학술논문

The Murchison Widefield Array: Design Overview
Document Type
Periodical
Source
Proceedings of the IEEE Proc. IEEE Proceedings of the IEEE. 97(8):1497-1506 Aug, 2009
Subject
General Topics for Engineers
Engineering Profession
Aerospace
Bioengineering
Components, Circuits, Devices and Systems
Computing and Processing
Engineered Materials, Dielectrics and Plasmas
Fields, Waves and Electromagnetics
Geoscience
Nuclear Engineering
Robotics and Control Systems
Signal Processing and Analysis
Transportation
Power, Energy and Industry Applications
Communication, Networking and Broadcast Technologies
Photonics and Electrooptics
Apertures
Telescopes
Optical design
Frequency synthesizers
Brightness temperature
Fluctuations
Hydrogen
Remote sensing
Field programmable gate arrays
Antenna arrays
astronomy
calibration
imaging
ionosphere
Language
ISSN
0018-9219
1558-2256
Abstract
The Murchison Widefield Array is a dipole-based aperture array synthesis telescope designed to operate in the 80–300 MHz frequency range. It is capable of a wide range of science investigations but is initially focused on three key science projects: detection and characterization of three-dimensional brightness temperature fluctuations in the 21 cm line of neutral hydrogen during the epoch of reionization (EoR) at redshifts from six to ten; solar imaging and remote sensing of the inner heliosphere via propagation effects on signals from distant background sources; and high-sensitivity exploration of the variable radio sky. The array design features 8192 dual-polarization broadband active dipoles, arranged into 512 “tiles” comprising 16 dipoles each. The tiles are quasi-randomly distributed over an aperture 1.5 km in diameter, with a small number of outliers extending to 3 km. All tile–tile baselines are correlated in custom field-programmable gate array based hardware, yielding a Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point spread function quality. The correlated data are calibrated in real time using novel position-dependent self-calibration algorithms. The array is located in the Murchison region of outback Western Australia. This region is characterized by extremely low population density and a superbly radio-quiet environment, allowing full exploitation of the instrumental capabilities.