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Title: A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA

Abstract

Radio frequency interference (RFI) is the principal factor limiting the sensitivities of radio telescopes, particularly at frequencies below 1 GHz. I present a conceptually new approach to mitigation of RFI in interferometric data. This has been used to develop a software tool (RfiX) to remove RFI from observations using the Giant Metrewave Radio Telescope, India. However, the concept can be used to excise RFI in any interferometer. Briefly, the fringe-stopped correlator output of an interferometer baseline oscillates with the fringe-stop period in the presence of RFI. RfiX works by identifying such a pattern and subtracting it from the data. It is perhaps the only purely software technique which can salvage the true visibility value from RFI-corrupted data. It neither requires high-speed hardware nor real-time processing and works best on normal correlator output integrated for 1-10 s. It complements other mitigation schemes with its different approach and the regime it addresses. Its ability to work with data integrated over many seconds gives it an advantage while excising weak, persistent RFI unlike most other techniques which use high-speed sampling to localize RFI in time-frequency plane. RfiX is also different in that it does not require RFI-free data to identify corrupted sections. Somemore » results from the application of RfiX are presented including an image at 240 MHz with a peak/noise ratio of 43,000, the highest till date at wavelengths greater than 1 m.« less

Authors:
 [1]
  1. National Centre for Radio Astrophysics, P.O. Bag 3, Pune University Campus, Pune 411007 (India)
Publication Date:
OSTI Identifier:
21300719
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 696; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/696/1/885; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; COMPUTER CODES; DATA ANALYSIS; IMAGE PROCESSING; IMAGES; INTERFEROMETERS; RADIO TELESCOPES; RADIOWAVE RADIATION; SENSITIVITY

Citation Formats

Athreya, Ramana. A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA. United States: N. p., 2009. Web. doi:10.1088/0004-637X/696/1/885; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
Athreya, Ramana. A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA. United States. https://doi.org/10.1088/0004-637X/696/1/885; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)
Athreya, Ramana. 2009. "A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA". United States. https://doi.org/10.1088/0004-637X/696/1/885; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA).
@article{osti_21300719,
title = {A NEW APPROACH TO MITIGATION OF RADIO FREQUENCY INTERFERENCE IN INTERFEROMETRIC DATA},
author = {Athreya, Ramana},
abstractNote = {Radio frequency interference (RFI) is the principal factor limiting the sensitivities of radio telescopes, particularly at frequencies below 1 GHz. I present a conceptually new approach to mitigation of RFI in interferometric data. This has been used to develop a software tool (RfiX) to remove RFI from observations using the Giant Metrewave Radio Telescope, India. However, the concept can be used to excise RFI in any interferometer. Briefly, the fringe-stopped correlator output of an interferometer baseline oscillates with the fringe-stop period in the presence of RFI. RfiX works by identifying such a pattern and subtracting it from the data. It is perhaps the only purely software technique which can salvage the true visibility value from RFI-corrupted data. It neither requires high-speed hardware nor real-time processing and works best on normal correlator output integrated for 1-10 s. It complements other mitigation schemes with its different approach and the regime it addresses. Its ability to work with data integrated over many seconds gives it an advantage while excising weak, persistent RFI unlike most other techniques which use high-speed sampling to localize RFI in time-frequency plane. RfiX is also different in that it does not require RFI-free data to identify corrupted sections. Some results from the application of RfiX are presented including an image at 240 MHz with a peak/noise ratio of 43,000, the highest till date at wavelengths greater than 1 m.},
doi = {10.1088/0004-637X/696/1/885; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)},
url = {https://www.osti.gov/biblio/21300719}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 696,
place = {United States},
year = {2009},
month = {5}
}