We present beam measurements of the CHIME telescope using a radio calibration source deployed on a drone payload. During test flights, the pulsing calibration source and the telescope were synchronized to GPS time, enabling in-situ background subtraction for the full N2 visibility matrix for one CHIME cylindrical reflector. We use the autocorrelation products to estimate the primary beam width and centroid location, and compare these quantities to solar transit measurements and holographic measurements where they overlap on the sky. We find that the drone, solar, and holography data have similar beam parameter evolution across frequency and both spatial coordinates. This paper presents the first drone-based beam measurement of a large cylindrical radio interferometer. Furthermore, the unique analysis and instrumentation described in this paper lays the foundation for near-field measurements of experiments like CHIME.
@article{arxiv.2407.04848,
title = {Beam Maps of the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Measured with a Drone},
author = {Will Tyndall and Alex Reda and J. Richard Shaw and Kevin Bandura and Arnab Chakraborty and Emily Kuhn and Joshua MacEachern and Juan Mena-Parra and Laura Newburgh and Anna Ordog and Tristan Pinsonneault-Marotte and Anna Rose Polish and Ben Saliwanchik and Pranav Sanghavi and Seth R. Siegel and Audrey Whitmer and Dallas Wulf},
journal= {arXiv preprint arXiv:2407.04848},
year = {2025}
}
Comments
15 Pages, 12 Figures, 1 Table. This is a pre-copyedited, author-produced PDF of an article accepted for publication in the IEEE Open Journal of Antennas and Propagation following peer review (18 March 2025). The version of record is available online at: https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=10938182