Near-field calibration of SKA-Low stations using unmanned aerial vehicles

Abstract

The low frequency part of the Square Kilometre Array (SKA-Low), currently in development, will need accurate calibration [1]. A self-calibration is widely used in the radio astronomy literature and allows the calibration of several SKA pathfinders. However the increased sensitivity and the very large number of antennas of the SKA-Low reduce the hope for relying only on self-calibration. Research involving artificial sources carried by an unmanned aerial vehicle (UAV) has already led to successful far-field calibrations of radio telescopes [2], [3]. In this work, we show a characterization of the embedded element patterns (EEPs) carried out in the near field on a SKA-Low station composed of 256 log-periodic antennas. Two antennas mounted on a UAV act as calibration sources. Several flight strategies are studied with uncertainties on the UAV position and attitude. Using simulations, we show that near-field calibration enables to correctly model the array pattern. An advantage of near-field calibration is the lower required altitude which reduces the covering area of the UAV flight.

BibTex

@INPROCEEDINGS{LVAN19Eucap,
author={L. {Van Hoorebeeck} and J. {Cavillot} and H. {Bui-Van} and F. {Glineur} and C. {Craeye} and E. {de Lera Acedo}},
booktitle={2019 13th European Conference on Antennas and Propagation (EuCAP)},
title={Near-field calibration of SKA-Low stations using unmanned aerial vehicles},
year={2019},
volume={},
number={},
pages={1-5},
keywords={autonomous aerial vehicles;calibration;log periodic antennas;radioastronomy;radiotelescopes;radiowave interferometers;near-field calibration;SKA-Low station;unmanned aerial vehicle;low frequency part;Square Kilometre Array;radio astronomy literature;SKA pathfinders;calibration sources;log-periodic antennas;embedded element patterns;UAV flight;Antenna arrays;Calibration;Unmanned aerial vehicles;Europe;Antenna measurements;Antenna radiation patterns;Irregular antenna arrays;HARmonic Polynomial (HARP) Representation;Method of Moments;Square Kilometre Array (SKA);Unmanned Aerial Vehicle (UAV)},
doi={},
ISSN={null},
month={March},}

Reference

• (2019) L. Van Hoorebeeck, J. Cavillot, H. Bui-Van, F. Glineur, C. Craeye and E. de Lera Acedo, “Near-field calibration of SKA-Low stations using unmanned aerial vehicles,” 13th European Conference on Antennas and Propagation (EuCAP), Krakow, Poland, 2019, pp. 1-5. (abstract/BibTex, IEEE Xplore)

Slides

See here.