Description of control file keywords of VLBI data processing software PIMA
L. Petrov
Abstract:
This document provides detailed description of syntax of the language
used for specification of control file for VLBI data processing
package PIMA
Table of contents:
- 1 General rules
- 2 General keyword
-
- 2.1 SESS_CODE:
-
-
- 2.2 BAND:
-
-
- 2.3 UV_FITS:
-
-
- 2.4 STAGING_DIR:
-
-
- 2.5 SOU_NAMES:
-
-
- 2.6 STA_NAMES:
-
-
- 2.7 PCAL:
-
-
- 2.8 TSYS:
-
-
- 2.9 GAIN:
-
-
- 2.10 SAMPLER_CAL:
-
-
- 2.11 OBS:
-
-
- 2.12 INCLUDE_OBS_FILE:
-
-
- 2.13 EXCLUDE_OBS_FILE:
-
-
- 2.14 WARNING:
-
-
- 2.15 DEBUG_LEVEL:
-
-
- 2.16 CHECK_SEVERITY:
-
-
- 2.17 FRINGE_ERRORS:
-
-
- 2.18 FFT_METHOD:
-
-
- 2.19 FFT_CONFIG_FILE:
-
-
- 2.20 NUM_THREADS:
-
- 3 Observation processing keywords
-
- 3.1 AP_TOLERANCE:
-
-
- 3.2 MIN_SCAN_LEN:
-
-
- 3.3 MAX_SCAN_LEN:
-
-
- 3.4 MAX_SCAN_GAP:
-
-
- 3.5 SCAN_LEN_SKIP:
-
-
- 3.6 SCAN_LEN_USED:
-
-
- 3.7 FRT_OFFSET:
-
-
- 3.8 STA_REF:
-
-
- 3.9 VTD_CONFIG_FILE:
-
-
- 3.10 EXPER_DIR:
-
-
- 3.11 UV_EXCLUDE_FILE:
-
-
- 3.12 BANDPASS_USE:
-
-
- 3.13 BANDPASS_FILE:
-
-
- 3.14 POLARCAL_FILE:
-
-
- 3.15 BANDPASS_MASK_FILE:
-
-
- 3.16 PCAL_MASK_FILE:
-
-
- 3.17 INTMOD_FILE:
-
-
- 3.18 INTMOD_TYPE:
-
-
- 3.19 CORR_FLAG_MIN:
-
-
- 3.20 TIME_FLAG_FILE:
-
-
- 3.21 TEC_FILE:
-
-
- 3.22 FRINGE_FILE:
-
-
- 3.23 FRIRES_FILE:
-
-
- 3.24 BEG_FRQ:
-
-
- 3.25 END_FRQ:
-
-
- 3.26 FRQ_GRP:
-
-
- 3.27 POLAR:
-
-
- 3.28 WVR_FILE:
-
-
- 3.29 WVR_USE
-
-
- 3.30 WVR_SMOOTHING_INTERVAL
-
-
- 3.31 WVR_SMOOTHING_SIGMA
-
-
- 3.32 PHASE_ACCELERATION:
-
-
- 3.33 PHASE_ACCEL_MIN:
-
-
- 3.34 PHASE_ACCEL_MAX:
-
-
- 3.35 EPHEMERIDES_FILE:
-
-
- 3.36 EPHEMERIDES_USE:
-
- 4 Baseline fringe fitting keywords
-
- 4.1 FRIB.SEARCH_TYPE:
-
-
- 4.2 FRIB.DELAY_WINDOW_CENTER:
-
-
- 4.3 FRIB.RATE_WINDOW_CENTER:
-
-
- 4.4 FRIB.DELAY_WINDOW_WIDTH:
-
-
- 4.5 FRIB.RATE_WINDOW_WIDTH:
-
-
- 4.6 FRIB.AUTOCORR_CALIB:
-
-
- 4.7 FRIB.AMPL_FUDGE_TYPE:
-
-
- 4.8 FRIB.AMPL_EDGE_WINDOW_COR:
-
-
- 4.9 FRIB.AMPL_EDGE_BEAM_COR:
-
-
- 4.10 FRIB.OVERSAMPLE_MD:
-
-
- 4.11 FRIB.OVERSAMPLE_RT:
-
-
- 4.12 FRIB.FINE_SEARCH:
-
-
- 4.13 FRIB.AUTOCORR_THRESHOLD:
-
-
- 4.14 FRIB.WEIGHTS_THRESHOLD:
-
-
- 4.15 FRIB.NOISE_NSIGMA:
-
-
- 4.16 FRIB.SNR_DETECTION
-
-
- 4.17 FRIB.FRQ_TRANSFER_BAND:
-
-
- 4.18 FRIB.FRQ_TRANSFER_METHOD:
-
-
- 4.19 FRIB.FRQ_TRANSFER_DEG:
-
-
- 4.20 FRIB.FRQ_TRANSFER_MSEG:
-
-
- 4.21 FRIB.2D_FRINGE_PLOT:
-
-
- 4.22 FRIB.PLOT_DELAY_WINDOW_WIDTH:
-
-
- 4.23 FRIB.PLOT_RATE_WINDOW_WIDTH:
-
-
- 4.24 FRIB.OVERSAMPLE_PLOT_MD:
-
-
- 4.25 FRIB.OVERSAMPLE_PLOT_RT:
-
-
- 4.26 FRIB.1D_RESFRQ_PLOT:
-
-
- 4.27 FRIB.1D_FRQ_MSEG:
-
-
- 4.28 FRIB.1D_RESTIM_PLOT:
-
-
- 4.29 FRIB.1D_TIM_MSEG:
-
-
- 4.30 FRIB.1D_DRF_PLOT:
-
-
- 4.31 FRIB.1D_DRF_SPAN:
-
- 5 Bandpass processing keywords
-
- 5.1 BPS.MODE:
-
-
- 5.2 BPS.MODE:
-
-
- 5.3 BPS.NOBS_ACCUM:
-
-
- 5.4 BPS.MSEG_ACCUM:
-
-
- 5.5 BPS.NOBS_FINE:
-
-
- 5.6 BPS.MINOBS_FINE:
-
-
- 5.7 BPS.MSEG_FINE:
-
-
- 5.8 BPS.SNR_MIN_ACCUM:
-
-
- 5.9 BPS.SNR_MIN_FINE:
-
-
- 5.10 BPS.DECOR_TIM_MIN:
-
-
- 5.11 BPS.AMPL_REJECT:
-
-
- 5.12 BPS.PHAS_REJECT:
-
-
- 5.13 BPS.INTRP_METHOD:
-
-
- 5.14 BPS.DEG_AMP:
-
-
- 5.15 BPS.DEG_PHS:
-
-
- 5.16 BPS.NORML:
-
-
- 5.17 BPS.SEFD_USE:
-
- 6 Phase reference fringe fitting keywords
-
- 6.1 FRIP.SCAN_FILE:
-
-
- 6.2 FRIP.STA_INC_FILE:
-
-
- 6.3 FRIP.STA_EXC_FILE:
-
-
- 6.4 FRIP.STA_REFS:
-
-
- 6.5 FRIP.RESOLUTION:
-
-
- 6.6 FRIP.OVERSAMPLE:
-
-
- 6.7 FRIP.SCA:
-
-
- 6.8 FRIP.MAP_DIR:
-
-
- 6.9 FRIP.ATM_ZEN_FILE:
-
-
- 6.10 FRIP.CAL_PLOT:
-
-
- 6.11 FRIP.CAL_RES:
-
-
- 6.12 FRIP.TAG_PLOT:
-
-
- 6.13 FRIP.TAG_RES:
-
-
- 6.14 FRIP.BEAM_PLOT:
-
-
- 6.15 FRIP.FRQ_MSEG:
-
-
- 6.16 FRIP.TIM_MSEG:
-
-
- 6.17 FRIP.RA_CENTER:
-
-
- 6.18 FRIP.DEC_CENTER:
-
-
- 6.19 FRIP.RA_STEP:
-
-
- 6.20 FRIP.DEC_STEP:
-
-
- 6.21 FRIP.RA_RANGE:
-
-
- 6.22 FRIP.DEC_RANGE:
-
- 7 Splt keywords
-
- 7.1 SPLT.SOU_NAME:
-
-
- 7.2 SPLT.FRQ_MSEG:
-
-
- 7.3 SPLT.TIM_MSEG:
-
-
- 7.4 SPLT.WEIGHT_TYPE:
-
-
- 7.5 SPLT.POLAR:
-
-
- 7.6 SPLT.AUTOCORR_NRML_METHOD:
-
-
- 7.7 SPLT.BPASS_NRML_METHOD:
-
-
- 7.8 SPLT.BPASS_NRML_RANGE:
-
-
- 7.9 SPLT.SUBARRY_CONSOLIDATION:
-
-
- 7.10 SPLT.TOTAL_UV:
-
-
- 7.11 SPLT.TOTAL_UV:
-
-
- 7.12 SPLT.GAIN_CORR_FILE:
-
-
- 7.13 SPLT.STA_BASED:
-
- 8 ONOF processing keywords
-
- 8.1 ONOF.GEN_FLAGS_MODE:
-
-
- 8.2 ONOF.KERNEL_START_SHARE:
-
-
- 8.3 ONOF.KERNEL_END_SHARE:
-
-
- 8.4 ONOF.COHERENT_INTERVAL:
-
-
- 8.5 ONOF.COHERENT_INTERVAL:
-
-
- 8.6 ONOF.NSIG_THRESHOLD:
-
-
- 8.7 ONOF.MIN_LOW_AP:
-
- 9 Creation of the output database keywords
-
- 9.1 MKDB.OUTPUT_TYPE:
-
-
- 9.2 MKDB.SRT:
-
-
- 9.3 MKDB.GD_MAX_ADD_ERROR:
-
-
- 9.4 MKDB.GD_MAX_SCL_ERROR:
-
-
- 9.5 MKDB.FILTER:
-
-
- 9.6 MKDB.FRINGE_ALGORITHM:
-
-
- 9.7 MKDB.2ND_BAND:
-
-
- 9.8 MKDB.VCAT_CONFIG:
-
-
- 9.9 MKDB.OUTPUT_NAME:
-
-
- 9.10 MKDB.DESC_FILE:
-
1 General rules
Control file for PIMA consists of lines of variable length. Lines which
starts from characters # or * are considered as comments and ignored by
parsing software. Each line consists of a keyword and the value. All
keywords must be specified, no defaults are allowed. A value should be
separated from the keyword by one or more blanks. The first line and
the last of the control file should have the label of the format version.
The current label version is
# PIMA_CONTROL file. Format Version of 2015.09.01
If the file does not have correct format label, PIMA will issue
an errors message and stop. New keywords may be added in the future.
PIMA control files may require an upgrade if the control file
satisfies specifications of the old version of PIMA, but it misses
some keywords added in the newer version. An upgrade of control file
can be done automatically with task upgr. This task accept the
name of the control file in the old, obsolete format and generate
the output control file that conforms to the current format b
adding lines with new keywords that are set to some defaults.
All keywords may be defined more than once. With exception of
the keywords UV_FITS and INTMOD_FILE the latest definition supersedes
the previous definition.
PIMA supports a number of kludge environment variables that tweak
the normal operation. They are are either for printing debugging
information or modifying existing code that are invoked on an
exceptional basis. These environment variables have prefix PIMAVAR_.
They can be either defined outside PIMA or placed in the control file.
In that case colon is appended to the end of the environment variable
name.
2 General keyword
2.1 SESS_CODE:
SESS_CODE: value
Session code. It may be different from the experiment code embedded
in FITS-IDI code. This session code is appended to names of
scratch files.
2.2 BAND:
BAND: value
One character letter in upper case that describes the band of the
experiment. For processing multifrequency data usually two or more
control files are used. The band helps to distinguish different
control files and, if necessary, to coming multi-frequency
observations.
2.3 UV_FITS:
UV_FITS: file
Full path name of the data file with the correlator output that
conforms to FITS-IDI standard. More than one UV_FITS: keyword may
be specified and, unlike to other keywords, the next definition does
not supersede the previous one. Restrictions:
1) Files should follow in chronological order.
2) The number of spectral channels for all intermediate frequencies
(IF) should be the same.
3) The source names and station names should be consistent
between files, i.e. the same name should be used for the same
source.
2.4 STAGING_DIR:
STAGING_DIR: directory
directory -- This keyword specifies the name of staging directory.
When the name of staging directory is specified, PIMA
first checks whether the directory has all files with
visibilities. If not, then PIMA removes all files from
that directory and copies there files with visibilities.
If drive where the staging directory is significantly
faster than the directory with UV data specified UV_FITS
keyword(s), PIMA will run faster. It is recommended
to have SSD RADI-0 disk arrays for staging directory.
NB: of a side effect: PIMA will remove from that
directory all files which are not UV-files for this
experiment.
NO -- no staging directory is specified
2.5 SOU_NAMES:
SOU_NAMES: file
Name of the source definition file. The purpose of this file is
to match the source names in FITS-IDI files with the source names
used in data reduction. Correlator may use non-standard names.
The source definition file has a separate column that associate
non-standard names used by the correlator with standard names.
In addition, the source definition file may have several entries
for the same source in the column with source name alias and these
entries may have a "splitting" flag. In that case PIMA will treat
these same uv-data as belonging to two different sources with
different a priori coordinates. Supported data format: SOURCE_NAMES.
2.6 STA_NAMES:
STA_NAMES: file
Name of the station definition file. The purpose of this file is
to match station names in FITS-IDI files with the station names
used in data analysis. Correlators often use 2-characters long
names, while data analysis software uses 8-characters long names.
2.7 PCAL:
PCAL: [NO or USE_ONE or USE_ALL or tone_index][:action:[station[:station]...]
This keyword specified how information about measured phases and
amplitudes of phase calibration information should should be used
for fringe fitting. Supported values:
NO -- no measured calibration is applied.
USE_ONE -- to apply one tone per intermediate frequency (IF).
If two tone are available, then the tone with the
lowest frequency will be applied. If more than two
phase calibration tones are available, then the tone
with index equal to the ratio of the total number of
phase cal tones per IF will be applied. The phase
of phase-calibration signal will be subtracted
with appropriate sign from cross-correlation
phases in every spectral channels of a given IF.
USE_ALL -- to apply all tones per intermediate frequency (IF).
PIMA computes group delay and phase delay in phase
calibration signal. Using these two values,
it computes ph-cal phase for every spectral channel
in the IF and then subtracts them with an appropriate
sign from cross-correlation phases in every spectral
channels of a given IF.
tone_index -- to apply one tone per intermediate frequency (IF).
The value of tone_index sets the index of the phase
calibration tone. If the index is out of range,
then the tone with index equal to the ratio of the
total number of phase cal tones per IF will be applied.
The value may has an optional qualifier for fine-grained station selection.
The qualifier is separated from the value with a column. Sub-value
action can be TO_USE or NOT_TO_USE. A column separated list of
stations follows the action sub-value. The action is case insensitive.
Either column or comma can be used as a separation in the station list.
If action is TO_USE, then pcal only from the stations form the list will
be considered for using. If action is NOT_TO_USE, then pcal from the
stations on the list will not be used. If phase calibbration for
a given station is not available or was deselected with task gean pcal_off,
then fine-grained phase calibration will have no effect. Task gean
pcal_off has a precedence over fine-grained selection.
2.8 TSYS:
TSYS: [NO or MEASURED or MODELED or CLEANED]
This keyword specified how system temperature calibration should
be used. Keywords MEASURED or CLEANED or MODELED instruct PIMA from
which slot to take the Tsys. In order to use CLEANED or MODELED
Tsys, the Tsys model has to be computed with task tsmo before.
NO -- System temperature is ignored
MEASURED -- System temperature measured when the antenna was on the
specified source will be used. PIMA will find Tsys
measurement of the same source to the epoch the nearest
of the fringe reference time.
Value INTRP is equivalent to MEASURED and supported for
compatibility with control files generated before 2017.08.30
MODELED -- System temperature from the "model" slot will be used.
It it is assumed task tsmo ran before and populated
"modeled" Tsys slot. See documentation of task tsmo for
details. In short, task tsmo decompose Tsys into a product
of regular functions of IF, elevation and time assuming
a) Tsys ratio between IFs is constant during the experiment;
b) Tsys dependence on elevation is not changing with time;
c) Tsys is can be decomposed on somewhat smoothed functions
of time and elevation. Task tsmo flags outliers and computes
the decomposition using the dataset free from outliers"
CLEANED -- System temperature from the "clean" slot. Tsys from that
slot is a mixture of MEASURED and MODELED Tsys. Tsys
in the CLEANED slot is the same as in the MEASURED slot
for the points that has measured Tsys that is not flagged
out by tsmo task. System temperature is equal to the Tsys
from the MEASURED slot for the points without measured Tsys
or for the points that were flagged out.
2.9 GAIN:
GAIN: [NO or USE]
NO -- do not use antenna gains in the input file or internal PIMA
data structures. This is equivalent to using gain 1 Jy/K
USE -- use antenna gains in the input file or internal PIMA
data structures if during calibration new gain tables have
been loaded in PIMA.
2.10 SAMPLER_CAL:
SAMPLER_CAL: [NO or USE]
NO -- do not apply calibration for amplitude distortion due
to digitization in the samplers.
USE -- apply calibration for amplitude distortion due
to digitization in the samplers.
2.11 OBS:
OBS: [ALL or index or index1:index2 or file]
This keyword specifies which observations are to be used for
processing. It should be considered as the second filter that is
applied after the first filter specified by the keyword INCLUDE_OBS_FILE.
Keyword OBS restricts a set of processed observations among those that
passed the first filter. The third filter specified by the keyword
EXCLUDE_OBS_FILE impose further restrictions that are imposed on the set
of observations that passed the second filter.
ALL -- all observations will be used.
index -- Index of the observation that will be used.
index1:index2 -- Range of indices that will be used.
index2 should be greater or equal than index2.
file: -- Name of the ascii file that contains indices of
observations. The file has one observation index
per line. Lines that start from # are considered
as comments and bypassed.
2.12 INCLUDE_OBS_FILE:
INCLUDE_OBS_FILE: [NO or file]
This keyword specifies the first filter of observations that are
to be used. Those observations that passed this filter are considered
as eligible for checking for the second filter specified by the keyword
OBS: and the third filter specified by the keyword EXCLUDE_OBS_FILE:
NO -- all the observations are to be used.
file -- Name of the file that specifies indices of observations that are
put in the include list. The file has one observation index
per line. Lines that start from # are considered as comments
and bypassed.
2.13 EXCLUDE_OBS_FILE:
EXCLUDE_OBS_FILE: [NO or file]
This keyword specifies the third filter of observations that are
to be used. Those observations that passed this filter form the final
list of used observations.
NO -- Exclude list is empty. That means that all observations
that passed the first filter specified by the keyword
INCLUDE_OBS_FILE: and the second filter specified by
the keyword OBS: are considered as eligible.
file -- specifies indices of observations that form the exclude list.
The observations indices specified in this files are excluded
from the list that passed the first and the second filter.
2.14 WARNING:
WARNING: [NO, ON, OFF]
NO -- No warning messages will be printed
OFF -- No warning messages will be printed
ON -- Warning messages will be printed.
2.15 DEBUG_LEVEL:
DEBUG_LEVEL: value
Level of verbosity of information messages issued by PIMA
0 -- completely silent mode. Only errors or warnings
(if WARNING: ON is specified) are printed.
1 -- terse mode. Only very important messages are printed.
2 -- normal mode.
3 -- talkative mode. More messages are displayed.
4 -- chat-box mode. A lot of messages are displayed that
may be annoying.
5-99 -- debugging messages are printed. These messages are
are for facilitation of debugging.
2.16 CHECK_SEVERITY:
CHECK_SEVERITY: value
Level of severity of checks for internal data consistency.
During loading the data, situations occur when a portion of
data is corrupted. PIMA detects data corruption and issues
warning, but then it should decide what to do further: to
continue or to stop. The level of severity governs the algorithm.
0 -- permissive mode. Unless the error is fatal that prevents
further data processing, PIMA discards corrupted data
and continues.
1 -- normal mode. PIMA may or may stop after an error depending
on its severity. It stops if corrupted data *may* produce
bogus results.
2 -- strict mode. PIMA stops if it finds corrupted data.
2.17 FRINGE_ERRORS:
FRINGE_ERRORS: [IGNORE, STOP]
This keywords set the action if fringe search ended with error
IGNORE -- the error is ignored and PIMA proceeds to the new
observation. Code failure is written in the status field
for the affected observation.
STOP -- pima stops on the error.
2.18 FFT_METHOD:
FFT_METHOD: [FFTW or MKL]
PIMA supports two software packages that implements fast Fourier
transform: MKL (Math Kernel Library by Intel) and open source FFTW.
MKL support is optional and depends on PIMA configuration in compile
time. Keyword FFT_METHOD defines which library to use. Both libraries
produce correct answers, but depending on size of the problem
have different speed. If in doubt, please use FFTW method.
MKL -- use the MKL library
FFTW -- use open source FFTW library
2.19 FFT_CONFIG_FILE:
FFT_CONFIG_FILE: [NO or file]
When FFTW is used, its configuration, so-called "wisdom" that keeps
optimal setting should be loaded. Refer to PIMA INSTALL document,
Post-Installation section with a detailed explanation how to create this
configuration file. PIMA will run without FFTW configuration, but its
performance will be significantly degraded.
NB: FFTW configuration depends on the number of threads. Single threaded
configuration file will be rejected if FFTW is called in multi-thread
mode and performance will be severely impacted. An M-threaded configuration
file will be rejected if the number of threads for FFTW is not equal to M.
NO -- no FFTW configuration file is specified. FFTW configuration
file is ignored if FFT_METHOD MKL is used. You can use NO value
even if FFTW methods is used, but PIMA performance will be worse
by a factor of 2-20.
file -- name of the FFTW configuration file.
2.20 NUM_THREADS:
NUM_THREADS: value
The number of threads used by FFT. Usually, FFT_NUM_THREADS is set
to the number of processors (cores) available. But you may want to
reduce the number of threads for load balancing.
3 Observation processing keywords
3.1 AP_TOLERANCE:
AP_TOLERANCE: value
PIMA assumes the time epochs of all the uv data within each scan forms
a rail of ticks with spacing equal to some constant, accumulation
period length. Parameter AP_TOLERANCE sets the tolerance in seconds for UV
data to have time epochs with interval slightly greater or less than the
accumulation period length. If PIMA finds UV data that have time epoch
that differs from previous accumulation period by more than AP_TOLERANCE,
it will discard that data point. NB: the start time of a scan may be not
commensurate to the accumulation period length counted from the previous
scan, only time stamps within each scan are checked.
For geodesy and astrometry applications AP_TOLERANCE should not exceed
1.D-6 seconds. For imaging application the tolerance may be relaxed.
3.2 MIN_SCAN_LEN:
MIN_SCAN_LEN: value
Parameter MIN_SCAN_LEN determines the minimum scan duration in seconds.
It instructs the PIMA internal algorithm for splitting visibility data
into scans that a scan should not be shorter than that value. If it finds
a set of visibility data shorter than this value that cannot be attached
to another scans in accordance with the constraints set by other parameters
of PIMA, it will flag these visibilities.
3.3 MAX_SCAN_LEN:
MAX_SCAN_LEN: value
Parameter MAX_SCAN_LEN determines the maximum scan duration in seconds.
It instructs the PIMA internal algorithm for splitting visibility data
into scans that a scan should be not longer than not that value. Scan
duration is set as an interval between the beginning of the first
accumulation period and the end of the last accumulation period. A set
of data of the same source may last longer than MAX_SCAL_LEN. In that
case that set of data will be split into several scans. Splitting
of data into scans occurs in chronological order. Thus, after putting
the earliest visibility set into a given scan, the scan end is fixed,
and the visibilities for the following epochs are put into the next scan.
3.4 MAX_SCAN_GAP:
MAX_SCAN_GAP: value
Parameter MAX_SCAN_GAP controls maximum duration of a gap in data
within each scan for the algorithm that splits visibilities into scans.
If a gap in visibility data of the same source long than this value
occurred, it triggers setting the scan boundary at the beginning of the
gap. The start time epoch of the new scan is set to the the first time
epoch after the gap.
3.5 SCAN_LEN_SKIP:
SCAN_LEN_SKIP: value
This parameter instructs PIMA to discard the visibilities at the
beginning of a scan from the nominal scan start for the interval of time
equal to this value in seconds. The value of SCAN_LEN_SKIP cannot be
negative.
3.6 SCAN_LEN_USED:
SCAN_LEN_USED: value
This parameter instructs PIMA to discard the visibilities at the end of
a scan. It control the duration of the interval in seconds with used
visibilities. The beginning of the interval is counted from the nominal
scan length if SCAN_LEN_SKIP is 0. If SCAN_LEN_SKIP > 0, the beginning
of the interval is offset at SCAN_LEN_SKIP with respect to the nominal
scan start. The visibility data beyond the interval specified by this
keyword are discarded.
3.7 FRT_OFFSET:
FRT_OFFSET: [AUTO or value or file]
Keyword FRT_OFFSET instructs PIMA how to determine to fringe reference
time, i.e. the time to which residual phase related.
AUTO -- Instructs PIMA to determine the fringe reference time
automatically. PIMA determines it as a mean weighted
epoch within a scan for each observation separately.
NB: In general, the fringe reference time for different
observation of a given scan is not the same.
value -- sets the offset of the fringe reference time with
respect to the nominal scan start.
file -- Specifies the file with fringe reference time.
The file is in ASCII format. Each line has two words
separated by one or more blanks. The first word
defines the observation index, the second words
defines the fringe reference frame in seconds with
respect the scan nominal start. Lines that start
from # are considered as comments and ignored.
3.8 STA_REF:
STA_REF: Station name
Specifies the name of the reference station. The reference station
is used for computation of the complex bandpass.
3.9 VTD_CONFIG_FILE:
VTD_CONFIG_FILE: file
Specifies the name of VTD (VLBI Time Delay) control file. The VTD
control file specifies parameters of the VLBI model for path delay.
3.10 EXPER_DIR:
EXPER_DIR: directory
Name of the directory where PIMA task load writes index files.
Index files have names that start from the session name and end on
specific extensions.
3.11 UV_EXCLUDE_FILE:
UV_EXCLUDE_FILE: []file or AUTO or NO]
file -- File name with indices of visibility dates that are
excluded from processing. Lines that start from #
are considered as comments and ignored.
AUTO -- invokes a special algorithm for automatic accounting for
bad uv data points for PIMA task load. The algorithm first
searches for
a file in EXPER_DIR directory with the name that has
the first part session name and the last part _uv.exc
If it finds that file, it reads it. The file is contains
the indexes of the visibility data that are excluded
before further analysis. These are s- called a priori
excluded visibilities. If PIMA finds bad visibilities,
it generates a list of bad visibility names. These are
so-called a posteriori bad visibilities. If there is
at least one bad a posteriori visibility, PIMA combines
the indexes of a priori and a posteriori bad visibilities,
writes them down into a file with the same name:
the first part session name and the last part _uv.exc,
and sets exit code 23.
If the control file has UV_EXCLUDE_FILE: AUTO and the
first run of PIMA task load returned exit code 23, then
the second run is recommended. Bad points identified
in the first run, will be bypassed during the second run.
NO -- No visibility data are excluded.
3.12 BANDPASS_USE:
BANDPASS_USE: [AMP or PHS or AMP_PHS or NO]
This keyword controls whether to apply complex bandpass and if
to apply, then how. A bandpass is a complex function of frequency.
For each station, each IF and each spectral channel, a complex value
is defined. Applying the bandpass is an operation when raw visibilities
are divided by this value.
AMP -- apply the amplitude part of the bandpass, i.e. to change
only amplitudes, but do not change phases.
PHS -- apply phase part of the bandpass, i.e. to change only
phases, but do not change amplitudes.
AMP_PHS -- apply the complex bandpass, i.e. change both amplitudes
and phases.
NO -- do not apply the complex bandpass.
3.13 BANDPASS_FILE:
BANDPASS_FILE: file or NO
This keyword controls the name of the bandpass file. Bandpass is
a complex function of frequency. It defines a complex number for each
station, each spectral channel of each IF. The visibility is divided
by a product of bandpasses for the pair of stations of the baseline.
Bandpass file name is an output parameter for task bpas. Therefore, it
may not exist for this task. The bandpass file name is an input
parameters for many other tasks, such as frib, splt, mkdb. PIMA checks
whether the specified file exists and stops with an error message,
if cannot find it and read.
file -- name of the bandpass file.
NO -- No bandpass file exists. You cannot specify NO with bpas task.
3.14 POLARCAL_FILE:
POLARCAL_FILE: file or NO
This keyword controls the name of the polarization bandpass file.
In a case of dual-polarization data PIMA supports two bandpasses.
The first bandpass is for RR data. It is defined in the file specified
by BANDPASS_FILE name. The second bandpass determines the complex
function of frequency that describes the ration of complex response
of LL band with respect to RR. That second bandpass is specified by
POLARCAL_FILE. Therefore, the LL bandpass is the product of these
two bandpasses. When PIMA calibrates RR data, it uses only the first
bandpass. When PIMA calibrates LL data, it uses the product of two
bandpasses. When PIMA calibrates data for polarization I, which it
computes on the fly, it uses both bandpasses. POLARCAL_FILE is not
used for single-polarization data. Bandpass file name is an
output parameter for task bpas. Therefore, it may not exist for this
task. The bandpass file name is an input parameters for many other
tasks, such as frib, splt, mkdb. PIMA checks whether the specified
file exists and stops with an error message it it cannot find
it and read.
file -- name of the second polarization bandpass file.
NO -- No polarization bandpass is to be used or to be created.
Task bpas will not compute polarization bandpass
if POLARCAL_FILE: NO.
3.15 BANDPASS_MASK_FILE:
BANDPASS_MASK_FILE: file or NO
This keyword controls the name of the mask file. Mask file consists
of 0 and 1 for each station, each IF, each frequency channel. PIMA
defines 4 masks: 1) for autocorrelation; 2) for computation of bandpass;
3) for fringe fitting, and 4) for task splt. Normally mass 2-3-4 are
the same. When PIMA processes autocorrelation, it multiplies
autocorrelation data by the mask value 0 and 1. Then it interpolates
the autocorrelation and puts on place those spectral channels that
were masked out (i.e. had 0 in the mask file) the value computed by
interpolation between neighboring channels that were not masked out.
When PIMA processes cross correlation data, it multiplies visibilities
on mask values. If a given channels is masked out, it is effectively
excluded from further processing.
Bandpass mask file must define mask values for all spectral channels,
all IFs, all stations. PIMA supports task bmge (Bandpass Mask GEneration)
that allows to describe in an ascii files only those spectral channels,
IFs or their ranges that have to be masked out. Task bmge reads the
input mask definition file and generates the output bandpass mask file.
file -- name of the the bandpass mask file. This file name is the
output for task bmge. When task bmge is used, this file may
not exist. For other tasks this file should exists. PIMA will
stop with an error message if it will not find it.
NO -- No bandpass file exists. You cannot specify NO with bmge task.
3.16 PCAL_MASK_FILE:
PCAL_MASK_FILE: file or NO
This keyword controls the name of the mask file for phase calibration
data. It is applied only when all phase calibration tones are used
(PCAL: USE_ALL). Phase calibration signal is often affected by internal
radio interference. The mask file allows to exclude (to mask out) the
tones that are affected by the RFI. When the interpolation spline is
computed to approximate the frequency dependence of phase calibration
signal, these tines are excluded from computation of the spline.
Phase calibration mask file must define mask values for all spectral
channels, all IFs, all stations. PIMA supports task pmge (Phase
calibration Mask GEneration) that allows to describe in an ascii files
only those spectral channels, IFs or their ranges that have to be masked
out. Task pmge reads the input mask definition file and generates the
output polarization mask file.
file -- name of the the phase calibration mask file. This file name
is the output for task pmge. When task bmge is used, this
file may not exist. For other tasks this file should exists.
PIMA will stop with an error message if it will not find it.
NO -- No polarization make file exists. You cannot specify NO
with pmge task.
3.17 INTMOD_FILE:
INTMOD_FILE: [directory or NO]
Normally, the a priori interferometric model is defined inside
the FITS-IDI data. However, some correlators omit these sections
in FITS-IDI files, which prevents astrometry and geodetic applications
that require computation of the total phases, group delays, phase
delay rates and group delay rates. As a workaround PIMA supports
import of interferometric models in the form that were used by
the correlator. Keyword INTMOD_FILE specifies the directory tree(s)
that contains files with the a priori model for path delay.
Interpretation of files depends on the correlator. In a case of
VERA hardware correlator in Mitaka, PIMA searches for files
that has "ANT." pattern and ignores all others. In a case of
SFXC correlator, PIMA searches for files with extension ".del"
and ignores all others. This keyword is used by task moim
(MOdel IMport).
More than one keyword INTMOD_FILE can be specified.
directory -- directory name where PIMA will search for files with
a priori model, including all sub-directories.
NO -- No directory name is specified. NO can be specified
only when INTMOD_TYPE is NO.
3.18 INTMOD_TYPE:
INTMOD_TYPE: [VERA1000 or VERA2000 or SFXC or NO]
This keywords defines the type of external path delay model.
This value of this keyword controls how PIMA should interpret
the files with a priori path delay used by the correlator specified
by the keyword INTMOD_FILE.
VERA1000 -- delay files are in CODA format for VERA1000 recording
systems. The files are named ANT.x, where x is an
integer number.
VERA2000 -- delay files are in CODA format for VERA2000 recording
systems. The files are named ANT.x, where x is an
integer number. NB: VERA1000 and VERA2000 have different
format.
SFXC -- delay files are in ASCII format for SFXC correlator.
The files have extension .del
NO -- format is undefined. Should be used when INTMOD_TYPE: NO
and cannot be specified otherwise.
3.19 CORR_FLAG_MIN:
CORR_FLAG_MIN: value
This keyword defines the threshold for discarding the data that
are marked by the correlator as potentially corrupted. The data
with CORR_FLAG_MIN equal or less are discarded. Usually,
CORR_FLAG_MIN: 1 is a good choice. That means any data flagged
by the correlator will be discarded. However, if you think that
the correlator discards too many 'good' data, you can lower
the threshold.
FITS-IDI specifications define the flag the following way:
-1 No severity level assigned
0 Data are known to be useless
1 Data are probably useless
2 Data may be useless
The VLBA hardware correlator may assign flag -1 (i.e. undefined
severity). In that case FITS-IDI keyword CORR_FLAG_REASON string that
describes the problem that resulted in flagging must be defined. When
PIMA finds a severity flag -1 it parses the string with the reason.
Then it assigns the severity level, i.e the correlator flag,
the following way:
2-16 ghz synthesizer #2 -- FLAG = 2
2-16 ghz synthesizer #2 -- FLAG = 2
antenna not in point mod -- FLAG = 0
Antenna not pointed -- FLAG = 0
antenna position error t -- FLAG = 0
Antenna off source -- FLAG = 0
BBC Synth Unlocked -- FLAG = 2
channel 1 bbc synthesize -- FLAG = 2
channel 2 bbc synthesize -- FLAG = 2
channel 3 bbc synthesize -- FLAG = 2
channel 4 bbc synthesize -- FLAG = 2
channel 5 bbc synthesize -- FLAG = 2
channel 6 bbc synthesize -- FLAG = 2
channel 7 bbc synthesize -- FLAG = 2
channel 8 bbc synthesize -- FLAG = 2
Ellipsoid posn error -- FLAG = 2
ellipsoid position error -- FLAG = 2
observing system idle -- FLAG = 2
Recorder 1 head posn err -- FLAG = 2
Recorder 1 not running -- FLAG = 2
Recorder 2 head posn err -- FLAG = 2
Recorder 2 not running -- FLAG = 2
Source change in progres -- FLAG = 0
source change in progres -- FLAG = 0
Subreflector error -- FLAG = 2
Synthesizer 1 unlocked -- FLAG = 2
Synthesizer 2 unlocked -- FLAG = 2
Synthesizer 3 unlocked -- FLAG = 2
System idle -- FLAG = 0
subreflector position er -- FLAG = 2
2-16 ghz synthesizer #1 -- FLAG = 2
2-16 ghz synthesizer #2 -- FLAG = 2
2-16 ghz synthesizer #3 -- FLAG = 2
If it does not find CORR_FLAG_REASON string or finds a string
that is not in the table above, its stops with an error message.
value -- the threshold of the correlator flag. If a UV point
has the correlator flag equal or less than that code,
PIMA flags that observation out, i.e. replaces the
visibility data with zeroes.
3.20 TIME_FLAG_FILE:
TIME_FLAG_FILE: [file or NO]
This keyword defines the name of the file that sets multiplicative
reweighting factors for all visibilities at specified time epochs
at specified observations. Observations weight will by multiplied by
this factor. Usually, these reweighting factors are zero. In that case,
TIME_FLAG_FILE sets the accumulation periods that PIMA must discard.
The ascii TIME_FLAG_FILE consists of lines that contains three words:
observation index, ap index from the nominal observation start, weight.
Usually this file is generated automatically either by a user
application or by PIMA task onof.
file -- name of the time flag. When PIMA uses onof task in the mode
of time flag file generation, the file name must be specified.
PIMA will stop if the file name is not specified. For all
other tasks, keyword TIME_FLAG_FILE with the file name
specified means that PIMA should read this file and update
weights for the specified observations, specified accumulation
periods.
NO -- means no multiplicative reweighting factors will be applied.
3.21 TEC_FILE:
TEC_FILE: file or NO
TEC file name. At the moment is not supported. Reserved for future use.
TEC_FILE: NO should be specified.
3.22 FRINGE_FILE:
FRINGE_FILE: file
Name of the ascii output file where results of fringe fitting
are written. If the file exists, PIMA will append records to its end.
PIMA first writes the header that starts with # character
and writes a terse footer at the end.
3.23 FRIRES_FILE:
FRIRES_FILE: file
Name of the ascii output file where residuals of fringe fitting
are written. If the file exists, PIMA will append records to its end.
PIMA first writes the header that starts with # character
and writes a terse footer at the end.
3.24 BEG_FRQ:
BEG_FRQ: value
The start intermediate frequency (IF) index that is used by PIMA.
Cannot be less than 1.
3.25 END_FRQ:
END_FRQ: value
The end intermediate frequency (IF) that is used by PIMA. Cannot be
less than BEG_FRQ and cannot be greater than the last IF.
3.26 FRQ_GRP:
FRQ_GRP: [value or value_min:value_max or value_min-value_max]
Frequency group. In a case if the input FITS-IDI data have more than
one intermediate frequency (IF), the IFs can form one or more groups.
This keywords specifies which frequency groups will be used. A valid
FITS-IDI file contains at least one frequency group with index 1.
NB: PIMA can perform fringe fitting only within one frequency group.
value -- the index of the used frequency group.
Cannot be less than 1 and cannot be greater than
the total number of frequency groups.
value_min:value_max -- merge several frequency groups together for
overlapping data. It is assumed that there are
visibility data for the same time epochs
within groups that are being merged.
value_min and value_max are the indexes of
the first and the last frequency group
to merge. They form a virtual frequency group.
The number of IFs in the merged frequency
group is the sum of the number of IFs in
participating groups.
value_min-value_max -- combine several frequency groups together for
non overlapping data. It is assumed that there
are no visibility data for the same time epochs
within the groups that are being combined.
A new virtual group is created with the index
that is by one greater than the number of
non-virtual groups. The new combined group
has all IFs of its constituents.
NB: keep in mind the distinction between merged and combined frequency
groups.
3.27 POLAR:
POLAR: [RR or LL or RL or LR or I]
Polarization code. In the case if one polarization was correlated,
it must be either RR or LL depending on used polarization. If two
polarization were correlated, it can be RR or LL or I. In a latter
case PIMA apply the bandpass to RR and both bandpass and polarization
bandpass to LL polarizations, rotates RR fringe phase at the
parallactic angle and LL fringe phases at the same angle but with the
opposite sign and forms a calibrated linear combination I = (RR + LL)/2.
The SNR of this combination is at 40% better than the SNR of RR or LL
data. NB: polarization I should be used only after both bandpass
and polarization bandpasses were computed. Otherwise, the results will
be totally unsatisfactory.
3.28 WVR_FILE:
WVR_FILE: file name
file_name: Full path name of the WVR data. At the moment,
only form "* WVR_EFL data. Format version 2014.07.24"
is supported. If no WVR data are available, NO should
be used. More than one file can be specified,
one file per station.
3.29 WVR_USE
WVR_USE: usage
usage: WVR usage. Specifies the algorithm for interpolation and
smoothing of original WVR data and the contribution of
WVR path delay phases should be subtracted from the
visibility phases. Supported values:
NO -- do not apply visibility phases
WVR_3SPL -- Expand original data into smoothing
spline of the 3rd degree.
WVR_LIN -- Expand original data into smoothing
spline of the 1st degree.
WVR_AVR -- Expand original data into smoothing
spline of the 3rd degree.
3.30 WVR_SMOOTHING_INTERVAL
WVR_SMOOTHING_INTERVAL: value
value: interval of the smoothing spline in seconds.
10-40 seconds is usually adequate
3.31 WVR_SMOOTHING_SIGMA
WVR_SMOOTHING_SIGMA: value
value: Reciprocal weight of the constraint imposed
on WVR smoothing spline in seconds. The smaller
parameter, the close smoothing spline to the
averaged path delay. The bigger parameter,
the greater fluctuations in WVR phases are
allowed. 2.0D-11 is usually adequate.
3.32 PHASE_ACCELERATION:
PHASE_ACCELERATION: value
Ad hoc phase acceleration that will be applied to visibilities.
Units: rad/s^2. Normally 0.0 value used. Values different from
zero are used for radio interferometer with a station at the
space.
3.33 PHASE_ACCEL_MIN:
PHASE_ACCEL_MIN: value
Minimal phase acceleration in rad/s^2 that will be used for
iterations. PIMA supports the mode when it tries a range of phase
accelerations with a step that it determines automatically. The step
is found in such a way that the maximum contribution of the phase
acceleration term be less than 0.33 rad. PIMA runs N times fringe
fitting with different phase accelerations for each observation.
PHASE_ACCEL_MIN: 0.0 and PHASE_ACCEL_MAX: 0.0 tells PIMA that no
tries with a range of phase acceleration should be done
3.34 PHASE_ACCEL_MAX:
PHASE_ACCEL_MAX: value
Maximal phase acceleration in rad/s^2 that will be used for
iterations. PIMA supports the mode when it tries a range of phase
accelerations with a step that it determines automatically. The step
is found in such a way that the maximum contribution of the phase
acceleration term be less than 0.33 rad. PIMA runs N times fringe
fitting with different phase accelerations for each observation.
PHASE_ACCEL_MIN: 0.0 and PHASE_ACCEL_MAX: 0.0 tells PIMA that no
tries with a range of phase acceleration should be done
3.35 EPHEMERIDES_FILE:
EPHEMERIDES_FILE: [file or NO]
Name of the ephemeride file for space interferometer. The file
should conform CCSDS_OEM_VERS specifications. This ephemerides
file is used for computation of the position of the station that
is in space. If one of the stations is marked in antenna description
file used by VTD as space station, ephemerides file must be specified.
NO -- no ephemerides file is specified. If you analyze an experiment
only with ground station, use NO.
3.36 EPHEMERIDES_USE:
EPHEMERIDES_USE: [NO or RA_PUSCH or RA_GBT or RA_GB140 or EARTH_OR
or STA_ORB or INTERPLA]
This keyword specifies the type of space interferometer. It instructs
the algorithm for computation of path delay.
RA_PUSCH -- Radioastron type of interferometer. The space station
has its H-maser that does not keep time between scans
and is synchronized with the ground H-maser at PUSCHINO
radiotelescope.
RA_BGT -- Radioastron type of interferometer. The space station
has its H-maser that does not keep time between scans
and is synchronized with the ground H-maser at GB-VLBA
radiotelescope.
RA_GB140 -- Radioastron type of interferometer. The space station
has its H-maser that does not keep time between scans
and is synchronized with the ground H-maser at NRAO140
radiotelescope.
EARTH_OR -- the space radio telescope is Earth orbiting. Its clock are
synchronized before the experiment.
INTERPLA -- the space radio telescope is an interplanetary station.
NO -- there are no space radio telescopes in this experiment.
4 Baseline fringe fitting keywords
The baseline fringe fitting procedure is the main task of PIMA.
The goal of the fringe fitting procedure is to find group delay,
group delay rate, phase delay rate and possibly phase delay
acceleration in such a way that would minimize the loss of coherency
during averaging over time and frequency.
Baseline fringe fitting is done for each observation independently.
It consists of two steps: coarse fringe search and refinement.
In general, optimal determination of group delay, group delay rate,
phase delay rate and phase delay acceleration is a non-linear
procedure. The goal of the mandatory coarse fringe search is to find
an approximate value of group delay and phase delay rate in order
to shrink the search area and make possible linear estimator.
PIMA supports several algorithms of fine search that improves
result of the coarse fringe search. Results of fringe search and
statistics of residuals are written in the ascii output files
defined by keywords FRINGE_FILE and FRIRES_FILE.
4.1 FRIB.SEARCH_TYPE:
FRIB.SEARCH_TYPE: 2FFT
At the moment the only supported fringe search type is 2FFT. It is
based in the procedure that uses 2D FFT in order to find the maximum of
the visibility for the observation averaged with respect to time and
frequency with trial group delay and phase delay rate.
4.2 FRIB.DELAY_WINDOW_CENTER:
FRIB.DELAY_WINDOW_CENTER: value
PIMA allows to restrict the area in group delay, phase delay rate
space where the maximum of visibilities averaged over frequency and
time is sought. This rectangular area is determined by four parameters:
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH.
Keyword FRIB.DELAY_WINDOW_CENTER sets the center of the window over
group delay in seconds.
If you want to set the maximum search window, i.e. you do not see
a reason to restrict it, please set all four parameters
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH to zero.
4.3 FRIB.RATE_WINDOW_CENTER:
FRIB.RATE_WINDOW_CENTER: value
PIMA allows to restrict the area in group delay, phase delay rate
space where the maximum of visibilities averaged over frequency and
time is sought. This rectangular area is determined by four parameters:
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH.
Keyword FRIB.RATE_WINDOW_CENTER sets the center of the window over
phase delay rate. This quantity is dimensionless.
If you want to set the maximum search window, i.e. you do not see
a reason to restrict it, please set all four parameters
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH to zero.
4.4 FRIB.DELAY_WINDOW_WIDTH:
FRIB.DELAY_WINDOW_WIDTH: value
PIMA allows to restrict the area in group delay, phase delay rate
space where the maximum of visibilities averaged over frequency and
time is sought. This rectangular area is determined by four parameters:
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH.
Keyword FRIB.DELAY_WINDOW_WIDTH sets the half-width of the
delay in seconds. That means the search window is
[FRIB.DELAY_WINDOW_CENTER - FRIB.DELAY_WINDOW_WIDTH,
FRIB.DELAY_WINDOW_CENTER + FRIB.DELAY_WINDOW_WIDTH].
If the value is zero, then the maximum search window is set up:
1.0/Chan_with where Chan_width is the spectral resolution of
visibility data in Hz. NB: setting FRIB.DELAY_WINDOW_WIDTH greater
than the maximum search window has no effect. Parameter
FRIB.DELAY_WINDOW_WIDTH used for restricting the search window, not
for its increase.
If you want to set the maximum search window, i.e. you do not see
a reason to restrict it, please set all four parameters
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH to zero.
4.5 FRIB.RATE_WINDOW_WIDTH:
FRIB.RATE_WINDOW_WIDTH: value
PIMA allows to restrict the area in group delay, phase delay rate
space where the maximum of visibilities averaged over frequency and
time is sought. This rectangular area is determined by four parameters:
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH.
Keyword FRIB.DELAY_WINDOW_WIDTH sets the half-width of the
delay in seconds. That means the search window is
[FRIB.DELAY_WINDOW_CENTER - FRIB.DELAY_WINDOW_WIDTH,
FRIB.DELAY_WINDOW_CENTER + FRIB.DELAY_WINDOW_WIDTH].
If the value is zero, then the maximum search window is set up:
1.0/Chan_with where Chan_width is the spectral resolution of
visibility data in Hz. NB: setting FRIB.DELAY_WINDOW_WIDTH greater
than the maximum search window has no effect. Parameter
FRIB.DELAY_WINDOW_WIDTH used for restricting the search window, not
for its increase.
If you want to set the maximum search window, i.e. you do not see
a reason to restrict it, please set all four parameters
FRIB.DELAY_WINDOW_CENTER, FRIB.RATE_WINDOW_CENTER,
FRIB.DELAY_WINDOW_WIDTH, FRIB.RATE_WINDOW_WIDTH to zero.
4.6 FRIB.AUTOCORR_CALIB:
FRIB.AUTOCORR_CALIB: [NO or CNST1 or CNST2 or SQRT_MEA or
SQRT_KOG]
Correlators apply arbitrary normalization factors that affect
both autocorrelation and cross-correlation PIMA allows to re-normalize
cross-correlation visibilities.
NO -- no re-normalization is performed. NB: it is a bad idea to
use the data without renormalization for imaging.
CNST1 -- cross-correlation is divided by a constant
PIMA__ACCR_CNST1 defined in pima.i
CNST2 -- cross-correlation is divided by a constant
PIMA__ACCR_CNST2 defined in pima.i
SQRT_MEA -- PIMA computed re-normalization factors under assumptions
that 1) the correlator applied the same normalization
factor to both autocorrelation and cross-correlation;
2) the mean of the autocorrelation spectrum is 1.
The autocorrelation spectrum is corrected for sampling
distortion. This is done by transforming the spectrum to
the time domain, applying the digital sampler correction
that may differ from the digital sampler correction of
cross-correlator data since the autocorrelation data have
much larger amplitude, normalizing the autocorrelation
function to 1 at the zero lag and transforming the
corrected autocorrelation data back to the spectral
domain. Then the mean autocorrelation spectrum over an
IF is computed for each station, and the cross-correlation
visibilities are divided by the square root of the
product of the mean autocorrelation spectrum for both
stations of the baseline.
SQRT_KOG -- Similar to SQRT_MEA, but the original algorithm of Leonid
Kogan used. The author of PIMA considers Kogans's
algorithm erroneous, although the error affects the fringe
amplitude at the amount of 0.5-3%.
4.7 FRIB.AMPL_FUDGE_TYPE:
FRIB.AMPL_FUDGE_TYPE: [VLBA or DIFX or KOGAN or NO]
Fudge factor that accounts for disparity of amplitude distortion
of the autocorrelation and cross-correlation. This factor is correlator
dependent.
VLBA -- the factor that is due to register saturation in VLBA
*hardware correlator*. It depends on polarization and
on data weights. NB: if you process the data processed
with the software correlator located at Socorro you should
NOT apply this correction.
KOGAN -- the factor that is due to register saturation in VLBA
*hardware correlator*. The difference with respect to
a case VLBA (see above) is that all weights are
considered 1.0
DIFX -- For DiFX correlator: the fudge factor is 1.0
NO -- No fudge factor is applied.
4.8 FRIB.AMPL_EDGE_WINDOW_COR:
FRIB.AMPL_EDGE_WINDOW_COR: [USE or NO]
There are three factors that reduces fringe amplitude when we observe
a source that is off the main beam. The first factor is due to data loss
at the edge of a frame with raw voltage record due to shifting of data
streams. If the frame has N points, we can cross-multiplies all N points
of both streams when no shift is applied. If one of the streams is
shifted at K points, we can cross-multiply only N-K points and the
amplitude of the average will become less by the (N-K)/N factor.
This factor is linear with respect to the group delay delay and the
amplitude is reduced by the factor of 0.5 at the edge of the natural
search window determined as a quantity reciprocal to the spectral
resolution. The second factor is the power pattern of the primary beam.
The third factor is appearance of the phase acceleration due to
the third derivative of path delay over time, two times, and over
source coordinates.
This keyword determines whether to apply the amplitude correction
due to the amplitude loss for
USE -- to apply the amplitude correction for the amplitude loss
in cross-multiplication of the data streams when due to
data stream shift. If in doubt, set USE.
NO -- do not apply the amplitude correction due to non data stream
shifts. You should well understand what you are doing when
you use this option.
4.9 FRIB.AMPL_EDGE_BEAM_COR:
FRIB.AMPL_EDGE_BEAM_COR: [YES or NO]
This keyword specifies whether to apply the amplitude correction
for the antenna beam. Antenna beam is here the ratio of the power
of the signal from a uniformly emitting sphere at angle theta from
the beam direction to the power at tetra=0.
YES -- to apply the correction for the primary beams of both
antennas of a baseline. If in doubt, set YES.
NO -- not to apply the correction for the primary beams of both
antennas of a baseline. You should well understand what
you are doing when you use this option.
4.10 FRIB.OVERSAMPLE_MD:
FRIB.OVERSAMPLE_MD: value
Oversampling factor over group delay axis. When PIMA grids the data
for fringe search, it can reduce the step of the grid and pad the
samples between grid points. When no oversampling is used, the
amplitude of the coarse fringe may by less by a factor of 2.5 when
the maximum happens just between grid points. The week sources may be
overlooked. When the oversampling factors are 4 for both group delay
and phase delay rate, the amplitude drop of the coarse fringe search
is only 5%. It should be noted that the amplitude is affected by
the coarse fringe search only. If the sources is detected by the coarse
fringe search, the fine fringe fitting corrects the amplitude
underestimation.
value -- oversampling factor. General recommendation: 4, unless
you can tolerate the detection limit drop up to the factor
of 2.5. If you can tolerate it, set the oversampling
factor to 1. The factor cannot be less than 1.
4.11 FRIB.OVERSAMPLE_RT:
FRIB.OVERSAMPLE_RT: value
Oversampling factor over phase delay rate axis. See description
of FRIB.OVERSAMPLE_MD. Usually the oversampling over both axes is
applied.
value -- oversampling factor. General recommendation: 4, unless
you can tolerate the detection limit drop up to the factor
of 2.5. If you can tolerate it, set the oversampling
factor to 1. The factor cannot be less than 1.
4.12 FRIB.FINE_SEARCH:
FRIB.FINE_SEARCH: [LSQ or ACC or PAR or BIN or TEC or NO]
This keyword specifies the algorithm for fine fringe fitting that
follows the coarse fringe fitting.
LSQ -- the parameters following parameters are determined with
least square: group delay, group delay rate, phase delay
rate, and fringe phase at the fringe reference time and
the reference frequency. The reference frequency is the
lowest frequency of the data that are processed.
Fringe phase for each visibility point is assigned
according the the a priori SNR. The algorithm
seeks the variance factor that corrects the a priori weights
in such a way that the ratio of the weighted sum of the
postfit residuals to its mathematical expectation be close
to unity. The algorithm computes these reweighting parameters
for two cases: multiplicative reweighting and additive
reweighting, i.e. in the the first case the a posteriori
weight is the a priori weight multiplied by the reweighting
parameter, and in the second case the a posteriori weight
is the a priori weight with the reweighted parameter added
in quadrature. The algorithm returns three estimates of
group delay, group delay rate, phase delay rate, phase and
amplitude of observation-averaged visibilities: without
reweighting, with multiplicative reweighting and with additive
reweighting.
ACC -- the same as LSQ, but phase delay acceleration is evaluated
instead of group delay rate.
PAR -- the fine fringe fitting is done by the parabolic fit
through three points of the delay resolution function around
the maxima. The search of the maxima is performed separately
for delay and delay rate. The Lagrange interpolating
polynomial is computed, and the linear equation which
equalizes the derivative to zero is solved. The algorithm
returns the estimates of group delay, phase delay rate, phase
and amplitude of observation-averaged visibilities.
BIN -- the fine fringe fitting is done by binary division method.
The algorithm returns the estimates of group delay, group
delay rate, phase delay rate, phase and amplitude of
observation-averaged visibilities.
TEC -- not implemented
NO -- no fine fringe fitting is performed.
4.13 FRIB.AUTOCORR_THRESHOLD:
FRIB.AUTOCORR_THRESHOLD: value
The threshold for autocorrelation. The autocorrelations
that are less than this threshold are discarded. This
results in discarding related cross-correlations if
AUTOCORR_CALIB is SQRT_MEA or SQRT_KOG. Value 0.05
for DiFX correlator is usually adequate.
4.14 FRIB.WEIGHTS_THRESHOLD:
FRIB.WEIGHTS_THRESHOLD: value
The threshold for visibility weights. The visibility points
with weights less that this threshold are discarded. Value 0.2
is usually adequate.
4.15 FRIB.NOISE_NSIGMA:
FRIB.NOISE_NSIGMA: value
This parameter controls computation of the mean amplitude
of noise. The 2d Fourier transform of visibility data over
time an over frequency is analyzed for a search of the signal
from the radio source. The result is analyzed also for determination
of the mean amplitude of the noise. Among the results of the
2D Fourier transform the minimum among 32768 or 1/2 of the
number of elements are randomly selected. The amplitudes
of these random points of the spectrum are sorted in
the ascending order. Then the iterative procedure for
outlier elimination is launched. If the amplitude of the top
point of the list is greater than FRIB.NOISE_NSIGMA times the
root mean square over amplitudes in the list, the point is
discarded, the root means squares is recomputed, and the
procedure is repeated. Outlier elimination is made mainly to
eliminate from statistics computation those points that are
associated with signal rather than this signal.
value 4.0 is usually adequate.
4.16 FRIB.SNR_DETECTION
FRIB.SNR_DETECTION: value
Sets the threshold for detection. Observations with the SNR
less than this threshold are considered as non-detections.
Task splt discards observations with the SNR less than this
threshold. Task mkdb set flag "non-detection" for observations
with the SNR below this threshold. The detection limit depends
on the number of visibility data used for fringe fitting. PIMA
cannot determine the a priori threshold. It is set by a user.
It is possible to determine the SNR detection limit by analyzing
statistics of residuals from observations of the same type.
The SNR is defined as the ratio of the fringe amplitude to
the mean value of amplitude of noise. If to consider that
real and image part of noise are independent and have Gaussian
distribution with variance \sigma, the mean amplitude is
\sqrt(\pi/2) \approx 1.253 \sigma. The variance of the amplitude
noise is \sqrt(2 - \pi/2} \approx 0.655 \sigma.
4.17 FRIB.FRQ_TRANSFER_BAND:
FRIB.FRQ_TRANSFER_BAND: value
Controls how phase transfer from one frequency of simultaneous
observations to another should be performed by tasks frtr.
NO -- no phase transfer is made
control_file -- name of the secondary control file for the
lower band of this VLBI experiment. That
control file determines the frequency band
whether fringe phases should be taken
for the phase transfer to the frequencies
of the band specified in the main control
file.
4.18 FRIB.FRQ_TRANSFER_METHOD:
FRIB.FRQ_TRANSFER_METHOD: method
Defines the smoothing method applied to phase before frequency
transfer.
SPLINE -- phase at the lower band is expanded in B-spline basis
with the number of knots specified by keyword
FRIB.FRQ_TRANSFER_DEG
LEGENDRE -- phase at the lower band is expanded in Legendre basis
with the degree specified by keyword
FRIB.FRQ_TRANSFER_DEG
ASIS -- phase at lower band is not expanded and transferred
as is.
4.19 FRIB.FRQ_TRANSFER_DEG:
FRIB.FRQ_TRANSFER_DEG: degree
Defines the degree of the polynomial or the number of knots of
B-spline for smoothing phase before frequency transfer.
degree -- The meaning of this keyword depends on
FRIB.FRQ_TRANSFER_METHOD. If the expansion basis is
LEGENDRE, then FRIB.FRQ_TRANSFER_DEG is the
degree of the Legendre polynomial for expansion of
the phase at the low band. If the expansion basis is
SPLINE, then FRIB.FRQ_TRANSFER_DEG is the number of
spline knots in each intermediate frequency for
expansion of the amplitude of the phase at the low
band. It is ignored if method is ASIS.
4.20 FRIB.FRQ_TRANSFER_MSEG:
FRIB.FRQ_TRANSFER_MSEG: segment_length
Defines the length of the segment that will be coherently averaged
before frequency transfer.
segment_length -- The averaging factor for the phase at low band
to be used for interpolation before transfer.
An integer number in a range [1, NCHN], where
NCHN is the number of spectral channels in
an IF, or AUTO. Value AUTO forces PIMA to
determine segment length in order to have
the SNR within a segment no less than 1.5
4.21 FRIB.2D_FRINGE_PLOT:
FRIB.2D_FRINGE_PLOT: [XW or GIF or PS or TXT or NO]
This keyword specifies the format of the 2D fringe
plot. The 2D fringe plots shows the amplitude of the visibility
averaged over frequency and time within the observation as
a function of group delay and phase delay rate. The name of
the output file is
fr2d_{scan_name}_{band_name}_{station1}_{station2}.
All components are in lower case. The plot is placed in
subdirectory {EXPER_DIR}/{SESS_CODE}_fpl/ where EXPER_DIR is
the experiment scratch directory and {SESS_CODE} is the session
code.
XW -- to display the plot of the 2D function on the screen
using the PGPLOT library.
GIF -- to generate the plot in GIF format. Extension of the output
file is .gif
PS -- to generate the plot in Postscript format. Extension of the
output file is .ps
TXT -- to write the table with the averaged amplitude as a function
of group delay and phase delay rate. Extension of the output
file is .txt
NO -- do not generate the 2D fringe file output.
4.22 FRIB.PLOT_DELAY_WINDOW_WIDTH:
FRIB.PLOT_DELAY_WINDOW_WIDTH: value
This parameter sets the width of the 2d fringe plot along
group delay axis. Units are sec.
4.23 FRIB.PLOT_RATE_WINDOW_WIDTH:
FRIB.PLOT_RATE_WINDOW_WIDTH: value
This parameter sets the width of the 2d fringe plot along
phase delay rate axis. Units are sec.
4.24 FRIB.OVERSAMPLE_PLOT_MD:
FRIB.OVERSAMPLE_PLOT_MD: value
This parameter sets the oversampling factor along the group delay
axis for generation of the 2D fringe plot. Natural choice is '
FRIB.OVERSAMPLE_PLOT_MD: 1. If to increase the value, the lines
will become thicker.
4.25 FRIB.OVERSAMPLE_PLOT_RT:
FRIB.OVERSAMPLE_PLOT_RT: value
This parameter sets the oversampling factor along the phase delay
rate axis for generation of the 2D fringe plot. Natural choice is
FRIB.OVERSAMPLE_PLOT_RT: 1. If to increase the value, the lines will
become thicker.
4.26 FRIB.1D_RESFRQ_PLOT:
FRIB.1D_RESFRQ_PLOT: [XW or GIF or PS or SAV or TXT or NO]
This keyword specifies the format of the 1D fringe plot that shows
amplitude and phase of the visibilities averaged over time as
a function frequency. The name of the output file is
fr1d_frq_{scan_name}_{band_name}_{station1}_{station2}_all.
All components are in lower case. The plot is placed in
subdirectory {EXPER_DIR}/{SESS_CODE}_fpl/ where EXPER_DIR is
the experiment scratch directory and {SESS_CODE} is the session
code.
XW -- to display the 1D plot of the fringe phase and fringe
amplitude on the screen using the PGPLOT library.
SAV -- to write the plot in the internal format of graphic
library DiaGI. Extension of the output file is .sav
The plot can be displayed with program diagi_rst that
accepts the name of the plot file in SAV format as
its argument.
GIF -- to generate the plot in GIF format. Extension of the output
file is .gif
PS -- to generate the plot in Postscript format. Extension of the
output file is .ps
TXT -- to write the table with fringe phase and fringe amplitude
as a function of frequency. Extension of the output
file is .txt
NO -- do not generate the 1D fringe plot versus frequency output.
4.27 FRIB.1D_FRQ_MSEG:
FRIB.1D_FRQ_MSEG: value
The averaging factor for 1D fringe plot over frequency.
An integer number in a range [1, NCHN], where NCHN is the number
of spectral channels in an IF. If FRIB.1D_FRQ_MSEG > 1, then
the complex visibility is averaged over FRIB.1D_FRQ_MSEG consecutive
spectral channels, and the number of points in the plot will be
reduced by the same factor. Frequency averaging is used for displaying
fringe plot of a weak source.
4.28 FRIB.1D_RESTIM_PLOT:
FRIB.1D_RESTIM_PLOT: value
This keyword specifies the format of the 1D fringe plot that shows
amplitude and phase of the visibilities averaged over frequency as
a function time. The name of the output file is
fr1d_tim_{scan_name}_{band_name}_{station1}_{station2}_all.
All components are in lower case. The plot is placed in
subdirectory {EXPER_DIR}/{SESS_CODE}_fpl/ where EXPER_DIR is
the experiment scratch directory and {SESS_CODE} is the session
code.
XW -- to display the 1D plot of the fringe phase and fringe
amplitude on the screen using the PGPLOT library.
SAV -- to write the plot in the internal format of graphic
library DiaGI. Extension of the output file is .sav
The plot can be displayed with program diagi_rst that
accepts the name of the plot file in SAV format as
its argument.
GIF -- to generate the plot in GIF format. Extension of the output
file is .gif
PS -- to generate the plot in Postscript format. Extension of the
output file is .ps
TXT -- to write the table with fringe phase and fringe amplitude
as a function of frequency. Extension of the output
file is .txt
NO -- do not generate the 1D fringe plot versus time.
4.29 FRIB.1D_TIM_MSEG:
FRIB.1D_TIM_MSEG: value
The averaging factor for 1D fringe plot over time.
An integer number in a range [1, NAP], where NAP is the number
of accumulation periods. If FRIB.1D_TIM_MSEG > 1, then
the complex visibility is averaged over FRIB.1D_TIM_MSEG consecutive
accumulation periods, and the number of points in the plot will be
reduced by the same factor. Frequency averaging is used for
displaying fringe plot of a weak source.
4.30 FRIB.1D_DRF_PLOT:
FRIB.1D_DRF_PLOT: value
This keyword specifies the format of the 1D plot of the delay
resolution function -- dependence of the fringe amplitude averaged
over frequency and time on group delay. The argument of the DRF is
group delay with respect to the value found by the fringe fitting
procedure. The name of the output file is
fr1d_drf_{scan_name}_{band_name}_{station1}_{station2}_all.
All components are in lower case. The plot is placed in
subdirectory {EXPER_DIR}/{SESS_CODE}_fpl/ where EXPER_DIR is
the experiment scratch directory and {SESS_CODE} is the session
code.
XW -- to display the 1D plot of the fringe phase and fringe
amplitude on the screen using the PGPLOT library.
SAV -- to write the plot in the internal format of graphic
library DiaGI. Extension of the output file is .sav
The plot can be displayed with program diagi_rst that
accepts the name of the plot file in SAV format as
its argument.
GIF -- to generate the plot in GIF format. Extension of the output
file is .gif
PS -- to generate the plot in Postscript format. Extension of the
output file is .ps
TXT -- to write the table with fringe phase and fringe amplitude
as a function of frequency. Extension of the output
file is .txt
NO -- do not generate the 1D delay resolution function plot.
4.31 FRIB.1D_DRF_SPAN:
FRIB.1D_DRF_SPAN: value
This parameter sets the half-width of the interval of the argument
for a delay resolution plot. Units are sec.
5 Bandpass processing keywords
5.1 BPS.MODE:
BPS.MODE: value
5.2 BPS.MODE:
BPS.MODE: [INIT or ACCUM or FINE]
The mode of the complex bandpass computation procedure. This
keyword specifies the stage where bandpass computation should stop.
There are three stages for bandpass calculation.
INIT -- to run the bandpass in the init mode. PIMA analyzes the
input file with the fringe fitting results and finds
the observations with the maximum SNR for each baseline
with the reference station. NB: PIMA obeys INCLUDE_OBS:
and EXCLUDE_OBS: keywords and checks only those observations
that satisfies the filter. PIMA computes the visibilities
averaged over time with parameters of fringe fitting
applies. These time-averaged visibilities are a function of
frequency. The phase of the complex bandpass is the residual
phase of the visibilities after subtraction the time and
frequency averaged phase over the observation. The amplitude
of the bandpass is the amplitude of time-averaged visibility
after dividing it over the amplitude averaged over time and
frequency within the IF to which the individual point of the
bandpass belongs. The bandpass can be considered as the
averaged visibility. The normalization for phase is computed
by averaging over all IFs, and normalization for amplitude
is computed by averaging over individual IFs. In the case of
dual-polarization data when POLAR: I is specified, the
procedure is repeated twice: first for the RR polarization
bandpass second for the LL polarization with respect to the
RR polarization data.
ACCUM -- to run bandpass in the accumulation mode. After computation
the bandpass in the init mode, the bandpass is applied to
K observations at every baseline with the reference station.
PIMA selects these observations as the ones that have the
greatest SNR.
FINE -- to run bandpass in the fine mode. After computation the
bandpass in the accumulation mode, the bandpass is re-computed
using least squares. Accumulation bandpass is applied.
Correction to the accumulation bandpass is computed by
estimating parameters of the phase and amplitude bandpass
using M observations with the highest SNR among all
baselines with the references station. Estimated parameters
for the phase part are coefficients of expansion over Legendre
polynomials of B-spline basis. Estimated parameters for
the amplitude part are coefficients of expansion of the
logarithm of the residual amplitude ratios into either
Legendre polynomials or the B-spline basis. After computing
a solution, observations are checked for outliers. If the
residual phases or amplitudes exceed a certain threshold, the
observation is marked as outlier and the bandpass is recomputed.
The procedure is repeated till either no outlier is found.
If at a given baseline the number of remaining observations
fell to the specified threshold Q, no more outliers at that
baseline is eliminated.
5.3 BPS.NOBS_ACCUM:
BPS.NOBS_ACCUM: value
This keyword specified how many observations with the highest SNR
at each baseline are taken for computation of the accumulation bandpass.
5.4 BPS.MSEG_ACCUM:
BPS.MSEG_ACCUM: value
This keyword specifies how many adjacent spectral channels are
coherently averaged during phases of the initial and accumulation
bandpass calculation. Cannot be less than 1 or exceed the number
of spectral channels in the IF.
5.5 BPS.NOBS_FINE:
BPS.NOBS_FINE: value
This keyword specified how many observations with the highest SNR
at each baseline are taken for computation of the accumulation bandpass.
5.6 BPS.MINOBS_FINE:
BPS.MINOBS_FINE: value
The keyword specified the minimum number of observation at each
baseline that should remain during bandpass computation in the fine
mode. This parameter limits the number of outliers rejected.
5.7 BPS.MSEG_FINE:
BPS.MSEG_FINE: value
This keyword specifies how many adjacent spectral channels are
coherently averaged during phases of the fine bandpass calculation.
Cannot be less than 1 or exceed the number of spectral channels in
the IF.
5.8 BPS.SNR_MIN_ACCUM:
BPS.SNR_MIN_ACCUM: value
This keyword specifies the minimum SNR for an observation to be
eligible for being used for bandpass computation in accumulation
mode. Observations with the SNR less than this limit are not considered.
If the SNR is too small, there is a chance that the bandpass computation
procedure will derail. If there are no high SNR observations in the
experiment, parameter BPS.ACCUM_MSEG should be raised.
5.9 BPS.SNR_MIN_FINE:
BPS.SNR_MIN_FINE: value
This keyword specifies the minimum SNR for an observation to be
eligible for being used for bandpass computation in fine mode.
Observations with the SNR less than this limit are not considered.
5.10 BPS.DECOR_TIM_MIN:
BPS.DECOR_TIM_MIN: value
This keyword specifies the minimum time decorrelation value computed
by the fringe fitting for the observation to be eligible for being
used for bandpass computation in any mode. It can be in a range of
0 to 1. DECOR_TIM is the ration of the correlated amplitude coherently
averaged over the scan to the arithmetic average (i.e. the incoherent
average) of the correlated amplitude computed over elementary segments
used by the procedure of fine fringe fitting. DECOR_TIM is close to 1
for a perfect observation. Phase variations due to atmosphere of
frequency standard degrades DECOR_TIM. This degradation is harmless
for bandpass calculation. However, DECOR_TIM may be reduced due to
catching artificial signal, either internal or external RFI. The
purpose of this filter is to prevent using observations affected
by RFI. Recommended value: 0.8 at frequencies below 15 GHz and 0.5
at frequencies above 15 GHz. Value 0.0 disables this filter entirely.
5.11 BPS.AMPL_REJECT:
BPS.AMPL_REJECT: value
The threshold for the residual amplitude after applying bandpass
in the fine mode for being marked as the outlier. The observation
is marked as the outlier if the the rms of the deviation of the
normalized amplitude from 1.0 in any intermediate frequency
exceeds BSP.AMPL_REJECT.
5.12 BPS.PHAS_REJECT:
BPS.PHAS_REJECT: value
The threshold for the residual phase after applying bandpass
in the fine mode for being marked as an outlier. Unit: radian.
The observation is marked as an outlier if the the rms of the
residual phase in any intermediate frequency is greater than
BSP.PHAS_REJECT. Typical value is 0.4 rad.
5.13 BPS.INTRP_METHOD:
BPS.INTRP_METHOD: [LEGENDRE or SPLINE]
The keyword specifies the basis for expansion the bandpass.
LEGENDRE --Legendre polynomial
SPLINE -- B-spline of the 3rd degree.
5.14 BPS.DEG_AMP:
BPS.DEG_AMP: value
The meaning of this keyword depends on BPS.INTRP_METHOD.
If the expansion basis is LEGENDRE, then BPS.DEG_AMP is the
degree of the Legendre polynomial for expansion of the
amplitude of the bandpass. If the expansion basis is SPLINE,
then BPS.DEG_AMP is the number of spline knots in each
intermediate frequency for expansion of the amplitude of the
bandpass.
5.15 BPS.DEG_PHS:
BPS.DEG_PHS: value
The meaning of this keyword depends on BPS.INTRP_METHOD.
If the expansion basis is LEGENDRE, then BPS.DEG_PHS is the
degree of the Legendre polynomial for expansion the phase
of the bandpass. If the expansion basis is SPLINE, then BPS.DEG_AMP
is the number of spline knots in each intermediate frequency
for expansion of the phase of the bandpass.
5.16 BPS.NORML:
BPS.NORML: [NO or IF or BAND]
This keywords specifies the way how the bandpass normalization
is made.
NO -- No normalization is applied.
IF -- The bandpass is normalize to have the mean amplitude
1.0 over each individual intermediate frequency.
This is a typical choice.
BAND -- The bandpass is normalized to have the mean amplitude 1.0
over the band, i.e. over all intermediate frequencies.
5.17 BPS.SEFD_USE:
BPS.SEFD_USE: value
Not used. Should be NO
6 Phase reference fringe fitting keywords
6.1 FRIP.SCAN_FILE:
FRIP.SCAN_FILE: file or NO
Not implemented. Should be NO.
6.2 FRIP.STA_INC_FILE:
FRIP.STA_INC_FILE: file or NO
Name of the file that with station names. Should be NO.
6.3 FRIP.STA_EXC_FILE:
FRIP.STA_EXC_FILE: file or NO
Not implemented. Should be NO.
6.4 FRIP.STA_REFS:
FRIP.STA_REFS: value
Not implemented. Should be SAME.
6.5 FRIP.RESOLUTION:
FRIP.RESOLUTION: value
Not implemented. Should be 4096.
6.6 FRIP.OVERSAMPLE:
FRIP.OVERSAMPLE: value
Not implemented. Should be 1.
6.7 FRIP.SCA:
FRIP.SCA: value
Not implemented. Should be ALL.
6.8 FRIP.MAP_DIR:
FRIP.MAP_DIR: directory or NO
Not implemented. Should be SAME.
6.9 FRIP.ATM_ZEN_FILE:
FRIP.ATM_ZEN_FILE: file or NO
Not implemented. Should be NO.
6.10 FRIP.CAL_PLOT:
FRIP.CAL_PLOT: value
Not implemented. Should be GIF.
6.11 FRIP.CAL_RES:
FRIP.CAL_RES: value
Not implemented. Should be 400.
6.12 FRIP.TAG_PLOT:
FRIP.TAG_PLOT: value
Not implemented. Should be GIF.
6.13 FRIP.TAG_RES:
FRIP.TAG_RES: value
Not implemented. Should be 400.
6.14 FRIP.BEAM_PLOT:
FRIP.BEAM_PLOT: value
Not implemented. Should be GIF.
6.15 FRIP.FRQ_MSEG:
FRIP.FRQ_MSEG: value
Not implemented. Should be 128.
6.16 FRIP.TIM_MSEG:
FRIP.TIM_MSEG: value
Not implemented. Should be 1.
6.17 FRIP.RA_CENTER:
FRIP.RA_CENTER: value
Not implemented. Should be APRIORI.
6.18 FRIP.DEC_CENTER:
FRIP.DEC_CENTER: value
Not implemented. Should be APRIORI.
6.19 FRIP.RA_STEP:
FRIP.RA_STEP: value
Not implemented. Should be 0.1.
6.20 FRIP.DEC_STEP:
FRIP.DEC_STEP: value
Not implemented. Should be 0.1
6.21 FRIP.RA_RANGE:
FRIP.RA_RANGE: value
Not implemented. Should be 1.0.
6.22 FRIP.DEC_RANGE:
FRIP.DEC_RANGE: value
Not implemented. Should be 1.0.
7 Splt keywords
Operation splt gathers all visibilities for the specified source(s),
applies all calibrations, transforms baseline dependent group delays,
phase delay rates, and group delay rates from baseline dependent
quantities to station based quantities, rotates visibility phases for
results of fringe fitting, averages visibilities over time and frequency,
applies specified re-normalizations, and writes averaged visibilities
in output FITS files, one file per sources, in a form suitable for
imaging using software DIFMAP.
7.1 SPLT.SOU_NAME:
SPLT.SOU_NAME: [Bname or Jname or ALL]
Name of the source that is to be processed. All visibilities
related to that sources subject of constraint in INCLUDE_OBS_FILE,
EXCLUDE_OBS_FILE, OBS, and SNR_DETECTION_LIMIT keywords are
considered.
Bname -- B1950 8-character long source name.
Jname -- J2000 10-character long source name.
ALL -- operation splt is performed in a cycle over all source
names.
7.2 SPLT.FRQ_MSEG:
SPLT.FRQ_MSEG: value
The keyword specifies the number of spectral adjacent channels that will
averaged. It should be no less than 1. Value 1 means no frequency averaging.
The value should be exceed the number of channels in the intermediate
frequency. Typical choice: the total number of spectral channels in the IF.
In that case the number of IFs in the output FITS file is the same as the
number of used IFs in the input data. If SPLT.FRQ_MSEG is less than the number
of spectral channels in the intermediate frequency, the number of IFs in the
output file will be greater than the number of IFs in the input data.
PIMA does not support hierarchy spectral channel+IF in the output FITS files.
The number of spectral channels is always 1 in the output file.
7.3 SPLT.TIM_MSEG:
SPLT.TIM_MSEG: value
The keyword specifies the number of adjacent accumulation periods for
time averaging. Value 1 means no time averaging. IF SPLT.TIM_MSEG exceeds
the number of accumulation periods in the scan, all accumulation periods
are averaged.
7.4 SPLT.WEIGHT_TYPE:
SPLT.WEIGHT_TYPE: [ONE, OBS_SNR, OBS_MS, SEG_RMS, AUTO]
This keywords species the method for computing visibility
weights in the output FITS file.
ONE -- all weights are unity.
OBS_SNR -- Calibrated amplitude is computed over the observation.
The SNR for a given IF is computed based on the SNR
over the observation. Rms of noise is computed as
a ratio of calibrated amplitude to the SNR over the
IF. Weight is reciprocal to the square of noise
rms. Thus, the weight is computed for a given IF
using all accumulation periods of the observation.
OBS_RMS -- Weighted variance of calibrated visibilities is computed
for a given IF using all accumulation periods of a given
observation. Weight is reciprocal to the variance.
SEG_RMS -- Weighted variance of calibrated visibilities is computed
for a given IF using all accumulation periods over
a given segment. Weight is reciprocal to the variance.
AUTO -- If the number of accumulation periods per segment is
greater of equal than the threshold (currently 8),
WEIGHT_TYPE AUTO is equivalent to WEIGHT_TYPE: SEG_RMS.
If the number of accumulation periods per segment is
less than the threshold (currently 8), weighted variance
of calibrated visibilities is computed over so-called
"weights segments". These weight segments are longer than
the output visibility segments. Weight for a given IF,
given segment is reciprocal to the variance of the weight
segment with the middle epoch nearest to the to the epoch
of the given segment.
7.5 SPLT.POLAR:
SPLT.POLAR: [RR or LL or RL or LR or I or PAR or ALL]
This keyword specifies for which polarizations the visibilities
should be in the output FITS file. If the input data had single
polarization then SPLT.POLAR value should be that polarization
code. In a case of dual polarization the choice is
RR -- RR-polarization only.
LL -- LL-polarization only.
RL -- RL-polarization only.
LR -- LR-polarization only.
I -- I-polarization only. The I-polarization data are computed
on the fly.
PAR -- RR-polarization and LL-polarization data. This is a usual
choice when no cross-polarization analysis is intended.
ALL -- all polarization data present in the input FITS files
are exported to the output FITS file.
7.6 SPLT.AUTOCORR_NRML_METHOD:
SPLT.AUTOCORR_NRML_METHOD: [AVERAGED or NO]
This keyword specifies whether to apply the renormalization factor
for system temperature due to discarding some spectral channels.
The system temperature is measured over entire intermediate frequency.
However, in general, the spectrum of noise is not constant over
the band. PIMA uses autocorrelation function to compute the factor of
Tsys(used)/Tsys(tot), where Tsys(used) is the system temperature over
the used portion of the bandwidth, and Tsys(tot) is the Tsys over
the entire IF, i.e. measured Tsys. The portion of the bandwidth for
renormalization is defined by [ICHN_1ST, ICHN_LAST] range *and* the
band mask.
AVERAGED -- to apply the system temperature to renormalization due
to discarded spectral channels.
NO -- do not apply the system temperature to renormalization
7.7 SPLT.BPASS_NRML_METHOD:
SPLT.BPASS_NRML_METHOD: [WEIGHTED or NO]
This keywords specifies whether to apply the bandpass renormalization
factors for given intermediate frequencies using only a part of the
bandwidth. Initially, the bandpass is normalized to unity over the
*entire* bandwidth of the IF. However, often decorrelation occurs at the
edges of the band. PIMA allows to specify the portion of the band that
is considered "representative". It is expressed in parameters Bl, Bh
that stands for bandwidth low range and bandwidth high range that are
specified in SPLT.BPASS_NRML_RANGE. The representative bandwidth is
[F_low + Bl*Fw, F_low*Bh*fw]. Renormalization factor
R = (sum B_r/N_r ) / Sum B_t/N_t, where B_r -- bandpass in the bandwidth
is [F_low + Bl*Fw, F_low*Bh*fw], N_r -- the number of points in that
bandwidth; B_t bandpass in the total bandwidth, N_t the total number of
points in the entire IF. The IF-dependent factors scale the bandpass
to make makes its normalized over the representative bandwidth within
a given IF [F_low + Bl*Fw, F_low*Bh*fw]. Usually, the factor is less
than 1.0. If unsure, use WEIGHTED.
WEIGHTED -- to apply the bandpass renormalization.
NO -- not to apply the bandpass renormalization.
7.8 SPLT.BPASS_NRML_RANGE:
SPLT.BPASS_NRML_RANGE: low:high
These keyword specifies the range of the bandwidth as a share of
the nominal bandwidth that are considered representative for bandpass
renormalization. The parameters of the range are between [0,1].
The parameter is discarded when SPLT.BPASS_NRML_METHOD: NO.
If unsure, specify 0.2:0.8
low -- the low frequency of the IF that belongs to the
representative range. Should be in a range [0, 1).
high -- the high frequency of the IF that belongs to the
representative range. Should be in a range (0,1].
High should be greater than low.
Example: let the IF frequency range 32 MHz, the number of spectral
channels is 256. If SPLT.BPASS_NRML_RANGE: 0.2:0.75, then
the low frequency of the representative range is 0.2*32 = 6.4 MHz,
the first spectral channel within the range is 52. The high
frequency of the representative range is 0.75*32 = 24 MHz,
the last spectral channel within the range is 192. Thus the bandpass
renormalization will be done in such a way that the mean bandpass
over spectral channels with indices 52-192 be unity.
7.9 SPLT.SUBARRY_CONSOLIDATION:
SPLT.SUBARRY_CONSOLIDATION: [NO or MIN or MAX]
Since PIMA performs fringe fitting in the baseline mode, an individual
scan may not have detections less than N*(N+1)/2 baselines of a N-station
network. PIMA designate a subnetwork with detections at a given scan
as an subarray. Normally PIMA unites observations of different scans
with the same subnetwork in a subarray. PIMA computes station-based
visibility phases for each subarray individually. Keyword
SPLT.SUBARRY_CONSOLIDATION controls how subarrays are consolidated after
initial process for converting baseline-depended fringe phases into
station-based fringe phases.
NO -- means to disable subarray consolidation.
MIN -- instructs PIMA to preform minimal subarray consolidation:
if all stations of subarray A are present in the subarray B,
then the subarray B is consolidated with subarray A.
MAX -- instructs to preform maximum subarray consolidation: if a
subarray has at least one common station with subarray B, both
subarrays are consolidated.
7.10 SPLT.TOTAL_UV:
SPLT.TOTAL_UV: [NO or YES]
Specifies whether or not to generate output files with the total
visibilities averaged over frequency and over all accumulation period
over the scan after applying phase rotation for the results of fringe
fittings. The total visibilities are referred to the band reference
frequency. If YES is specified, the files with total visibilities
are written in the same output directories averaged visibilities,
in addition to them.
7.11 SPLT.TOTAL_UV:
SPLT.SNR_MIN: [value]
Specifies the minimum SNR over the entire scan for the data to
be used by splt to export to the output fits-file. The data
from the observation with the SNR less than that limit are not
exported.
The SNR is defined as the ratio of the fringe amplitude to
the mean value of amplitude of noise. If to consider that
real and image part of noise are independent and have Gaussian
distribution with variance \sigma, the mean amplitude is
\sqrt(\pi/2) \approx 1.253 \sigma. The variance of the amplitude
noise is \sqrt(2 - \pi/2} \approx 0.655 \sigma.
7.12 SPLT.GAIN_CORR_FILE:
SPLT.GAIN_CORR_FILE: [NO or file]
Specifies the name of the gain correction file. The gain correction file
contains empirical gain corrections. This keyword is used by tasks splt and
gaco.
NO -- no gain correction will be applied
file -- name of the gain correction file. It consists of records of fixed
lengths in plain ascii. Each record defines gain correction, its
formal errors and the number of observations used to derived for
a specific station and specific IF. Task splt checks whether
keyword SPLT.GAIN_CORR_FILE defines a file. If it does it multiplies
visibility by the product of two gain corrections for each station
of a baseline.
7.13 SPLT.STA_BASED:
SPLT.STA_BASED: [YES or ALL or NO]
This keyword specifies whether the station based or baseline based
algorithm for computation of averaged visibilities will be used.
Usually, station-based algorithm is required for imaging since
baseline based algorithm does not preserve phase misclosure.
However, station based algorithm prevents putting observations with
less than three baselines in the output FITS-IDI file. Therefore,
sometimes it is desirable to have a possibility to write the averaged
visibilities split into sources even of they belong to a subarray
with only two stations.
YES -- to use a station-based algorithm for computing averaged
visibilities. All observations that passed input filter
controlled by keywords INCLUDE_OBS_FILE, EXCLUDE_OBS_FILE,
OBS, and SNR_DETECTION_LIMIT are process for computation
of station-based quantities. The same observations are
used for generating the output.
ALL -- to use a station-based algorithm for computing averaged
visibilities. All observations that passed input filter
controlled by keywords INCLUDE_OBS_FILE, EXCLUDE_OBS_FILE,
OBS, and SNR_DETECTION_LIMIT are process for computation
of station-based quantities. All observations between
the station for which station-based group delays, phase
delay rates, and group delays are used for generating
the output regardless whether they passed the input
filter or not. If unsure, specify ALL.
NO -- to use a baseline-based algorithm. Suitable mainly for
processing single-baseline data.
8 ONOF processing keywords
PIMA task onof computes good start and stop time for every scan.
This routine is used for mitigation of incorrect on/off time written
by the field system in logs. The task finds the time interval at the
beginning and the end of the scan with the fringe amplitude below
the threshold and the flags accumulation periods that fits criteria
of "not on source" interval.
8.1 ONOF.GEN_FLAGS_MODE:
ONOF.GEN_FLAGS_MODE: [NO, CREATE, UPDATE]
NO -- onof procedure is not running
CREATE -- original flagging status for a given observation is set
to 1.0, i.e. unflag.
UPDATE -- original flagging status for a given observation is
honored. Onof does not see flagged scans and preserves
their flag value.
8.2 ONOF.KERNEL_START_SHARE:
ONOF.KERNEL_START_SHARE: value
value -- The start epoch of the kernel interval defined
as an offset with respect to the nominal start
time as a share of the scan length. Should be
in a range [0, 1]. For instance if the scan
length is 100s, and ONOF.KERNEL_START_SHARE: 0.2,
then the start epoch of the kernel is 20s.
8.3 ONOF.KERNEL_END_SHARE:
ONOF.KERNEL_END_SHARE: value
value -- The send epoch of the kernel interval defined
as an offset with respect to the nominal start
time as a share of the scan length. Should be
in a range [0, 1]. For instance if the scan
length is 200s, and ONOF.KERNEL_END_SHARE: 0.9,
then the start epoch of the kernel is 180s.
8.4 ONOF.COHERENT_INTERVAL:
ONOF.COHERENT_INTERVAL: value
value -- Interval of coherency in seconds used for
computation of mean amplitude. In a case
if the kernel interval is longer than the
coherency interval, the mean and wrms of
visibilities is computed over the shorter
coherency interval. If unsure, set it to 1200.
8.5 ONOF.COHERENT_INTERVAL:
ONOF.AMPL_THRESHOLD: value
value -- Threshold criterion. An AP with amplitude
times ONOF.AMPL_THRESHOLD of the mean
amplitude over the scan kernel is considered
as a candidate for flagging.
ONOF.AMPL_THRESHOLD: 0.0 means no amplitude
threshold criterion is checked.
8.6 ONOF.NSIG_THRESHOLD:
ONOF.NSIG_THRESHOLD: value
value -- N-sigma criterion. An AP with amplitude
ONOF.AMPL_THRESHOLD times wrms of the visibility
over the scan kernel is considered as a candidate
for flagging. ONOF.NSIG_THRESHOLD: 0.0 means
no amplitude n-sigma criterion is checked.
8.7 ONOF.MIN_LOW_AP:
ONOF.MIN_LOW_AP: value
value: 0 means that the AP that satisfied flagging
criteria ONOF.AMPL_THRESHOLD or ONOF.NSIG_THRESHOLD
is flagged out. If ONOF.MIN_LOW_AP > 0, then
onof checks how many consecutive APs have low
amplitude. If ONOF.MIN_LOW_AP APs has low
amplitude, then the rest of the scan portion
(before the kernel interval or after kernel
interval) is flagged out. If after k APs with
low amplitude ( k < ONOF.MIN_LOW_AP ) follows
an AP with high amplitude, these k APs are not
flagged.
9 Creation of the output database keywords
The fringe fitting procedure writes results in an ascii file.
Task mkdb computes total group delay, phase delay rate, group
delay rates and a number of auxiliary quantities using the
results of the fringe fitting. The results of task are written
in either plain ascii format or in GVF format that is native
for geodesy/astrometry VLBI processing software VTD/post-Solve.
9.1 MKDB.OUTPUT_TYPE:
MKDB.OUTPUT_TYPE: [TEXT or GVF or AMPL]
Format of the output file generated by task mkdb.
TEXT -- total group path delays, phase delay rates and other
quantities are written in a table in plain ascii format,
one line per used observation.
GVF -- total group path delays, phase delay rates and other
quantities are written in a binary GVF format suitable
for processing with geodesy/astrometry software
VTD/post-Solve.
AMPL -- fringe amplitude, fringe phase, Tsys, gain, uv baseline
projections and other parameters are written in a plain
ascii table, one line per used observation.
9.2 MKDB.SRT:
MKDB.SRT: [MID_SCAN or SRT_FRT or file]
This keyword controls the logic for computation of scan reference
time (SRT). Since PIMA processes all observations independently,
in general, fringe reference time of observations of the same scan
is not the same. Group delays, phase delay rates, and fringe phases
of the same scan, the same subarray are referred to a common epoch
that is called scan reference time. PIMA computes this scan reference
time in such a way that the errors of group delays is minimized.
If unsure, use MID_SCAN.
MID_SCAN -- PIMA finds the scan reference time near in the middle
of a scan that. In a simplest case when all stations
started and ended a scan at the same time and there
were no data losses, the scan reference time is the
middle scan epoch rounded to 1 sec. Computation of scan
reference time is not trivial if good data started
and ended at different stations at different epochs.
First PIMA finds the interval of time of valid
accumulation periods (AP) over all used observations
of a scan. If it finds observations that are not in
common range, it splits the scan into subarrays that
are treated as separate scans. Then within each subarray
it finds for each observation the range of time for
which the formal uncertainty of group delay increases
by no more than either an additive parameter
MKDB.GD_MAX_ADD_ERROR and by no more than scaling factor
MKDB.GD_MAX_SCL_ERROR. If it finds observations that are
not in common range, it splits the scan into subarrays
that are treated as separate scans. Finally, for each
remaining subarray PIMA assigns the scan reference time
that is in the middle of the common range, subject of
constraints imposed on allowed increase of group delay
formal uncertainty. The scan reference time is rounded
to the nearest second.
SRT_FRT -- scan reference time is the same as fringe reference time.
If this value is specified, the scan reference time
may be different for each observation.
file -- name of the file with scan reference time. PIMA allows
to compute the best fringe reference time externally
and import it using MKDB.SRT keyword.
9.3 MKDB.GD_MAX_ADD_ERROR:
MKDB.GD_MAX_ADD_ERROR: value
Parameter MKDB.GD_MAX_ADD_ERROR controls MID_SCAN algorithm for
setting the scan reference time. When the reference time epoch
is changed, the uncertainty of group delay is increased.
MKDB.GD_MAX_ADD_ERROR controls the tolerance to this increase
as an addition to the group delay uncertainty at fringe reference
time. Units: sec. If unsure, use 5.D-15
9.4 MKDB.GD_MAX_SCL_ERROR:
MKDB.GD_MAX_SCL_ERROR: value
Parameter GD_MAX_SCL_ERROR controls MID_SCAN algorithm for
setting the scan reference time. When the reference time epoch
is changed, the uncertainty of group delay is increased.
GD_MAX_SCL_ERROR controls the tolerance to this increase
as a fraction pf the group delay uncertainty at fringe reference
time. Units: dimensionless. If unsure, use 0.2. Value 0.2
means that 20% increase of formal uncertainty due to a change
of the scan reference time with respect to the fringe reference
time is allowed.
9.5 MKDB.FILTER:
MKDB.FILTER: [NO or ONLY_DET]
ONLY_DET -- only detected observations are put into the database,
i.e. the observations with the SNR exceeding
SNR_DETECTION_LIMIT. NB: if an observation has the SNR
greater than the limit, this does not necessary means
the observation is a detection.
NO -- no filter is applied. All observations regardless their
SNR are put into the output database.
9.6 MKDB.FRINGE_ALGORITHM:
MKDB.FRINGE_ALGORITHM: [DRF or LSQ or MUL or ADD or NO]
This keyword specifies what estimate of group delay,
phase delay rate, group delay rate and their formal
uncertainties to put in the output database. PIMA computes
four estimates of group delays then fine fringe search algorithm,
but only one estimate can be put in the output database. This
keyword determines which estimate is to he put in the output file.
If unsure, specify LSQ.
DRF -- estimates of group delay, phase delay rate, fringe phase,
and fringe amplitude from the coarse fringe fitting
will be put into the output database. Group delay rate
is zero.
LSQ -- estimates of group delay, phase delay rate, group delay
rate, fringe phase, and fringe amplitude from the LSQ fine
fringe fitting algorithm without applying re-weighting
will be put into the output database.
MUL -- estimates of group delay, phase delay rate, group delay
rate, fringe phase, and fringe amplitude from the LSQ fine
fringe fitting algorithm with applying multiplicative
re-weighting will be put into the output database. The
formal uncertainties are scaled by a certain factor in order
to make the ratio of the weighted sum of squares of
residuals to their mathematical expectation close to unity.
ADD -- estimates of group delay, phase delay rate, group delay
rate, fringe phase, and fringe amplitude from the LSQ fine
fringe fitting algorithm without applying re-weighting
will be put into the output database. An additive parameter
is found in such a way that after being added in quadrature
to the a priori weights the ratio of the weighted sum of
squares of residuals to their mathematical expectation close
to unity.
NO -- estimates of group delay and phase delay rate from coarse
fringe fitting will be put into the output database.
9.7 MKDB.2ND_BAND:
MKDB.2ND_BAND: [NO or file]
This keyword specifies whether to chain results from two bands
into one database.
NO -- results from fringe fitting from one band specified in the
current control file will be put in the output database.
file -- name of the second control file. Fringe fitting results
from two bands, two control files, will be put in the output
database. The first band is the band specified in the current
database. The second band is the band specified in
MKDB.2ND_BAND keyword.
NB: Although PIMA does not require bands be in a certain order
an order, VTD/Post-Solve does. VTD/Post-Solve requires the first
band to have a higher frequency and the second band to have a lower
frequency.
9.8 MKDB.VCAT_CONFIG:
MKDB.VCAT_CONFIG: [NO or file]
Name of the VCAT configuration file. Required if MKDB.OUTPUT_TYPE is
GVF and ignored otherwise. See VTD/Post-Solve documentation for format
of VCAT configuration file.
9.9 MKDB.OUTPUT_NAME:
MKDB.OUTPUT_NAME: value
Meaning of this value depends on the value of MKDB.OUTPUT_TYPE keyword.
If MKDB.OUTPUT_TYPE is AMPL or TEXT, then MKDB.OUTPUT_NAME specifies
the name of the output file for task mkdb. If MKDB.OUTPUT_TYPE is GVF,
then MKDB.OUTPUT_TYPE specifies a suffix of the database name.
The GVF compliant database name is yyyymmddS_vNNN.env, where S is
a one-letter long lower case suffix and NNN is the version number.
9.10 MKDB.DESC_FILE:
MKDB.DESC_FILE: [file or NO]
The name of the file with additional information about the experiment
that propagates to the GVF database. If no information is available,
NO can be specified. This parameter is used only by task mkdb when the
output data type is GVF.
Questions and comments about this guide should be directed to:
Leonid Petrov ( http://astrogeo.org/petrov )
Last update: 2020.05.02