IRIS-S121 (International Radio Interferometric Surveying - South) 1997 Dec.15 Notes prepared by Arno Mueskens Geodetic Institute of the University of Bonn, Germany Schedule name: is121.skd on CDDISA [dec97] Nominal Start: 12:00 U.T. on Dec.15 (day 349) name yyddd-hhmmss Gc Hh Wf Wz Ft NRAO512 97349-120000| 120 160 160 70 70| Nominal Stop : 12:00 U.T. on Dec.16 (day 350) name yyddd-hhmmss Gc Hh Wf Wz Ft 1921-293 97350-115515| 70 70 70| 1351-018 97350-115716| 240 240 | NRAO512 97350-115930| 150 195 | 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. With the addition of Fairbanks this network produced excellent EOP results. This network with long noth-south and east-west baselines as well as the wideband capability provides a good EOP determination even with the inclusion of the O'Higgins antenna. 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 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 21 at X-band and 16 at S-band for all baselines. On the baseline HartRAO-Fortaleza the SNR goal for the X-band is 30. 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, . local 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 25 min 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. FREQUENCY SEQUENCE: The NEOS-wideband RF band frequency sequence ------------------ is used for this experiment. THIS SCHEDULE HAS A 10 SECOND EARLY TAPE START: ----------------------------------------------- To gain synchronization time at the correlator. REMARKS: ======= FORTLEZA tagalong ----------------- Fortaleza was scheduled in the tagalong mode. Because it's not clear if Fortaleza will be up by December 15. WESTFORD and FAIRBANKS RECORDING ON THIN TAPES --------------------------------------------- Westford will record this session at high (56kbpi) density !! Fairbanks (Gilcreek) will record this session on thin tape with low (33kbpi) density !! Correlation =========== This experiment will be processed at Bonn in one correlation pass with all baselines to be correlated. An extra correlation report will be sent after completion. Appendix ======== SKED Summary from file is121.skd for experiment IRS121 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066I x x x x x x I 6 6 1.7 0048-097I x x x xx xxx x x I 10 20 4.3 0059+581Ix xxx xx x xx x xxxxxx xx xxx xx xxx x x x x x I 31 91 11.4 0104-408I x x I 2 4 1.2 0119+115I x x x x x x x x xx x x x xI 14 20 3.8 0119+041Ix xx x x x x x xI 9 13 2.7 0229+131Ix x x I 3 5 .9 CTA26 I x x x I 3 3 .8 0454-234I x x x x x xI 6 11 3.4 0458-020Ix x x x x x x x x x I 10 10 2.3 0528+134Ixxx xxxx xx xx x x x x x x x x xxx I 24 55 11.0 0552+398Ixxxxxxxx xxxx xxxx xxx x x x xx x xxxxx xxxxI 35 160 28.5 0718+793I x x I 2 4 .5 0727-115Ix x x xxx xx x x x I 11 35 7.4 0749+540I xxxx xxxx xxx xxxxxxxxxxxxxx xx xxx x xxx xx xI 38 112 14.0 0805+410I x x x xI 4 6 .6 0823+033I x x x x x xxx x x xxx x I 14 16 3.4 4C39.25 Ixx xxxxxxxxx xx x xxxxxxx x xx xx x x x xx xI 34 145 25.5 OK290 I xx xx x x x x x I 9 9 1.3 0955+476Ix xx xx xx xx xx xx xx xx xx x x x x x I 26 72 9.8 1034-293I x x x x x I 6 8 2.3 1044+719I x xx x xx x x xxxxxxx xxxxxx x xx x x x x I 28 84 10.5 1124-186I x x x x I 4 8 2.6 1128+385I x x x I 3 12 2.2 1255-316I x I 1 1 .3 1308+326I x x x x x x x x xx x x x xx x I 16 33 5.2 1334-127I x x x I 3 5 1.1 1351-018I x x xx x x x x I 8 8 1.9 1357+769I x xx x x x x x x I 9 27 3.4 1606+106I x xx x x x x x xx x x xx x I 15 21 4.2 1622-253I x I 1 1 .3 NRAO512 Ix x x xx xx x xxxxxxxx xx x x xx xxx x xxx x I 33 102 17.1 1726+455I xx x x x x I 6 16 2.2 1739+522I xx x xx xxx xx xx xxx xxxx x xx x xxx xxx xxI 33 99 12.9 1741-038I xxxxxxx xx xx xx I 13 50 10.8 1749+096I x I 1 3 .6 1921-293I x xx x x x I 6 16 4.7 1958-179I x xx I 3 10 3.1 2121+053I x I 1 3 .6 2128-123I x x I 2 4 .9 2145+067I xx x xx xxx I 8 20 4.1 2234+282I x x x x xx x x x xI 10 26 3.7 Total scans, obs: 501 1354 Average number of obs. per baseline per source (normalized by up-time) = 4.2 Min = .0 Max = 42.5 (Baseline Hh-Wz on 0552+398) RMS = 8.6 Total time: 1441 minutes ( 24.0 hours). Key: Gc=GILCREEK Hh=HARTRAO Wf=WESTFORD Wz=WETTZELL Ft=FORTLEZA Gc Hh Wf Wz Ft Avg % obs. time: 41 22 53 51 9 35 % cal. time: 4 1 4 4 0 3 % slew time: 21 20 18 14 10 17 % idle time: 33 55 22 29 78 43 # of tapes : 1.1 1.3 .8 2.8 1.3 total # scans: 372 126 415 402 75 278 # scans/hour : 15 5 17 16 3 11.6 Avg scan (sec): 95 153 111 109 113 116 # OF OBSERVATIONS BY BASELINE | Gc Hh Wf Wz Ft StnTotal ---------------------------------- Gc|372 36 339 287 33 704 Hh| 126 62 116 44 805 Wf| 415 319 63 266 Wz| 402 55 481 Ft| 75 452 Number of 2-station scans: 178 Number of 3-station scans: 270 Number of 4-station scans: 41 Number of 5-station scans: 12 Total # of scans, observations: 501 1354 Average baseline components for all observations Average XY = 5586. Average XZ = 5111. Average YZ = 4936. Average length = 6643.