Calibration schemes with O(N log N) scaling for large-N radio interferometers built on a regular grid

  title={Calibration schemes with O(N log N) scaling for large-N radio interferometers built on a regular grid},
  author={Deepthi Gorthi and Aaron Parsons and Joshua S. Dillon},
  journal={Monthly Notices of the Royal Astronomical Society},
Future generations of radio interferometers targeting the 21\,cm with $N\gg 1000$ antennas could face a significant computational challenge in building correlators with the traditional architecture, whose computational resource requirement scales as $\mathcal{O}(N^2)$ with array size. The fundamental output of such correlators are the cross-correlation products of all antenna pairs in the array. The FFT-correlator architecture reduces the computational resources scaling to $\mathcal{O}(N\log_2N… 
1 Citations

Redundant-baseline calibration of the hydrogen epoch of reionization array

In 21-cm cosmology, precision calibration is key to the separation of the neutral hydrogen signal from very bright but spectrally smooth astrophysical foregrounds. The Hydrogen Epoch of Reionization



An efficient feedback calibration algorithm for direct imaging radio telescopes

We present the E-field Parallel Imaging Calibration (EPICal) algorithm, which addresses the need for a fast calibration method for direct imaging radio astronomy correlators. Direct imaging involves

A real-time, all-sky, high time resolution, direct imager for the long wavelength array

The first successful deployment of the E-field Parallel Imaging Correlator (EPIC) on the LWA station in Sevilleta, New Mexico, USA (LWA-SV) is described and the imaging performance is verified by detecting a meteor impact on the atmosphere using continuous all-sky imaging at 50 ms time resolution.

A generic and efficient E-field Parallel Imaging Correlator for next-generation radio telescopes

Modern radio telescopes are favouring densely packed array layouts with large numbers of antennas ($N_\textrm{a}\gtrsim 1000$). Since the complexity of traditional correlators scales as

Omniscopes: Large area telescope arrays with only NlogN computational cost

We show that the class of antenna layouts for telescope arrays allowing cheap analysis hardware (with correlator cost scaling as NlogN rather than N{sup 2} with the number of antennas N) is

Non-linear Redundancy Calibration

This work proposes to use a standard non-linear minimization algorithm to solve for both the antenna gains as well as the true visibilities of radio interferometric arrays, and demonstrates that the estimator is indeed statistically efficient, achieving the Cramer-Rao bound.

Mitigating the effects of antenna-to-antenna variation on redundant-baseline calibration for 21 cm cosmology

The separation of cosmological signal from astrophysical foregrounds is a fundamental challenge for any effort to probe the evolution of neutral hydrogen during the Cosmic Dawn and epoch of

Fast Fourier transform telescope

We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid,

MITEoR: a scalable interferometer for precision 21 cm cosmology

We report on the MIT Epoch of Reionization (MITEoR) experiment, a pathfinder low-frequency radio interferometer whose goal is to test technologies that improve the calibration precision and reduce

Comparing Redundant and Sky-model-based Interferometric Calibration: A First Look with Phase II of the MWA

The first results from comparing both calibration approaches with MWA Phase II observations are presented, showing substantial agreement between redundant visibility measurements after calibration and improved calibration by combining OMNICAL and FHD.

Precision calibration of radio interferometers using redundant baselines

The errors and biases in existing redundant calibration schemes are explored through simulations, and it is shown how statistical biases can be eliminated and slight deviations from perfect redundancy and coplanarity can be taken into account.