Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 35 for “"Radio telescopes"”.
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Software defined networking for radio telescopes: a case study on the applicability of SDN for MeerKAT
Scientific instruments like radio telescopes depend on high-performance networks for internal data exchange. The high bandwidth data exchange between the components of a radio telescope makes use of multicast networking. Complex multicast networks are hard to maintain and grow, and specific …
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Adventures in radio astronomy instrumentation and signal processing
… analogue astronomical signals collected using radio telescopes. Modern radio telescopes have significant digital signal processing demands that are typically best met using custom processing engines implemented in Field Programmable Gate Arrays. These demands essentially stem from the …
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Thermal design and analysis of the SKA SA MeerKAT Digitiser
… venture attempting to build the world's largest radio telescope. Australia and South Africa (together with other African countries), will be host to the SKA site. Both countries are building pre-cursor radio telescopes to demonstrate their ability to successfully host the project. Square …
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Multi-Layered Dual-Band Dual-Polarized Reflectarray Design Toward Rim-Located Reconfigurabable Reflectarrays for Interference Mitigation in Reflector Antennas
… for an interference mitigation solution for radio telescopes. In the envisioned application, When the reflectarray is placed around the circumference of an existing radio telescope, it can drive a null into the radio telescopes radiation pattern sidelobe distribution. Since the reflectarray …
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The low frequency array and the transient and variable radio sky
… and characterising the transient and variable radio sky, using both existing radio telescopes, and the next generation of radio facilities such as the Low Frequency Array (LOFAR). Studies of well known variable radio sources are presented in conjunction with blind searches of parameter space …
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A scalable database model of RFI data for the MeerKAT/SKA radio telescope
In radio astronomy, radio frequency interference (RFI) refers to any signal captured by a radio telescope that did not originate from the observed target in the sky. RFI from terrestrial and other sources is a recognized problem that contaminates the desired signal and must be tracked and …
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On the instrumentation of the Omniscope
… an instrument capable of 21-cm tomography. Radio telescopes are particularly well suited to the task. However, the cost of scaling a traditional radio telescope to achieve the necessary sensitivity is prohibitive. The Omniscope is an elegant solution to this problem. It is a new type of …
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Studies of the Ionised Interstellar Medium at Low Radio Frequencies using LOFAR
… /> As pulsars are mostly observed at radio frequencies, their radiation is affected by interstellar propagation effects like dispersion, which causes a frequency-dependent propagation delay that can vary with time when there is relative motion between the Earth, the pulsar and the gas …
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Time domain classification of transient RFI
Since the emergence of radio astronomy as a field, it has been afflicted by radio frequency interference (RFI). RFI continues to present a problem despite increasingly sophisticated countermeasures developed over the decades. Due to technological improvements, radio telescopes have become more …
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Mitigation of Interference From Iridium Satellites by Parametric Estimation and Subtraction
Radio astronomy is the science of observing the universe at radio frequencies. In recent years, radio astronomy has faced a growing interference problem as radio frequency (RF) bandwidth has become an increasingly scarce commodity. Communication systems such as Earth orbiting communication …
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Characterization of a Phased Array Feed Model
… integrating PAFs with current and future radio telescopes, which is a goal of many groups around the globe. This thesis characterizes the latest models of a 19 element hexagonal PAF of dipoles used by the BYU radio astronomy research group and presents comparisons of these models with …
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Real-time Adaptive Cancellation of Satellite Interference in Radio Astronomy
Radio astronomy is the science of observing the heavens at radio frequencies, from a few kHz to approximately 300 GHz. In recent years, radio astronomy has faced a growing interference problem as radio frequency (RF) bandwidth has become an increasingly scarce commodity. A programmable real-time …
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Millimeter-wavelength remote sensing of the atmospheric structure and composition of Venus
Microwave radiometric observations and radio occultations are capable of providing insight into the properties of the Venus atmosphere within and below layers of clouds which cover the entire planet. To interpret such observations, accurate models for the absorption of the atmospheric constituents …
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Laboratory and Observational Studies of Transient Molecules at Microwave and Millimeter/Submillimeter Wavelengths
… and electronic character could be obtained. Radio telescopes were used to measure the spectra of molecules in different interstellar environments. A new molecule, FeCN, was detected toward the circumstellar envelope of the carbon-rich asymtotic giant branch star, IRC+10216, marking the first …
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Dark matter searches with cosmic-ray detectors and the Square Kilometre Array
… such as AMS, Fermi-LAT and PAMELA, and radio telescopes, such as the SKA. In this work, we focus on the positron fraction measured in the Solar System due to dark matter annihilating in the dark matter galactic halo, but also on radio signals from the Milky Way and dwarf spheroidal …
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Heart of darkness
… Horizon Telescope, a project which will combine radio telescopes around the world to peer into the innermost spacetime warps surrounding Sagittarius A*. If all goes well, astronomers may finally glimpse the "silhouette" of the Milky Way's central super massive black hole within the next decade, …
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Measuring Galaxy Asymmetry in Different Dimensions
… galaxy color and structure. The upcoming SKA radio-telescopes will record unprecedented numbers of HI cubes. An SKA pathfinder, the upcoming WALLABY survey will record thousands of HI galaxy cubes. Galaxy Asymmetry can be used as a fast non-parametric measure to infer the physical properties …
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Radio Frequency Interference: Simulations for Radio Interferometry Arrays
Radio Frequency Interference (RFI) is a massive problem for radio observatories around the world. Due to the growth of telecommunications and air travel RFI is increasing exactly when the world's radio telescopes are increasing significantly in sensitivity, making RFI one of the most pressing …
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GPU-based acceleration of radio interferometry point source visibility simulations in the MeqTrees framework
Modern radio interferometer arrays are powerful tools for obtaining high resolution images of low frequency electromagnetic radiation signals in deep space. While single dish radio telescopes convert the electromagnetic radiation directly into an image of the sky (or sky intensity map), …
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Wideband Digital Filter-and-Sum Beamforming with Simultaneous Correction of Dispersive Cable and Antenna Effects
… ``station'' of the Long Wavelength Array (LWA) radio telescope, consisting of 512 bowtie-type antennas and operating at frequencies between 10 MHz and 88 MHz. However, this work is applicable to a variety of systems which suffer from non-white spatial noise and directional interference and are …
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