IRIS-S150
(International Radio Interferometric Surveying - South)
2000 Mai. 08
Notes prepared by Arno Mueskens
Geodetic Institute of the University of Bonn, Germany
Nominal Start: 14:00 U.T. on May.08 (day 129)
name yyddd-hhmmss Ft Gc Hh Wf Wz
0552+398 00129-140001| 90 90 200 200 90|
Nominal Stop : 14:00 U.T. on May.09 (day 130)
name yyddd-hhmmss Ft Gc Hh Wf Wz
0104-408 00130-135307|100 100 |
0955+476 00130-135518| 90 90|
OJ287 00130-135731| 110 110|
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.
In addtion the mobile VLBI telescope TIGOWTZL was scheduled with a
"maximum scan number" approach in order to be checking equipment
and to get more experience about very short baselines.
It will not influence the standard IRIS schedule.
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
TIGOWZTL was schedules in the tag-along mode.
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, TIGOWTZL and HartRAO record
at high (56kbpi) density (thin tape).
Fortaleza record on thick tapes (33kbpi)
Appendix
========
SKED Summary from file is150.skd for experiment IS150
(all scans with at least one subnet station)
SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl
0003-066I xx x x x x I 6 10 1.7
0048-097I x x x xx x xx x x I 10 50 7.6
0104-408I x x xxxxxx x xx I 11 11 2.5
0119+041I x x x x I 4 4 .5
CTA26 I x xxx x xxxxxxx I 12 20 3.1
0402-362I xx xxx xxx I 8 8 1.8
0454-234I xx xxx xx x xx x I 13 65 14.1
0458-020I x x I 2 2 .3
0528+134Ixxx x xxxxxx xx xx xxxx xxI 21 84 11.2
0537-441I x I 1 1 .3
0552+398Ix xx x x x xxxxxx x xxxxxxxxxxxxx xxx xxxxxxxxI 39 283 33.1
0718+793I x x I 2 6 .5
0727-115Ix x xxx xx x x x xx x xI 14 56 8.2
0749+540I xx xx xxxxxxxxxxx xxxxxxx x xx xxxxx xxxx xxxI 37 260 27.6
0804+499I xx x x x xxx xxxx x xxxx xxxx x xxxxx x xx I 32 199 21.3
0805+410I x x xxxx xxx xxx x xx x xx x xx x I 23 73 5.5
0823+033I x xx x x I 5 12 1.7
OJ287 Ix xxxxxxx x xx x x x I 14 28 3.3
0920-397I xxx I 3 3 .7
4C39.25 I xxxxxx x x x xxxxxx xxxx xxxx xxx xxxxI 31 255 30.1
OK290 Ixx x x x x I 6 14 1.4
0955+476I x xx x xx x xx x xxxx x x I 16 93 9.3
1034-293I x I 1 3 .8
1044+719I x x x x x x x xxx xx xxx x x x x x xI 21 125 11.1
1057-797I x x x x I 4 4 1.1
1124-186I x x xxx x xI 7 20 3.9
1128+385I x x x x x x x x x x I 12 37 2.9
1144-379I x x x x xxxI 7 9 2.1
1308+326I x xx I 3 5 .8
1351-018Ix xx x x x I 6 12 1.9
1357+769I x x x x x x x x x x x x xx x x I 16 101 10.2
1424-418I xxx x x x I 6 6 1.4
1606+106I x x xxx x x x xx x x x x I 14 38 4.9
1610-771I x x x x I 4 4 1.1
1622-253Ix xx x x I 5 12 2.6
NRAO512 I xxxx xxx xx x xxx x xx x x x I 20 166 18.6
1726+455Ix xx xx xx xxx x x x x x I 16 77 6.8
1739+522I xxxxxxx xx xx x x xx x xx I 19 103 8.6
1741-038I x x xx xx x xxx xxxx xxx xxx I 21 100 14.7
1749+096I xxxx x x xxx xx xx xx x x x x I 21 137 19.1
1815-553I I 0 0 .0
1921-293I x xxx xxx xxxxx xxx I 16 56 12.6
1954-388I xxx xxx xxx xx xx I 15 15 3.5
1958-179Ixx x x x xxxx xxx xx x I 15 81 16.9
2121+053Ix x x x I 4 6 .8
2145+067I x x xx x xx xx xx x xI 13 35 4.8
2234+282I x x xx xI 5 12 1.1
2255-282I x x x x x I 6 10 1.9
Total scans, obs: 587 2711
Average number of obs. per baseline per source (normalized by up-time) = 6.2
Min = .0 Max = 44.9 (Baseline Ft-Wf on 0552+398) RMS = 9.9
Total time: 1439 minutes ( 24.0 hours).
Key: Ft=FORTLEZA Gc=GILCREEK Hh=HARTRAO Tg=TIGOWTZL Wf=WESTFORD
Wz=WETTZELL
Ft Gc Hh Tg Wf Wz Avg
% obs. time: 42 51 32 39 56 50 45
% cal. time: 2 4 2 4 4 4 3
% slew time: 31 19 37 12 15 11 21
% idle time: 23 24 27 44 22 33 29
# of tapes : 2.6 .9 .5 .5 1.0 .8
total # scans: 253 377 191 375 407 369 328
# scans/hour : 10 15 7 15 16 15 13.7
Avg scan (sec): 146 118 148 90 120 117 123
# OF OBSERVATIONS BY BASELINE
| Ft Gc Hh Tg Wf Wz
----------------------------
Ft|253 98 135 173 132
Gc| 377 27 325 255
Hh| 191 57 130
Tg| 353
Wf| 407 240
Wz| 369
Total # of scans, observations: 587 1611
Average baseline components for all observations
Average XY = 4734.
Average XZ = 4578.
Average YZ = 4543.
Average length = 5909.