CORE-A082
(Continuous Observations of the Rotation of the Earth-A082)
2000 March 21
Notes prepared by
Cynthia Thomas and Dan MacMillan,NVI/GSFC
Schedule name: CA082.SKD on CDDISA
Nominal Start: 18:00 U.T. on March 21 (day 081)
first observation at 18:00 U.T. on 0119+115 for AP-GC-MA
first observation at 18:00 U.T. on 1124-186 for HH-HO-TS
Nominal Stop: 18:00 U.T. on March 22 (day 082)
last observation at 17:57 U.T. on 2145+067 for AP-GC
last observation at 17:58 U.T. on 1219+044 for HH-HO-MA-TS
Correlator: Haystack
**Frequency Sequence**: CDP-WBCA - Modified CDP wide-band SX sequence.
(720 MHz wide at X, 125 MHz wide at S),
Shifted to avoid RFI at Matera
1 letter 2 letter
Station Code Code # of tapes # of obs Occupation Code
Algonquin G AP 2 (HDT) 265 72828201
Fairbanks A GC 1 (TT) 353 40476601
HartRAO J HH 1 (TT) 198 72326201
Hobart H HO 2 (HDT) 248 72425901
Matera I MA 1 (TT) 266 72435701
Tsukuba T TS 1 (TT) 401 73452301
Purpose
=======
Comparison of simultaneous CORE-A and NEOS sessions from 1997 to 1999 show
that there are significant systematic differences between EOP estimates from
the two networks. In addition, a bias can be seen between the CORE-A network
of 1999, which replaced Hobart with Medicina, and the network for the
previous two years. Further investigation is necessary to determine how to
minimize this network sensitivity. Therefore, we plan to continue the CORE-A
sessions in 2000 to provide more comparison data. The planned network for 10 of
the sessions will be the 1998 network with Tsukuba replacing Westford, which
will improve the formal uncertainties of polar motion estimates by a factor
of 1.5-2.0. Westford participated in the other three sessions since Hobart was
not available.
Schedule
========
This is a new schedule generated by C. Thomas with the automatic mode of
sked. Following are the characteristics of the CORE-A schedule file:
1) This schedule was optimized for sky coverage.
2) Only the observations in the previous 3 hours of the schedule were
considered for the minor options. The best 50% of the configurations
were considered for minor options.
3) The "minor options" were set to select observations to maximize the
total number of observations, to minimize the idle time between scans,
and to minimize time between scans on the same source by thirty minutes.
5) The minimum SNR limits for the baselines were set to 20 for X-band
and 15 for S-band.
6) This schedule was made using 63 sources which helped improve the sky
coverage.
Simulation Results
==================
Simulated data from this schedule was used in a global solution to
estimate the formal errors. The table below lists the formal errors
for Earth orientation parameters. These results meet the simulation
goals for the CORE-A network.
Also shown in the table are the maximum correlations between the Earth
orientation parameters and other parameters. The results from the 1998
CORE-A network showed very high (~70%) correlations between certain
parameters and this was one of the motivations for re-design of the
network.
____________________________________________
| | | | |
| EOP |Formal| Other | |
|Parameters |Errors|Parameters|Correlation|
|____________|______|_________ |___________|
| | | | |
|X-Wobble | 34.78| ------- | under 40% |
| | | | |
|Y-Wobble | 38.50|Tsukuba Z | 48% |
| | | | |
|UT1-TAI | 2.28|Tsukuba X | 43% |
| | | | |
|UT1-TAI Rate| 4.44| ------- | under 40% |
| | | | |
____________________________________________
Flux Information
================
Several years ago John Gipson wrote a program called snranal which
compares the measured performance of an experiment with respect to the
predicted. One of the things this program calculates is an empirical
flux density for each source. Recently J. Gipson compared the fluxes
generated by this program with those from more careful modeling. The
agreement is generally good (~15%) for those sources which have been
observed more than 20 times. In order to account for changes in the flux
catalog since the last update, J. Gipson adjusted the fluxes in the flux
catalog for the sources in the current source catalog using the following
databases:
Date Experiment
==== ==========
99NOV02 CORE-A074
99NOV02 NEOS-A340
99NOV09 NEOS-A341
99NOV16 NEOS-A342
99NOV30 NEOS-A344
99DEC14 NEOS-A346
99DEC21 NEOS-A347
99DEC28 NEOS-A348
Procedures
==========
Please generate the procedures for this session using drudg.
Correlation
==========
This experiment will be correlated at the Haystack Correlator with all
baselines being correlated.
SKED Summary from file ./ca082.skd for experiment CA082
(all scans with at least one subnet station)
SOURCE |0 6 12 18 | #SCANS #O BS #Obs/bl
0003-066I I 0 0 .0
0048-097I xx x xxx xI 7 15 3.1
0059+581I x xx x x x x x x x x xx xx xI 16 32 3.2
0104-408I xxx x xx x xx x x x xx x I 15 19 5.6
0119+115I xx x x xx x xxx x x x xx x x x I 18 46 6.7
0119+041Ixx xxx x xxx x x xx x x xx I 17 29 4.3
0208-512I I 0 0 .0
0229+131I xxx x x xx x x I 9 11 1.3
0235+164Ixx x xx x x x x x x x I 12 43 5.6
CTA26 I x x xx x x x x x x x x x x I 14 14 2.2
0402-362I x x x I 3 3 .9
0454-234I x xxx xxx xx x x x x xxx x x x I 19 23 4.1
0458-020I xx x xxxx x x x x x x I 13 33 5.3
0528+134Ix xx x x x xx x x x x x x I 14 22 2.8
0537-441I x xx x x xx x x xx xx I 13 15 4.4
0552+398I x x x xx xx xxx xxx xx x x xx x x x x xI 24 90 10.1
0556+238Ix x x xx xx xx x x x x x x x x I 17 19 2.0
0637-752I x x x x x I 5 5 2.0
0727-115I x x xxxx xxx xx xxxxxx x xx x I 21 25 3.7
0749+540I x x x xx x x x x x x x xI 13 64 6.5
0804+499I x x x x I 4 18 2.0
0805+410I x x x xI 4 10 1.0
0823+033I xx x x x xxx xxxx xxxx xx x x xxxI 23 27 3.9
OJ287 I x x x x x xx xxx x x I 12 25 3.2
0919-260I I 0 0 .0
0920-397I I 0 0 .0
4C39.25 I x x x x x x x xx xx x xx x x x xI 18 61 7.5
OK290 I xx x xx x x x xxx xx x I 14 16 1.7
0955+476I x x x x x x x x x x xx I 12 40 4.6
1034-293Ix x xxx x x xxx xx x xx x x I 17 17 2.7
1044+719I x x x x x x x x x x I 10 32 3.2
1053+815I I 0 0 .0
1057-797I x x x x I 4 4 1.6
1104-445I x I 1 1 .3
1124-186Ix x x x xxxx xxx xxx x xxxx xxx xxxI 25 37 6.9
1128+385I x x I 2 6 .5
1144-379Ix xx x xx x x x xx x x I 13 19 5.7
1219+044I xx x x xx x xxx x xx xxxx x xxxx xx xxx xxI 29 77 11.4
1255-316I I 0 0 .0
1300+580Ix x x x x x x x x x I 10 24 2.4
1313-333I I 0 0 .0
1334-127Ix x x x x x xx x xx I 11 21 6.0
1351-018I x x x xx x x xx x x x I 12 12 1.9
1357+769I x x x x x x x x x I 9 48 4.8
1424-418I x x x x I 4 6 1.8
1451-375I x x I 2 2 .6
1606+106I xxxx x xxx xx xx xxx x xx xx xxxxx xx x I 28 66 9.0
1622-253I x xx xxx xx x x x x x xx x xI 17 19 3.5
NRAO512 I x x x x x xx xx xx x x xx I 15 43 4.3
1726+455Ix x x x x x x x x xx I 11 17 1.9
1739+522Ix x x x x x x I 7 9 1.0
1741-038Ix xx x xxxx x x x xx x xxxx xx xxxx xx I 26 28 4.6
1749+096Ix x x x x x x xI 8 28 4.1
1815-553I x x I 2 2 .8
1908-201I x x x x x xx x xx x xxI 13 13 2.3
1954-388Ix x x xx x x xxx xI 11 11 3.0
1958-179I x x xx x xxx xxx x xx x x I 16 31 6.3
2052-474Ix xx I 3 3 .8
2121+053Ix xxx xx xx xxxx xx x xx xx x xx x x xx xxxI 29 71 10.4
2128-123I x xx x I 4 4 2.2
2145+067I x x x x I 4 9 1.3
2234+282I xx x x x x x xx xx x xx xx x xxI 19 46 4.8
2255-282I x x I 2 2 .6
Total scans, obs: 701 1413
Average number of obs. per baseline per source (normalized by up-time) = 3.6
Min = .0 Max = 31.7 (Baseline Hh-Ma on 2121+053) RMS = 5.9
Total time: 1440 minutes ( 24.0 hours).
Key: Ap=ALGOPARK Gc=GILCREEK Hh=HARTRAO Ho=HOBART26 Ma=MATERA
Ts=TSUKUB32
Ap Gc Hh Ho Ma Ts Avg
% obs. time: 25 39 31 29 40 42 34
% cal. time: 3 4 2 2 3 4 3
% slew time: 52 24 40 32 18 17 31
% idle time: 18 31 25 35 37 35 30
# of tapes : 1.6 .7 .5 1.8 .7 .8
total # scans: 265 353 198 248 266 401 288
# scans/hour : 11 14 8 10 11 16 12.0
Avg scan (sec): 82 97 138 101 131 90 106
# OF OBSERVATIONS BY BASELINE
| Ap Gc Hh Ho Ma Ts StnTotal
--------------------------------------
Ap|265 205 35 9 117 94 460
Gc| 353 9 57 92 236 599
Hh| 198 72 139 40 295
Ho| 248 22 200 360
Ma| 266 86 456
Ts| 401 656
Number of 2-station scans: 425
Number of 3-station scans: 224
Number of 4-station scans: 51
Number of 5-station scans: 1
Number of 6-station scans: 0
Total # of scans, observations: 701 1413
Average baseline components for all observations
Average XY = 5243.
Average XZ = 6107.
Average YZ = 5691.
Average length = 7443.