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    "story_id": "mp-2026-07-16-026",
    "source_story_id": "tmp-story-gps-radiation-belt-cross-calibration",
    "edition_id": "mp-2026-07-16-morning-0007",
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    "position": 15,
    "story_type": "dispatch",
    "section": "infrastructure",
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    "headline": "Twenty-Five GPS Satellites Become One Space-Weather Instrument",
    "slug": "twenty-five-gps-satellites-become-one-space-weather-instrument",
    "dek": "Cross-calibration reconciled decades of energetic-electron readings that had differed by orders of magnitude between spacecraft.",
    "summary": "Cross-calibration reconciled decades of energetic-electron readings that had differed by orders of magnitude between spacecraft.",
    "body_text": "Particle detectors aboard GPS satellites have monitored relativistic electrons in Earth's outer radiation belt since the late 1990s, but instrument-to-instrument differences made the constellation difficult to use as one continuous record. Researchers systematically cross-calibrated measurements from 25 satellites, correcting discrepancies that could reach orders of magnitude in low-flux conditions. The resulting dataset spans two solar cycles and turns navigation infrastructure into a long-duration observatory for radiation-belt changes that can damage satellites through internal charging and discharge. Calibration improves consistency; it does not eliminate every uncertainty in extreme space-weather conditions.",
    "why_it_matters": "Cross-calibration reconciled decades of energetic-electron readings that had differed by orders of magnitude between spacecraft.",
    "limitations": [
      "Calibration improves consistency; it does not eliminate every uncertainty in extreme space-weather conditions."
    ],
    "importance": 8,
    "canonical_url": "https://themachinepress.com/story/mp-2026-07-16-026/twenty-five-gps-satellites-become-one-space-weather-instrument",
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    "first_published_at": "2026-07-16T09:00:00.000-04:00",
    "modified_at": "2026-07-16T09:00:00.000-04:00",
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        "text": "Cross-calibration reconciled decades of energetic-electron readings that had differed by orders of magnitude between spacecraft.",
        "source_ids": [
          "source-2026-07-16-015"
        ],
        "qualification": "Calibration improves consistency; it does not eliminate every uncertainty in extreme space-weather conditions."
      }
    ],
    "source_ids": [
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    "tags": [
      "GPS",
      "radiation belts",
      "space weather",
      "satellites"
    ],
    "image_url": null,
    "corrections": []
  },
  "sources": [
    {
      "source_id": "source-2026-07-16-015",
      "title": "Chinese Academy of Sciences via Newswise: GPS space-weather calibration",
      "publisher": "Chinese Academy of Sciences via Newswise",
      "url": "https://www.newswise.com/articles/gps-satellite-data-gets-a-long-overdue-calibration-for-space-weather-studies",
      "canonical_url": "https://www.newswise.com/articles/gps-satellite-data-gets-a-long-overdue-calibration-for-space-weather-studies",
      "source_type": "secondary_reporting",
      "is_primary_source": false,
      "published_at": "2026-07-15T18:15:00.000-04:00",
      "accessed_at": "2026-07-16T08:21:29.993-04:00",
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  "publisher": {
    "name": "The Machine Press",
    "url": "https://themachinepress.com",
    "description": "A daily newspaper for the age of artificial intelligence."
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  "cite_this_report": {
    "title": "Twenty-Five GPS Satellites Become One Space-Weather Instrument",
    "publisher": "The Machine Press",
    "published_at": "2026-07-16T09:00:00.000-04:00",
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