IRIS-S167 (International Radio Interferometric Surveying - South) 2001 Oct. 01 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Oct.01 (day 274) name yyddd-hhmmss Ft Gc Hh Wf Wz 4C39.25 01274-140000| 70 70 40 40| 1749+096 01274-140310| 50 50| Nominal Stop : 14:00 U.T. on Sept.25(day 274) name yyddd-hhmmss Ft Gc Hh Wf Wz 0528+134 01275-134833| 50 50 | 1741-038 01275-134851| 180 180| 1610-771 01275-135617| 170 170 | 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 : 40 seconds. The most recent source flux models are included. SNR goals are 22 at X-band and 20 at S-band for all baselines. 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 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). Fortleza record on thick tapes (33kbpi) Hobart and O'Higgins are not able to participate. Appendix ======== SKED Summary from file is166.skd for experiment IS166 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #0BS #Obs/bl 0003-066I x xx x I 4 4 1.0 0048-097I x I 1 1 .4 0059+581I x x I 2 6 .8 0104-408I x x xx x x xxxI 9 9 2.7 0106+013Ixx x xx xx xxx x x x x x I 15 33 7.1 0119+115I x xxx xx I 6 8 1.5 0229+131I xxx xx x x x I 8 16 2.8 CTA26 Ix xx x x x xxx x x x x I 13 15 3.4 0454-234Ixx xx x x xxxxx I 11 17 5.0 0528+134I x x xx xxx xx x xxxxx x I 16 26 4.6 0537-441I xxxx xxx x xx I 10 10 3.5 0552+398Ix xxxx xxx x xx x xxxx xxxxxx xxx xxx x xx xxI 33 143 25.5 0637-752I x x I 2 2 .7 0718+793I x x I 2 2 .3 0727-115I x xxxx xxx x xx x xxxxx x x I 19 47 9.9 0749+540I x x x x x x x I 7 18 2.8 0804+499I xxx x x x x xI 8 10 1.3 0823+033I x xxx xxx I 7 7 1.5 OJ287 Ix xxx xxx xx xxx xxxxxxxx xxxxxxxxx I 29 96 18.7 0920-397I xx I 2 2 .6 4C39.25 Ixxxxxx xx xx x xxxxxxxx xxxx xxxxxx x xxxI 33 102 16.0 OK290 I x I 1 1 .1 0955+476I xx xxx xx x x xxxxx xx xx xxI 20 63 10.8 1034-293I x I 1 1 .3 1044+719I xx x x x x x x x x x x x x x x I 16 42 5.3 1057-797I x x I 2 2 .7 1053+815I x I 1 1 .3 1104-445I x I 1 1 .3 1124-186I x x x I 3 5 1.5 1128+385I xx x x xxx xx x I 10 16 1.8 1144-379I x x xx I 4 4 1.2 1255-316I x I 1 1 .3 1300+580I x x xx xx x xx x xI 11 29 3.6 1334-127I x xx x x xx I 7 13 2.8 1351-018I x I 1 1 .3 1357+769I x x x x x x x x x x x x xx x xI 16 56 11.1 1424-418I I 0 0 .0 1606+106I x x x xx xx x x x x xxxx xI 16 22 4.5 1610-771I x x x x I 4 4 1.4 1622-253I x I 1 1 .3 NRAO512 I x x x xxxx x x x I 10 14 1.5 1726+455I xx x x xxxx I 8 8 1.0 1739+522I x x I 2 2 .3 1741-038I x xx x xx x xxx xx x x x xx I 17 31 6.8 1749+096Ix xx xx x xxxx xx x x xxx x x I 19 60 12.7 1921-293Ixxxxx xxxx x x xxI 13 13 3.9 1954-388I x I 1 1 .3 1958-179Ix xx x xxx xxxxx xxx xxI 17 38 11.5 2121+053Ixxx xxx x x xx x x x x xI 15 39 8.2 2128-123I xx xx xxx I 7 7 1.5 2145+067Ixx xxxx xx xx x x x x xI 15 25 5.1 2234+282Ixx xxx xx xxx xx x x x I 15 27 3.7 2255-282I x x x xx I 5 5 1.5 Total scans, obs: 497 1107 Average number of obs. per baseline per source (normalized by up-time) = 3.7 Min = .0 Max = 33.7 (Baseline Ft-Wf on 0552+398) RMS = 6.9 Total time: 1439 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 43 48 33 59 50 46 % cal. time: 2 3 1 3 3 2 % slew time: 30 17 28 15 10 20 % idle time: 23 31 35 21 35 29 # of tapes : 2.5 .8 .5 .9 .8 total # scans: 208 292 150 332 278 252 # scans/hour : 8 12 6 13 11 10.5 Avg scan (sec): 178 142 193 154 156 164 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|208 57 99 135 105 396 Gc| 292 10 247 169 483 Hh| 150 27 94 230 Wf| 332 164 573 Wz| 278 532 Number of 2-station scans: 303 Number of 3-station scans: 128 Number of 4-station scans: 60 Number of 5-station scans: 6 Total # of scans, observations: 497 1107 Average baseline components for all observations Average XY = 5330. Average XZ = 5139. Average YZ = 5160. Average length = 6633.