IRIS-S155 (International Radio Interferometric Surveying - South) 2000 Oct. 11 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 18:30 U.T. on Oct.11 (day 285) name yyddd-hhmmss Ft Gc Hh Ho Oh Wf Wz 1749+096 00285-183000| 130 90 90 130| 0537-441 00285-183100| 270 270 | 0749+540 00285-183350| 90 90 90| Nominal Stop : 18:30 U.T. on Oct.12 (day 286) name yyddd-hhmmss Ft Gc Hh Ho Oh Wf Wz 1749+096 00286-180906| 140 90 90 140| 1424-418 00286-181613| 100 100 | 0749+540 00286-182505| 90 90 90| 0106+013 00286-182550| 240 240 | 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. Wettzell, Westford, Fairbanks (Gilcreek) and HartRAO record at high (56kbpi) density (thin tape). Appendix ======== SKED Summary from file is155.skd for experiment IS155 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x xx x xxxx xx I 12 16 1.7 0048-097I x x xx x xxx I 10 10 1.3 0104-408I xxxx x xxxx x x x x xx xxx xxx xI 23 29 3.4 0106+013I x xx x xxxx x I 10 16 1.6 0119+041I x x x x x I 5 5 .5 0229+131I xxx x xxx x x I 10 10 .9 CTA26 I x x x x xxxxI 8 10 1.0 0402-362Ixx x xx x x xxxxxxx I 15 15 1.9 0454-234I x x xx xxx x x xxxxxxx I 17 21 2.7 0458-020I x xxxx x xxxx x x xI 14 14 1.6 0528+134I x x xx xxx xx I 10 22 1.9 0537-441Ix xxxxxxx x x x xxxxxxxx x xxx xx xx I 31 37 4.4 0552+398I xxxx x x xxxxxx xxxxxxxxxxxxx x xxxx xxxI 39 151 16.4 0637-752I x x xx x x I 6 6 .5 0718+793I x x I 2 2 .2 0727-115Ixxxx x xxx xxx x xxx xxxxx xx x xx I 25 50 5.4 0749+540Ixxxx xxx x x xxx xxxxxxxxx x xx xxxxxxxxxxxxxxI 42 162 18.3 0804+499Ixxx xxx x x x xxxx xx xx x xx x xI 23 49 4.3 0805+410Ixx x x xx x x x I 11 13 .9 0823+033Ix xxxxxxxx xx x I 14 16 1.6 OJ287 I xxx xxxx xxxxxx xxxxxx xx I 23 63 5.8 0920-397Ixx x I 3 3 .4 4C39.25 I x x x x xxxxxxxxxx xxxxxxxxxxx xI 31 127 11.3 OK290 I xx x xxxxx x I 9 9 .7 0955+476Ix x xx x x x x x x xx xxxxxx x I 20 57 6.6 1034-293I x I 1 1 .1 1044+719I x x x xx x x x xx x x I 12 30 2.5 1057-797I x x I 2 2 .3 1124-186I x xxx xx xx x xxxx xx xxxxx I 20 35 4.5 1128+385I x xx x I 4 4 .2 1144-379I xxx xxxx xxx I 10 10 1.3 1300+580I x I 1 1 .1 1308+326I x x I 4 4 .3 1357+769I x x x x x x x x x x x x x I 13 35 2.9 1424-418I xxxx x x xx x xx xxx x xI 18 24 2.7 1606+106I xxxxxxx x x x x x x xx xx xxxxxxI 26 28 2.5 1610-771I x x x x x x x x xI 9 9 1.1 1622-253I xxxxxx x x I 8 10 1.4 NRAO512 Ix xxxxxxx xx xxxx x x xxx xxI 22 24 1.6 1726+455I x xx x x x I 6 10 .9 1739+522Ixx xx x xx x x x x xxx x x xxxx xx xxI 25 67 5.7 1741-038I x xxxx xxx x xxxxx xxx I 23 37 3.8 1749+096Ix x x x x x xxxx x x x x xxx xxxxxxxxI 26 84 8.4 1815-553I I 0 0 .0 1921-293Ixxxx xxxx x x xxx xx xxxxxxx xxxI 32 32 3.9 1954-388I x x x x I 4 4 .4 1958-179Ix x xx xxx xx x x I 12 18 2.3 2121+053I x x xx I 4 4 .4 2128-123I xxx I 5 5 .5 2145+067Ix x xx x x xxxx x x xx x xx xxxxI 22 40 3.9 2234+282I xxx xxxxx I 8 8 .5 2255-282I x xxx xx x I 8 8 1.0 Total scans, obs: 738 1447 Average number of obs. per baseline per source (normalized by up-time) = 2.4 Min = .0 Max = 42.0 (Baseline Gc-Wf on 0749+540) RMS = 6.3 Total time: 1440 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Ho=HOBART26 Oh=OHIGGINS Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Ho Oh Wf Wz Avg % obs. time: 35 53 42 50 22 57 52 45 % cal. time: 2 4 2 2 0 4 3 2 % slew time: 29 20 38 28 2 16 11 20 % idle time: 32 21 16 18 75 20 32 31 # of tapes : 1.9 .8 .6 2.8 1.4 .8 .8 total # scans: 214 375 214 208 52 394 330 255 # scans/hour : 8 15 8 8 2 16 13 10.6 Avg scan (sec): 143 122 173 210 367 127 137 182 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Ho Oh Wf Wz StnTotal ------------------------------------------ Ft|214 70 75 8 0 153 98 404 Gc| 375 10 39 0 280 223 622 Hh| 214 111 3 18 74 291 Ho| 208 52 6 14 230 Oh| 52 0 0 55 Wf| 394 213 670 Wz| 330 622 Number of 2-station scans: 505 Number of 3-station scans: 164 Number of 4-station scans: 60 Number of 5-station scans: 9 Number of 6-station scans: 0 Number of 7-station scans: 0 Total # of scans, observations: 738 1447 Average baseline components for all observations Average XY = 5810. Average XZ = 5696. Average YZ = 4886. Average length = 7002.