IRIS-S149 (International Radio Interferometric Surveying - South) 2000 Apr. 24 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Nominal Start: 14:00 U.T. on Apr.24 (day 115) name yyddd-hhmmss Ft Gc Hh Wf Wz 0552+398 00115-140001| 90 150 150 | 1044+719 00115-140001| 90 90 | 1044+719 00115-160347| 90 90 90| ( Wz start at 115-1603 due to I00115 ) Nominal Stop : 14:00 U.T. on Apr.25 (day 116) name yyddd-hhmmss Ft Gc Hh Wf Wz 0749+540 00116-134427| 90 90 90| 0048-097 00116-135733| 250 250 200 150| 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 0003-066I x x x xx x xx x I 9 9 2.4 0048-097I x x x xx xxx xx x x I 12 40 8.7 0104-408I x xxxx xxx xxx x x I 13 13 3.9 CTA26 I xx xx x x x xxx xx I 13 15 3.5 0402-362I xx x x I 4 4 1.2 0454-234I xxx xx xx xx x xxx xx I 15 31 9.5 0458-020I x x x I 3 3 .7 0528+134Ixxxx xx xxxx x xxx x xxxxx xxx x I 24 74 15.1 0537-441I x x I 2 2 .7 0552+398Ixxx xxx xx xx x xxxxxx xx xxxx x x xxxxx xxxx xxI 37 136 24.2 0637-752I x I 1 1 .4 0718+793I x x x x x I 5 7 .9 0727-115Ixx x xxxx x x xx x I 12 28 5.9 0749+540Ix x xx xxx xx xx xxxx xx xxx x xxx x xx xxI 29 110 18.3 0804+499I x x x x x x x xI 8 34 6.7 0805+410Ix x x x xx x x x x x x x I 13 21 2.3 0823+033I x xx x x x xx I 8 12 2.5 OJ287 I xxxxxx x xxxx x I 12 12 1.9 0920-397I x x I 2 2 .6 4C39.25 I x x xx xxx x xxx x xxx xx xxxxxI 22 105 19.3 OK290 I xx xx x x x I 7 7 1.0 0955+476I x xxxxx x xx xx x xx x xxxx I 19 48 6.9 1034-293I x I 1 1 .3 1044+719I x x x x x x x x x x xx x x x xI 17 53 8.1 1057-797I x x I 2 2 .7 1124-186Ix xxx xx x x I 8 23 6.9 1128+385I x x x x x x x x xx x x x x x I 15 25 2.9 1144-379Ix x xx x xI 6 6 1.8 1300+580I x I 1 1 .1 1308+326I xx x x x I 5 5 .9 1334-127I xx x xI 4 6 1.3 1351-018I x x x x x x xI 7 7 1.7 1357+769I x x x x x x x x x x x x I 12 38 6.8 1424-418Ixx xx x x x x xI 9 9 2.7 1606+106I xx x x x xxxx xxx x x x x x I 18 26 5.0 1610-771I x x x I 3 3 1.1 1622-253I x x x xx x xx x I 9 15 4.4 NRAO512 I xx x x xxxx x x xx x xx x x xx x x xxx x I 25 102 17.8 1726+455Ixx xx x xx xx xx x x x x x I 16 38 5.2 1739+522Ix x x xx x xx x x xxxxx xx xxI 19 52 7.1 1741-038I xxxx xxxxx xx xx xxxx xxx xx xxI 24 75 16.4 1749+096Ixx x xx xxx xxx x x x xx x x x I 19 70 14.9 1921-293I xx xxxx x xxxx xxxx x I 17 31 9.2 1954-388I xxxxxxx xxxx xxx x I 15 15 4.5 1958-179I xxx xxx xxxxxxx x x I 15 57 17.5 2121+053I x x xxx x I 7 9 1.8 2128-123I x I 1 1 .3 2145+067I xx x x x xx x xx x I 11 15 3.0 2234+282Ix x x x xx I 6 8 1.1 2255-282I x xx xx x x I 7 11 3.3 Total scans, obs: 569 1418 Average number of obs. per baseline per source (normalized by up-time) = 5.0 Min = .0 Max = 38.3 (Baseline Ft-Wf on 0552+398) RMS = 7.9 Total time: 1441 minutes ( 24.0 hours). Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft Gc Hh Wf Wz Avg % obs. time: 42 46 33 56 49 45 % cal. time: 2 3 2 4 3 3 % slew time: 32 18 38 16 11 23 % idle time: 21 31 26 23 34 27 # of tapes : 2.2 .7 .5 .8 .7 total # scans: 255 330 193 386 340 300 # scans/hour : 10 13 8 16 14 12.5 Avg scan (sec): 144 122 149 125 126 133 # OF OBSERVATIONS BY BASELINE | Ft Gc Hh Wf Wz StnTotal ---------------------------------- Ft|255 73 144 166 130 513 Gc| 330 21 277 212 583 Hh| 193 59 122 346 Wf| 386 214 716 Wz| 340 678 Number of 2-station scans: 310 Number of 3-station scans: 162 Number of 4-station scans: 87 Number of 5-station scans: 10 Total # of scans, observations: 569 1418 Average baseline components for all observations Average XY = 5427. Average XZ = 5206. Average YZ = 5349. Average length = 6783.