Pointing offset calibration pipeline

Introduction

The SDP must calculate pointing offsets in near-real time following a reference pointing observation. This functionality is required for AA0.5 onward. The pointing offset is the difference between the actual pointing as determined by measurement with astronomical source  versus the expected pointing direction. It is measured on one source a time and may be applied as a "local" correction immediately or used for further analysis of the "global" pointing model.

The aim of this feature is to develop an initial version of a pipeline capable of calculating pointing offsets for Mid Band 2, given the visibilities and the commanded/encoder position direction data as inputs. It is not required to be integrated into the SDP system; this will be implemented in a subsequent feature.

The commanded sequence of telescope pointings used for the observation is often a simple five points in a cross pattern but will be specified by the commissioning team in just in case things like finite band, any hysterisis, settle times etc lead to a change in the usual pattern.

Who?

• SDP developers.
• Commissioning scientists.

What?

• Pipeline to calculate pointing offsets for Band 2 given visibility data and nominal pointing as input.
• Data sets suitable for testing the pipeline (most likely simulations).

Why?

• Begins development of an essential piece of SDP functionality required for Mid at AA0.5.

References

• AA0.5 Scenarios, see AA0.5 Mid Interferometric Pointing.