RFI Mitigation in Radio Astronomy (invited)

Baan, Willem A.

doi:10.22323/1.107.0001

Cited by 7 publications

(1 citation statement)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This is an issue that needs to be concerned. To solve this problem, a wide range of methods for identification and mitigation of RFI has been considered [17] including post-correlation matrix projection methods [18,19], blanking [20]) and coherent subtraction [21]. Therefore, in this work, we presented the initial results of a spectral overview of selected sites and compare with our site [22].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Radio Frequency Interference (RFI) in the Region of Solar Burst Type III Data at Selected CALLISTO Network

Hamidi

Shariff

Monstein

2014

ILCPA

View full text Add to dashboard Cite

Compact Astronomical Low-frequency, Low-cost Instrument for Spectroscopy in TransportableObservatories (CALLISTO) is a global network of spectrometer system with the purpose to observe the Sun's activities. There are 25 stations that are used for this purpose. Radio Frequency Interference (RFI) is a major obstacle when performing observation with CALLISTO. We have confirmed at least 2 stations out of 10 stations with a complete overview spectral (OVS) made available to us showed clear detection of these consistent types of RFI for each specific region. In Malaysia, these RFI are also clearly detected. The major RFI affecting CALLISTO within radio astronomical windows below 1 GHz are local electronic system specifically radio navigation (at 73.1 MHz and 75.2 MHz), broadcasting (at (i) 151 MHz, (ii) 151.8 MHz and 152 MHz), aeronautical navigation (at (i) 245.5 MHz, (ii) 248.7 MHz and (iii) 249 MHz and fixed mobile at (i) 605 MHz, (ii) 608.3 MHz, (iii) 612.2 MHz, (iv) 613.3 MHz). It is obviously showed that all sites within this region are free from interference at 320-330 MHz and is the best specific region to be considered for solar burst monitoring. We also investigate the effect of RFI on detection of solar burst. We have considered type III solar bursts on 9 th March 2012 in order to measure the percentage of RFI level during the solar burst. The RFI level is as low as 6.512 % to 80.769 % above solar burst detection.

show abstract

Section: Introductionmentioning

confidence: 99%

Comparison of the Radio Frequency Interference (RFI) in the Region of Solar Burst Type III Data at Selected CALLISTO Network

Hamidi

Shariff

Monstein

2014

ILCPA

View full text Add to dashboard Cite

show abstract

Radio frequency interference from radio navigation satellite systems: simulations and comparison to MeerKAT single-dish data

Engelbrecht,

Santos,

Fonseca

et al. 2024

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Radio Frequency Interference (RFI) is emitted from various sources, terrestrial or orbital, and creates a nuisance for ground-based 21-cm experiments. In particular, single-dish observations will be highly susceptible to RFI due to their wide primary beam and sensitivity. This work aimed to simulate the contamination effects from the Radio Navigational Satellite System (RNSS) within the 1100-1350 (MHz) frequency band. The simulation can be divided into two parts: i) satellite positioning, emission power, and the beam response on the telescope, and ii) calibration of the satellite signals to data to improve the original model. We utilise previously observed single-dish L-band data from the Meer-Karoo Array Telescope (MeerKAT), which requires special calibration to account for regions contaminated by satellite-based RFI. We find that we can recreate the satellite contamination with high accuracy around its peak frequencies provided the satellite is not too close to the telescope’s pointing direction. The simulation can predict satellite movements and signals for past and future observations, aiding in RFI avoidance and testing novel cleaning methods. The predicted signal sits below the noise in the target cosmology window in the L-band (970 - 1015 MHz) making it difficult to confirm any out-of-band emission from satellites. However, in our simulations, this contamination still overwhelmed the 21-cm auto-power spectrum. Nevertheless it is possible to detect the signal in cross-correlations after mild foreground cleaning. Whether such out of band contamination does exist will require further characterisation of the satellite signals far away from their peak frequencies.

show abstract

Subspace smearing and interference mitigation with array radio telescopes

Hellbourg

2015

2015 IEEE Signal Processing and Signal Processing Education Workshop (SP/SPE)

View full text Add to dashboard Cite

Active Radio Frequency Interference (RFI) mitigation becomes a necessity for radio astronomy. The solution commonly applied by the community consists in monitoring the statistics of the received signal, and flag out the detected corrupted data. Subspace projection with array radio telescopes has been suggested as an alternative to data excision to avoid important losses of data and overcome its inherent ineffectiveness with continuous interference.Spatial filtering relies on the estimation of the RFI spatial contribution, and the projection of the subspace spanned by the RFI out of the observed data vector space. To perform well, the dimensionality of the RFI subspace is constrained.RFI subspace estimation techniques assume the source of RFI to be spatially stationary over the sample covariance matrix evaluation. When the relative movement between the telescope and the interferer becomes significant, the RFI subspace gets smeared over the whole data vector space. The subspace projection can then no longer be applied without affecting the source of interest recovery. This paper addresses the effect of RFI subspace smearing on the subspace projection approach, and suggests an alternative technique based on a covariance matrix subtraction, improving the performance of spatial filtering in the case of high subspace smearing.

show abstract

RFI Mitigation in Radio Astronomy (invited)

Cited by 7 publications

References 37 publications

Comparison of the Radio Frequency Interference (RFI) in the Region of Solar Burst Type III Data at Selected CALLISTO Network

Comparison of the Radio Frequency Interference (RFI) in the Region of Solar Burst Type III Data at Selected CALLISTO Network

Radio frequency interference from radio navigation satellite systems: simulations and comparison to MeerKAT single-dish data

Subspace smearing and interference mitigation with array radio telescopes

Contact Info

Product

Resources

About