Manpage of gpbuddy
Section: User Commands (1)
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gpbuddy - Inherit gains from a nearby (buddy) antenna
GPBUDDY is a MIRIAD task that copies the gain table of a selected
number of antennas into a second set of antennas in another dataset.
It is intended to be used in conjunction with UVCAL,to perform
antenna-based atmospheric phase correction (PACS).
All non-selected antennas have the option of having their gains
interpolated from paired antennas using different methods.
GPBUDDY will take the gains corresponding to the antennas in list2
from the dataset specified by vis2, then set their amplitudes to one
and multiply the phases by a given scale factor, then unwrap them and write
them into the antenna-based phaseatm uv variable in the vis dataset for
the antennas in list1. Antennas present in vis but not listed in list1
will get a phaseatm value that is obtained from the application of
the specified method. Antennas for which the method produce no solution will
be flagged during that time interval. UVCAL options=atmcal will interpret
these phaseatm tables at phases at the LO1 frequency and correctly compute
and apply the atmospheric delays.
Example: phase correction for 3mm
gpbuddy vis=carma vis2=sza out=carma.out
uvcal vis=carma.out out=carma.atm options=atmcal
The input visibility file, containing the visibility data
to be copied with an additional phaseatm table.
Output file for vis, if selected. This file will contain the phaseatm
variable derived from the gains of a buddy antenna.
The 2nd input visibility file, containing a selfcal gain table from
which gains will be applied to antennas in the primary
dataset (the gain table of the input visibility file).
Default is to leave this blank, which will simply copy
gains internally from the primary visibility dataset.
Show the East-North layout (in meters) in tabular format.
LISTOBS will also print these out by default.
The list of primary antennas to receive new gains.
The 2nd list of paired antennas to apply gains to primary
This is usually a number larger than 1 and can normally be
computed from the ratio of the effective frequencies at which the two
gain solutions were derived.
Currently no default allowed, since we have not properly
obtained these effective frequencies. The usual numbers are 3.09 for
3mm and 7.4 for 1mm.
** not used at the moment **
gains or phaseatm.
For gains the gains of the input file(s) are overwritten,
For phaseatm you will need to supply (an) output file(s).
DO NOT USE, since gains option do not apply freq dependant
Use nearest neighbor for time interpolation. If not, linear
interpolation is used.
Will become false, since nearest doesn't know how to flag
when nothing in the interval.
By default, the projected UV coordinates (in ns) are used to
compare distances, by using antpos=TRUE, regular distances are used
between the antennae, except these are used in m!!! When using
a weighting scheme such as gaussian, units are m.
Method by which antenna phases of non-paired antennas are
Currently implemented are:
power: inverse power law weighted average on projected distance
gaussian: Gaussian weighted average on projected distance
tophat: equal weights within a projected radius
parabol: inverse projected distance square within a radius
none: none, the phase corrections for non-buddies are 0 (not implemented)
Parameter for the weighting function method.
For power-law: negative of the power index
For gaussian: Gaussian FWHM (in ns, or m, depending on antpos=)
For tophat: radius (in ns, or m)
For parabol: radius (in ns, or m)
If antpos=false, make sure length units are ns,
for antpos=true, units are m.
Compute antenna phases for non-paired antennas by interpolating
over paired antennas using a user-selectable weighting function
specified by wscheme and param
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This document was created by
using the manual pages.
Time: 18:35:38 GMT, July 05, 2011