IRIS-S146 (International Radio Interferometric Surveying - South) 2000 Jan. 10 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Jan.10 (day 010) name yyddd-hhmmss Ft Gc Hh Wf Wz 1741-038 00010-140001| 70 70 70 70| 1044+719 00010-140334| 70 80 80| Nominal Stop : 14:00 U.T. on Jan.11 (day 011) name yyddd-hhmmss Ft Gc Hh Wf Wz 1954-388 00011-135654| 120 120 | 1739+522 00011-135837| 100 120 120| 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 is146.skd for experiment IS145 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066Ixx xx x x xx xI 9 9 2.3 0048-097I x x xxxx x xxx x x x I 13 39 8.5 0104-408I xxxxxx xx x x x I 12 12 3.6 0119+041I xx x x x I 5 7 1.5 0229+131I xx x xx x xx xxx x x x I 14 18 3.5 CTA26 I xxxxxxxx x xx xxxxx x I 17 21 4.9 0402-362I xxx xxx x xxI 10 10 3.0 0454-234Ix xx xxxx xxxxx x xx xI 16 40 12.2 0458-020I x xI 2 2 .5 0528+134I xx xxxxx x xx xx xxx x xx I 18 56 11.4 0537-441I xxxx I 4 4 1.4 0552+398Ixxxx xxxx xx xxx xx xxx xxxxxx xxxx x xxxxx I 34 144 25.6 0637-752I x x I 2 2 .7 0718+793Ix x I 2 2 .3 0727-115Ixx xxx xxx x xx x xx x xI 16 52 11.2 0749+540I x xx xx x xxx x x xxxx xxxx xxx xx xxxx x xx I 31 123 20.7 0804+499I xx x x x x x xxxxx x x x xx xx x I 20 72 12.5 0805+410I x xx xx x x x x xx x xxx xx x x xx x I 23 47 5.3 0823+033I x x x xxx I 6 6 1.3 OJ287 I x xxx xx xx xxx xx x I 14 35 6.5 0920-397I x I 1 1 .3 4C39.25 I xxx xx x xx xx xx x x x xx x xI 20 93 17.6 OK290 I x x x xx x x I 7 7 1.0 0955+476I xx x x xxxx xxx xx x I 14 32 4.3 1034-293I x I 1 3 .9 1044+719Ix x x x x x x x x x x x x x x x x x I 18 54 6.8 1057-797I x x I 2 2 .8 1124-186Ixx x x x xI 6 15 4.6 1128+385I x xx x x xxx x x xxxxx xI 16 26 3.0 1144-379I xxxxx x I 6 6 1.8 1255-316I x x I 2 2 .6 1308+326I xxx x x I 5 5 1.1 1334-127I x x x I 3 3 .7 1351-018I x x x xx xx xx I 9 9 2.2 1357+769I x x x x x x x x x x x x x I 13 45 8.1 1424-418I xx x x xxx x I 8 8 2.8 1606+106I x xx x x xx x x xxx xx xxxxx I 21 27 5.3 1610-771I x x x I 3 3 1.1 1622-253I x x x xx xx x I 8 14 4.2 NRAO512 I xxxx xx x xx xx xxxxx xx xxx x xxI 25 83 14.2 1726+455I xx xx x x x xx x x xxx xxxxx xxx x I 23 53 7.3 1739+522Ix xxxx xx xxxx xx x xx x xxx xx xx xxx xxx xx I 32 88 11.4 1741-038I xxx xx x xxxx xxxx xxxx xx x I 22 64 14.3 1749+096I x x xx xx x x xxxx xx xx I 18 81 17.4 1954-388I x xxxxxxxxxxx xxx I 15 15 4.5 2121+053I x xx x xx xx x I 9 9 2.0 2128-123I x I 1 1 .3 2145+067Ixx x xx xx xx x xxx x x xI 16 20 4.1 2234+282Ix x x x x I 5 7 .9 2255-282I x x x x x I 5 9 2.7 Total scans, obs: 602 1486 Average number of obs. per baseline per source (normalized by up-time) = 5.1 Min = .0 Max = 34.1 (Baseline Ft-Gc on 0552+398) RMS = 8.3 Total time: 1440 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 39 50 33 51 51 45 % cal. time: 2 4 2 4 4 3 % slew time: 31 20 38 17 14 24 % idle time: 26 23 25 26 29 26 # of tapes : 2.3 .8 .5 .8 .8 total # scans: 216 378 193 404 396 317 # scans/hour : 9 15 8 16 16 13.2 Avg scan (sec): 159 116 149 110 112 129 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|216 74 126 136 114 450 Gc| 378 19 320 261 674 Hh| 193 49 132 326 Wf| 404 255 760 Wz| 396 762 Number of 2-station scans: 324 Number of 3-station scans: 186 Number of 4-station scans: 79 Number of 5-station scans: 13 Total # of scans, observations: 602 1486 Average baseline components for all observations Average XY = 5455. Average XZ = 5155. Average YZ = 5153. Average length = 6700.