IRIS-S145 (International Radio Interferometric Surveying - South) 1999 Dec. 06 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Nov.15 (day 340) name yyddd-hhmmss Ft Gc Hh Wf Wz 1954-388 99340-140001| 70 70 | 1128+385 99340-140010| 80 140 140| Nominal Stop : 14:00 U.T. on Nov.16 (day 341) name yyddd-hhmmss Ft Gc Hh Wf Wz 1749+096 99341-135622| 70 70 70 70| 1739+522 99341-135955| 220 220 100 70| 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 : 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 ) 65% 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). Appendix ======== SKED Summary from file is145.skd for experiment IS145 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I xx x xx x I 6 6 1.5 0048-097I x x x x x xx xx I 9 38 8.2 0059+581Ixx x x x xx x x x x x x x x x xxxx xx xxx x I 26 110 20.4 0104-408Ix x x xx xxx xx I 10 10 3.0 0119+041I x xx I 3 5 1.1 0229+131I xxx x x x x I 7 13 2.4 CTA26 I x xx xx x x x xx I 11 15 3.4 0402-362I x xx xxxI 6 6 1.8 0454-234Ixxx xx x xxx x xxI 12 41 12.7 0458-020I x x I 2 2 .4 0528+134I xxxxxxxx x x xxxx xI 15 60 12.3 0552+398I xxxxx xx xxx xx xx x x x x xxx xxxxxI 26 144 27.3 0637-752I x x I 2 2 .7 0718+793I x xI 2 4 .5 0727-115Ix xxxxxx xx x I 10 46 9.9 0749+540Ixx x xx xx x xxx xx x x xxx xxx xx x xxx xxx I 30 114 19.6 0804+499I xx xx x x x I 7 34 7.0 0805+410I x x x x x x xx xI 9 17 1.9 0823+033I x x x I 3 3 .6 OJ287 I x x xxxxx xx xx xx x x x x I 17 61 11.8 4C39.25 Ix xx x xxxxx xxxxxx x xx xx x xx x xx I 26 132 24.7 0955+476Ix x x x x xx xxxxx x x x xx xxxx x I 22 65 11.1 1044+719Ix x x x x x x x x xx x x x x x x x I 18 53 7.4 1124-186I x x I 2 7 2.2 1128+385I x x x x x xx x x x I 10 18 2.1 1255-316I xxx I 3 3 .9 1308+326I x x x I 3 3 .5 1334-127I x x I 2 2 .5 1351-018I x x x x xxx xx I 9 9 2.2 1357+769I x x x x x x xx x x x x x I 13 46 9.4 1424-418I x x I 2 2 .7 1606+106I x x x x xxxx x x xxxxxxx xxxxxx I 23 25 4.9 1610-771I x x I 2 2 .8 NRAO512 I xx x x xxxx xxxx x x xx xxxx xx xI 23 105 19.8 1726+455I x x x x x x xx xxxxx xI 14 34 4.7 1739+522Ixx x x x x x x xx xx xxxxx xxx xx xxxx x x I 28 118 22.4 1741-038I xxxxxx xxxxxx x xxx x xx x x I 24 72 15.9 1749+096I x x x x xxxxxxxx x x x xx xI 18 72 15.5 1921-293I xxxxx xx x x x x I 11 23 6.9 1954-388I xx xxx xx x x I 9 9 2.7 1958-179I xx xx xx xxxxx x x I 13 34 10.3 2121+053Ix x I 2 2 .4 2128-123I xxx I 3 3 .6 2145+067Ix x x xxxx x xx x xxx xx I 17 25 5.2 2234+282Ix x x x I 4 10 1.4 2255-282I x x I 2 4 1.2 Total scans, obs: 516 1609 Average number of obs. per baseline per source (normalized by up-time) = 5.8 Min = .0 Max = 38.6 (Baseline Ft-Wf on 0552+398) RMS = 9.1 Total time: 1443 minutes ( 24.1 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 42 49 28 48 43 42 % cal. time: 2 3 2 4 4 3 % slew time: 33 18 34 18 14 24 % idle time: 21 28 34 28 37 29 # of tapes : 2.5 .8 .5 .8 .7 total # scans: 235 334 181 375 366 298 # scans/hour : 9 13 7 15 15 12.4 Avg scan (sec): 158 127 136 112 102 127 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|235 114 124 175 164 643 Gc| 334 25 303 241 382 Hh| 181 68 136 738 Wf| 375 259 751 Wz| 366 704 Number of 2-station scans: 214 Number of 3-station scans: 163 Number of 4-station scans: 121 Number of 5-station scans: 18 Total # of scans, observations: 516 1609 Average baseline components for all observations Average XY = 5471. Average XZ = 5341. Average YZ = 5374. Average length = 6858.