Session Notes for rd1610 Prepared by K. Baver, NVI, Inc./GSFC =========================================================== Purpose and general notes: IVS-INT01 schedules currently use all geodetic sources that are visible to the Kokee-Wettzell baseline. But tests have indicated that the use of a restricted set of sources is likely to reduce the sessions' UT1 formal errors. The geodetic sources that are mutually visible at Kokee and Wettzell are well-distributed in the sky but include weaker sources that, if scheduled, can reduce the number of observations and increase the UT1 formal error. The use of Sked's bestsource command to select a smaller number of well-distributed, but, on average, stronger sources is expected to address the problem of weak sources and to lower the UT1 formal error. Tests using the metric of the UT1 formal error, as well as secondary metrics, such as robustness against source loss, indicate that selecting 50 sources through the bestsource command is a promising strategy. We divide the eight stations in this session into two subnets which are scheduled independently: 1.) The first subnet is Fortaleza, Hartrao, Hobart26, Kashim34, Nyales20, and Onsala60. This runs from 17:30 on October 5 to 17:30 on October 6. This network will observe independently of the second subnet and will serve as an independent external check on EOP obtained from the second subnet. 2.) The second subnet is the intensive network of Kokee-Wettzell. This will start at 18:00:32 on October 5 and end with a final observation at 17:50:59 on October 6. These observing times are offset from the standard RD1610 observing times of 17:30 October 5 through 17:30 October 6 by special arrangement. These times are necessary to observe specific areas of the sky as explained below. Unlike 24 hour sessions, which can observe the whole sky, intensives can observe only a small slice of the sky, and this slice varies depending on the day of the year and the time of day when the intensive starts. The slice of sky observed is likely to have different distributions of sources at different times, in extreme cases offering sparse coverage or exceptionally good coverage, as well as variations in the strengths of the observable sources. Because of this, the results from intensive sessions will depend partly on what part of the sky is observed, and any tested strategy should be compared to the use of a control strategy that observed the same part of the sky. The GST at which an intensive session starts identifies the area of the sky observed. The goal of RD1610 and a companion R&D session, RD1608, is to observe 24 areas of the sky with both the standard IVS-INT01 list of sources and a test list. In each R&D session, the Kokee-Wettzell network was scheduled as a series of 24 consecutive, independent pseudo-intensives using the alternating strategies of a) using the full geodetic source list, which is the standard IVS-INT01 strategy and serves here as the control strategy and b) selecting 50 sources from the geodetic source list using the Sked program's bestsource command (the test strategy). In RD1610, the intensives that start at odd hours of GST (GST 01:00, 03:00, ..., 23:00) are scheduled using the full geodetic source list and are the control intensives. The intensives that start at even hours of GST (e.g., 00:00, 02:00, ..., 22:00) are scheduled using the restricted source list that contains 50 sources and are the test intensives. This source list was selected using a flux catalog developed on September 26, 2016, and fluxes from the September 26, 2016 flux catalog were used for both the control and the test pseudo-Intensive sessions. In the companion R&D, RD1608, the strategies were switched, so that pseudo-intensives that started at odd hours of GST were scheduled as test intensives and ones that started at even hours of GST were scheduled as control intensives. This will allow the direct comparison of the two techniques at 24 starting GST times (00:00, 01:00, ..., 23:00). The GSFC IVS Analysis Center will analyze the 24 pseudo intensive sessions with a goal of determining if one of the scheduling strategies is better in terms of metrics such as lower UT1 formal errors, better agreement with independent measures of UT1, and robustness. =========================================================== ----- Parameter listing -------------------------------------- Experiment: RD1610 Description NEOSA Scheduler: NASA Correlator: HAYS Start: 2016-279-17:30:00 End: 2016-280-18:00:32 Current yyyyddd: 2016279 (2016.76) ( 17667 MJD, WED. 5OCT.) Greenwich sidereal time: 18:29:16 (17:30:00 UT) Sun's RA and DEC: 12h 47.5m -5d 5.7 =========================================================== First observations Observation listing from file ./rd1610.skd for experiment RD1610 Source Start DURATIONS name yyddd-hhmmss Ft Hh Ho Kb Kk Ny On Wz 2113+293 16279-173000| 400 400 400 400 400 | 1418+546 16279-173851| 68 60 68 | 0256-005 16279-173904| 60 60 | 0202+319 16279-174214| 60 60 60 60 | 1519-273 16279-174345| 114 114 | 0016+731 16279-174505| 60 60 60 | 0804+499 16279-174713| 111 111 | 0808+019 16279-174910| 60 60 | 1751+288 16279-175116| 109 60 65 109 | 0537-441 16279-175216| 60 60 | 0606-223 16279-175441| 60 60 | 1741-038 16279-175447| 60 60 60 | 0955+476 16279-175715| 109 109 | 0402-362 16279-175716| 60 60 | 0544+273 16279-180012| 62 62 | 2300-683 16279-180028| 65 65 | 1803+784 16279-180032| 40 40| 0743+277 16279-180206| 95 95 | 1128+385 16279-180209| 128 128| 0131-522 16279-180406| 60 60 | 0951+268 16279-180436| 144 144 | 0133+476 16279-180539| 79 79| End of listing. =========================================================== Last observations Observation listing from file ./rd1610.skd for experiment RD1610 Source Start DURATIONS name yyddd-hhmmss Ft Hh Ho Kb Kk Ny On Wz 1954-388 16280-171317| 86 86 | 0716+714 16280-171453| 83 83| 0016+731 16280-171700| 48 48| 3C418 16280-171720| 102 60 62 102 | 1300+580 16280-171846| 139 139| 0131-522 16280-171911| 60 60 | 2309+454 16280-171952| 71 248 248 | 1156+295 16280-172154| 80 80| 0008-264 16280-172301| 73 73 60 | 1324+224 16280-172356| 200 200| 0202+319 16280-172714| 60 60 60 60 | 1417+385 16280-172757| 200 200| 1308+328 16280-173154| 200 200| 0716+714 16280-173619| 84 84| 0133+476 16280-173834| 93 93| 0202+319 16280-174047| 40 40| 0340+362 16280-174209| 200 200| 1417+385 16280-174658| 200 200| 1324+224 16280-175059| 200 200| End of listing. =========================================================== SKED Summary from file ./rd1610.skd for experiment RD1610 (all scans with at least one subnet station) Average number of obs. per baseline per source(normalized by up-time) = 2.3 Min = 0.0 Max = 90.0 (Baseline Hh-Ny on 1741-038) RMS = 6.8 Total time: 1464 minutes ( 24.4 hours). Key: Ft=FORTLEZA Hh=HARTRAO Ho=HOBART26 Kb=KASHIM34 Kk=KOKEE Ny=NYALES20 On=ONSALA60 Wz=WETTZELL Ft Hh Ho Kb Kk Ny On Wz Avg % obs. time: 38 36 36 36 66 54 54 66 48 % cal. time: 2 3 3 4 5 4 3 5 4 % slew time: 30 45 38 34 20 17 20 9 27 % idle time: 29 16 21 25 8 24 21 18 21 total # scans: 199 236 287 364 447 312 305 447 324 # scans/hour : 8 10 12 15 18 13 13 18 13 Avg scan (sec): 168 132 112 86 130 153 155 130 132 # data tracks: 16 16 16 16 16 16 16 16 # Mk5 tracks: 16 16 16 16 16 16 16 16 Total TB(M5): 1.1 1.0 1.0 1.0 1.9 1.5 1.5 1.9 1.4 # OF OBSERVATIONS BY BASELINE | Ft Hh Ho Kb Kk Ny On Wz Total -------------------------------------------------- Ft| 108 44 25 0 72 92 0 341 Hh| 93 62 0 68 96 0 427 Ho| 194 0 49 29 0 409 Kb| 0 202 168 0 651 Kk| 0 0 447 447 Ny| 256 0 647 On| 0 641 Wz| 447 Number of 2-station scans: 800 Number of 3-station scans: 207 Number of 4-station scans: 84 Number of 5-station scans: 8 Number of 6-station scans: 0 Number of 7-station scans: 0 Number of 8-station scans: 0 Total number of scans: 1099 Total number of obs: 2005 Total integrated obs-time: 259871 Average obs-time: 129.6 Histogram of observation durations Dur: 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 380 400#Obs: | 72| 934| 167| 115| 101| 71| 46| 200| 20| 14| 25| 25| 25| 18| 2| 10| 15| 145Average X-band SNRs by baseline | Ft Hh Ho Kb Kk Ny On Wz AVG ------------------------------------------------- Ft| 32 21 42 - 33 32 - 31 Hh| 37 46 - 41 34 - 37 Ho| 53 - 34 24 - 42 Kb| - 65 46 - 54 Kk| - - 35 35 Ny| 51 - 51 On| - 43 Wz| 35 Average S-band SNRs by baseline | Ft Hh Ho Kb Kk Ny On Wz AVG ------------------------------------------------- Ft| 20 19 22 - 15 16 - 18 Hh| 31 33 - 21 20 - 24 Ho| 42 - 21 16 - 33 Kb| - 32 25 - 33 Kk| - - 25 25 Ny| 19 - 23 On| - 20 Wz| 25 ===========================================================