[daip] Support for Swinburne Software correlator in AIPS

[Eric Greisen]

Chris Phillips writes:

 > The S2 VLBI correlator which has been supporting the LBA for the last 12 
 > years is about to be decommissioned and we are moving to using the 
 > Swinburne software correlator for all LBA observations. As AIPS has some 
 > correlator specific "switches"  I guess some tweaks to AIPS will be 
 > required. Currently the data is being labelled as ATLBA to be the same as 
 > the S2 correlator but I gues we will have to change that as the correlator 
 > architecture is FX rather that XF so tasks like CVEL will definitely not 
 > work.
 > 
 > I guess we need to do a code "audit" and track down array specific code 
 > and decide in each case which switch is the appropriate one (and create a 
 > new correlator code). A number of other groups have expressed interest in 
 > using the Swinburne software correlator so the number of people using this 
 > specific correlator make increase in the future.
 > 
 > How do you suggest the best way of doing this?
 > 
 >   - A local audit and
 >      o A summary of the suggested changes set to you?
 >      o Us making the required code changes and sending you the modified
 >        code?
 >      o Us making changes via CVS (on a branch maybe)?
 >   - Us sending you the appropriate details (correlator model etc).
 >   - Something else...?
 > 
 > 
 > >From memory the main issues will be
 > 
 >   - ANTENNA table "handiness"
 >   - CVEL (because of fringe rotation).
 > 

The issue is what reference point is used for the fringe rotation and
the sign of the Y coordinate in the antenna tables.  In BPASS and BP
table application, the issue arises whether the BP tables need to be
shifted as a function of time or not.  I suggest that you make a local
audit and a list of desired changes (as detailed as possible) but let
me make the actual changes in the code base.  Note that we start a
code roll over this weekend so all changes will be to 31DEC07 only.

Eric Greisen