I xx xxxxx xx x x x I 13 13 3.0 0106+013I x xx xx x x xxI 11 29 4.2 0119+041I xx x I 3 3 .4 0229+131I x x x x x xx x xxx I 11 20 2.4 CTA26 I xx xxx x x x xx x I 11 27 4.0 0402-362I xx xxxxx I 7 7 1.6 0454-234I x x x x x x x I 7 24 5.1 0458-020I x x x x I 4 10 1.5 0528+134I x x x x xxxx x xxx I 12 40 4.7 0537-441I xxxxxxxxx xx I 12 12 3.1 0552+398I xxxx xxxx xxxxx xxxxxx xxxxxxxx xxxxx xx x xxI 38 265 30.0 0637-752I x x x I 3 3 .8 0718+793I x x x x I 4 10 .8 0727-115I x xxx xxxxxx xxx x x I 15 88 13.0 0749+540Ixxxxx xxxxxxxx x xxx xxxxxxxxx xxxxxxxxxxxxxx I 41 287 30.6 0804+499I x x x xxx x x xx x x x I 13 63 5.4 0805+410I x x x x xxxx x I 9 22 1.6 0823+033I xx xxxx xxx xx xx I 13 35 4.9 0920-397I x x I 2 2 .5 4C39.25 Ixx x x x x x x xxx xxxxxxxx xxxx x x x x I 27 195 22.5 0955+476Ixxxxx xx xxx xx x xxx x x xxxx xI 24 135 13.2 1044+719I x x x xx x x x x x x x I 12 66 5.5 1057-797I x x I 2 2 .5 1124-186I x xx x x xx x xx I 10 54 11.4 1144-379I x I 1 1 .2 1308+326I x xxx I 4 6 .7 1334-127I x x x I 3 9 1.5 1351-018I xx x xxx xI 8 10 1.6 1357+769I x x x xx x x x xI 9 51 4.3 1424-418I xx xxx x x xxx x I 12 12 2.8 1606+106Ixxx xx x x x x x x xxxxxI 16 46 5.9 1610-771I x x x x I 4 4 1.1 1622-253I x x x x I 5 9 1.9 NRAO512 Ixxx x x xxxxxx xx x x xxxx xxxxx xxxxxxx xxxI 34 122 9.5 1726+455I x x x x x xx x xx I 10 36 3.2 1739+522Ix x x xx xx xxx xx x x x xx xxx x xx xx x x xI 28 159 13.3 1741-038Ixxxx x x x x xxxxxx x xx I 17 47 6.9 1749+096Ix x xxx x x x xxxx x xxx xxx x xx I 22 114 16.0 1921-293I xxxx xxx xxx x xxI 13 21 4.2 1954-388I x xxx I 4 4 .9 1958-179I x x x I 3 5 .9 2121+053I x x I 2 2 .3 2145+067Ix xx x x xxx x x x x xxxxx I 18 51 7.0 2234+282I x xxx x x xx x x I 10 32 3.0 2255-282I xx I 2 2 .4 Total scans, obs: 543 2229 Average number of obs. per baseline per source (normalized by up-time) = 4.9 Min = .0 Max = 41.0 (Baseline Gc-Wf on 0749+540) RMS = 8.7 Total time: 1445 minutes ( 24.1 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Tg=TIGOWTZL Ft Gc Hh Wf Wz Tg Avg % obs. time: 40 51 35 59 55 35 46 % cal. time: 2 3 1 4 3 3 3 % slew time: 27 17 32 15 11 11 19 % idle time: 30 27 29 20 29 48 30 # of tapes : 2.2 .8 .5 .9 .8 .4 total # scans: 195 339 161 371 328 344 289 # scans/hour : 8 14 6 15 13 14 12.1 Avg scan (sec): 178 131 193 138 145 90 145 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz Tg StnTotal -------------------------------------- Ft|195 56 113 113 86 94 462 Gc| 339 16 292 226 237 827 Hh| 161 33 91 98 351 Wf| 371 223 234 895 Wz| 328 317 943 Tg| 344 980 Number of 2-station scans: 186 Number of 3-station scans: 138 Number of 4-station scans: 154 Number of 5-station scans: 54 Number of 6-station scans: 11 Total # of scans, observations: 543 2229 Average baseline components for all observations Average XY = 4726. Average XZ = 4336. Average YZ = 4299. Average length = 5708. End of listing.