NOTES FOR: rd0209 Prepared by C. Thomas, NVI, Inc./GSFC =========================================================== Parameter values for experiment RD0209 Experiment description: R&D Scheduler: NASA Correlator: HAYSTACK Nominal start: 2002-310-18:00:00 Nominal end: 2002-311-18:00:00 Current yyyyddd: 2002310 (2002.85) ( 12585 MJD, WED. 6NOV.) Greenwich sidereal time: 21: 3: 7.19 (18: 0: 0 UT) Sun's RA and DEC: 14h 46.8m -16d 5.1 =========================================================== First observations Source Start DURATIONS name yyddd-hhmmss Ap Gc Kk Ma Ny Wf Wz 1357+769 02310-180000| 68 248 454 475 333 475 331| =========================================================== Last observations Source Start DURATIONS name yyddd-hhmmss Ap Gc Kk Ma Ny Wf Wz 4C39.25 02311-173544| 30 30 51 51 49 | 2145+067 02311-173856| 96 76 96 76| 1334-127 02311-174213| 30 42 42 | 1741-038 02311-174558| 30 46 46 41| 2128-123 02311-174807| 122 122| 1622-253 02311-174828| 32 32 | =========================================================== Notes by Dan MacMillan, Feb 27, 2002 Purpose of Experiment The goal of this experiment is to investigate instrumental errors by scheduling observations with very high SNR. The high SNR is necessary in order to allow phase delay ambiguities to be resolved. With the much more precise phase delay observables one can then investigate possible systematic variations. For instance, we have seen subdaily cycles in the time variation of solution residuals. If these systematic variations can be identified, it may be possible to introduce corrections for them. Additionally, we will investigate intra-scan variations of residual fringe phase. Usually VLBI experiments are scheduled with target minimum SNRs of 20 at X-band and 15 at S-band. To resolve phase delays, we chose a much higher minimum of 80 at X-band and 60 at S-band. Once this experiment is analyzed, we will assess whether such high limits are necessary since this significantly reduces the number of observations/hour that can be observed at each site. Type of Experiment This experiment uses a 7-station northern hemisphere geodetic network. We had to compromise between the parameters of a standard geodetic schedule made with smooth sky coverage and the high SNR requirement that significantly reduces the possible number of station observations/hour. The antenna at Harteboestoek was available, but we decided not to include it because schedule simulations showed that HartRAO was not connected well enough to observe more than 2-3 observations/hour. Simulations showed that EOP formal uncertainties were not significantly improved by including HartRAO at this level. The high SNR requirement reduced the number of observations for this network significantly from an average of about 12-15 observations/hour for other routine schedules to 7-8 observations/hour (for non-HartRAO sites). Another consideration in making the schedule was that we decided to reduce the possible number of sources observed to increase the average number of observations made on each source. The standard list of 70 sources was reduced to 36 sources by taking out infrequently observed sources or sources that were redundant in the sense of being close to other more frequently observed sources. We tried to maintain good low elevation coverage for atmosphere parameter estimation. =========================================================== SKED Summary from file ./rd0209.skd for experiment RD0209 (all scans with at least one subnet station) Average number of obs. per baseline per source (normalized by up-time) = 5.5 Min = .0 Max = 35.1 (Baseline Ny-Wf on 1741-038) RMS = 7.1 Total time: 1429 minutes ( 23.8 hours). Key: Ap=ALGOPARK Gc=GILCREEK Kk=KOKEE Ma=MATERA Ny=NYALES20 Wf=WESTFORD Wz=WETTZELL Ap Gc Kk Ma Ny Wf Wz Avg % obs. time: 15 25 30 36 31 31 34 29 % cal. time: 2 2 1 2 2 2 2 2 % slew time: 58 16 10 18 12 10 7 19 % idle time: 23 55 56 43 54 55 54 49 # of tapes : .9 1.4 1.7 2.0 2.0 1.9 1.9 total # scans: 214 200 168 192 185 178 216 193 # scans/hour : 8 8 7 8 7 7 9 8.1 Avg scan (sec): 60 109 156 162 143 153 138 131 tape change times (hhmm): 0000 1056 0919 0442 0356 0552 0620 # OF OBSERVATIONS BY BASELINE | Ap Gc Kk Ma Ny Wf Wz StnTotal ------------------------------------------ Ap|214 120 98 74 97 162 93 644 Gc| 200 146 52 106 86 64 574 Kk| 168 18 71 72 27 432 Ma| 192 122 89 191 546 Ny| 185 102 140 638 Wf| 178 101 612 Wz| 216 616 Number of 2-station scans: 163 Number of 3-station scans: 93 Number of 4-station scans: 54 Number of 5-station scans: 47 Number of 6-station scans: 32 Number of 7-station scans: 15 Total # of scans, observations: 404 2031 =========================================================== Recording mode Name Code GEOSX4F 4F Recording mode setup for: ALGOPARK Mode Tot.Rate Tot.BandW #chan #bits Barrel Mk341:2 256.000 Mbits 128.000 MHz 14 1 NONE Chan.BW #Subpasses Tracks(*fan) Tot.tracks Speed 8.00 MHz 1 16(*2) 32 160.00 X-band spanned bw= 720.0 MHz rms spanned bw= 280.4 MHz S-band spanned bw= 120.0 MHz rms spanned bw= 48.8 MHz Effective number of channels recorded per sub-pass X S Total 10.000 6.000 16.000 Recording mode setup for: GILCREEK Mode Tot.Rate Tot.BandW #chan #bits Barrel VLBA1:2 256.000 Mbits 128.000 MHz 14 1 8:1 Chan.BW #Subpasses Tracks(*fan) Tot.tracks Speed 8.00 MHz 1 16(*2) 32 160.00 X-band spanned bw= 720.0 MHz rms spanned bw= 280.4 MHz S-band spanned bw= 120.0 MHz rms spanned bw= 48.8 MHz Effective number of channels recorded per sub-pass X S Total 10.000 6.000 16.000 Recording mode setup for: KOKEE Mode Tot.Rate Tot.BandW #chan #bits Barrel VLBA1:2 256.000 Mbits 128.000 MHz 14 1 16:1 Chan.BW #Subpasses Tracks(*fan) Tot.tracks Speed 8.00 MHz 1 16(*2) 32 160.00 X-band spanned bw= 720.0 MHz rms spanned bw= 280.4 MHz S-band spanned bw= 120.0 MHz rms spanned bw= 48.8 MHz Effective number of channels recorded per sub-pass X S Total 10.000 6.000 16.000 Recording mode setup for: MATERA NYALES20 WESTFORD WETTZELL Mode Tot.Rate Tot.BandW #chan #bits Barrel Mk341:2 256.000 Mbits 128.000 MHz 14 1 16 Chan.BW #Subpasses Tracks(*fan) Tot.tracks Speed 8.00 MHz 1 16(*2) 32 160.00 X-band spanned bw= 720.0 MHz rms spanned bw= 280.4 MHz S-band spanned bw= 120.0 MHz rms spanned bw= 48.8 MHz Effective number of channels recorded per sub-pass X S Total 10.000 6.000 16.000 =========================================================== Tape types ID Station Tape length Density Ap ALGOPARK 17400feet (Thin ) 56250. (High) Gc GILCREEK 17400feet (Thin ) 56700. (High) Kk KOKEE 17400feet (Thin ) 56700. (High) Ma MATERA 17400feet (Thin ) 56250. (High) Ny NYALES20 17400feet (Thin ) 56250. (High) Wf WESTFORD 17400feet (Thin ) 56250. (High) Wz WETTZELL 17400feet (Thin ) 56250. (High) =========================================================== SNR Targets Minimum SNR by baseline for multi-baseline scans X-band (margin 5) S-band (margin 5) Ap Gc Kk Ma Ny Wf Ap Gc Kk Ma Ny Wf Gc 80 Gc 60 Kk 80 80 Kk 60 60 Ma 80 80 80 Ma 60 60 60 Ny 80 80 80 80 Ny 60 60 60 60 Wf 80 80 80 80 80 Wf 60 60 60 60 60 Wz 80 80 80 80 80 80 Wz 60 60 60 60 60 60