An Update on the External Calibrator for Hydrogen Observatories (ECHO)

TL;DR

This paper reports updates to the ECHO drone-based system for precise beam pattern measurements of low frequency radio arrays, improving drone performance, reducing interference, and enhancing transmitter design for better calibration accuracy.

Contribution

The paper introduces improvements to the ECHO system, including a new drone platform, interference mitigation techniques, and a redesigned transmitter, advancing drone-based calibration methods.

Findings

Enhanced drone stability and flight performance.

Reduced electromagnetic interference from the drone.

Improved transmitter design for accurate beam measurements.

Abstract

Precision measurements of the beam pattern response are needed to predict the response of a radio telescope. Mapping the beam of a low frequency radio array presents a unique challenge and science cases such as the observation of the 21\,cm line at high redshift have demanding requirements. Drone-based systems offer the unique potential for a measurement which is entirely under experimenter control, but progress has been paced by practical implementation challenges. Previously, a prototype drone system, called the External Calibrator for Hydrogen Observatories (ECHO), demonstrated good performance in making a complete hemispherical beam measurement. This paper reports updates to the system focusing on performance of a new drone platform, minimizing interference from the drone, and a new transmitter.