39 research outputs found
SETI Detection Strategies for Single Dish Radio Telescopes
Radio Searches for Extra Terrestrial Intelligence aim at detecting artificial
transmissions from extra terrestrial communicative civilizations. The lack of
prior knowledge concerning these potential transmissions increase the search
parameter space. Ground-based single dish radio telescopes offer high
sensitivity, but standard data products are limited to power spectral density
estimates. To overcome important classical energy detector limitations, two
detection strategies based on asynchronous ON and OFF astronomical target
observations are proposed. Statistical models are described to enable threshold
selection and detection performance assessment
Spatial filtering experiment with the Murchison Widefield Array
Spatial Radio Frequency Interference (RFI) filtering offers both RFI rejection and potential signal-of-interest recovery. It is as such an attractive RFI mitigation technique for radio interferometry. This paper describes an experiment of spatial filtering of an amateur radio transmission originating from the International Space Station corrupting the Murchison Widefield Array low-frequency radio telescope
A Cross-Correlation based Spectral Kurtosis RFI Detector
Accurate flagging of Radio Frequency Interference (RFI) is necessary to recover instrumental efficiency and avoid false astronomical detections. Spectral Kurtosis ((SK)Ì‚) is a popular operator in RFI flagging for radio astronomy due to its detection sensitivity to non-Gaussian emissions and its competitive computational cost. Most (SK)Ì‚ detection pipelines are applied to single antennas or autocorrelations products. This paper investigates the application of the (SK)Ì‚ to antennas cross-correlations, and demonstrates an improved detection performance compared to the auto-correlation-based approaches
A Cross-Correlation based Spectral Kurtosis RFI Detector
Accurate flagging of Radio Frequency Interference (RFI) is necessary to recover instrumental efficiency and avoid false astronomical detections. Spectral Kurtosis ((SK)Ì‚) is a popular operator in RFI flagging for radio astronomy due to its detection sensitivity to non-Gaussian emissions and its competitive computational cost. Most (SK)Ì‚ detection pipelines are applied to single antennas or autocorrelations products. This paper investigates the application of the (SK)Ì‚ to antennas cross-correlations, and demonstrates an improved detection performance compared to the auto-correlation-based approaches
Performance analysis of the Karhunen–Loève Transform for artificial and astrophysical transmissions: denoizing and detection
In this work, we propose a new method of computing the Karhunen–Loève Transform (KLT) applied to complex voltage data for the detection and noise level reduction in astronomical signals. We compared this method with the standard KLT techniques based on the Toeplitz correlation matrix and we conducted a performance analysis for the detection and extraction of astrophysical and artificial signals via Monte Carlo (MC) simulations. We applied our novel method to a real data study-case: the Voyager 1 telemetry signal. We evaluated the KLT performance in an astrophysical context: our technique provides a remarkable improvement in computation time and MC simulations show significant reconstruction results for signal-to-noise ratio (SNR) down to −10 dB and comparable results with standard signal detection techniques. The application to artificial signals, such as the Voyager 1 data, shows a notable gain in SNR after the KLT
Performance analysis of the Karhunen–Loève Transform for artificial and astrophysical transmissions: denoizing and detection
In this work, we propose a new method of computing the Karhunen–Loève Transform (KLT) applied to complex voltage data for the detection and noise level reduction in astronomical signals. We compared this method with the standard KLT techniques based on the Toeplitz correlation matrix and we conducted a performance analysis for the detection and extraction of astrophysical and artificial signals via Monte Carlo (MC) simulations. We applied our novel method to a real data study-case: the Voyager 1 telemetry signal. We evaluated the KLT performance in an astrophysical context: our technique provides a remarkable improvement in computation time and MC simulations show significant reconstruction results for signal-to-noise ratio (SNR) down to −10 dB and comparable results with standard signal detection techniques. The application to artificial signals, such as the Voyager 1 data, shows a notable gain in SNR after the KLT
Cellular Wireless Networks in the Upper Mid-Band
The upper mid-band -- roughly from 7 to 24 GHz -- has attracted considerable
recent interest for new cellular services. This frequency range has vastly more
spectrum than the highly congested bands below 7 GHz while offering more
favorable propagation and coverage than the millimeter wave (mmWave)
frequencies. Realizing the full potential of these bands, however, will require
fundamental changes to the design of cellular systems. Most importantly,
spectrum will likely need to be shared with incumbents including communication
satellites, military RADAR, and radio astronomy. Also, due to the wide
bandwidth, directional nature of transmission, and intermittent occupancy of
incumbents, cellular systems will need to be agile to sense and intelligently
use large spatial and bandwidth degrees of freedom. This paper attempts to
provide an initial assessment of the feasibility and potential gains of
wideband cellular systems operating in the upper mid-band. The study includes:
(1) a system study to assess potential gains of multi-band systems in a
representative dense urban environment; (2) propagation calculations to assess
potential cross interference between satellites and terrestrial cellular
services; and (3) design and evaluation of a compact multi-band antenna array
structure. Leveraging these preliminary results, we identify potential future
research directions to realize next-generation systems in these frequencies.Comment: 11 page