AIPS HELP file for DTSIM in 31DEC24
As of Wed Apr 24 22:45:44 2024
DTSIM: Task to generate fake UV data
INPUTS
OUTNAME Output UV file name (name)
OUTCLASS Output UV file name (class)
OUTSEQ 0.0 9999.0 Output UV file name (seq. #)
OUTDISK 0.0 9.0 Output UV file disk unit #
INFILE Parameter file name.
PRTLEV Print level (0=>none;
1=> echo text file)
DPARM 0.0 Default year, month, day
(4) > 0 leave parallactic
angle in the data
FPARM 0.0 default GAIN(ifnum) in Jy/K
VPARM 0.0 default TSYS(ifnum) in K
HELP SECTION
DTSIM
Task: This task will generate fake uv-data for the primary
purpose of testing AIPS tasks. It is used in conjunction
with task DTCHK, which measures the degree of compliance
with the expected test result.
Adverbs:
OUTNAME....Output UV file name (name). Standard defaults.
OUTCLASS...Output UV file name (class). Standard defaults.
OUTSEQ.....Output UV file name (seq. #). 0 => highest.
OUTDISK....Disk drive # of output UV file. 0 => any.
INFILE.....External text file containing data simulation
parameters in KEYIN format.
PRTLEV.....Print level (>0: echo external parameter file
on input.
DPARM......Default values for (1) year, (2) month, (3) day used in
the schedual, flag, and bandpass sections.
(4) The visibilities as computed take into account the
difference and sum of the parallactic angles. This means
the RR and LL for a point source at the origin will have
opposite phases due to the difference in parallactic
angle for the two antennas. By default, this is taken
out. > 0 => leave it in (and let CLCOR deal with it).
FPARM......Default values for the GAIN (Jy/K) in the CAL_ERR
section, one value per IF. IFS > 30 use FPARM(30).
VPARM......Default values for the TSYS (K) in the CAL_ERR
section, one value per IF. IFS > 30 use VPARM(30).
EXPLAIN SECTION
DTSIM: Task to generate fake uv-data
Documentor: A. Kemball, Eric W. Greisen
Related Programs: DTCHK
OVERVIEW
This task will generate fake uv-data for the primary purpose of
testing AIPS tasks. It is used in conjunction with task DTCHK,
which measures the degree of compliance with the expected test
result. The input parameters defining the simulated dataset are
provided in the form of an external text file in KEYIN format.
This file is used by DTCHK in checking test compliance. DTSIM
can be used alone, however, to generate datasets containing
simulated data for other purposes.
PARAMETER FILE
The format of the parameter file consists of several different
groups, which are defined below:
ANTENNA TABLES
==============
The attached antenna tables are defined in the following format:
AN_TABLE VER = n / (* defines AN table version number *)
KEY (* required to use the next 3, do once
before any STATION *)
CAL_ERR (* copy feed cal. err. to the AN table *)
POLTYPE = 'xxxx' (* set polzn. POLTYPE keyword; known are
'APPROX', 'ORI-ELP', 'X-Y LIN', 'VLBI' *)
ARRNAM = 'array' / (* defines AN keyword ARRNAM; eg 'VLBA' *)
STATION = 'name' (* station name (up to 8 characters) *)
LONG = hh:mm:ss (* station longitude and latitude *)
LAT = dd:mm:ss
MNT = 'AZEL' or 'HADC' (* az-el is default, equatorial or
or 'ORB' or orbiting or Nasmyth right or left *)
'NASR', NASL'
NO = n (* antenna number in AN table *)
ELEV = x (* station elevation in (m) *)
ORBPARM = 6*x / (* orbital parameters (six) *)
CARTPOS= X, Y, Z (* XYZ earth-centered coordinates in a
right-handed system with Z towards
North, X through Greenwich, and Y
through Europe, ***THIS MAY BE SPECIFIED
IN PLACE OF LONG, LAT, ELEV*** *)
Multiple STATION records can be defined for any given AN table.
END / (* end of station records *)
STATION = 'SPEC_NAM' / (* alternate format for specifying station
information, SPEC_NAM is chosen from the
following list:
VLBA_xx : xx = BR, FD, HN, KP, LA, MK,
NL, OV, PT, SC
GB, AR, EB, Y, Y1
ALL_VLBA : all 10 VLBA antennas
ALL_HSA : all 10 VLBA, GB, AR, EB, Y
VLA_Yx : x = A, B, C, D arrays
VLA_na : n = 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 12, 14, 16, 18,
20, 24, 28, 32, 36, 40,
48, 56, 64, 72 pad pos.
a = N, W, E arms
*** NOTE that specifying VLA_YA and
VLA_YB will specify some common
antennas -this could cause problems-
it would be advisable to specify the
antennas individually in this case.
Other alternate formats can be added by
request *)
SOURCE TABLE
============
The source table is defined as follows:
SU_TABLE /
SU_ID = n (* source ID *)
NAME = 'name' (* source name (16 characters) *)
REST_FQ = Nif * x (* rest freq. for each IF in MHz *)
LSR_VEL = Nif * x (* LSR vel. for each IF in km/s *)
RAEPO = hh:mm:ss (* RA at epoch *)
DECEPO = dd:mm:ss (* DEC at epoch *)
EPOCH = nnnn / (* epoch, e.g. 2000 is default *)
Multiple source records can be specified for the SU table.
END / (* end of source records *)
FREQUENCY TABLE
===============
The frequency table is defined as follows:
FQ_TABLE /
FQID = n (* frequency ID *)
FREQ = Nif * x (* freq. for each IF in MHz *)
TOTBW = Nif * x (* bandwidth for each IF in MHz *)
CHANBW = Nif * x (* channel BW for each IF in MHz *)
SIDE = Nif * {0|1} / (* sideband (0=LSB; 1=USB) per IF
1 is default *)
Multiple FQ ID records can be specified for the FQ table.
END / (* end of FQ ID records *)
CATALOG HEADER
==============
The catalog header, which defines the overall structure of the
AIPS uv-data file, is specified as follows:
CAT_HDR
REF_FREQ = x (* reference freq. in MHz *)
REST_FQ = x (* rest frequency in MHz *)
NO_IF = n (* number of AIPS IF channels *)
NO_CHAN = n (* number of freq. channels per IF *)
STOKES = 4*{'RR'|'LL'|'RL'|'LR'}
(* Stokes parameters defined in the file *)
REF_DATE = 'dd/mm/yy' (* reference date *)
or 'yyyymmdd'
COMPRESS (* if present, then compress output data;
this option not yet implemented *)
/ (* end of catalog header parameters *)
CALIBRATION ERRORS
==================
Calibration errors for each antenna, IF=n and polarization
p = {R,L} are specified as follows:
[A constant rather than time variable value may be had for cheb
functions by setting the amplitude to 0 and the offset to the
desired constant number. A Tsys is needed even if constant.]
CAL_ERR LINPOL / (* LINPOL selects linearized polzn.
errors - otherwise 2nd order is used *)
STATION = 'name' (* REQUIRED define which antenna *)
FQID = n (* define FQID for this calibration error
record - default 1 *)
BP_np = {1, bwth, cheb, phs, norm, v_1, v_2, v_3, v_4 }
(* bandpass error (type 1), where
bwth = Butterworth order for ampl. response
cheb = Chebyshev order for phase response
phs = Phase response ampl. (deg.)
norm = {0 => no normalization; 1 => normalize}
v_j = variability parameters (set to zero
for no variability)
or, *)
{2, frac, time}
(* bandpass error (type 2), where
phs = phase/ampl. slope across band (0..1)
time = phase/ampl. slope in time (0..1) *)
DELA_np = 1, cheb, range, delay, offset
(* delay errors, where
cheb = Chebyshev order for delay error poly.
range = Period in days for delay poly. from UT 0
delay = Delay error poly. ampl. (ns)
offset = Polynomial offset (ns) *)
PHAS_np = 1, cheb, range, phs, offset
(* phase errors where,
cheb = Chebyshev order of phase error poly.
range = Period in days for phase poly. from UT 0
phs = Phase error poly. ampl. (deg)
offset = Polynomial offset (deg) *)
FEED_np = 1, ampl, phas
(* polarization D-terms, where:
ampl = D-term amplitude
phas = D-term phase (deg.) *)
GAIN_np = 1, gval
(* gain, where
gval = point source sensitivity (Jy/K)
may be defaulted with FPARM(n) > 0 *)
TSYS_np = 1, cheb, range, tval, offset
(* Tsys, where
cheb = Chebyshev order of Tsys poly.
range = Period in days of Tsys poly from UT 0
tval = Amplitude of Tsys polynomial
offset = Polynomial offset
default with VPARM(n) > 0 is
TSYS_n* = 1, 2, 1, 0, VPARM(n) *)
GERR_np = 1, cheb, range, amperr, offset
(* multiplicative gain error, where
cheb = Chebyshev order of gain error poly.
range = Period in days for err. poly. from UT 0
amperr = Gain error poly. ampl.
offset = Gain error offset *)
/ (* end of calibration record for this STATION
and FQID *)
Multiple records can be defined for each STATION and FQID
combination.
END / (* end of the calibration error group *)
SOURCE MODEL
============
The source model data are specified as follows:
SU_MODEL /
SOURCE = 'name' (* source name REQUIRED *)
TYPE = {1, ra, dec, I, Q, U, V}
(* point source, where
ra = RA offset (asec)
dec = DEC offset (asec)
I, Q, U, V = flux density (Jy) *)
{2, ra, dec, pa, maj, min, I, Q, U, V}
(* Gaussian component, where
ra = RA offset (asec)
dec = DEC offset (asec)
pa = position angle (deg)
maj = major axis (asec)
min = minor axis (asec)
I, Q, U, V = flux density (Jy) *)
/ (* end of this source model *)
Multiple source models can be defined.
END / (* end of the source model data *)
SCHEDULE RECORDS
================
The fake data are specified via schedule records not unlike those
accepted by SCHED. The format is given below:
SCHEDULE /
DAY = n MONTH = n YEAR = nnnn (* day, month and year REQUIRED
may be init with DPARM, each
new record defaults to those
of the previous *)
START = hh:mm:ss (* start of scan *)
STOP = hh:mm:ss (* end of scan *)
SOURCE = 'name' (* source name *)
SUBA = n (* subarray number 1=default *)
FQID = n (* frequency ID 1=default *)
SELECT = +stat or -stat (* select (+) or de-select all
baselines to a given station *)
TINT = x / (* integration time (sec)
1.0 = default *)
Multiple schedule records can be defined.
END / (* end of schedule *)
FLAG RECORDS
============
Pieces of the fake data may be marked as flagged or even omitted by
entering flagging records as
FLAG /
DAY = n MONTH = n YEAR = nnnn (* day, month and year REQUIRED
may be init with DPARM, each
new record defaults to those
of the previous *)
START = hh:mm:ss (* start of flag interval *)
STOP = hh:mm:ss (* end of flag interval *)
SOURCE = 'name' (* source name or 'ALL' *)
SUBA = n (* subarray number, default = 0 => all *)
FQID = n (* frequency ID, default = 0 => all *)
BIF = n (* start IF, default 0 => 1 *)
EIF = n (* end IF, default 0 => max *)
BCHAN = n (* start channel, default 0 => 1 *)
ECHAN = n (* end channel, default 0 => max *)
ANT_1 = 'antenna_1' (* antenna 1 name or 'ALL';REQUIRED *)
ANT_2 = 'antenna_1' (* antenna 2 name or 'ALL'; REQUIRED *)
PFLAG = 'xxxx' / (* polarization selection, x = 0 (no) or 1
(yes), e.g., '1011' flags RR, RL, LR *)
Multiple flag records can be defined.
END / (* end of flag *)
BP_TABLE RECORDS
================
If the CAL_ERR BP option has been used, then one can construct a
bandpass table to match.
BP_TABLE /
KEY (* required to use the next 3, do once
before any STATION *)
NANT = N (* Number of antennas in the BP table *)
BPTYPE = 'x' (* 'CHEBSHEV' for polynomial bandpass,
' ' for normal bandpass *)
NUMSHF = n / (* n=1 cross-power, n=2 total-power,
else unknown origin of BP solutions *)
STATION = 'name' (* station name (up to 8 characters)
REQUIRED *)
DAY = n MONTH = n YEAR = nnnn (* day, month and year REQUIRED
may be init with DPARM, each
new record defaults to those
of the previous *)
SUBA = n (* subarray number, default = 0 => all *)
FQID = n (* frequency ID, default = 0 => all *)
START = hh:mm:ss (* start of scan *)
STOP = hh:mm:ss (* end of scan *)
TINT = t (* integration time of each entry, seconds *)
INTERV = Dt (* spacing of BP solutions in time, minutes
*)
CAL_ERR (* Use CAL_ERR values, else null BP (1,0) * )
AC (* Auto-correlation data produced the
bandpass solution *)
XC (* Cross-correlation data produced the
bandpass solution (default) *)
FLAGPOL = Nif * i (* Polarization number to be flagged 1 or 2,
<= Nif values *)
FLAGIF = Nif * j (* Corresponding IF number to be flagged,
<= Nif values *)
FLAGCHAN = Nif * c1,c2 (* Corresponding range of spectral channels
to be flagged, <= Nif pairs of values *)
/
Multiple BP records can be defined.
END / (* end of BP table *)
EXAMPLE INPUT FILE
==================
An example input file is given below:
Adverbs:
DPARM 2010 11 Default year, month, day
11 *rest 0
FPARM 5 5 default GAIN(ifnum) in Jy/K
*rest 0
VPARM 45 55 default TSYS(ifnum) in K
*rest 0
And the INFILE:
!----------------------------------------------------------------------
!
! EVLA example
!
AN_TABLE VER=1 /
KEY
ARRNAM = 'EVLA' /
STATION = 'VLA_YC' /
END /
!
! FQ table data
!
FQ_TABLE /
FQID = 1
FREQ = 4988.0, 5244.0
TOTBW = 128., 128.0
CHANBW = 8.0, 8.0 /
END /
!
! SU table data
!
SU_TABLE /
SU_ID = 1
NAME = '3C286'
RAEPO = 13:31:08.29
DECEPO = 30:30:32.96 /
SU_ID = 2
NAME = 'Target'
RAEPO = 13:18:08.29
DECEPO = 55:30:32.96 /
END /
!
! Catalog header
!
CAT_HDR /
REF_FREQ = 4988.0
NO_IF = 2
NO_CHAN = 16
STOKES = 'RR', 'LL', 'RL', 'LR'
REF_DATE = '20101111'/
!
! Calibration errors: N arm less sensitive IF 1
!
CAL_ERR /
STATION = 'VLA_2N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_4N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_6N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_8N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_10N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_12N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_14N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_16N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
STATION = 'VLA_18N' FQID = 1
GAIN_1R = 1, 7
GAIN_1L = 1, 7 /
END /
!
! Source model data: point source unit flux density
!
SU_MODEL /
SOURCE = '3C286'
TYPE = 1, 0,0, 9,1,.5,0, 0,0,0
SPEC = 0,0,0,0,0
VEL = 0,0
/
SOURCE = 'Target'
TYPE = 1, 0,0, 9,0,0,0, 0,0,0
/
SOURCE = 'Target'
TYPE = 2, -10,10, 0,20,10, 4,0,0,0
/
SOURCE = 'Target'
TYPE = 2, 20,-20, 90,20,10, 8,0,0,0
/
END /
!
! Schedule records
!
SCHEDULE /
!
! All antennas
!
START = 16:31:00 STOP = 16:35:00
SOURCE = '3C286' SUBA = 1 FQID = 1
TINT = 20 /
!
START = 16:40:00 STOP = 17:25:00
SOURCE = 'Target' SUBA = 1 FQID = 1
TINT = 20 /
!
START = 17:31:00 STOP = 17:35:00
SOURCE = '3C286' SUBA = 1 FQID = 1
TINT = 10 /
!
START = 17:40:00 STOP = 19:02:00
SOURCE = 'Target' SUBA = 1 FQID = 1
TINT = 20 /
!
START = 19:08:00 STOP = 19:13:00
SOURCE = '3C286' SUBA = 1 FQID = 1
TINT = 10 /
END /
!