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The Murchison Wide field Array began science observations in the summer of 2013, with the goal of measuring the Epoch of Reionization (EoR) power spectrum through redshifted 21 cm neutral hydrogen emission. With the first semester of observing completed, the EoR analysis team faces the challenge of reducing 350 hours of data to a manageable size for the power spectrum pipeline. Several obstacles exist...
The Precision Array for Probing the Epoch of Reionization (PAPER) is a focused experiment aimed at detecting the spatial power spectrum of neutral hydrogen emission during the Epoch of Reionization (EoR). PAPER is an interferometer operating from 100 – 200 MHz at the site of the future Square Kilometre Array (SKA) site in South Africa. The PAPER antennas measure linear polarization and the correlator...
The effect of mutual coupling between array elements is known to substantially degrade direction-of-arrival (DOA) estimation performance. Rank-reduction (RARE) methods can eliminate the mutual coupling effect without loss of array aperture. However, they might yield serious ambiguous DOA estimates in some scenarios. This letter proposes a modified RARE algorithm for DOA estimation, which overcomes...
Mapping our universe in 3D by imaging the redshifted 21 cm line from neutral hydrogen has the potential to overtake the cosmic microwave background as our most powerful cosmological probe, because it can map a much larger volume of our Universe, shedding new light on the epoch of reionization, inflation, dark matter, dark energy, and neutrino masses. We report on MITEoR, a pathfinder low-frequency...
A self-calibration technique was developed for SAR analog-to-digital converters that employ binary-weighted capacitors. High-accuracy calibration is achieved by finding and correcting the mismatch of each capacitor independently. The mismatch errors are extracted at power-up, and corrected by individual calibration DACs during the conversion. Unlike in previous schemes, in the proposed method the...
In December 2010 we started observations with a partially completed LOFAR, to prepare ourselves for the calibration and processing of deep (hundreds of hours) integrations in a number of Galactic halo windows. These observations are aimed at detecting the redshifted 21cm signals from the Epoch of Reionization using the LOFAR HBA antennas (115–190 MHz, zHI=11.4–6.5). Two fields (windows) have been...
Generally GPR transmits and receives radio waves with a single polarization using two parallel antennas. But it is possible to improve the GPR ability of discrimination and imaging of subsurface targets by analyzing the backscattered wave with a variety of polarizations. So we are developing a full-polarimetric GPR system, including PC, network analyzer, rectangular coordinates robot, switch driver,...
This paper describes a novel method based on self-adaptive subdivision mesh for geometry correction of multi-cameras in a panoramic video system. The system hardware consists of an array of six board cameras pointing outwardly. Digitally combining synchronized frames from each camera, a wide-field panoramic video can be created. Using sparse initial corresponding points between the ideal target surface...
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