[bananas] CVEL patch
Eric Greisen
egreisen at nrao.edu
Mon Apr 5 16:22:50 EDT 2010
The 31DEC09 amd 31DEC10 code of CVEL after 20 September 2009 lost the
logical variable that told a bottom level routine to compute velocities
for the VLBA based on the center of the Earth rather than the antenna
position. Thus CVEL has been doing the wrong thing for VLBA data since
that time. The code in 31DEC10 has been corrected and will be available
by MNJ tomorrow. The code in 31DEC09 has already been corrected and may
be downloaded as a patch or by MNJ now.
This does bring up a major issue in CVEL. That task assumes that the
fringe stopping in the correlator shifts the frequency to that
appropriate for one of the two antennas. CVEL uses the lower numbered
antenna for all arrays except EVN and, for both the old and new VLBA
correlators, it ignores the antenna location. I am told that some
non-VLBA correlators have changed to use the Earth center also but CVEL
does not now support that. Furthermore, there is a danger that antennas
will be renumbered so that the lower number becomes the higher and vice
versa which makes a mockery of the above algorithm. Any further
information you can provide about what correlators actually do should be
helpful.
Eric Greisen
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