Radio frequency interference mitigation based on the asymmetrically reweighted penalized least squares and SumThreshold method

2020 ◽  
Vol 500 (3) ◽  
pp. 2969-2978
Author(s):  
Qingguo Zeng ◽  
Xue Chen ◽  
Xiangru Li ◽  
J L Han ◽  
Chen Wang ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Least Squares ◽  
Interference Mitigation ◽  
Detection Algorithm ◽  
Radio Frequency Interference ◽  
Penalized Least Squares ◽  
Radio Telescopes ◽  
Processing Pipeline ◽  
Different Types ◽  
And Performance

ABSTRACT As radio telescopes become more sensitive, radio frequency interference (RFI) is becoming more important for interesting signals of radio astronomy. There is a demand for developing an automatic, accurate and efficient RFI mitigation method. Therefore, we have investigated an RFI detection algorithm. First, we introduce an asymmetrically reweighted penalized least squares (ArPLS) method to estimate the baseline more accurately. After removing the estimated baseline, several novel strategies were proposed based on the SumThreshold algorithm for detecting different types of RFI. The threshold parameter in SumThreshold can be determined automatically and adaptively. The adaptiveness is essential for reducing human intervention and for the online RFI processing pipeline. Applications to data from the Five-hundred-meter Aperture Spherical Telescope (FAST) show that the proposed scheme based on ArPLS and SumThreshold is superior to some typically available methods for RFI detection with respect to efficiency and performance.

scholarly journals Stochastic calibration of radio interferometers

2020 ◽  
Vol 493 (4) ◽  
pp. 6071-6078 ◽  
Author(s):  
Sarod Yatawatta
Keyword(s):  
Data Processing ◽  
Radio Frequency ◽  
Computational Cost ◽  
Spatial Localization ◽  
Radio Frequency Interference ◽  
Radio Telescopes ◽  
Data Rates ◽  
Data Volume ◽  
Radio Transients ◽  
Processing Steps

ABSTRACT With ever-increasing data rates produced by modern radio telescopes like LOFAR and future telescopes like the SKA, many data-processing steps are overwhelmed by the amount of data that needs to be handled using limited compute resources. Calibration is one such operation that dominates the overall data processing computational cost; none the less, it is an essential operation to reach many science goals. Calibration algorithms do exist that scale well with the number of stations of an array and the number of directions being calibrated. However, the remaining bottleneck is the raw data volume, which scales with the number of baselines, and which is proportional to the square of the number of stations. We propose a ‘stochastic’ calibration strategy where we read only in a mini-batch of data for obtaining calibration solutions, as opposed to reading the full batch of data being calibrated. None the less, we obtain solutions that are valid for the full batch of data. Normally, data need to be averaged before calibration is performed to accommodate the data in size-limited compute memory. Stochastic calibration overcomes the need for data averaging before any calibration can be performed, and offers many advantages, including: enabling the mitigation of faint radio frequency interference; better removal of strong celestial sources from the data; and better detection and spatial localization of fast radio transients.

scholarly journals Adaptive Radio Frequency Interference Mitigation for Passive Bistatic Radar Using OFDM Waveform

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Zhixin Zhao ◽  
Sihang Zhu ◽  
Yuhao Wang ◽  
Siyuan Cheng ◽  
Sheng Hong
Keyword(s):  
Radio Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Interference Mitigation ◽  
Short Wave ◽  
Good Choice ◽  
Hf Radar ◽  
Bistatic Radar ◽  
Radio Frequency Interference ◽  
Wave Band ◽  
Passive Bistatic Radar

High frequency passive bistatic radar (HFPBR) is a novel and promising technique in development. DRM broadcast exploiting orthogonal frequency division multiplexing (OFDM) technique supplies a good choice for the illuminator of HFPBR. HFPBR works in crowded short wave band. It faces severe radio frequency interference (RFI) problem. In this paper, a theoretical analysis of the range-domain correlation of RFI in OFDM-based HF radar is presented. A RFI mitigation method in the range domain is introduced. After the direct-path wave rejection, the interference subspace is constructed using the echo signals at the reserved range bins. Then RFI in the effective range bins is mitigated by the subspace projection, using the correlation among different range bins. The introduced algorithm is easy to perform in practice and the RFI mitigation performance is evaluated using the experimental data of DRM-based HFPBR.

scholarly journals DIVISION X WORKING GROUP on RADIO FREQUENCY INTERFERENCE MITIGATION

2010 ◽  
Vol 6 (T27B) ◽  
pp. 243-245
Author(s):  
Tasso Tzioumis ◽  
Willem Baan ◽  
Darrel Emerson ◽  
Masatoshi Ohishi ◽  
Tomas Gergely ◽  
...  
Keyword(s):  
Radio Frequency ◽  
Working Group ◽  
Interference Mitigation ◽  
Regulatory Function ◽  
Radio Frequency Interference

The IAU Working Group on Radio Frequency Interference (RFI) Mitigation was setup in the 2000 IAU GA in Manchester and its mandate was renewed at subsequent IAU GAs in 2003 and 2006. It was noted that that there are important issues related to RFI mitigation that extend beyond the regulatory function of IUCAF, and hence a more extended working group, which may include IUCAF members, was established.

scholarly journals Experimental verification of radio frequency interference mitigation with a focal plane array feed

Radio Science ◽  
2007 ◽  
Vol 42 (6) ◽  
Author(s):  
James R. Nagel ◽  
Karl F. Warnick ◽  
Brian D. Jeffs ◽  
J. Richard Fisher ◽  
Richard Bradley
Keyword(s):  
Radio Frequency ◽  
Experimental Verification ◽  
Focal Plane ◽  
Interference Mitigation ◽  
Focal Plane Array ◽  
Radio Frequency Interference
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