CORE-3001 (Continuous Observations of the Rotation of the Earth-3001) 2000 July 12 Notes prepared by Nancy Vandenberg and Cynthia Thomas,NVI/GSFC Schedule name: jul00/c3001.skd on CDDISA Nominal Start: 18:30 U.T. on July 12 (day 194) first observation at 18:30 U.T. on 0804+499 Nominal Stop: 18:00 U.T. on July 13 (day 195) last observation at 18:16 U.T. on 0955+476 Observing Mode: 2F (see details below) Correlator: Haystack 1 letter 2 letter Station Code Code # of tapes # of obs Occupation Code Fairbanks A Gc 2 (TT) 340 40476601 Kokee K Kk 2 (TT) 286 72983001 Matera I Ma 2 (TT) 331 72435701 Onsala T On 2 (TT) 315 72137701 Westford E Wf 2 (TT) 291 72097301 Wettzell V Wz 2 (TT) 345 72247801 Purpose ======= The CORE-3 sessions mark the start of the regular CORE oberving program. These sessions will provide a monthly 72-hour continuous data set from July through December (CORE-1 + NEOS + CORE-3). There are three additional CORE-3s scheduled during October and November which also will provide at least 48 hours of continuous data. CORE-3 sessions will be recorded in a Mark 4 mode which requires that the participating stations have Mark 4 capability. Observing Mode ============== This is the first CORE session that uses a "Mark 4" style observing mode. The mode for CORE-3 uses fan-out and records on all 32 tracks to achieve a data rate of 128 Mb/s, more than twice that of the standard geodetic Mode C which is 56 Mb/s. CORE Mode "2F" (twice the standard mode C, fanned out) ----------------------------------------------------------------- Number of frequencies 14 (standard wide-band frequency sequence) Number of channels 16 (14 USB + 2 LSB) Channel bandwidth 4.0 MHz Sample rate 8 Mb/s Bits per sample 1 Total data rate 128 Mb/s Data rate on tape 4 Mb/s/track Fan-out 1:2 Tape speed 80 ips Tracks per pass 32 Passes per tape 14 Barrel roll no Track frame format Mark4 (*) The 16 recorded channels are comprised of the standard 14-channel USB frequency sequence plus the LSB channels of the first and last frequencies at X-band. The two outer X-band LSB channels give extra sensitivity. They also slightly narrow the peak of the delay resolution function, resulting in better group delay precision. The stations with VLBA backends, Fairbanks and Kokee, could use barrel roll but we will wait to use it until the Mark 4 correlator does more testing. Stations with Mark 4 formatters cannot barrel roll. (*) Special Instructions for Fairbanks and Kokee ================================================ The current version of drudg forces the recording format to "v" in the FORM command for stations that have VLBA backends, instead of honoring the format specified in the schedule file. There is some debate about the right thing for drudg to do, but the desired format on tape for the CORE-3 sessions is Mk3/4 not VLBA. Please edit your procedure library to change the one instance of the form command from "form=v..." to "form=m...". Schedule ======== This schedule was made by C. Thomas using sked. Schedule setup parameters: Early start 20 sec (*) Minimum scan length 50 sec Maximum scan length 600 sec Minimum SNR 20 at X-band, margin of 5 15 at S-band, margin of 3 (*) It is anticipated that the time required at the correlator to synchronize tapes will decrease to just a few seconds. When that capability is available, the value of early start will be lowered. Automatic scheduling setup: optimize for uniform sky coverage at all stations, maximize the number of observations, minimize slewing time, minimize time between scans, consider the top 50% of ranked scans for selection, consider the last 3 hours of scans for sky coverage calculations, minimum 50 min between scans on the same source. The characteristics of the generated schedule are listed below. These will vary slightly for each schedule that is generated. The characteristics also will change when Ny Alesund is used in the network instead of Onsala. Schedule characteristics: Average scan length 120 sec Average SNR 50 at X-band, 30 at S-band Number of observations 2700 obs Average scans per station 320 scans 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. ___________________________________________________________ | | | | | | EOP | Formal | Other | | |Parameters | Errors |Parameters|Correlation| |____________|_____________________|_________ |___________| | | | | | |X-Wobble | 67.05 micro-arcsec | UT1-TAI | 66% | | | | | | |Y-Wobble | 56.31 micro-arcsec | ------ | under 40% | | | | | | |UT1-TAI | 2.28 micro-sec | X-Wobble | 66% | | | | | | |UT1-TAI Rate| 5.38 micro-sec/sec | ------- | under 40% | | | | | | ___________________________________________________________ Flux Information ================ Program snranal compares the measured performance of a session with respect to the predicted. The program calculates an empirical flux density for each source. In order to account for changes in the flux catalog since the last update based on source modeling, the fluxes in the flux catalog for the sources in the current source catalog were adjused using the following databases: Date Session ==== ========= 00FEB01 NEOS-A353 00FEB08 NEOS-A354 00FEB08 CORE-A081 00FEB22 NEOS-A356 00FEB29 NEOS-A357 00MAR14 NEOS-A359 00MAR21 NEOS-A360 00MAR28 NEOS-A361 00APR04 NEOS-A362 00APR11 NEOS-A363 Procedures ========== Please generate the procedures for this session using drudg. SKED Summary from file ./c3001.skd for experiment C3001 (all scans with at least one subnet station) SOURCE |0 6 12 18 | #SCANS #OBS #Obs/bl 0003-066Ix x x x x x x x x x x x xx x xI 16 54 9.0 0048-097I x x x x x xx xx I 9 20 3.9 0059+581I x xI 2 4 .3 0106+013Ix x x x x x x x x x x x xx x x x x x I 19 61 8.8 0119+115Ix xx x x x x x xx x x x x x x xx xx x x x I 23 92 11.3 0119+041I x x x x x I 5 9 1.2 0229+131I x xI 2 4 .5 0235+164I x x x x x x xx x xx x x I 13 62 7.1 CTA26 I x x x x x x x x x I 9 20 3.1 0458-020Ix x x x x x xx x xx x xx x I 15 53 8.1 0528+134Ix x x x x x x x x x x x x x x x x I 17 65 7.8 0552+398I xx x x x x x x x x x x xx x x x x x x x x xI 23 201 17.0 0556+238Ix x x x x x x x x xI 10 18 1.8 0718+793Ix x x x x x x x x I 9 9 .6 0727-115I x x x x x x x x x x x x xxI 14 39 7.7 0749+540I xx x x x x x x x x x x x xx x x x xI 19 245 18.4 0804+499I x x x x x x I 6 75 5.9 0805+410I x x I 2 21 1.8 0823+033I x x x x x xx x x x x x xx x x x x x xxI 21 68 9.5 OJ287 I x x x x x xx x x x x x x x x I 15 67 7.4 0919-260I x x x xx I 5 9 4.3 0920-397I I 0 0 .0 4C39.25 I x x x x x x x xx x x x x x x x x x x x I 20 159 13.4 OK290 Ix x x x x x x x x x x x x I 13 22 2.2 0955+476Ix x x x x x x x x x x x x x x I 15 152 12.1 1044+719I x x x x x x x x x x I 10 104 7.1 1053+815I I 0 0 .0 1128+385I x x I 2 25 2.2 1219+044Ix x x xx x x x x x x x x x xx x x x I 19 59 8.1 1300+580I x x x x x I 5 46 3.5 1334-127I x xx x x x x x x x x xx x x xI 16 41 8.6 1351-018Ix x x x x xx x x x x x I 12 26 4.1 1357+769I x x x x x x x x x x x I 11 165 11.0 1606+106Ix x x x x x x x xx xx x x x x x x x x x x I 22 77 9.6 1622-253I xx x x xx x x x x I 10 16 5.8 NRAO512 I x x x x x x x x x x x x xI 13 116 9.7 1726+455I x x x x x x x x x xI 10 12 .8 1739+522I x x x x x x x x x x x I 11 106 7.8 1741-038I x x x x x x x x x xx x x xx x x x xxI 20 60 9.5 1749+096Ix x x x x x x x x x I 10 53 6.8 1908-201I x x x x x x x x x xI 10 25 7.7 1921-293Ix x x x x x I 6 6 2.6 1958-179Ix x x x x I 5 11 3.1 2121+053I x x x x x x x x x x x x x x x x x I 17 53 7.1 2128-123Ix x x x x x x x x xI 10 25 5.9 2134+00 I x x x x x x x x xI 9 15 2.1 2145+067Ix x x x x x x x x x x x x x x I 15 49 6.5 2234+282Ix x x x x x x x x x x x x x x xI 16 74 7.3 2255-282Ix x x x x I 5 5 2.1 Total scans, obs: 566 2698 Average number of obs. per baseline per source (normalized by up-time) = 6.3 Min = .0 Max = 31.1 (Baseline Gc-Kk on 2128-123) RMS = 6.8 Total time: 1427 minutes ( 23.8 hours). Key: Gc=GILCREEK Kk=KOKEE Ma=MATERA On=ONSALA60 Wf=WESTFORD Wz=WETTZELL Gc Kk Ma On Wf Wz Avg % obs. time: 36 43 48 50 47 38 43 % cal. time: 3 3 3 3 3 4 3 % slew time: 23 15 22 19 14 11 17 % idle time: 36 37 25 27 35 46 34 # of tapes : 1.1 1.3 1.4 1.4 1.4 1.1 total # scans: 340 286 331 315 291 345 318 # scans/hour : 14 12 13 13 12 14 13.3 Avg scan (sec): 90 130 125 136 138 94 118 # OF OBSERVATIONS BY BASELINE | Gc Kk Ma On Wf Wz StnTotal -------------------------------------- Gc|340 266 125 143 201 141 876 Kk| 286 57 75 163 69 630 Ma| 331 291 172 329 974 On| 315 182 303 994 Wf| 291 181 899 Wz| 345 1023 Number of 2-station scans: 164 Number of 3-station scans: 190 Number of 4-station scans: 94 Number of 5-station scans: 74 Number of 6-station scans: 44 Total # of scans, observations: 566 2698 Average baseline components for all observations Average XY = 4426. Average XZ = 3823. Average YZ = 2875. Average length = 4739.