IRIS-S148 (International Radio Interferometric Surveying - South) 2000 Mar. 27 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Mar.27 (day 087) name yyddd-hhmmss Ft Gc Hh Wf Wz 0402-362 00087-140001| 300 300 | 1726+455 00087-140011| 130 130 110| Nominal Stop : 14:00 U.T. on Mar.28 (day 088) name yyddd-hhmmss Ft Gc Hh Wf Wz 0805+410 00088-135434| 150 150| 2255-282 00088-135827| 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 ) 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 NONE!! SECOND EARLY TAPE START ------------------------------------------------ Wettzell, Westford, Fairbanks (Gilcreek) and HartRAO record at high (56kbpi) density (thin tape). Fortaleza record on thick tapes (33kbpi) Appendix ======== SKED Summary from file is148.skd for experiment IS148 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS 0104-408I xx xxxxxxx x x x I 12 12 3.6 0229+131Ix x x x x x x x x x xxxx x I 16 20 3.7 CTA26 Ix x x xxxxxx x x x x xI 16 20 4.6 0402-362I xxxxxxxxx x I 10 10 3.0 0454-234I x x xxxx x x xx xxxI 15 27 8.0 0458-020I x I 1 1 .3 0528+134I xxxx xx xxxxxx x x x xxxxxxxxI 25 75 15.2 0537-441I xx I 2 2 .7 0552+398Ixx x xxx xxxx xxxxxxx x x x xxxxxx xxxxxxxxxI 36 147 25.9 0637-752I x I 1 1 .4 0718+793I x x I 2 2 .3 0727-115Ix x xx xxx xxxxx xx xxI 16 50 10.6 0749+540I x xx xx x xxx xx xxx xxxx xx xx x xx xx x xxI 30 121 20.7 0804+499I x xx x x xx x x I 9 28 5.4 0805+410I x x xx xxxx x xxx x x x x xx x x x x xI 23 37 4.0 0823+033I x xxx I 4 6 1.3 OJ287 I x xxx xxxx x xxx x x I 14 28 5.1 0920-397I x x I 2 2 .6 4C39.25 Ix xx xx x x xx xx xxxxx xxx x I 20 115 21.8 OK290 I x xxxxx x x x xx I 11 11 1.5 0955+476Ix x xxx xx xxxxxx x xxx x x x I 20 54 8.2 1034-293I x I 1 1 .3 1044+719I x x x x x x x x x x x x x x x xx I 17 52 7.2 1057-797I x x x I 3 3 1.1 1124-186I x x I 2 7 2.2 1128+385I xx xx x x x x x xxx xx x I 15 25 2.9 1144-379I x x x x I 4 4 1.2 1255-316I x x I 2 2 .6 1308+326I x x xxx I 5 5 1.1 1334-127Ix I 1 1 .2 1351-018I xx x x xxx I 7 7 1.7 1357+769I x x x x x x x x x x x x xI 13 46 8.8 1424-418I xx x xx x I 6 6 1.8 1606+106I xxx x x xxxxx xx xxxx x xxI 20 30 5.7 1610-771I x x x I 3 3 1.1 1622-253Ix x x x xxxxx I 9 15 4.4 NRAO512 Ix xx x xx xxx xxxxxxxx x xxxxx x xxx x xI 29 122 21.3 1726+455I xx x xx xxx xx xxxxxx x xx x x I 21 47 6.4 1739+522Ixx x x xx xxx xx x x xx x x I 17 45 5.7 1741-038I x xx x xxxx xxx xx xxx x xx xxI 22 70 15.3 1749+096Ix xxx x xx xxx x xx xxx x xx x I 20 69 14.6 1815-553I I 0 0 .0 1921-293I xxxxxxxx x xxxxx xx x I 17 33 9.8 1954-388I xx xxxxx xxxxxxx xx I 17 17 5.1 1958-179I x xxxx xxxxxxx x xx I 15 47 14.3 2121+053I x x x x I 4 6 1.2 2128-123I x I 1 1 .3 2145+067I x x x xxx x x x x x xx x I 14 16 3.3 2234+282I x x x I 3 3 .4 2255-282I x xxx x I 5 11 3.3 Total scans, obs: 578 1463 Average number of obs. per baseline per source (normalized by up-time) = 5.1 Min = .0 Max = 40.2 (Baseline Ft-Wf on 0552+398) RMS = 8.4 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: 41 49 33 55 48 45 % cal. time: 2 4 2 4 4 3 % slew time: 31 19 36 17 11 23 % idle time: 24 26 28 23 35 27 # of tapes : 2.2 .7 .5 .8 .7 total # scans: 249 355 193 392 347 307 # scans/hour : 10 14 8 16 14 12.8 Avg scan (sec): 144 121 148 121 121 131 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|249 87 137 162 126 512 Gc| 355 25 303 227 642 Hh| 193 54 123 339 Wf| 392 219 738 Wz| 347 695 Number of 2-station scans: 310 Number of 3-station scans: 169 Number of 4-station scans: 86 Number of 5-station scans: 13 Total # of scans, observations: 578 1463 Average baseline components for all observations Average XY = 5451. Average XZ = 5251. Average YZ = 5283. Average length = 6782.