{
  "abstract": "The detection and excision of radio-frequency interference (RFI) is usually approached by asking how best to identify RFI within a given data product. I address a prior question: which data product is a given RFI emitter is most detectable in? I develop a model for the suppression of RFI in visibilities and tied-array beams by the antenna primary beam, near-field wavefront curvature, bandwidth smearing, and fringe tracking. The comparison between antenna-based and array-based detection reduces to a single quantity related to the mean per-baseline RFI coherence. Cross-correlation detection is preferred only above a coherence threshold of $(N-1)^{-1/2}$, where $N$ is the number of antennas. I evaluate this model for four array configurations (the Very Large Array A and D configurations, and the fixed MeerKAT and Deep Synoptic Array / DSA configurations) and five representative RFI emitters spanning distances of 5\\,km to medium-Earth orbit. Compact, filled, arrays favor the cross-correlations for stationary terrestrial emitters, whereas extended sparse arrays do not. RFI emitters with significant motion relative to radio arrays, in particular aircraft and low- and medium-Earth-orbit satellites, favor the sum of antenna autocorrelations everywhere by one to seven orders of magnitude, because their coherence is destroyed by rapid fringe rotation. For RFI below the single-antenna noise, no phase-unknown cross-correlation statistic is more sensitive than the autocorrelation sum. Tied-array beams are the least sensitive data product of all: the array factor supplies no suppression of terrestrial RFI, so a beam sees an emitter as a single antenna does. I describe a real-time, GPU-based implementation of autocorrelation-based excision for the 110-antenna Deep Synoptic Array, and outline the design implications for upcoming arrays.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.01308",
  "author_total": 1,
  "authors": [
    {
      "name": "Vikram Ravi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bvrmyvp8qj81w.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.01308",
  "fulltext_url": null,
  "id": "bvrmyvp8qj81w",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.01308",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.IM"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.01308",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bvrmyvp8qj81w.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.01308",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.01308"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    }
  ],
  "title": "Detection and excision of radio-frequency interference in radio arrays",
  "title_text": "Detection and excision of radio-frequency interference in radio arrays",
  "type": "preprint",
  "updated_at": "2026-11-05T15:20:18Z",
  "url": "https://research.draconitic.com/paper/bvrmyvp8qj81w",
  "venue": "arXiv",
  "versions": []
}