AIPS HELP file for DELZN in 31DEC24
As of Thu Oct 10 18:07:34 2024
DELZN: Determines residual atmosphere depth at zenith
INPUTS
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK Input UV file disk unit #
SNVER Input SN table version
0 => last
GAINVER Input CL table to copy to
CL#=high+1 and then correct
0=>high
APARM control parameters:
1: what data to plot
0=>zenith atmos. delay
1=>clock error
2=>Reference antenna
3=>dispersion
2: Number of terms in time
polynomial for zen. atm.
delay or dispersion
0 => no atm fitting
3: Number of terms in time
polynomial for clock
0 => no clock fitting
4: Create CL table?
0 => not create
1 => create
5: What correction to make
in CL table?
0 => only atmosphere
1 => atmosphere + clocks
6: Number of iterations in
robust fit to data
0 => none.
7: > 0 -> plot points omitted
from fit
8: 0 => output file at evenly
distributed times
1 => output file at the
CL table times.
9: 0 => no plotting residuals
1 => plot residuals
10: 0 =>plot model vs
recalculated data
1 =>plot direct SN table
data vs fitted models
see help
SOURCES Source list ' '=>all.
CALSOUR Calibrator list ' ' => all
STOKES Stokes type to process
SELBAND Bandwidth to select (kHz)
SELFREQ Frequency to select (MHz)
FREQID Freq. ID to select, 0=>all
BIF 0.0 100.0 Lowest IF number 0=>all
EIF 0.0 100.0 Highest IF number 0=>all
TIMERANG Time range to use. 0=>all
ANTENNAS Antennas to select. 0=>all
SUBARRAY 0.0 9999.0 Subarray; 0 => 1.
NPLOTS Number of plots per page
0=>5, -1=> Don't make plots
XINC 0.0 5000.0 Plot every XINC'th point
OPTYPE What data to read from the
SN table:
'MDEL' => multi band delay
'PHAS' => phase delay
'DISP' => dispersion
'RATE' => fringe rate
' ' => 'MDEL'
OUTFILE Table of delays/derivatives
for selected set of antennas
in format suitable for
CLCOR's option 'ATMO'/'ATMD'
PRTLEV 0=> no printout.
1 => print coefficients
2 => print coefficients
and their errors
and rms of residual
DOHIST >0 => put coefficients in
history file.
DOTV -1.0 1.0 > 0 Do plot on the TV, else
make a plot file
GRCHAN 0.0 8.0 Graphics channel 0 => 1.
BADDISK 0.0 9999.0 Disks to avoid for scratch
HELP SECTION
DELZN
Task: This task estimates the zenith atmosphere delay dependence
and clock error based on the SN table output for the selected
calibrators. For details on how to observe and use DELZN see
AIPS Memo 110, "Strategy for Removing Tropospheric and Clock
Errors using DELZN".
The model that is fit for multi-band delay is
MBdel = Clock(t) + Atmo(t) / sin (elevation)
where both Clock and Atmo are polynomials in time with the
order of the polynomials specified by APARM(3) and APARM(2),
resp. Dispersion is fit as Disp(t) / sin (elevation) with the
order of the polynomial given by APARM(2).
Adverbs:
INNAME.....Input UV file name (name). Standard defaults.
INCLASS....Input UV file name (class). Standard defaults.
INSEQ......Input UV file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV file. 0 => any.
SNVER......Input SN table version. If SNVER is equal zero or
greater than the total number of the SN tables
then SNVER is equal to the last existing SN table
GAINVER....Input CL table version. If GAINVER is equal zero or
greater than the total number of the CL tables
then GAINVER is equal to the last existing CL table.
The input CL table version (GAINVER) is copied to
the output CL table version=(the last one+1), and then
the output CL table is corrected.
APARM......control parameters:
1: what data to plot?
0=> zenith atmosphere delay
Actually the following is plotted:
VAL(IANT-RANT)-CLOCK(IANT)+ATM(RANT)
The relevant polynomial presentation for ATM(IANT)
is plotted also
1=> clock error
Actually the following is plotted:
VAL(IANT-RANT)-ATM(IANT)+ATM(RANT)
The relevant polynomial presentation for CLOCK(IANT)
is plotted also
2=> reference antenna, if the reference antenna
is constant for the whole experiment
Actually the following is plotted:
-VAL(IANT-RANT)+CLOCK(IANT)+ATM(IANT)
The relevant polynomial presentation for ATM(RANT)
is plotted also.
The polynomial is the same (reference antenna)
But data are different as taken with different IANT
3=> dispersion
what is plotted is VAL(IANT-RANT)+DISP(RANT)
VAL(IANT-RANT) data of SN table;
IANT is the antenna number;
RANT is the reference antenna number;
2: Number of terms at the polynomial for zenith atmosphere
presentation: linear =>2; quadratic => 3
0 => no atmosphere fitting
3: Number of terms at the polynomial for clock
presentation: linear =>2; 2 is recommended
0 => no clock fitting
4: Create CL table?
0 => not create
1 => create
5: What correction to make in CL table?
0 => only atmosphere
1 => atmosphere and clocks
6: Number of iteration in robust attempt at a solution
0 => none
At each iteration of the input data (SN table), the
residual of each data point relative to the solution
is found. If the residual exceeds given number of
R.M.S, the data are not used in the following solution.
7: > 0 => plot the data samples omitted during the last
iteration of the robust solution.
8: What times for the output file to calculate?
0 => output file at the even distributed times at
the data time interval. This option is desired
when the calibrators and target sources are
located at the different UV data. So correction
of CL table should be excluded.
Put APARM(4) = 0.
1 => output file at the CL table times.
9: 0 => do not plot residuals
1 => plot residuals (in panel separate from values/fit)
10: 0 => plot the requested model (APARM(1)) AND the
adjusted data versus time.
In the case of OPTYPE='MDEL', the adjusted data
are for antenna Ant
aparm(1)=0 MBdelays + model(RefAnt) - model(clock)
1 MBdelays + model(RefAnt) - model(Ant)
2 MBDelays - model(Ant) - model(clock)
where model(xx) is the fitted polynomila in time
for parameter xx. The data samples are drawn as
vertical lines and the model of delay, clock, or
reference antenna delay is drawn as a connected
line,
1 => plot the data directly and the fitted models
versus time. The data are vertical lines and the
model points are horizontal lines. If the
residuals are small, the two then make plus
signs.
314 => fource simulated rate for optype='rate'
else => use the actual rate from the SN table
SOURCES....list of sources to process.
' ' = all; a "-" before any source name
means ALL listed sources will be skipped.
CALSOUR....list of calibrators to use.
' ' = all; a "-" before any calibrator name
means ALL listed calibrators will be skipped.
STOKES.....The desired Stokes type of the output data:
'R', 'L', ' '=> all available.
SELBAN.....Bandwidth to select (kHz)
SELFREQ....Frequency to select (MHz)
FREQID.....Frequency ID to select. 0=>all
BIF........First IF to process. 0=>all.
EIF........Highest IF to process. 0=>all higher than BIF
TIMERANG...Time range of the data to be used. In order:
Start day, hour, min. sec, end day, hour, min. sec.
Days relative to reference date. 0=>all
ANTENNAS...A list of the antennas to be calibrated, plotted and
corrected. If any number is negative then all
antennas listed are ignored.
All 0 => use all antennas.
SUBARRAY...The subarray to calibrate. Does only one at a time.
NPLOTS.....Number of plots per page; 0=>5.
If NPLOTS < 0, then no plots are made.
XINC.......Plot every XINC'th point
OPTYPE.....What data to read from the SN table:
'MDEL' => multi band delay
'DISP' => dispersion
'PHAS' => phase delay
Formally OPTYPE = 'PHAS' works, but there is
nothing to solve the twopi phase ambiguity
'RATE' => fringe rate
The OPTYPE='RATE' is recommended when accuracy
using delay is not high (bandwidth is small),
but accuracy using fringe rate is better
(time averaging is high)
' ' => 'MDEL'
OUTFILE....For MDEL:
Table of zenith atmosphere delays, clocks shift and
their derivatives for selected set of antennas in
format suitable for CLCOR's option 'ATMO'.
The file format:
The first line is number of the data rows.
The remaining lines specify the data with one
line for each antenna/time as:
Column 1: antenna number;
Column 2-5: day, hour, min, sec
Column 6: zenith atmosphere delay, in cm
Column 7: clock delay, in cm
Column 8: derivative of the zenith atmosphere
delay, in sec/sec*1.0E14
Column 9: derivative of the clock delay (clock
drift), in sec/sec*1.0E14
The values given at the atmosphere/clock delay
and their derivatives correspond to the desired
corrections. CLCOR should add them to the corrected
CL table values.
For DISP:
Table of zenith dispersive delays and their
derivatives for selected set of antennas in format
suitable for CLCOR's option 'DISP'.
The file format:
The first line is number of the data rows.
The remaining lines specify the data with one
line for each antenna/time as:
Column 1: antenna number;
Column 2-5: day, hour, min, sec
Column 6: zenith dispersive delay, in 1/cm
Column 7: derivative of the zenith dispersive
delay, in sec/m^2/sec*1.0E14
PRTLEV.....0 => Don't print the coefficients.
1 => print the fitted coefficients for each antenna.
2 => print coefficients and their errors and
rms of residual for each antenna.
DOHIST.....if DOHIST > 0, the gain coefficients are written
into the history file.
DOTV.......> 0 Do plot on the TV, else make a plot file
GRCHAN.....Graphics channel 0 => 1.
BADDISK....A list of disks on which scratch files are not to
be placed. This will not affect the output file.
EXPLAIN SECTION
DELZN: Task to estimate the zenith delay and clock error dependence
on time based on the CALIB output SN table for the selected
calibrators.
Documenters: L.R. Kogan
Related Programs: CLCAL, ELINT
PURPOSE
Model of the atmosphere delay and the clock error implemented into a
correlator never coincides with the actual values.
The task restores the residual atmosphere delay at the given elevation
observing calibrators at wide range of elevations. The task reads the
SN table, taking the information about the delays (rate) at given antenna
observing given calibrator. This delay (rate) is contributed by delay
at the atmosphere and delay (rate) due to the clock error.
The task separates the atmosphere and clock delays using the
least square method to fit polynomial of the chosen degree to the clock
error and polynomial of the chosen degree for the zenith atmosphere delay.
Having known these polynomials the task calculates the zenith
atmosphere delay and records it to the output file ready for use
as input file for the task CLCOR (option 'atmov').
The fitted zenith atmosphere delay and clock error is used to
correct the delay for target sources putting the correction to
the output CL table by the same way CLCOR does at option 'atmov'.
For details on how to observe and use DELZN (OPTYPE='mdel') see
AIPS Memo 110, "Strategy for Removing Tropospheric and Clock Errors
using DELZN".
Leonia's explanantion of APARM(10)
10: 0 =>plotting model vs recalculated data
for example: OPTYPE=MDEL;
then the direct SN table data are:
VAL(IANT-RANT) = MODEL_ZATM_IANT*MAP_IANT -
MODEL_ZATM_RANT*MAP_RANT + MODEL_CLOCK (1)
If we want to plot zenith atmosphere at the IANT
APARM(1)=0 then
the fitted model of zenith atmosphere at the IANT
MODEL_ZATM_IANT is derived from the equation(1) and
plotted as the function of SN table data VAL(IANT-RANT)
and of MODEL_ZATM_RANT and of MODEL_CLOCK.
Thus, the following equation is plotted:
MODEL_ZATM_IANT = [VAL(IANT-RANT)+
MODEL_ZATM_RANT*MAP_RANT -
MODEL_CLOCK] / MAP_IANT (2)
The relevant polynomial presentation for the zenith
atmosphere at the IANT is plotted also.
1 =>plotting direct data versus fitted models:
The direct data from SN table VAL(IANT-RANT)
(left side of the equation 1)
is plotted versus the right side of the equation 1.
The relevant models are the fitting polinomials.