Re: [alma-sw-ssr] Pipeline Requirements new version

[Mark Holdaway <mholdawa@nrao.edu>]

Mel wrote:

> 1. At the lower
> frequencies, there may be a sufficiently strong compact
> source within the primary beam which could be used as
> a continuous atmospheric phase monitor. The pipeline
> could derive the antenna phases.

I think this is the same as self-calibration.

> 2. At high frequencies, a suitable monitoring source
> may be found in the offset beam corresponding
> to a low frequency band. These
> offset beams move w.r.t. the target source, so the
> monitoring source will change with time, but one
> is only interested the phase, not the source.
> The simultaneous observation of the target at
> high frequency and a monitoring source in an offset beam
> at low frequency  requires  a few things, like
> 2 active receivers, sharing bandwidth and correlator,
> but has the advantage of a continuous phase calibration
> on a nearby source.

I think dual frequency observations have been ruled out by the systems
group.

> 3. If one uses different frequencies for the target and phase calibrator,
> then a calibration of the phase offset between the 2 bands is required
> at an interval determined by the phase stability of the system. A
> stronger calibrator can be used for this. The pipeline should
> keep track of this phase offset, its interpolation and the
> calibration interval required.

This is also a requirement of fast switching.

> 4. Suitable phase calibrators could be found from a quick
> mosaic around the target source at the start of an observation
>  This is a job for the pipeline too.

This is also a requirement of fast switching.

	-M