NOTES FOR RD0202 PREPARED BY N. R. VANDENBERG, NVI, INC./GSFC =========================================================== Parameter values for experiment RD0202 Experiment description: R&D Scheduler: NASA Correlator: Haystack Nominal start: 2002-064-17:30:00 Nominal end: 2002-065-17:30:00 Current yyyyddd: 2002064 (2002.18) ( 12339 MJD, TUES 5MAR.) Greenwich sidereal time: 4:23: 9.64 (17:30: 0 UT) Sun's RA and DEC: 23h 4.6m -5d 55.2 =========================================================== FIRST OBSERVATIONS Observation listing from file ../schedules/rd0202.skd for experiment RD0202 Source Start DURATIONS name yyddd-hhmmss Ap Gc Kk Ma Ny Wf Wz 0235+164 02064-173000| 98 297 381 600 177| 1044+719 02064-173000| 91 91 | End of listing. =========================================================== LAST OBSERVATIONS Observation listing from file ../schedules/rd0202.skd for experiment RD0202 Source Start DURATIONS name yyddd-hhmmss Ap Gc Kk Ma Ny Wf Wz 0106+013 02065-171025| 53 354 107 354 144| 1606+106 02065-171041| 30 30 | End of listing. =========================================================== 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 ../schedules/rd0202.skd for experiment RD0202 (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 = 70.2 (Baseline Ny-Wz on 1741-038) RMS = 7.7 Total time: 1421 minutes ( 23.7 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: 12 27 38 36 31 35 36 31 % cal. time: 2 2 2 2 2 2 2 2 % slew time: 59 16 11 14 11 10 8 18 % idle time: 25 53 47 47 54 51 52 47 # of tapes : .8 1.6 2.1 2.1 1.8 2.0 2.0 changes : 0000 0935 0504 0606 0733 0542 0516 0000 0000 1625 1710 0000 0000 0000 total # scans: 202 195 178 184 184 191 217 193 # scans/hour : 8 8 7 7 7 8 9 8.0 Avg scan (sec): 53 119 186 168 147 160 143 139 # OF OBSERVATIONS BY BASELINE | Ap Gc Kk Ma Ny Wf Wz StnTotal ------------------------------------------ Ap|202 106 99 71 101 179 97 653 Gc| 195 160 46 111 95 72 590 Kk| 178 19 77 84 41 480 Ma| 184 115 82 182 515 Ny| 184 106 144 654 Wf| 191 103 649 Wz| 217 639 Number of 2-station scans: 160 Number of 3-station scans: 88 Number of 4-station scans: 49 Number of 5-station scans: 46 Number of 6-station scans: 37 Number of 7-station scans: 17 Number of 8-station scans: 0 Total # of scans, observations: 397 2090 =========================================================== RECORDING MODE Name Code GEOSX4F 4F Recording mode setup for: ALGOPARK MATERA NYALES20 WESTFORD WETTZELL 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 =========================================================== 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