; RLDLY ;--------------------------------------------------------------- ;! fringe fit data to determine antenna R-L delay difference ;# TASK CALIBRATION AP VLBI ;----------------------------------------------------------------------- ;; Copyright (C) 2010-2013 ;; 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 ;----------------------------------------------------------------------- RLDLY LLLLLLLLLLLLUUUUUUUUUUUU CCCCCCCCCCCCCCCCCCCCCCCCCCCCC RLDLY: Task to fringe fit data for R-L delay difference 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 # Data selection (multisource): CALSOUR Calibrator sources QUAL -10.0 Calibrator qualifier -1=>all CALCODE Calibrator code ' '=>all SELBAND Bandwidth to select (kHz) SELFREQ Frequency to select (MHz) FREQID Freq. ID to select. TIMERANG Time range to use. IMPORTANT, NO DEFAULT BCHAN 0.0 2048.0 Lowest channel number 0=>all ECHAN 0.0 2048.0 Highest channel number CHINC 0.0 Spectral channel increment (data are averaged) ANTENNAS Antennas to select. 0=all SUBARRAY 0.0 1000.0 Subarray, 0=>all UVRANGE Range of uv distance for full weight WTUV Weight outside UVRANGE 0=0. WEIGHTIT 0.0 3.0 Modify data weights function Cal. info for input: DOCALIB -1.0 101.0 > 0 calibrate data & weights > 99 do NOT calibrate weights GAINUSE CL table to apply. DOPOL -1.0 10.0 If >0 correct polarization. PDVER PD table to apply (DOPOL>0) BLVER BL table to apply. FLAGVER Flag table version DOBAND -1.0 10.0 If >0 apply bandpass cal. Method used depends on value of DOBAND (see HELP file). BPVER Bandpass table version SMOOTH Smoothing function. See HELP SMOOTH for details. Solution control adverbs: REFANT 0.0 Reference antenna 0 -> all SOLINT Data integration time (sec) 0 => found in data DOIFS 0.0 64.0 0 => solve all IFs separately 1 => 1 solution for all IFs 2 => 2 solutions, 1 each for IFs by halves 3 => 3 solutions, 1 each for IFs by thirds 4 => 4 solutions, 1 each for IFs by quarters etc. BIF First IF included when DOIFS > 0 EIF Last IF included when DOIFS>0 PRTLEV 0.0 > 0 => diagnostic outputs BADDISK 0.0 15.0 Disk no. not to use for scratch files. ---------------------------------------------------------------- RLDLY Task: This task determines the group delay difference between the R and the L polarizations using observations of RL and LR correlations. The data must already be calibrated for any parallel-hand delays either through a SPLIT or through the CL tables applied while running RLDLY. The critical parameters are the reference antenna since only baselines to that antenna will be used and the choice of calibration source and the limited time range on that source. The source should have a significant flux in the cross polarizations so that the phase slope may be discerned. This can come from the D terms on an unpolarized source or a real Q and U signal from a polarized source. This task is a special version of FRING. The apparent delay difference will be averaged over the baselines included. Then, unlike FRING, this task copies the CL table to a new one correcting the phase and delay of the left-hand polarizations for the group delay difference found. 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. The following are used for multi-source data files only: CALSOUR....List of sources for which calibration constants are to be determined, i.e. the calibrator sources All ' ' = all sources; a "-" before a source name. means all except ANY source named. Note: solutions for multiple sources can only be made if the sources are point sources at their assumed phase center and with the flux densities given in the source (SU) table. QUAL.......Only sources with a source qualifier number in the SU table matching QUAL will be used if QUAL is not -1. CALCODE....Calibrators may be selected on the basis of the calibrator code: ' ' => any calibrator code selected '* ' => any non blank code (cal. only) '-CAL' => blank codes only (no calibrators) anything else = calibrator code to select. NB: The CALCODE test is applied in addition to the other tests, i.e. CALSOUR and QUAL, in the selection of sources for which to determine solutions. SELBAND....Bandwidth of data to be selected. If more than one IF is present SELBAND is the width of the first IF required. Units = kHz, 0=> all SELFREQ....Frequency of data to be selected. If more than one IF is present SELFREQ is the frequency of the first IF required. Units = MHz, 0=> all FREQID.....Frequency identifier to select (you may determine which is applicable from the OPTYPE='SCAN' listing produced by LISTR. If either SELBAND or SELFREQ are set their values override that of FREQID, however setting SELBAND and SELFREQ may result in an ambiguity, in which case the task will request that you use FREQID. 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. UNLIKE MOST TASKS, RLDLY requires real values in this adverb to specify a modest time interval in a scan on the calibration source. A single delay solution is found for this interval on all examined baselines. BCHAN......First channel to use. 0=>all. ECHAN......Highest channel to use. 0=>all higher than BCHAN CHINC......Channel increment in fitting - note channels are averaged BCHAN to BCHAN+CHINC-1, BCHAN+CHINC to BCHAN+2*CHINC-1, etc. This reduces the memory requirements and is suitable for delay errors that are not too large to cause channel-to-channel loss of coherence. ANTENNAS...A list of the antennas to have solutions determined. If any number is negative then all antennas listed are NOT to be used to determine solutions and all others are. All 0 => use all. The following may be used for all data files (except as noted): SUBARRAY...Subarray number to use. 0=>all. UVRANGE....The range of uv distance from the origin in kilowavelengths over which the data will have full weight; outside of this annulus in the uv plane the data will be down weighted by a factor of WTUV. WTUV.......The weighting factor for data outside of the uv range defined by UVRANGE. WEIGHTIT...If > 0, change the data weights by a function of the weights just before doing the solution. Choices are: 0 - no change weighting by 1/sigma**2 1 - sqrt (wt) weighting by 1/sigma may be more stable 2 - (wt)**0.25 3 - change all weights to 1.0 DOCALIB....If true (>0), calibrate the data using information in the specified Cal (CL) table for multi-source or SN table for single-source data. Also calibrate the weights unless DOCALIB > 99 (use this for old non-physical weights). Done before determining solutions. GAINUSE....(multisource) version number of the CL table to apply to the data. 0 => highest. DOPOL......If > 0 then correct data for instrumental polarization as represented in the AN or PD table. This correction is only useful if PCAL has been run or feed polarization parameters have been otherwise obtained. See HELP DOPOL for available correction modes: 1 is normal, 2 and 3 are for VLBI. 1-3 use a PD table if available; 6, 7, 8 are the same but use the AN (continuum solution) even if a PD table is present. PDVER......PD table to apply if PCAL was run with SPECTRAL true and 0 < DOPOL < 6. <= 0 => highest. BLVER......Version number of the baseline based calibration (BL) table to appply. <0 => apply no BL table, 0 => highest. FLAGVER....Specifies the version of the flagging table to be applied. 0 => highest numbered table. <0 => no flagging to be applied. DOBAND.....(multi-source) If true (>0) then correct the data for the shape of the antenna bandpasses using the BP table specified by BPVER. The correction has five modes: (a) if DOBAND=1 all entries for an antenna in the table are averaged together before correcting the data. (b) if DOBAND=2 the entry nearest in time (including solution weights) is used to correct the data. (c) if DOBAND=3 the table entries are interpolated in time (using solution weights) and the data are then corrected. (d) if DOBAND=4 the entry nearest in time (ignoring solution weights) is used to correct the data. (e) if DOBAND=5 the table entries are interpolated in time (ignoring solution weights) and the data are then corrected. BPVER......(multi-source) version of the BP table to be applied. 0 => highest; < 0 => no bandpass correction to be applied. SMOOTH.....Specifies the type of spectral smoothing to be applied to a uv database . The default is not to apply any smoothing. The elements of SMOOTH are as follows: SMOOTH(1) = type of smoothing to apply: 0 => no smoothing To smooth before applying bandpass calibration 1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc To smooth after applying bandpass calibration 5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc SMOOTH(2) = the "diameter" of the function, i.e. width between first nulls of Hanning triangle and sinc function, FWHM of Gaussian, width of Boxcar. Defaults (if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) = 1 - 4 and 5 - 8, resp. SMOOTH(3) = the diameter over which the convolving function has value - in channels. Defaults: 1,3,1,4 times SMOOTH(2) used when input SMOOTH(3) < net SMOOTH(2). REFANT.....The desired reference antenna for phases. Baselines to REFANT are the only ones used in the solution. 0 causes the task to loop over all possible REFANTs averaging the results and applying that weighted average. SOLINT.....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. DOIFS......Like APARM(5) in FRING: <= 0 -> separate solutions for each IF = 1 -> one solution for all IFs = 2 -> one solution for IFs 1 through NIF/2 and a second for IFs NIF/2+1 through NIF. This may be appropriate for the EVLA in which the first NIF/2 are from hardware IF AC and the others are from hardware BD. = N -> N solutions for IFs grouped consecutively in groups of NIF/N IFs. The task requires that NIF/N be an integer. BIF........First IF included when DOIFS>0 (all IFs receive the solution found for the appropriate group of IFs, but only BIF-EIF are used to find it). EIF........Last IF included when DOIFS>0 (all IFs receive the solution found for the appropriate group of IFs, but only BIF-EIF are used to find it). PRTLEV.....Print flag, -1=none, 0=time every 10th time, 1=time,some info, 2=more including the antenna signal to noise ratio, 3=a very great deal. BADDISK....A list of disk numbers to be avoided when creating scratch files. ----------------------------------------------------------------