Content-type: text/html 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. No default.
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. Default: false
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 phase corrections. Default: phaseatm
Use nearest neighbor for time interpolation. If not, linear interpolation is used. Default: true.

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. Default: FALSE
Method by which antenna phases of non-paired antennas are deduced. 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) Default: power
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. Default: 2
Compute antenna phases for non-paired antennas by interpolating over paired antennas using a user-selectable weighting function specified by wscheme and param Default: true




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Time: 18:35:38 GMT, July 05, 2011