Element gain drifts as an imaging dynamic range limitation in PAF-based interferometers

TL;DR

This paper investigates how element gain drifts in phased-array feeds affect imaging quality in interferometers, providing a simulation framework to relate hardware stability to image artefacts.

Contribution

It introduces a MeqTrees-based simulation framework to analyze the impact of element gain drifts on imaging in PAF-based interferometers.

Findings

EGDs cause calibration artefacts in interferometric images

Simulation results relate EGD levels to artefact severity

Framework aids in defining hardware calibration requirements

Abstract

Interferometry with phased-array feeds (PAFs) presents new calibration challenges in comparison with single-pixel feeds. In particular, temporal instability of the compound beam patterns due to element gain drifts (EGDs) can produce calibration artefacts in interferometric images. To translate imaging dynamic range requirements into PAF hardware and calibration requirements, we must learn to relate EGD levels to imaging artefact levels. We present a MeqTrees-based simulations framework that addresses this problem, and apply it to the APERTIF prototype currently in development for the WSRT.