; VLBAFRGP ;--------------------------------------------------------------- ;! Fringe fit phase referenced data and apply calibration ;# PROCEDURE VLBI UTILITY CALIBRATION ;----------------------------------------------------------------------- ;; Copyright (C) 1995-2001; 2006 ;; Associated Universities, Inc. Washington DC, USA. ;; ;; This program is free software; you can redistribute it and/or ;; modify it under the terms of the GNU General Public License as ;; published by the Free Software Foundation; either version 2 of ;; the License, or (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public ;; License along with this program; if not, write to the Free ;; Software Foundation, Inc., 675 Massachusetts Ave, Cambridge, ;; MA 02139, USA. ;; ;; Correspondence concerning AIPS should be addressed as follows: ;; Internet email: aipsmail@nrao.edu. ;; Postal address: AIPS Project Office ;; National Radio Astronomy Observatory ;; 520 Edgemont Road ;; Charlottesville, VA 22903-2475 USA ;----------------------------------------------------------------------- VLBAFRGP LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC VLBAFRGP: Procedure to fringe fit and calibrate phase ref. data Input uv data. INNAME UV file name (name) INCLASS UV file name (class) INSEQ 0.0 9999.0 UV file name (seq. #) INDISK 0.0 9.0 UV file disk drive # CALSOUR Source list to fringe fit NO DEFAULT TIMERANG Time range to use. BCHAN 0.0 2048.0 Lowest channel number 0=>all FOR SPEC. LINE EXP. ONLY ECHAN 0.0 2048.0 Highest channel number FOR SPEC. LINE EXP. ONLY GAINUSE CL table to apply. REFANT Reference antenna SUBARRAY 0.0 1000.0 Subarray, 0=>all SEARCH 0.0 1000.0 Prioritized reference antenna list - supplements REFANT SOLINT Solution interval (min) 0 => 10 min DPARM for strong sources, it is only necessary to set DPARM(4), DPARM(7) and for spec line exp DPARM(8). 4=int. time (sec) 0 => min. found in data 7 >0 => don't rereference phase; this should be 1 for polarization exp 8 > 0 => activate zero'ing options for rest see HELP VLBAFRGP SOURCES Source list to calibrate: Any sources in the SOURCE list that are not in the CALSOUR list will be phase referenced to the FIRST source in the CALSOUR list. INTERPOL Interpolation function: '2PT','SIMP','AMBG','CUBE', BADDISK 0.0 15.0 Disk no. not to use for scratch files. ---------------------------------------------------------------- VLBAFRGP Type: Procedure Use: This procedure does antenna based fringe fitting for phase referencing experiments using FRING and then applies those corrections using CLCAL. For more information on KRING and CLCAL see their respective HELP/EXPLAIN files. Type RUN VLBAUTIL to make the VLBAFRGP procedure available. Adverbs: INNAME.....Input UV file name (name). Standard defaults. INCLASS....Input UV file name (class). Standard defaults. INSEQ......Input UV file name (seq. #). 0 -> highest. INDISK.....Disk drive # of input UV file. 0 -> any. CALSOUR....List of sources for which calibration constants are to be determined. The default is not permitted nor are '-' sources, as you must select a phase reference source. The FIRST source in the list is the phase reference source and will be used to phase reference any sources in the SOURCES list that are NOT in the CALSOUR list. TIMERANG...Time range of the data to be used. In order: Start day, hour, min. sec, end day, hour, min. sec. Days relative to reference date. BCHAN......First channel to use. 0=>all. If this is not a spectral line experiment, leave as default. ECHAN......Highest channel to use. 0=>all higher than BCHAN. If this is not a spectral line experiment, leave as default. GAINUSE....(multisource) version number of the CL table to apply to the data. 0 => highest. REFANT.....The desired reference antenna for phases. SUBARRAY...Subarray number to use. 0=>all. SEARCH.....List of Prioritized antennas to be used when APARM(9)>0. This adverb supplements REFANT. It is recommended that SEARCH be filled with a list of antennas whose order reflects the user's notion of which baselines will be easiest to find fringes on. All baselines to each antenna in SEARCH will be searched in order looking for fringes. All remaining baselines will then be searched. Choosing SEARCH wisely will speed the FFT portion of FRING. The antenna chosen in REFANT is treated as SEARCH(0), ie all baselines to it are searched first. SOLINT.....The solution interval (min.) You really should set this; longer values are allowed beginning with 15OCT96. 0 => 10 minutes for all inputs If SOLINT > Scan/2 (in Multisource) SOLINT = Scan. DPARM......Delay rate parameters. For strong sources the only essential DPARMS are 4, 7 and 8. 8 is only important for spectral line experiments. DPARM(1)...Number of baseline combinations to use in the initial, coarse fringe search (1-3). Larger values increase the point source sensitivity but reduce the sensitivity to extended sources when an accurate model is not available. 0=>3. DPARM(2)...The delay window to search (nsec) centered on 0 delay. 0 => full Nyquist range defined by the frequency spacing. If DPARM(2) < 0.0 no delay search will be performed. DPARM(3)...The rate window to search (mHz) centered on 0 rate. 0 => full Nyquist range defined by the integration time. DPARM(4)...The minimum integration time of the data (sec); 0 => search the data to find the minimum integration time. The correct minimum of all baselines should be supplied. DPARM(5)...If > 0 then don't do the least squares solution. If the least squares solution is not done then only the coarse search is done and much less accurate solutions are obtained. DPARM(6)...If > 0 then the output data will not be averaged in frequency else, all frequencies in each IF will be averaged. Affects single source files only. DPARM(7)...If > 0 then the phase, rate and delays will not be re-referenced to a common antenna. This option is only desirable for VLBI polarization data. DPARM(8)...DPARM(8)>0 allows zero'ing of RATE, DELAY, and/or PHASE solutions. ** Note that the ZEROing is done _AFTER_ the FRING solution is found, this is not the mechanism for turning off the DELAY, RATE, or PHASE search, see DPARM(2-3) for that capability. ** DPARM(8) value zero RATES? zero DELAYs? zero PHASEs? 0 No No No 1 Yes No No 2 No Yes No 3 Yes Yes No 4 No No Yes 5 Yes No Yes 6 No Yes Yes 7 Yes Yes Yes SOURCES....Sources to calibrate. If this is left blank then all the sources are calibrated at once using the INTERPOL (i.e. CLCAL is only run once) and phase referenced to the FIRST source in the CALSOUR list. If sources are listed then CLCAL is run once for each source using the interpolation method stated in INTERPOL. Any sources that are in the SOURCE list but not in the CALSOUR list will be phase referenced to the FIRST source in the CALSOUR list. INTERPOL...The type of interpolation to be applied to the SN table: ' ' = linear vector interpolation with no SN smoothing. '2PT ' = linear vector interpolation with no SN smoothing. 'SIMP' = Simple linear phase connection between SN phase entries, assumes phase difference less than 180 degrees. 'AMBG' = Linear phase connection using rates to resolve phase ambiguities. 'CUBE' = As AMBG but fit third order polynomial to phases and rates. BADDISK....A list of disk numbers to be avoided when creating scratch files. ---------------------------------------------------------------- VLBAFRGP: Procedure to perform antenna based fringe fitting for phase referenced data using FRING and then apply these corrections using CLCAL. Documenter: Amy Mioduszewski Related Programs: VLBAUTIL, FRING, CLCAL, VLBAKRGP, VLBAFRNG This should be done after solving for the instrumental phase corrections (VLBAPCOR) and before applying all the calibration and averaging (SPLIT/SPLAT). After VLBAFRGP is run it is ESSENTIAL to check the solutions in POSSM setting GAINUSE to the CL table output by VLBAFRGP. VLBAFRGP will produce the highest SN and CL table. For details on FRING and CLCAL see their HELP/EXPLAIN files. It should be noted that this procedure will do the same thing as VLBAFRNG if all SOURCES are in the CALSOUR list. In order to have the target source phase referenced it must be missing from the CALSOUR list and in the SOURCES list or, alternatively, the SOURCES list must be left blank. The first option caused the sources listed in SOURCES but missing from CALSOUR to be phase referenced to CALSOUR(1), while the second caused ALL the sources to be phase referenced to CALSOUR(1). VLBAFRGP assumes: 1. there is only one FREQID 2. that all IFs should be calibrated 3. that all antennas should be calibrated 4. that the entire uv range should be calibrated 5. that the highest FG table is the one that should be applied 6. that this is a multisource file Steps in VLBAFRGP: 1. Runs FRING, which will do antenna based fringe fits. This will produce the highest SN table. 2. Runs CLCAL, with OPCODE 'CALI', SNVER output SN table from FRING; GAINVER input GAINUSE and GAINUSE = highest CL table +1. Output should be highest CL table. If SOURCES is blank then CLCAL is run only once and phase referenced to CALSOUR(1). If SOURCES is not blank then CLCAL is run for each source in SOURCES. If the source in SOURCES is in the CALSOUR list then it is referenced to itself, if not it is phase referenced to CALSOUR(1). After VLBAFRGP is run and the solutions are checked in POSSM SPLIT or SPLAT should be run with GAINUSE set to the CL output from VLBAFRGP and DOCAL=2.