IRIS-S143 (International Radio Interferometric Surveying - South) 1999 Oct. 25 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Sep.20 (day 263) name yyddd-hhmmss Ft Gc Hh Wf Wz 0805+410 99298-140001| 140 220 | 1610-771 99298-140011| 200 200 | 0955+476 99298-155259| 70 70 70| Nominal Stop : 14:00 U.T. on Sep.21 (day 264) name yyddd-hhmmss Ft Gc Hh Wf Wz 1726+455 99299-135639| 180 180 110| 1622-253 99299-135938| 220 220 130| 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 : 70 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 A 10 SECOND EARLY TAPE START ---------------------------------------------- Wettzell, Westford, Fairbanks (Gilcreek) and HartRAO record at high (56kbpi) density (thin tape). Appendix ======== SKED Summary from file is143.skd for experiment IS143 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x x x x xxx xx I 10 12 2.8 0048-097Ix xxx x x x x xxI 10 39 8.4 0059+581Ixx x x x x x xx x x x x x xx x xx xxx x x xx I 26 101 17.6 0104-408Ix xx xx xxI 7 7 2.1 0119+041I xx xx xI 5 9 1.9 0229+131I x xxx x x x I 7 13 2.4 CTA26 I x x x xx x I 6 8 1.8 0402-362I xx xI 3 3 .9 0454-234I x x xxxx x xx x xI 11 31 9.5 0458-020I x x I 2 2 .5 0528+134I xxx xxx xxx x x x xxx xxx x xI 20 67 14.0 0537-441I x I 1 1 .4 0552+398I xx xxxx xxxx xxx xxxxxx x xxx x x x x x x xxx I 32 150 27.3 0637-752I x I 1 1 .4 0718+793I x I 1 3 .4 0727-115Ix xx xxx xx x x x x x I 13 41 8.8 0749+540Ix xx xx x xx x xxxx xx xxx xxx xx x xx xxx xxI 31 117 20.0 0804+499I xx x x x x x x I 8 34 6.5 0805+410Ix xx x x x x xxx xx x xx I 15 23 2.5 0823+033I xx xx x I 5 7 1.5 OJ287 I x x x xxxx x x x xxx x x I 15 56 10.9 0920-397I x I 1 1 .3 4C39.25 I x xx x x xx x xxx xxx x x x xxx I 20 98 18.5 OK290 I xx x I 3 3 .4 0955+476Ix xx x x x xx xxx x xx xx x xI 18 45 6.6 1044+719Ix x x x x xx x x x x xx x x x x x I 18 53 7.4 1057-797I x x x I 3 3 1.2 1124-186I x x x x I 4 16 5.0 1128+385I x x x xx x xx I 8 12 1.4 1144-379I x x x I 3 3 .9 1255-316I x I 1 1 .3 1300+580I x I 1 3 .4 1308+326I x x x I 3 3 .7 1357+769I x x x x x x x x x x x x xI 13 45 8.9 1424-418I x x x I 3 3 1.1 1606+106Ix xx xx x xxx xxxx x x x x I 17 25 5.0 1610-771I x x x x I 4 4 1.5 1622-253I xx x I 3 5 1.5 NRAO512 Ixx xx x x x x xx xxx xx x x x xxxxx x I 24 90 15.7 1726+455Ixx x xx xx x x xx x x x x x xxx I 19 41 5.6 1739+522I xx x x xx x x x xx xx xx xxx xxx xxx xx xxxxI 30 124 22.9 1741-038I x xx x x xxx xxxx xxxxxxxx x xI 22 65 14.3 1749+096I xx xxxxx xxx xx xx xI 16 64 13.8 1921-293I x xxx xx x x x xx xx I 13 19 5.7 1954-388I x xxx x x x x xxx I 11 11 3.3 1958-179I x xxx xxxxxxxx x I 13 44 13.6 2121+053I x xx I 3 3 .6 2128-123I x x I 2 2 .5 2145+067Ixx x x xx x xx xx x x xI 15 21 4.4 2234+282I x x x x I 4 6 .8 2255-282Ix x x xxI 5 11 3.3 Total scans, obs: 529 1549 Average number of obs. per baseline per source (normalized by up-time) = 5.5 Min = .0 Max = 38.8 (Baseline Ft-Wf on 0552+398) RMS = 8.4 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 47 29 48 45 42 % cal. time: 2 3 2 4 4 3 % slew time: 31 18 33 17 14 23 % idle time: 23 29 34 28 36 30 # of tapes : 2.4 .8 .5 .8 .7 total # scans: 235 336 177 381 365 298 # scans/hour : 9 13 7 15 15 12.5 Avg scan (sec): 155 123 143 110 106 127 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|235 98 125 168 147 616 Gc| 336 21 297 246 349 Hh| 177 62 124 714 Wf| 381 261 726 Wz| 365 693 Number of 2-station scans: 229 Number of 3-station scans: 176 Number of 4-station scans: 112 Number of 5-station scans: 12 Total # of scans, observations: 529 1549 Average baseline components for all observations Average XY = 5480. Average XZ = 5256. Average YZ = 5296. Average length = 6798.